Bake on engine paint. warp concerns

[Superman74]

So I have some silica based engine paint I want to use on the engine case. It says to bake for 30 mins @ 250, 400, and finally 600 farenheit. Can I cause harm in doing this? The case is back from the machine shop and I am finally getting around to final assembly. I know that there are some rubber grommets around the case studs i ought to pull. Otherwise I wouldn't think there wouild be an issue.. perhaps to be prudent I should torque the case halves to spec first.. Thoughts?

[rockurob]

valve seats start failing/falling out at 450+ degrees
thus 600 degrees probably would not be a good idea
just my 2 cents, but you do what you want
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[Superman74]

I do not plan to touch the heads. I wouldn't gamble on my Steve Tim's. The case halves though, this is an AS-21 case stripped bare.. I need am curious how to pull this fuel inject ground or sensor out of the case.. but i would still like to bake the engine enamel on.. Thats what the concern is..

[75smith]

don't, bake on engine paint is for steel/iron cases, they can take more heat then aluminium/megnesiun can, personally I would not trust a fresh cut case to temps above 350, you can warp the case, even if torqued
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[rockurob]

[Randy in Maine]

I have been using this stuff on the outside of my case (and transaxle) with pretty good results. 2 coats please. Does a nice job on magnesium and aluminum alloys.

http://www.gibbsbrandlubricant.com/

[bugguy1967]

Painting cases should be punishable by death. If you MUST do it, just use a regular enamel like Duplicolor multipurpose auto paint. I'm sure Bernie Bergmann would be proud.
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[Hotrodvw]

[bluebus86]

That kind of heat will likely warp the case and change its microstructure.

600F is beyond the safe limit for most MG alloys. If you were to use this temperature, you would need great care to assure even heating and cooling cycles, but even then, 600F is too hot.
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[modok]

don't go over 300F, and make sure no bolts are tightened.

if you torque the case and bake it at 400, it will be junk. Yes really.

And besides all the paint would fall off in the oven from the oil and smoke coming out of the pores. You'd have to bake, paint, then bake again.

[75smith]

[modok]

Unless it's new probably more like clean, clean, clean, clean, bake, clean, paint, bake.



But it should work. My buddy brought me a case that was painted black. I cleaned it and it came out safety yellow. Can see it a mile away now. AH, that's why they painted over it. The paint is stronger than the magnesium so we'll just have to live with it.

Gotta love those gob-stopper engines.

We had a SBC that was metallic purple, under that was orange, then red, then orange. Came out all patchy and horrible looking. Careful with the paint!

[Howard 111]

Painting the case in or out is a bad idea. If it showed any benefit, don't you think the VW engineers would have done it? I've seen show only cars with painted cases for looks only, but they are hardly even driven. I prefer an engine that lasts.

[bluebus86]

it has been found that often a THIN coat of FLAT BLACK paint on the outside of the cylinder fins will help remove heat better than the bare iron finish. you want it thin a possible to get minimal coating, else it starts to insulate.

I read about this form several sources and then read about an experiment done at with thermal couples, and heated VW cylinders and their cooling rate. Rusty dirty ones were worst, bare new clean was much better, and by a bit more, the thin flat black paint was best at cooling. that flat black paint (thin) worked very well at heat removal on cylinder fins.

A thin coat on the motor could be beneficial in that it may help reduce oxidation of the case, a heavily oxidized case is rough, holds dirt , and can insulate. A Shiny new surface will not radiate much, like a flat black color. Crud and grime are worst and should be scraped off and washed away, as that insulates the heat in, like a little blanket.
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information

Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022

[75smith]

[bugguy1967]

Weren't cases coated with something from the factory which made them gold-ish colored on the outside? I don't think it was cosmoline either. I can passivate cases at work to prevent corrosion, and they'll still look like they haven't been coated at all.
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[75smith]

[Hotrodvw]

Krylon Semi-Gloss. Probably have 1500 miles on this paint job. If it was going to come loose, I'm thinking it would have by now. Case was hot tanked before assembly, so obviously it must be free of any and all oils or contamination.

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[theastronaut]

I did the visible area of the block on my 1679 a few years ago and it's still holding up very well. I used a stainless brush and wax/grease remover (auto paint prep) to prep the case (did that a few times), then sprayed it with a light coat of PPG DP40 epoxy primer. The top coat is PPG single stage urethane with hardener, and I added a flattening agent to make it a satin finish instead of gloss. Color is a light charcoal I made with leftover silver and black paints. Still looks great 24K miles later.

Close up taken today. I had to split the case to change the cam bearings which chipped the paint along the seam, but other than that it's held up great.

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[Superman74]

Well this conquest is the result of the VW club driving on Daytona beach every weekend.. and the resultant rust.. so I had flat black header paint. I will let it sit untorqued at 250 for an hour and a half. Thanks for the heads up guys.