Glyptal engine paint??
Well, not so fast. The oil soaks into the 'pores' of the cast iron and can stay there, especially when it gets baked on. Once it embeds itself, you can probably imagine what happens over time. Smoothing things out and removing casting flash probably provides more benefit than the glyptal though so if you were debating about whether or not to do anything, you would probably be best to start there and do the paint as a second measure.
So does painting the lifter valley add any real performance benefit? Probably not. The only thing that I can imagine is that it could help to keep oil recirculation at a peak level rather than having a delay when the oil from the top end drains back into the crankcase. It's probably a small thing but a 'thing' none the less. Maybe it can also lower oil temp a little since it acts as an insulating barrier between the oil and hot cast iron. I'm just guessing though.
If either of these things are true, perhaps there is slightly more longevity in bearing life since there is less opportunity for oil starvation in certain spots. It's doubtful whether you would see any evidence of that over a short period of time though. The only real way to know would be to build two exact engines, paint one with glyptal, run them the same amount and take 'em apart to see if there is any difference.
Look, if you have a 'performance' engine and are religious about oil changes and the motor runs right, then it's not really an issue. The OEMs never did it because there was an assumed level of maintenance. if you were negligent, well you were on your own anyway. If they thought it was necessary to prevent warranty work, they would have put it in there.
Well, not so fast. The oil soaks into the 'pores' of the cast iron and can stay there, especially when it gets baked on. Once it embeds itself, you can probably imagine what happens over time. Smoothing things out and removing casting flash probably provides more benefit than the glyptal though so if you were debating about whether or not to do anything, you would probably be best to start there and do the paint as a second measure.
So does painting the lifter valley add any real performance benefit? Probably not. The only thing that I can imagine is that it could help to keep oil recirculation at a peak level rather than having a delay when the oil from the top end drains back into the crankcase. It's probably a small thing but a 'thing' none the less. Maybe it can also lower oil temp a little since it acts as an insulating barrier between the oil and hot cast iron. I'm just guessing though.
If either of these things are true, perhaps there is slightly more longevity in bearing life since there is less opportunity for oil starvation in certain spots. It's doubtful whether you would see any evidence of that over a short period of time though. The only real way to know would be to build two exact engines, paint one with glyptal, run them the same amount and take 'em apart to see if there is any difference.
Look, if you have a 'performance' engine and are religious about oil changes and the motor runs right, then it's not really an issue. The OEMs never did it because there was an assumed level of maintenance. if you were negligent, well you were on your own anyway. If they thought it was necessary to prevent warranty work, they would have put it in there.
