Engine Vibrating Excessively

[Triton106]

My Atomic 4 has always had a bit more vibration when I put it in gear than when the engine is neutral. But recently I have noticed that the vibration has gotten worse (or I am just paying more attention to it now that I have dealt with the other system issues like fuel tank and exhaust). I have always admired the way Tim installs those brand new betas (my diesel envy is a separate issue) and how he meticulously lines up the mount with the cutless bearing. However, in my case I am not installing a new engine or even have adjustable mounts (most Atomic four are installed without adjustable mounts). I wonder how I can go about adjusting the engine to reduce vibration. I know one option is to add adjustable mounts but that will involve modifying the mount itself which is something I rather avoid if I can help it.

[Tim]

How's your Cutless bearing? Sloppy Cutless bearings, which are usually the direct result of improper engine alignment that has led to undue wear on the bearing, are often the most symptomatic cause of pronounced shaft vibration/wobble/etc. The firm engine mounting, poor access, and short shaft length of a Triton A4 installation contribute greatly to the conditions that eventually lead to the symptoms you are now seeing.

The bearing might be causing the problem you've immediately become aware of, but even if so, this points to poor engine alignment, which you should address in any event. The biggest obstacle to aligning your engine is the poor access you probably have. Otherwise, it's a matter of using shims (or removing them) to change the engine height as needed, and shifting the engine side-to-side (in its elongated mounting holes) for the transverse positioning, depending on how your shaft coupling might be misaligned with the engine coupling.

There's plenty of basic alignment guidance (i.e. tue basic steps involved) to be found in the usual online sources and boating books that probably illustrate it better than I could do here. The basic steps are very simple; the only hard part is dealing with corroded fasteners, tight access, invisibility, etc.

[earlylight]

Globe manufactures "alignment wedges" which are used in pairs specifically for this purpose. I used them on one of my previous boats with an Atomic 4. Check this site: http://www.a1discountprop.com/globedrivesavers.htm and scroll down the page about 85%

[Triton106]

Thanks Tim, Dick for your quick responses and for confirming what I suspected was the cause of my Atomic 4 vibration problem. The boat is in the water now and I don't plan to haul out until spring so it is hard to tell you the condition of the cutless bearing. By the level of vibration I am sensing it cannot be in too great a shape although I have not noticed any excessive water coming through it when I run my Atomic 4.

I will give Globesaver a call tomorrow to find out a little more about those alignment wedges they look like just the shims for the job.

[Quetzalsailor]

Ray, couple points. You may not have obviously 'adjustable' mounts, but rest assured that what you have is adjustable. Holes in the A4 casting are oval and somewhat oversized. The game is to shim under the engine casting until the engine is in a plane through which the center of the shaft passes and then shuggle it sideways until the crank and the flange are on that same center. My A4 had the toothy cast iron wedges that Dick mentions until I put mounts in. Any handy, but incompressible shim material will do, cut into a U shape so that you can slip it in around the bolt. (dad used multiple thicknesses of soda can, but he was an engineer)

Secondly, you're supposed to align the engine with the boat in the water. The hull changes shape enough between floating and sitting on stands.

I replaced the beds in our Morgan 27 when I found that the lagbolts that were intended to locate the engine were totally loose; the beds were rotted within the fiberglass wrapping. The engine vibrates more when it's not bolted down, but in our case, it had become incapable of producing enough horsepower to move the boat. All was well after new beds, mounts, and an upper end rebuild.

Those of us who have had an A4 out will recall that the center of the crank is on the plane formed by the bottom of the casting (can't remember whether it's the block or the oil pan) that the engine sits on, means that you can get things in mind, or close, with the engine out and pulling a string from center of cutless forward. It also means that you can make a plywood mockup of the engine to aid in aligning new engine beds, mounts, etc., which is lots lighter to move around. It would be well to note when planning new beds that the oil pan is a pretty regular shape...except for the bump that contains the dipstick; it's sooo embarrassing to find out later.

[Robert The Gray]

The basic steps are very simple; the only hard part is dealing with corroded fasteners, tight access, invisibility, etc.

That stuff can't be that hard can it? .........It has been said that only in the outer Philippine Islands are
there masters of monkey training that can train a monkey in the task of working on sailboat engines.
They prefer the spider monkeys because the little cotton coveralls are cheaper. They are trained to
work in groups of 4, with one given special underwater training for prop and cutlass bearing issues.
The monkey crew chiefs are usually ancient drunk orangutans.
They will steal your beer, but they know how to work those little monkeys. I think
Somerset Maughm wrote about them in one of his Malay/Borneo stories. Regardless,
the Philippine monkey crews do not travel well, so when I was working on my Triton's engine
I got a copy of an Idiot's Guide to Monkey Training. I would loan you my copy Ray, but the monkey
took it with him when he left. To be honest I had no real success in getting the monkey to
let go of his own tool much less pick up a wrench. I wish you the best of luck, and I share my cautious
tale to dissuades you from trying to use trained monkeys to work on your engine. I hope I have lived up
the the standards of advice normally found on this site. You guys have some wicked knowledge.

r

[Triton106]

Rob,

That's the best monkey training advice I ever received to be sure. I also think we need to get you a BOAT pronto lest your talent and energy go unused. Of course anytime you want to apply your talent and energy to a local Triton in need feel free to give me a call. I know of a particular Triton in desperate need of both... ;-)

Best regards,

[Henk]

One of the better trained monkeys.

[Triton106]

Well, I am definitely not as handy as one of Rob's well trained monkeys. I finally got around to work on the alignment issue today. After soaking the three bolts locking the two halves of the couplings together with BP Blast they came loose with relative ease. I did not take them off completely and proceeded to pry apart the two halves of the couplings with an old beat up but rather thick tape knife. That's when I realized that they are for all practical purpose "welded" together. I did not have enough time to try different approach as I had a family commitment to attend to in the afternoon. As I was driving back home it occured to me that I should have taken out the three bolts completely since they are the only mechanical mean holding the couplings together. Is that the right approach? If the two halves are fronzen together can I hammer hard on one half of the coupling? What do I need to be aware of? Thanks very much for any insights you can share.

[Tim]

Try a thin, stiff blade at the seam and gentle tapping with a hammer. Don't hit the coupling hard while it's attached to the transmission, ever, but some gentle persuasion may be needed to break that corroded seal between the transmission flange and the shaft coupling--but only after you try a better implement to help pry the two pieces apart. As always, pre-apply penetrating solvent to the area in question and give it time to work.

Also, remove all the bolts completely before you do this, to avoid any possibility that they are still helping hold things together.

If you have a couple big wrenches large enough to fit on the couplings, you can also try twisting the two parts apart.

[Quetzalsailor]

Remember, as you contemplate tapping, that the two items are flat, mostly, but one has a 1/8" X 2" dia, or so, raised area and the other a corresponding depression. They are a pretty snug fit with the intent of aligning the shaft and crankshaft perfectly. It's the shaft flange that has the depression.

Means that the edge of the depression/raised area is the offending bit and it's about 1" in from the edge. Wait for the PB Blaster to work it's magic. It also means that a little judicious heating (not so sure there's any such thing while hanging over an engine in a small flammable space) will expand the shaft flange in the correct direction.

[Matt B.]

Remember, as you contemplate tapping, that the two items are flat, mostly, but one has a 1/8" X 2" dia, or so, raised area and the other a corresponding depression. They are a pretty snug fit with the intent of aligning the shaft and crankshaft perfectly. It's the shaft flange that has the depression.

Means that the edge of the depression/raised area is the offending bit and it's about 1" in from the edge. Wait for the PB Blaster to work it's magic. It also means that a little judicious heating (not so sure there's any such thing while hanging over an engine in a small flammable space) will expand the shaft flange in the correct direction.

A big soldering iron might do the trick safely.

[Triton106]

After following the advices several of you posted I successfully uncoupled the shaft and engine coupling. I let the BP Blaster soak the joint for a while and took out the three locking bolts. After prying the joint with the tape knife I was able to get the couple to rotate independently and then backed out the shaft coupling.

But I am embarrassed to say that I am completed lost how to adjust the A4 engine alignment.

First of all, I am not even sure how to determine if the alignment is off and how it is off (side to side or fore and aft height). I read Don Casey and several other alignment methods. They are based on the same principles. I followed one of the common methods which entails bringing the two half couplings together with one bolt and tighten it until it is snug but not overly tight. I then used a feeler gauge to measure the gap at the bolt (off to the side of the bolt). The first time I used a .003 feeler gauge at the bolt, but I was not able to insert the feeler gauge in other positions (90 degrees, 180 degrees, and 270 degrees from the bolt). The second time I backed the shaft coupling further out and used a .015 feeler gauge at the bolt. I was able to move it all the way around the coupling but could not tell which position is tight and which position is loose and by how much. According to most references the differential should be less than .003 inches. How can I detect that small of a differential?

Many thanks in advance for your help.

[Triton106]

After some additional web search I came across the following method for measuring the gap between the two halves of the coupling. It is posted on the Moyer Marine Community (Atomic 4) Forum:

Here is what I did. With the bolts all free and the shaft uncoupled I held three small pieces of paper between the shaft coupling and the engine's flange at the bolt holes. I slid the shaft up against the engine flange and let the pieces of paper go. I adjusted the engine mounts until all three pieces of paper remained trapped by the shaft coupling when I let them go. It worked! Another KISS solution.

Given my inability to measure the gap with enough accuracy to detect a .003 inch differential I think this method may just be the right alternative for mechanically inept people like me. I was wondering if there are any known issues with this approach. Again, any help you can offer is much appreciated.

[Triton106]

Thanks Glenn, I have read Nigel Calder's instruction as well. I think you are right it is one of those things that comes with a lot of practice. I have used the feeler gauge on spark plugs and engine points before but they do not require .003 inch accuracy and you can do it standing or sitting down instead of lying down on the cockpit floor and reaching as far as your arm could stretch.

In any case, I found another website that has a pretty good description with pictures (http://www.pearson35.com/projects/engin ... .htm#Shaft). I will give it another try this weekend. I am confident I will be able to get there. Thanks for the encouraging words.

[Tim]

There are no magic spells to make the process faster or easier, which is why no one's chiming in with great ideas. As you have seen, the descriptions are pretty much the same wherever you read them; now it's just a matter of doing it and working out the nuances aboard your own boat.

You're never going to achieve 0.003" accuracy in an old Triton with that tiny, short shaft, aged couplings, and lack of easy adjustment on the A4 mounting system; the old coupling faces probably have at least this much error in them to begin with.

I'd wager that there are few boats anywhere that have achieved and maintained this hopeful ideal, so don't kill yourself trying for something you may never get. Getting the couplings to mate together cleanly and evenly is the goal; only when you mate them cleanly can you even think about using feeler gauges for that ultra-fine tuning. Get it as close as you can, but understand the limitations of what you're working with and match your expectations accordingly.

This is not an excuse or permission to be sloppy about the process, but it's also very important to understand that exacting alignment requires that all components also be exact to begin with--something that I would guess is certainly not the case in your boat, or most boats with old equipment.

Even brand-new couplings need to be "fitted and faced" at the machine shop in order to ensure the highest level of possible accuracy. This is a process where the coupling is installed on the shaft (as it would be on the boat) and the face of the coupling is then machined precisely to a flat face that is perfectly square with the shaft centerline. Your old coupling can't come close to hoping for this level of accuracy; ergo, you have a built-in error/inaccuracy beyond which you're never going to align. So work towards the best result you can, but accept that it's not likely to be as perfect as the idealized version.

And check your Cutless bearing at next haulout or sooner. A loose and worn bearing is the most likely contributor to the vibration you describe. Frankly, without knowing that the shaft is tight and centered in a good Cutless bearing, there's not much point to worrying about engine alignment, since you may be aligning to the improper angle. You need to know that the shaft is leading out the boat correctly in order to get your alignment right.

[Triton106]

Thanks Tim so much and sorry I had not responded sooner. I was hoping to get to the boat this weekend and give it another go at the alignment work but the NOAA forecast for the SF Bay Area for the weekend is rain, rain, rain, and more rain...

Your point on what to expect during an alignment exercise for an old coupling and unknown condition of the Cutless bearing is critical. It will save me countless hours of fruitless struggle and disappointment. I plan to give it another go when the weather window improves and if I cannot improve the vibration issue I will wait until Spril hullout. Thanks again for the valuable insight.

[Triton106]

Well, it did not rain here in the beautiful SF Bay Area until late evening around 6PM. So I was able to get to the boat and had another go at the alignment problem.

First of all, I went to talk to my friend Rob Heggen and find out how much his Atomic 4 vibrates. We fired up his engine and after warming it up a bit we put it in forward gear and rev'ed it up to 2000 rpm. It was noticeably quiter than mine in gear, although in neutral they are about the same. Then Rob explained how to use feeler gauge to me. I did not know that you are suppose to start with the smallest and go up one size at a time until you feel a little snug (a little catching).

I went back to my boat and followed Rob's instructions and after a few tries got a hang of it. Then I went about measuring the gap at 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions. The first set of measures are as follows: .007 (top), .014, .021(bottom), and .014. Then I turned the prop side of the coupling 180 degrees and took another set of measures and they are: .010 (top), .017, .025 (bottom, .025 is the largest one in the set but still feel a bit loose), and .018.

Given that both set of measures show tight gap at 12 o'clock and widest gap at 6 o'clcok (average difference is .014) and equal gap at 3 o'clock and 9 o'clock it seems that I need to raise the aft end of the engine. I did a simple calculation and concluded that the amount to raise at the aft mount is .072 inches (see diagram below).



Next week I will attempt to adjust the mount. Since my Atomic 4 is not mounted on adjustable engine mounts how should I go about lifting up the engine at the aft end in order to slide shimes under the fixed mount?

[Rachel]

See now there's the kind of word problem they should have in math class, instead of ones about trains or how to split four oranges amongst five people! Nice illustration, too :)

R.

[Triton106]

Rachel,

I can also calculate the gap using trigonometry or for that matter calculas ;-) (I have a degree in electrical engineering which clearly is not useful for much else on the boat other than the electrical system.) But I have no clue how to adjust the mount (well, a slight clue but not much).

[Quetzalsailor]

You report small gaps which means that the shaft is held on center by the previously discussed depression-projection machined into the flanges. I think you might want to evaluate whether you raise the aft end or lower the forward. Given reasonable competence in the past, it's reasonable to imagine that it's close to on axis...but not guaranteed.

However you decide, the A4 weighs only 315lbs so that's well within a Stanley bar's capability when ooching one or the other end.

[Triton106]

Boat projects seem to always involve detours and scope expansion. In order to gain better access to the engine (to adjust the shaft alignment) my friend Rob talked me into re-configuring the two existing round access hatches into one rectangular one similar to what Tim installs on his project boats (but mine is not aluminum and slightly narrower). That took me three weekends as I had to undo all fuel system since I could not cut into the cockpit floor without touching the fuel hose and tank. With that project done now the access is much better and I was able to undo the four lag bolts after I took out the water pump, the starter, and the oil pressure sensor. What was surprising with this part of the project is that some epoxy came out with the bolts. So Rob's suspicion is that the PO filled the four holes with epoxy and the epoxy did not adhere properly to the wood. Therefore, he talked me into taking the engine out and redrilling the holes and properly epoxy in embedded threaded inserts (similar to what Tim did with Circe).



So now my engine is disassembled again and I am at least 6 weeks behind on my project. Frustrating! The silver lining here is that I will finally be able to sand away the rust and repaint the A4 again. The last time it was painted was about 10 years ago when the PO had it rebuilt by Richmond Boat Works.

[Triton106]

Today was a productive day - sort of. I had already removed starter, alternator, water pump, exhaust manifold and disconnected fuel and exhaust hoses and electrical wires last week. I started the day by rigging up a make-shift lifting system. I used my main sheet purchase system and moved it to the middle of the boom (right over the companion way) and set up the topping lift and main halyard fore and aft of the purchase system. I was able to lift the engine off the mount without much trouble.

After moving the engine out of the way (I left it in the cabin as I was not going to perform any major overhaul) I went to work on the engine mount which I suspect was not holding the lag bolts. After I cleaned out the bige area and squared away the various hoses I drilled into the starboard and port mounts. Boy, was I surprised! Nothing but completely rotted wood from the aft mount locations. I switched to 7/8 spade bit and eventually switched to chisel. I did not want to cut off the mounts and rebuid new ones as it will take at least four weeks I estimate. In any case I want to see if the old ones are savagable. I know a number of you must be shaking your heads with dismay by now.

Well, I had to cut out nearly 1" (w) x 2" (l) x 1-1/2" (d) sections from both starboard and port side aft mount. The forward mount holes seem to be in much better condition, although I still drill out the existing epoxy filler. I mixed a large batch of epoxy filler (System 3 with West System 404). To add more holding power I cut up some fiberglass mat and added to the mix. I plan to add several layers of fiberglass tapes tomorrow, over the fillers to add a little more strength to the mount. I will take some pictures (forgot to bring the batteries with me today) tomorrow.

I also cleaned up the engine (lots of rust as you might imagine) and washed it with soap and then rinsed with clean water. I then brushed on Kleen Strip Rust Converter the bare metal parts. I have used it before but cannot say that I am confident that it will keep rust at bay. I decided to give it another try. I will paint the engine tomorrow after giving it 24 hours to cure.

[bigd14]

What a bummer! That was one of the reasons I decided to go to an outboard (a minor one, really). I was able to pull one of the lag screws out of an engine mount with a pair of pliers! One would think that the mounts would be made of solid glass. Good luck with the repairs. I wonder if you could zip the top of the mounts off with a circular saw, effect the repair, then reinstall the top portion?


Doug

[Triton106]

I thought a lot of about the next engine and still have not made up my mind. Believe me when I saw the work you (Doug) did on the Ericson 27 outboard mount it ignited my internal debate again. While we cannot have the outboard hang off the transom itself on Tritons (without a bracket) as the Ericsons can I have thought a lot about what James Baldwin did with the outboard well conversion. Tim, on the other hand, made an excellent arguement of the advantage of a reliable diesel for folks contemplating a long term cruising plan. About the only opinion I have not considered seriously is going without an engine.

In any case, I continued my work on the engine mount today. I sanded smooth the filler I put in yesterday and glassed on top 3 layers of tapes. I know this will raise the mount slightly higher than the previous level (the fiberglass tape I used is very thin). But I think I will have to adjust the engine alignment in anycase.

I am rethinking the choice of using threaded inserts vs. the original lag bolts. My friend Rob thinks that the epoxy filler will not accept lag bolts well. The pressure from the lag bolt thread will crack the filler. Does anyone know for sure whether one can lag bolt into epoxy filler?

[Rachel]

Ray,

I can't speak to whether this would be appropriate for your job, but WEST system does speak to "bonding" fasteners into epoxy, so it might be an option to research. Bonding studs is at the very bottom of the page.

Here's a link to the chapter (from the free and fabulous epoxy manual WEST puts out - each chapter is also available on their website, but the book is very handy to have on hand).

http://www.westsystem.com/ss/bonding-hardware/



Rachel

[Triton106]

Rachael, thanks very much for the tip! Your marine knowledge base is amazing. I have the West System booklets and have read them multiple times but for some reason I don't remember this section. So, I went on their website and did some additional material and come across this West System test result for bonded fastners -

For the preliminary tests, we bonded a ¾"×18" threaded steel rod into a 1" diameter hole drilled in the center of each panel. We drilled a 2" deep hole in one panel and a 3" deep hole in the other panel. The bonding adhesive for this test was WEST SYSTEM® 105 Resin and 206 Hardener with no fillers or additives. The bolt imbedded 2" into the laminate required 8,908 lb of force to pull the bolt loose. The bolt imbedded 3" into the laminate required 13,948 lb.

Here is the link to that page - http://www.epoxyworks.com/19/pdf/Ew19_T ... teners.pdf

Looks like that will be direction I will go. Thanks again!

[Quetzalsailor]

Pay attention to the bit about coating the fastener with some sort of release. I've used Teflon slip spray. Be sure the fastener does not have burrs or similar shapes which would be a physical bond.

Also, recall that epoxy is exothermic as it cures. Don't put so much epoxy filler into a huge hole or on such a hot day (LOL) that you will be in trouble.

Your friend's comment about adequacy of epoxy filler is worrisome: I presume you are using some sort of structural filler, not a cousin of Bondo. I hope you're using West's microfiber filler or their high strength filler additive. If using a structural filler you can drill and tap it or you can bond the fastener as West describes. Lag screws are fine: nice big coarse threads so that they are easy to fill with epoxy. Be sure to embed the fastener a little farther than you'll need to when assembling the mount.

I dodged this particular bullet on my A4 by arranging my new engine beds with cross-morticed places so that the engine mounts were simply bolted into place. I arranged the mortices with pats of fiberglass for bearing the washers. Sounds kinda' fussy, but really was not with the components on my workbench.

[Triton106]

Quetzalsailor wrote -

Your friend's comment about adequacy of epoxy filler is worrisome: I presume you are using some sort of structural filler, not a cousin of Bondo. I hope you're using West's microfiber filler or their high strength filler additive. If using a structural filler you can drill and tap it or you can bond the fastener as West describes. Lag screws are fine: nice big coarse threads so that they are easy to fill with epoxy. Be sure to embed the fastener a little farther than you'll need to when assembling the mount.

I used System Three general purpose resin, medium hardner, West System 404, and mixed it with a goodly amount of cut up fiberglass mat. That should be strong enough but I am not as confident of the repair considering the size of the rot that I have to fill, even with three layers of glass on top.

I called West System technical support about the proper process to bond fastners to the engine stringer. The tech guy was very very helpful. He explained to me that while their test result does show incredible bonding strenghth the test was performed under very controlled environment - i.e. the pressured applied was gradually increased from 0 to 8000 lbs over several minutes. In the real world with all of the vibrations and boats crashing from the crest of the wave to the bottom of the trough the forces are not linear. He said that it is important to install the nut in the picture so that when we crank down on the top nut it will not pull the stud out of the epoxy (because the bottom nut will be stopped by the engine). I think this is the approach I will take. Now the only question left is how big an all thread stud I will use. Given that there is only one bolt holding down each of the four corners of the A4 I think the minimum size will be 5/16" or 3/8". Any recommendations?

[Tim]

Use the largest bolt you can fit through the A4 flanges--probably 3/8".

[earlylight]

In addition to using the largest diameter, I would think that using a coarse thread would also be the proper choice,

[Quetzalsailor]

I have three of Vela's four bronze lagscrews in my hand. 3/8" dia. I recall that the holes in the A4 casting are quite a bit larger, but you'll need some slop for alignment. Vela now sails with PWI engine mounts and they had a much larger stud through the casting but also had transversely slotted bolt holes in the bottom portion for the beds. Transverse alignment was via the slotted holes, vertical by running the nuts up or down the stud.

Sounds like you can drill your filler and bond the new lagscrews into it. I think you'd get away with drilling and tapping, too, given enough depth of thread to compensate for 'glass in lieu of steel in the nut. Any lack of confidence and I'd bond rather than tap. I've bonded a number of fastenings and drilled and tapped for others, including 100 tiny adjustment screws in a harpsichord's jacks. Nothing like as rambunctious as a rarin' Atomic Four!

[Triton106]

Thanks Tim, Earlylight, for your help.

Quetzalsailor, one reason I am not confident about using lag bolts is that after bonding it in epoxy I don't know if I will be able to "crank down" on the lags (after the epoxy cured). That is what my friend Rob is concerned that cranking on it will cause the epoxy to crack. Do you know if that is a legitmate concern?

[Quetzalsailor]

Ray,

I don't think that you are bonding fasteners into the beds. You are creating threaded holes for fasteners by means of casting reinforced epoxy. You absolutely have to allow space for the fastener to extend into its new nest when its permanently installed. That's why I said to embed it deeper when casting than it needs to be when installed. Alternatively, you can install it with an extra washer or two. If you were bonding/casting-for the fasteners with the object in place, you can leave out the washers. Then on final assembly, use the washers; you'll have the extra depth for tightening the fastener.

A detail that the lag screw proponents missed (me also) is that the lags have to have cut threads (or the threads have to extend the full depth of the casting). This way, the threads pass harmlessly down the bore when they're reinstalled in the casting. If the lags are cheepies, like many steel Home Despot quality, they will be rolled threads; that is the metal is deformed inwards to shape the root of the thread and outwards to form the tips. Means the diameter of the threads are larger than the unthreaded portion and they will chew up the bore. And it's tougher to ensure that the fastener is going in so that the threads are engaging rather than trying to cut new threads.

This cracking of epoxy issue is true wherever/whenever you are repairing a stripped fastener hole. When I'm forced to repair a stripped hole I use as much wood as I can so that it's the new wood that deforms for the screw, rather than the epoxy (or carpenter's glue if it's furniture) that cracks or deforms the remaining old wood. Of course, there's never a really good repair for a stripped hole (shy of replacing that portion of the wood), since the new wood grain is inevitably end grain.

[Triton106]

Quetzalsailor,

Thanks very much for your explanation of cut thread vs. rolled thread and the tip on how to cast/bond lag bolts. Now I can see how lag bolts can work in this scenario. The lag bolts that came off the previous installation are very high quality bronze bolts and are in fine shape. I am comfortable reusing it. I suppose the lag bolts need to be coated with release agent before being casted/bonded in the stringer?

I also read about another approach where instead of casting/bonding the lag bolts a wooden dowel is epoxied in the hole and later drilled to allow lag bolts to cut into the wood grain instead of hardened epoxy. But as you pointed out then the wood will be end grain so I am not sure if that is a better solution.

Your knowledge of wood and metal work is incredible. Thanks!

[Rachel]

Given that there is only one bolt holding down each of the four corners of the A4...

Not that you don't want a completely strong and durable set-up, of course, but you do have one thing going for you in the general smoothness of the A-4 as compared to a diesel; so (only) four studs is less of a liability.

Nice that you got such attentive technical support from WEST.

Rachel

[Quetzalsailor]

Ray, re: knowlege: thanks for the undeserved compliment. I recognise that I'm a 'few tricks' pony. What I really am is too dumb, and too cheap to avoid doing things myself.

[Triton106]

Since the engine is out I decided to take advantage of the nice access to the bilge area to thoroughly clean it out and repaint the engine and engine room. In addition to the usual nuts and bolts I also found a adjustable wrench and a pencil that have been in there since I bought the boat over 10 years ago. Here are the pictures of the engine stringer repair, the repainted engine and engine room. I will have to wait until tomorrow to bond the bolts in. I am also thinking of installing an engine pan to catch oil while I have the access. What are the pros and cons of an engine pan?

[Quetzalsailor]

Re: making a pan. I've thought of doing the same sort of thing. I've got the same sort of never-neverland down in the keel, too, but far deeper. And, I've brought up more tools and fasteners than you (none have arrived down there from my hapless efforts, yet); an A4 coil so far has resisted retrieval.

A useful pan would collect drippings, or worse, from as many of the potential sources as possible and not preclude clean-up from the others. A useful pan would not receive non-hydrocarbon fluid from elsewhere (ex: water from a deck leak or similar). A useful pan would allow access for cleanup within and below. The pan should not make placing/running/replacing hoses and wiring any worse than they already are in a small boat. I think a retrofit pan should be integral with the hull (so you need not think of cleaning underneath), or removable when the engine is removed (to clean what lies beneath).

When I remade the engine beds in the Morgan 27, I made them act as an integral pan. The bottom of the boat was the pan and further forward was the sole, so this was a major improvement. No more oily mess on the sole after a mishap (happily, I never had a mishap after I did the work). However, any water collected below from aft of the pan ended up in the pan (never an overflow, and I made an accessible spongeable/pumpable sump).

A pan would be far harder to arrange suitably on our NE 38. The engine space is far smaller, the casework is quite close, there's all sorts of plumbing and wiring running under the engine and weaving through the beds. I get by with a oil-sorb cushion, luck and care.

[Triton106]

Quetzalsailor wrote -

A useful pan would collect drippings, or worse, from as many of the potential sources as possible and not preclude clean-up from the others. A useful pan would not receive non-hydrocarbon fluid from elsewhere (ex: water from a deck leak or similar). A useful pan would allow access for cleanup within and below. The pan should not make placing/running/replacing hoses and wiring any worse than they already are in a small boat. I think a retrofit pan should be integral with the hull (so you need not think of cleaning underneath), or removable when the engine is removed (to clean what lies beneath).

I went back to my boat today and thought about these criteria. I don't think it will be easy to run or replace/repair hoses or clean out the bilge if I installed the engine pan on Blossom due to the deep slack bilge. I also think one of the benefits of an integral pan (to the engine stringers) is that it ties the two otherwise separate stringers together and make it a much stronger unibody structure. Making it removable will not accomplish that purpose (at least not as well). At the end I decided to forgo adding the oil pan.

[earlylight]

On my previous boat with an Atomic 4, I was able to find an aluminum cake pan that just fit between the engine bed logs. I epoxied a 1/2" x 1/2" hardwood cleat to the inside of each bed log and the pan just slid in under the engine on these two cleats. I cut an oil absorbent sheet to fit the pan. It was a clean looking and easy installation. If one is unable to find an aluminum pan to fit, it would be quite easy to fabricate one over a male plug using fiberglass.

[Quetzalsailor]

Both Dick's and Ray's basic approach is to pan between the engine beds. Is this really enough? Fuel pump and connections, oil filter, oil switch are all outboard of the beds on an A4. Similarly in my Yanmar, these things are even farther outboard of the beds; the high-pressure nature of fuel pipes suggest that an even wider area should be panned. Pans I've seen in modern boats are quite wide and are formed so that the bolting positions are on raised areas.

Ray, your idea to pan between, and incidentally to add stiffness to those tallish beds is perfectly good. All you need to do is make the pan stiff enough to be useful and simply pinch it under the engine as it's bolted down. Of course, if the engine is bolted down without flexible mounts then the engine itself provides all the joining of the beds that you could possibly need. If you're really fretting about the stiffness of those beds then brace them outboard to the hull. That's similar to the arrangement of the beds in a Morgan 27: two fore and aft beds teeing (Pi-ing?) into a longish transverse member.

Dick's pan pan is quite clever; take it home and stick it in the dishwasher; don't tell the admirable admiral.

[The Froon]

Quoting Catepillar Tractor Company's 'Marine Engines Application and Installation Guide'...

The causes of linear vibrations can usually be identified by determining if:
1. The vibration amplitudes increase with the speed. If so, they are probably caused by centrifugal forces' bending components of the drive shafts. Check for unbalance and misalignment.
2. The vibrations occur within a narrow speed range. This normally occurs in equipment attached to the machinery - pipes, air cleaners, etc. When vibrations show a maximum amplitude or peak out at a narrow speed range, the vibrating component is in resonance. These vibrations can be modified by changing the natural frequency of the part by stiffening or softening the mounting.
3. The vibrations increase as a load is applied. This is caused by torque reaction and can be corrected by mounting the engine or driven equipment more securely or by stiffening the base or foundation. Defective or worn couplings can also cause this problem.

Doing some reading on marine diesel engines, and came across this in the trouble shooting section...

Brian

[Zach]

As far as the pan goes... make sure there is a break or lip before things roll right out on your cabin sole.

If you overfill the A4, or are in real rough conditions it'll puke out the front main seal. That means your pan has to extend past the front of the engine to account for drips/sloshes as the boat pitches...

Just a thought, I about ate it because my old sole was to close to the front of my A4... wet feet and an oil slick at the bottom of the ladder is no fun!

Zach

[Triton106]

My engine alignment attempt is now officially turning into a project of Panama Canal proportion.

I arrived at the marina early today and was excited about the prospect of finally able to load the Atomic 4 on the repaired engine stringers. Unfortunately my friend Rob had to work. Not wanting to further delay the project I went ahead and rigged up a 4-to-1 purchase with my main halyard again. At the aft end of the engine room I installed a snatch block and led a line from the aft end of the Atomic 4 througn the block then back to me (I was standing in front of the Atomic 4). I lifted the Atomic 4 up with the main halyard and used the other line as a lead to pull the Atomic 4 on the mount. Everything went smoothly, that is until I went to mate up the two coupling halves. Surprise! The engine half of the coupling was approximately 3/16" higher than the shaft half.

Remember, when I repaired the rot in the stringer I filled the cavity with thickened epoxy and added three layers of thin fiberglass tapes. At the time I thought the fiber glass tape was very thin and should not have to much effect on the height of the stringers. Now I know how much height the three layers of fiberglass added to the stringers!

So off the mount the A4 went, using the jerry rigged A-4 lift. Out came the belt sander and half an hour later I shaved off 3/16" from the top of the stringers. So the three layers of fiberglass are gone from the top of the stringers and I have to figure out how to strengthen the epoxy filler later. Now the main focus is getting the couplings to align.

On the mount the A4 went again. By then I was exhausted and my hands, back, and legs were aching. I rechecked the coupling alignment and more surprise! The engine half of the coupling was still 3/16" higher than the shaft half! How could that be? I checked the coupling mating surface and found that the gap at the top was greater than the gap at the bottom. Since I could not bolt the two halves together I did not see the use of measuring precisely how much the difference is between the two. I think the reason for the misalignment is that the forward end of the stringers were too low. I needed to shave off the aft ends of the stringers to even out the height of the couplings and narrow the difference between the gaps at the top and at the bottom.

So off the mount the A4 went again. Back to belt sanding the stringers again. Another half an hour later I shaved off another 3/16" from the aft ends of the stringers. By now I was completely exhausted and had no energy left to lift the engine back on the mount again. That will have to wait until next week. Anyway, here are two pictures of the couplings and A4 sitting on the stringers (the second time).

[Quetzalsailor]

Re: loosing your fiberglass wrap over the fill. Grind off another 3/16" (if you have to, see below) and put it back on.

Something seems a little fishy to me; surely the engine had shims on top of the beds? The original builder would not have made them perfect; he would have made them low and used the toothed iron wedges or washers. I'm surprised that you could have used up all his space with three thicknesses of 'glass.

I doubt that the disconnected shaft is lying on axis; I don't know the geometry of your stern tube, Cutless bearing, shaft and propeller but that whole shebang has some flexibility and the flange end of the shaft may be high or low. Be as sure as you can that the shaft is bearing on axis of the Cutless and stern tube. For a rough position, I placed the shaft as accurately as I could, shimmed it in position, then placed the engine to mate.

[Triton106]

Something seems a little fishy to me; surely the engine had shims on top of the beds? The original builder would not have made them perfect; he would have made them low and used the toothed iron wedges or washers. I'm surprised that you could have used up all his space with three thicknesses of 'glass.

There were no evidence of any shim when I removed the engine from the stringers. I know it is surprising. The engine was overhauled not long before I bought it by one of the best boat yard in the SF Bay Area (Richmond Boat Works, now owned by KKMI).

I doubt that the disconnected shaft is lying on axis; I don't know the geometry of your stern tube, Cutless bearing, shaft and propeller but that whole shebang has some flexibility and the flange end of the shaft may be high or low. Be as sure as you can that the shaft is bearing on axis of the Cutless and stern tube. For a rough position, I placed the shaft as accurately as I could, shimmed it in position, then placed the engine to mate.

I don't have a good picture of the shaft and stuffing box but Tritons have very short shafts. The distance between the stuffing box and the coupling is only a little more than one inch. There is not a lot of room for moving the shaft coupling up or down. When I mate up the coupling halves I tried to lift the shaft half as high as possible to match up with the engine half of the coupling. The first time it was not possible. The second time I had to pull very hard to bearly align the bolt holes. However, as mentioned earlier, the gaps would not close due to misalignment.

[bigd14]

Sorry to hear about the alignment trouble, Ray, sounds exhausting! Your Panama Canal analogy is one I can certainly relate to. I don't have any advice for this (one of the reasons I decided to go with an bolt-on-and-go outboard), but I wish you luck in solving it. Keep at it!

Doug

[Triton106]

Thanks for your encouragement Doug. Last week was pretty disappointing...

This week the battle turned in my favor a bit. Firstly, my friend Rob Heggen showed up to help. We started by loading the engine on the mount. To my utter surprise, the height is nearly perfect (after I shaved off the aft stringers as described in my previous posting). The athwartship alignment is nearly perfect. The top and bottom alignment is off by .008 of inch. Not perfect, but well within reasonable adjustable range.

Well, I thought great let's mark the spots for the four engine corners for drilling! But no... Rob had better idea. He thinks I should add some rubber cushion under the engine flanger to absorb vibration and to reduce stress on the coupling bolts. He further hypothesized that if we can sandwich a rubber gasket between two fender washers it will provide the vibration absorption and reduce the wear the bottom of the engine will have on the wood stringers. Good idea but that means I will have to shave off almost 1/4" more and god knows how the alignment will be. After some further discussion we thought what the heck I have gone through this much trouble already what is another 1/4" shaving.

Before doing any more work we decided to break for lunch and get the washers and rubber gaskets.

After lunch we shaved off the requisite height from the stringers and cut the rubber gasket material into round rubber washers. We lifted the engine back on the stringer again and inserted the rubber gasket sandwich under the engine. Voilà! The fit was near perfect again! After we replaced the thicker fender washer on the top (of the sandwich) with thiner regular washer the alignment is within .003 inch! Then we adjusted the fore and aft position of the engine on the mount slightly forward to ensure that the propeller is not sticking out too far to interfere with the rudder. Then we quickly marked the position of the holes.

We then removed the engine from the stringers again and drilled the stringers with 3/4" spade bits for the depth of the coupling nuts. The only minor problem is that because we move the engine slightly forward to give the rudder more room (the previous installation was too close to the rudder).the holes in the forward stringers are too close to the edge (see picture below). I have not decided if I want to strenthen the hole surroundings with more fiberglass tapes. Finally, we soaked the stringers with Smith brand penetrating epoxy. Then we left them to soak overnight. Tomorrow I will paint the top and set the coupling nuts in thickened West System epoxy.

Here are some pictures of the works done today.

[Top Picture] Engine stringer after applying penetrating epoxy. [Bottom Picture] Atomic 4 Lifting System - aka Main Sheet


[Top Picture] Home Made Engine Mount (Gasket Sandwich) [Bottom Picture] Mr. Rob Heggen Showed Up to Help

[Triton106]

Today's task is simple and straight forward, a nice change for once. We mixed up the West System epoxy resin and hardener. First coated the holes drilled yesterday without thickener. Then we mixed up the resin with West System 404 (excellent for bonding especially dissimilar materials, stainless steel and wood in this case). We filled the holes 1/2 full with the mix and coated the coupling nuts and finally set the coupling nuts in the stringers. I also coated the bolts with a light layer of marine grease and threaded it all the way to the bottom of the coupling nut. Here is a picture of it the setup.