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The guy at the machine shop swore my heads were fine - he was wrong | Engine Performance - Rigidtalk

The guy at the machine shop swore my heads were fine - he was wrong

I brought my 350 Chevy heads to a shop in Phoenix last month and the old timer behind the counter told me the 50 thousandths of warpage was 'within spec' and to just bolt them on. I listened to him and now I've got a coolant leak that's been driving me crazy for three weeks. Turns out he was just being lazy because his machine was down. Has anyone else had a machine shop give them bad advice just to avoid the work?

3 comments

3 Comments

brookes375mo ago

50 thou is a lot but plenty of guys have run warped heads for years without issues, so maybe it's not the shop's fault. Could be a gasket problem or a crack you missed, warpage alone doesn't always cause coolant leaks right away. Might be worth checking your block deck surface too before blaming the old timer completely.

wilson.claire5mo ago

Ngl brookes37 I gotta push back a little on that. Yeah warped heads can sometimes seal with a gasket if the gasket's good enough but 50 thou is a whole lot of warp for a cast iron head. That's like a quarter of a millimeter or more and at that point you're risking the head cracking just from the stress of torquing it down. Did that old timer actually surface the head or just check it for flatness and call it good? Because if he only checked it and didn't properly machine it flat then the warpage is still there and that's on him. And block deck surface is a fair point but most guys don't pull the block to deck it for a simple head gasket job. So honestly if the shop told him the head was flat and it's not that's on them.

bettyh845mo ago

And oh man, I had a shop in Tucson tell me my 302 Ford heads were "perfect" and then I found out later the guy was just trying to push me out the door before lunch. I feel like @wilson.claire is right, 50 thou is WAY too much to just ignore. My buddy's Nova had the same thing, warped heads, and the coolant leaked into the oil, turned it into a milkshake. He had to pull the whole top end again after the shop swore up and down it was fine.