Any thots on whether it is a bad or good idea to use Glyptal on these areas of older ( or new) pans and blocks ?
I powder coat all my oil pans. Tough bullet proof coating for an area that gets a lot of abuse. In fact I powder coat the outside of all my engines, save those things that are chrome or polished aluminum. Painting the innards of an engine has been going on for as long as there have been hot rods. Does absolutely nothing positive IMHO, but doesn't do any harm either. Just one of those things people keep doing that no one knows why!
I know the theories but still think it is the same usefulness as carbon black under your eyes in football!! But then I have never run a +1000hp engine so who am I to comment!!!!
The guys with 1000+hp don't normally run coated blocks, timing covers, oil pans. Take a walk thru the pits during a big NHRA race where you can see all different classes of cars/engines...see what there is to see, ask the owners what's painted inside the engine..! Various lubrication and heat barrier coatings - Pistons, bearings, yes. Combustion chambers and valve heads, sometimes. Various "cryo" (cold treating) treating of various gears and shafts, yes. With a smooth surface already, why would a painted surface be any better ? Aluminum, already smooth. Cast iron, a hand grinder will take care of the surface roughness. Mike P.s. - Does this question really fit here ?
I think it is a classic hot rodding issue so question seems reasonable. As you point out, hi-tech coatings are all over racing engine internals, none of which are for the purpose that Glyptal purports to serve. Again as you observe, modern racing engines are all slick aluminum and magnesium masterpieces so paint doesn't apply. That leaves good old cast iron engines that most of us unwashed masses who live in fly-over country are forced to run. I submit the biggest problem with oil return is woefully small return passages in heads and blocks. There is no way a slick painted surface will overcome the restriction caused by the typical couple 3/8" diameter drilled holes. Spend your time more beneficially figuring out how to open return passages is my thought.
Old cast iron [40's/50's] small engines were painted internally by the factory; looked to be before machining..My thought is that it was to seal the casting from porosity/loose sand...
That could be. One of the claims for painting is to 'seal loose casting sand' although I have never seen any sign of that problem in all the engines I have torn into. My '52 Hemi, Chevy 235 straight 6, '36 Pontiac straight 6, and the few other vintage engines I have worked on had no internal paint but I admit I have limited exposure to a lot of different ones.
Do your research on the proper way to use Glyptal. The block/head needs to be absolute oil free which means baked before you paint then baked to cure it. It is not worth it for the home shop guy.
Bad idea.... Glyptal was used on the heads and in the lifter valley to promote faster run-back of the oil. Being a very heavy-bodied paint that filled/smoothed the cast surface, it was easier than hand-polishing the cast iron plus you didn't have to remove any material, possibly weakening the castings. Really only needed on high RPM motors ran for extended periods where if the oil didn't run back fast enough, you could get oil starvation. In the crankcase, it's a bad idea. Being constantly 'blasted' by hot oil flung off the reciprocating assembly, it can come off, sometimes in sheets, and clog the oil pickup. It's also an insulator, so coating the pan will reduce the ability of the oil to cool. People forget that oil is not only a lubricant, but also acts as a cooling medium, carrying heat away from the areas not directly water cooled. Inhibiting that can lead to both higher engine and oil temps.
***************************************************************************************** Steve'e post parallels my thoughts that it's really only beneficial to F1 and Lemans type racing. Possibly high-mileage NASCAR, but even then, it might be a diminishing return type of thing. Roger
Some interesting thoughts, thanks for every comment. Interesting observations of differing practices between engine builders. Some use the coating, some don’t. I thot might be $ , as is pricey. I’m working aluminum. Fresh aluminum at that, so the sand , foughness and porosity ideas are in line with why asked question. Along with all these great ideas, I’m thinking that sludge etc will not stick to rough surfaces that are coated.
With modern detergent oils and attention paid to crankcase ventilation to prevent condensation, sludge shouldn't be a problem anymore.
Yeah detergent oil is what keeps engine contamination under control, in my opinion also. I think I’ll forego the coating. Some persuasive advice here , thanks !
Keep the oil changed regularly and keep the oily side down and shiny side up and a well built, non-painted internals engine will outlive you.
Folks say that the paint will seal and hold casting flaws, sand, etc. I tend to work on 50+ year old engines with a gazillion miles on them. I figure that anything that could come off did so a long time ago. 'Course I also paint the insides of my engines 'cause it is expected and looks purdy.
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