Body filler on valve covers

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4 speedin

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I am restoring a set of 340 valve covers and have a area under the breather that I can not metal finish and would like to know if body filler will hold up to the heat or if it will bubble or blister the paint.
Any advise would be greatly appreciated!
Thanks Mike
 
No.

If you want to test this, put your filler on some metal and put in in the oven at around 250°F. It will either get very soft, or melt, depending on the material. And I think valve covers might get even hotter than that.
 
you can use filler on the outside of the valve cover no problem. we do it all the time on fabricated valve covers to get them slick.
 
Ive actually blasted used covers that looked great only to find them full of mud. In that instance, it worked fine
 
Hard to imagine it worked. Are you sure that they are using body filler and not some really good epoxy? I think something like JB-Weld might stand a better chance of holding up.
 
I see that quite a bit and it's usually never done well enough to last. I've got some high temp filler just for that purpose.
 
If you're unsure, find yourself some "all metal" filler.

Good stuff. I've used it around door handles that have had rust through around them and it holds up.

Ron
 
I will test some body filler and JB weld in the oven tonight at about 275 degrees and let you all know the result.
Thank you all very much for you input:(
Mike
 
275? if your motor and parts are 275. You will have bigger problems than filler lifting off the valve covers at that temp.
 
Be careful heating JB weld or anything like it, it can out gas toxic fumes let alone put any of that stuff where you cook food.
 
prrc said:
275? if your motor and parts are 275. You will have bigger problems than filler lifting off the valve covers at that temp.
Click to expand...

230°F-260°F is considered to be normal oil temperature. So he's not so far off. (I said 250°F would be a good test.)
 
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