I am now the proud owner of a Three Demon 98s on an Offenhauser Intake manifold... My engine guy is polishing the inside (he was very grumpy about the finish of the inside of the Offy...
He said that after he polishes it, I should coat the exterior or it will look like junk in six months... He didn't have any immediate suggestions on what to coat it with however.

SO, as always, I turn to the experts...

Any thoughts?

Thanks in advance,

(Block now has new hardened exhaust valve seats, full flow oil, and the cam is in... valves to be installed soon, (my word, engine guy said next week, but that what he says about everything, every time I go there.. next week...)

 

call HPC, http://www.hpcoatings.com they do coatings on intakes and exhaust, and other engine parts..

I had them do my custom headers..

Sam

 

i'd say if you know someone that does powder coating, get them to spray it with clear powder coat, just dont use any kind of clear spray enamel, it turns yellow from engine heat, and flakes off most the time.
my 2 cents.

 

i'd say if you know someone that does powder coating, get them to spray it with clear powder coat, just dont use any kind of clear spray enamel, it turns yellow from engine heat, and flakes off most the time.
my 2 cents.

why did that post twice??? hey is there a moderator that can delete this?

 

Powdercoat is plastic and can peal or disolve with some chemicals. Coating the inside of an intake manifold may be asking for something in you engine you do not want. Be careful. Polishing the inside of an intake manifold in a street car or truck is just asking for problems. Polishing the inside of intake manifolds is left to very high RPM engines because of fuel condensation in the runners. We ported a lot but seldom polished anything that was going to see any RPM below 6500, not the red line. the lowest RPM once up to speed and little to no idleling. Good luck

 

**I can't believe the question was about coating the inside. That's ridiculous, as stated.

Do I understand correctly that this guy is polishing the OUTSIDE of your manifold? I won't polish anything under the hood, since I'll be polishing it more to keep it purty, which I don't want to do.

**Polishing the inside of intake runners is a waste of time. I am old school, where you port out the intakes and leave them rough finished (for the condensation thing). I polish the exhaust runners for smoother flow (at any rpm).

 

No, coating the OUTSIDE of the manifold.... not the inside.

I will ask him about polishing the inside... he does build race engines and is always looking for another 50 hp here or there.....

 

Not sure what the budget it, but I recently saw a low buck solution. Bead blast and rattle can "ceramic coat" engine paint CLEAR. I think that is a Duplicolor product good for 500 degrees. Looks good, and I'm confident it must last a while because the guy I got it from has ported literally hundeds of Mustang EFI intakes on a couple forums I frequent.

 

i was confused for a moment, but i was talking about coating only the outside.

 

There is a product for coating aluminum that is a clear liquid and brushes on, and can be touched up any time. Very popular for flathead aluminum heads. I'll have to find the name. It's not paint, it is something similar to waterglass. It prevents oxidation and is cheap. A websearch will pull it up, it's been discussed here and on lots of other forums.

 

Here's what my engine guy said...

Steve
I never per say (polish) the runners in either the head or intake. We finish up with 60 grit paper that leaves it rough although even. This will leave a boundary layer for fuel/air to flow across. Have done more testing and flowing on my dyno and flow bench than most people have years. But they are correct. It is a misnomer when we say polish. It is but it aint.
reed

Gonna stop by tomorrow and see how it's goin...
I'll update you guys.

 

Got my intake back from professional porter today. Just as you say. Very smooth compared to raw casting, but far from "polished" surface.

 

Gibbs brand?

Gibbs Brand penetrant

read through the info and checkout the pics...some pretty cool stuff!

 

dupli color as mentioned , and eastwood have a high temp clear in various finishes , glossy , satin etc. , that you can spray or brush on . was looking at 'em myself for a couple of brain farts i was having ...............

 

Gibbs brand?

Gibbs Brand penetrant

Anybody ever used this? Looks pretty cool... and not very expensive.