BUILD THREAD Engine paint burning off

[Gto-78]

Already tried searching multiple times before posting this question and my results end up with crap like- how to fix my broken wiper motor, or my tires won't hold air....bunch of nonsense. .. I have no idea why the search engine sucks so bad.

So anyway- I've got a 67 Pontiac 400, 670 heads. The paint on the right cylinder head only always burns off above the two middle cylinders. Why the right head only, I don't know??

I'm getting ready to prep and repaint everything with Hirsch Pontiac metallic blue (aside from the aluminum colored intake). Just sucks if it burns off again. I've read all kinds of totally different ways that work for some people to prevent it burning- but to me the bigger question is- WHY is only one head burning the paint? I'm thinking that if one head is much cooler than the other then there's got to be something I can fix before painting anything.

It's got 1 7/8" headers, so no blocked heat risers or anything. The engine temp gauge stays nice and cool, not sure if the right head is staying cool where the water jackets are though.

I have block off plates for the heat crossover through the intake.

Any ideas? I don't see an engine specific section to post this in either, just an engine "swap" section.

 

[jcelk]

you might be running lean in those cylinders pull the plugs and and read them all laser temp guns are cheap engines aren't

 

[scoti]

x2. Use one of those laser temp guns & see if those cylinders are 'running hotter' vs the others. Then research why they might be hotter vs the other cylinders for clues on what you might be able to tweak so the issue improves.

 

[Gto-78]

you might be running lean in those cylinders pull the plugs and and read them all laser temp guns are cheap engines aren't

The plugs all look the same, slightly brownish. I'll let it warm up though and check the temp with my handheld gun.

Just had a thought, the muffler on that side had begun rattling bad recently. I replaced it temporarily- was just basically a muffler bolted to each header with a side pipe. Last week I installed a Hooker full exhaust system with Borla ProXS mufflers. Maybe the old rattling muffler had a blockage

 

[jcelk]

good no speckles on those two plugs . blocked exhaust maybe .let us know what the temps look like after a good drive

 

[Bonnewagon]

I have run Pontiac engines forever. The center ports always burn the paint off. The paint that lasted the longest was some Eastwood Stainless Steel paint used as an undercoat. Even then the Pontiac blue discolored, and finally burnt after many years. If you have a head that doesn't burn the paint, you are luckier than I am.

 

[scoti]

I have run Pontiac engines forever. The center ports always burn the paint off. The paint that lasted the longest was some Eastwood Stainless Steel paint used as an undercoat. Even then the Pontiac blue discolored, and finally burnt after many years. If you have a head that doesn't burn the paint, you are luckier than I am.

All the one's I've ever been around did as well (several buddies love their 400's). I never looked into a possible cure since I didn't own one.