Cylinder Head Question

Messages
463
Location
Palatine, IL
I just purchased a used cylinder head that has been ported, polished, valves un-shrouded, gasket matched, etc. This head has not been used since the work was done. As part of the porting/polishing work, the entire head has been painted silver. While it looks great, I am concerned by the fact that the top of the combustion chamber is painted, the bottom of the head, where the head would meet the gasket, is painted, and the the spark plug threads are painted as well. Is this is normal? I would have expected the bottom of the head to have been masked, so that it was not painted. Will the paint be a problem? I worry about the head making good contact with the gasket, and the paint burning off of the cyl head, and causing probs, and the threads being too tight on the plugs. Anyone?????
 
Last edited:
Messages
21,668
Location
Apple Valley, California
I would remove the paint from the gasket area with some carb cleaner and run a tap through the spark plug holes. I wouldn't worry about the paint inside the combustion chambers as it will just burn off. You may find that the carb cleaner will take the paint off pretty easily and cleaning the entire head wont be too bad.
 
Messages
9,808
Location
New Jersey
it will be ok you can remove the paint from the mating surface if it makes you feel better when we paint them sometimes that happens but its nothing to worry about.. we also use plastic dowels in the spark plug holes but some engine shops dont and have no trouble with them... What kind of head/engine??
 

JHZR2

Staff member
Messages
44,860
Location
New Jersey
It may be a good thing that it is painted... though Im guessing that it is aluminum for a 1.8 and not iron?
 
Messages
2,097
Location
kansastan
 Originally Posted By: Chris142
I would remove the paint from the gasket area with some carb cleaner and run a tap through the spark plug holes. I wouldn't worry about the paint inside the combustion chambers as it will just burn off. You may find that the carb cleaner will take the paint off pretty easily and cleaning the entire head wont be too bad.
Agreed. On my own vehicle, I'd remove the paint. But for what it's worth, lots of old-timer mechanics will actually spray paint a head gasket before installing it (and they always seem to prefer silver paint). Invariably, these old farts claim that it'll help the gasket seal. Personally, I think that's hogwash... but I've seen it done lots of times and have never seen any obvious problems come of it. Paint applied to the bottom of a head would probably be a similar non-issue. Just the same, though... I'd remove the paint.
 
Messages
19,479
Location
Chicago Area
Remove the paint from the sealing surfaces and spark plug holes. Block to head, intake, exhaust, valve cover seating areas, combustion chamber, and thermostat hole, if applicable. This is your best chance at a perfect job.
 

DockHoliday

Thread starter
Messages
463
Location
Palatine, IL
 Originally Posted By: bdcardinal
who in their right mind would paint an aluminum head silver?
Okay, it is not really silver, it is more like Platinum.
 
Messages
588
Location
Chicago, IL
I see this on a lot of remanufactured components like alternators- the paint makes the metal look like it's virgin. It should be pretty easy to tell if a part that large was aluminum or iron- an aluminum head should feel light for its size, an iron one should feel really heavy for its size. I would remove it from the gasket mating surfaces and chase all the threads, for sure. Most likely, it was done just to make the part look nicer. But there is a possibility it was done to cover up some flaws. I recently took off my upper and lower intakes (aluminum) to change some gaskets, and noticed that the mating surfaces were mottled and pitted. On an intake, not a huge big deal. But on a head, that could be a deal breaker if its happening. You'd never get a good seal.
 
Messages
2,270
Location
SD
 Originally Posted By: swalve
Most likely, it was done just to make the part look nicer. But there is a possibility it was done to cover up some flaws.
Swalve has a point. I've seen reman water pumps that had some kind of epoxy smeared on to cover severe pitting where the hoses slide onto the casting. The entire casting was then painted silver.
 
Top