painting inside of iron blocks.

[Autoholic]

I've been doing a lot of research on this and there are a few things worth mentioning...

1. Prep has to be perfect and it's best to bake it to insure proper curing.

2. Is useful if there are porosity issues with a casting. There are however many paint options to deal with porosity.

3. Should it flake off as some do claim to have seen, it can become a big problem. Is it worth the risk?

4. If you want to smooth the engine's interior surfaces to help oil flow, you an grind / sand the surfaces smooth.

5. One person mentioned using dry graphite instead to help speed up oil flow. If the dry graphite flakes off, it is a dry lubricant anyways so chances of it blocking oil flow is very small.

The main thing I took away from all my reading was that a really well prepped block before assembly doesn't really need the added time and money spent on painting the insides with glyptal.

[fekbmax]

Two pro engine builders said no dice.....are we beating a dead horse now. 

I totally respect the great engine builders here with out a doubt. I value any and all information that can be gathered from anyone though. There's no doubt that there would be different experiences with any product and personally I like hearing from both sides. There's never to much info either pro or con, its up to the individual as to what they do with it. As far as the comment above goes, id be willing to bet that at least two other pro engine builders would say they use it regularly. .

[427Fastback]

I have a friend who glyptals all the blocks and heads he does .Just a hobby guy who likes it done that way..I have never done it..I deburred and polished up the valley in the 427 when I first got.Pretty easy to do and the high nickel (hee hee)polishes up real quick..

[Falcon67]

I've never used it on any engine, never seen a reason to do so.   I can see it on an all-out dry sump race setup where you want oil to get back donw there quick and be sucked out to the holding tank.  For other motors - meh.  Make work IMHO.  I personally rail at any overspray of any kind on internal engine parts or surfaces.  Drives me nuts to see engine or parts for sale with some paint color all over the valve springs, cylinder decks, etc.  Says "poor workmanship".

[Nightmist66]

I only use the brush on type. Never have to worry about overspray. I hate it too.

[cammerfe]

FWIW,I came into possession of a Cleveland-type manifold some years ago. It had had the full treatment including heat-barrier coatings on both inside and outside surfaces. The exterior was a dull black; the underside was a sorta-virulent bright green. I don't know that they still do such things but I was told that the surface treatment had added $400 to the prep of that manifold. It had come from a max-effort short-track team.

When I did an engine at Roush's Prototype Shop, I found it to be standard procedure to do the cartridge-roll clean-up on all as-cast interior surfaces. They were not enthusiastic regarding Glyptal.

KS

[jgkurz]

This thread hits home with me. I currently having a 1971 427 side-oiler service block at my machinist for an upcoming build. The lifter valley is painted with Glyptal 1201. I have been told that service blocks had this done by Ford but it is only hearsay. I had to have the lifter bores sleeved which ruined much of the paint in those areas. I did some research and would rather re-apply the Glyptal paint and re-bake instead of grinding off ALL the old paint. Apparently Glyptal can be painted over old Glyptal as long as it's scored, prepped,and cleaned, cleaned, and cleaned again. I will be baking the block as recommended. Prior to the sleeving, the paint was in superb condition so I feel confident it will last me another 44 years.

[Autoholic]

FWIW,I came into possession of a Cleveland-type manifold some years ago. It had had the full treatment including heat-barrier coatings on both inside and outside surfaces. The exterior was a dull black; the underside was a sorta-virulent bright green. I don't know that they still do such things but I was told that the surface treatment had added $400 to the prep of that manifold. It had come from a max-effort short-track team.


KS

Are the inside walls of the manifold smooth or a little rough? I've seen a lot of discussion about smooth walls vs rough finish in order to give optimal flow. Has to do with the boundary layer at the wall, how it effects turbulence and keeping the fuel suspended in the air.

[cammerfe]

The runners are certainly not polished inside. I think it's generally accepted that a sanded-to-even-things-out-but-slightly-rough surface is best for the reasons you mentioned.

KS

[MeanGene]

I never use it, and won't- just smooth up with the cartridge roll and several cleanings with carb cleaner then soapy water blast. Saw a 351W once with smoked bearings and the pump screen full of Glyptal- back when it was all the rage. Never thought much of the fad of Scotchbrite treatment on bearings either- better to leave the coating on the bearings