Stripping/repainting engine

Trecksail · Post by **Trecksail** » Thu Feb 26, 2009 12:04 am

Wondering what's the best way to go - paint remover/sand/soda blaster?
Thanks

cmartin · Post by **cmartin** » Thu Feb 26, 2009 12:25 am

Is the engine still in the boat or sitting on the bench in pieces?

Trecksail · Post by **Trecksail** » Thu Feb 26, 2009 1:00 am

It's in the boat right now, but I'm plannig on pulling it and putting it on a stand. Not planning on dissasembling. I'm thinking about converting the aft portion of my bilge into diesel tank and figure if I do I might as well clean the engine up and get some better protection (paint) on it.

Peter · Post by **Peter** » Thu Feb 26, 2009 1:45 am

In my experience, if the engine is not being torn down and boiled out:
-Plug all orfices
-Remove belts
-De-grease with a spray-on engine cleaner, then wash with hot soapy water, and rinse well.
-Use a rust remover to clean off any rust
-Wire brush off any loose or flaking paint
-Blow engine dry with compressed air.
-Mask all hoses, fuel and water (if you leave them on) and factory labels.
-Spray engine with desired color engine paint (my preference is the original factory color.)

Unless the old paint is a complete diaster there's no need to remove it all.

I avoid pressure washing because 1: I don't have one, and 2: it tends to drive dirt and grease where it doesn't belong.

Hope this helps!

My 26 year old 2GMF:

Triton106 · Post by **Triton106** » Fri Feb 27, 2009 12:43 am

What do you do if one is rebuilding the engine, including hot tanking the block, manifold, head, and oil pan? I was told that the machine shop will usually prime the casting for you. What type/brand paint will you recommend?

Peter, your Yanmar looks clean enough to eat off of.

Peter · Post by **Peter** » Fri Feb 27, 2009 1:14 am

Ray wrote:Peter, your Yanmar looks clean enough to eat off of.

Thanks, Ray. I like to keep it smelling sweet :-)

I used a can of Yanmar's engine enamel in a spray-can. I'm not a great fan of spray-can paint jobs, but this one is holding up very well.
A quick Google turns up a lot of spray-can options, but if I were going from scratch on a complete rebuild I'd probably go thePORroute. I used that stuff on the inside of my boat trailer brake drums and it prevented rust, despite frequent salt water submersion.
A well painted engine is easy to keep clean.

jhenson · Post by **jhenson** » Fri Feb 27, 2009 8:34 am

Peter,

I’m planning on painting what I can get to on my Yanmar 3GM without removing the engine. Do you recall what brand of rust remover you used?

Yours looks great!

Joe

Rachel · Post by **Rachel** » Fri Feb 27, 2009 10:05 am

Sure, parade that amazing Tartan engine access past us while saying "the parts I can get to...."

;)

R.

Peter · Post by **Peter** » Fri Feb 27, 2009 1:18 pm

Joe,
There was not much rust on my Yanmar. A little wire brushing, some phosphoric acid, and a rinse, and it was pretty clean.

One thing that interests me is the use of molasses to remove rust. Try Googling molasses rust for some verry interesting info. Seems to be big in Australia.

jhenson · Post by **jhenson** » Sat Feb 28, 2009 8:09 am

Rachel,

I will enjoy that access, to be sure. I'm told the engine can add a lot of heat to the cabin, which won't be any fun in August with our light Chesapeake winds.

Peter,

Thanks. I was planning to wire brush the worst of it, as well.

Joe

David · Post by **David** » Sat Feb 28, 2009 9:07 am

<<Try Googling molasses rust for some verry interesting info. Seems to be big in Australia.>>

I have read of people using Coke to remove rust as well. I came across this yesterday..a water based rust remover:

http://www.theruststore.com/Evapo-Rust-Gallon-P1C1.aspx

Supposedly it is meant to be used by soaking the rusted part in the solution, but I think it could be bushed on or sprayed on successfully also. I've ordered a gallon so we will see.

David

boatsnh · Post by **boatsnh** » Sat Feb 28, 2009 10:12 am

Hi Joe,
I'd suggest that if you have the availability of someone who can walnut shell, or "carefully" media blast the engine I'd follow that route. In the yard where I've kept my boat they have access to a "traveling" media blaster who will swing by the yard and blast engines, trannys and or anything else they require. They charged (last summer) $100 and its amazing to see...Tape off the engine "delicates" with heavy zip lok plastic bags & duct tape & in 20 minutes -done!! Blow everything off with air and good to go.
Prime with epoxy paint or a good quality etching (the green stuff) primer & paint. Me, I'd spend the few dollars for a quart of Imron Industrial paint at the local automotive store -all of $55 & well worth it.

Me, on the other hand, spent a winter 3 years ago rebuilding my Westerbeke 4-107. The "blaster" was un-available the week I removed my engine & I just "had" to move it north to New Hampshire to the garage. Stupid me! The engine had sat in the bilge for 35 years & looked it. So, as I took the thing apart (total re-build & new injection pump) I found ways to remove rust - none of them fun. Wire wheels on drills, scrapers and scrapers. did I mention degreasing??? fun.

I eventually settled on an electrolosis bath for non critical (like engine block & head) that worked wonderfully - hook up to the battery charger, drop in the liquid - next day - no rust. Saved tons of time, but still a PITA. Ospho works well on rust, as does phosphoric acid as a post/pre treatment prior to paint. (that's what's going on when folks use coke - phosphoric acid). My basement work shop was cool all winter ( 45 degrees) so I used a moisture cure urethane aluminum filled paint 'cause it cures in cold weather. Worked O.K., but I'd use a 2 part urethane or high quality enamel next time - A shiny finish that sheds dirt/water/gump better. I know folks have good luck with POR 15 on engines -It's tough stuff & nice colors.

After all this was done, a buddy of mine trailered a large snow blower (This is New Hampshire...) to a local "sandblaster". The whole thing was blasted & painted with etching primer for $75 - what's not to like?
Mike

megalops · Post by **megalops** » Fri Mar 06, 2009 12:00 am

Use aluminum foil to wrap around your hoses instead of masking them. It works great.

David · Post by **David** » Fri Mar 13, 2009 11:47 am

Just reporting on the Evapo-Rust: I have derusted every old tool in my shop. The stuff really works--the longer you leave the rusted part in a bath of the solution the cleaner it gets. If you take it out of the bath and let it air dry it turns the part sort of gun-metal dark gray but the company claims it will not rust again.

David

Rachel · Post by **Rachel** » Fri Mar 13, 2009 5:32 pm

Is the dark grey something that will rub off on your hands? Or is it a permanent "structural" color change?

Does this mean it has changed the metal somehow? (For good or for bad)

R.

David · Post by **David** » Fri Mar 13, 2009 8:00 pm

It's permanent; doesn't rub off. I put a 50 year old pipe wrench that had been rusted since it was new...I left it in for two days..it looks brand new now. Really amazing. It is also not caustic. I picked the tools out of the bath with bare fingers, no burning, no particular odor; it seems very benign.

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stripping/repainting engine