hi guys, im new to the site. Im helping a friend go thru his 1990 302. he went with an f cam and wants to mill the heads a little. my question is, he got a good deal on a stock rotating assy. with machined valve clearance pockets. the pistons look really clean as far as scuffing on the skirts & what not. what is the loosest acceptable piston to wall clearance we could run. i miced the pistons he's gonna use and set up a dial bore gauge to check the bores and theres .0055 -.006 total clearance between them. he's on a budget & dont want to bore & buy new pistons. we want to pass a ball hone to knock the glaze off the cylinders so the new rings will seat. the bores are clean of any scratches & round within .0005.,so i dont think we will have to hone much at all. also, the stock heads are port matched, could we safely mill .02 off them? like i said valve clearance should not be an issue. thanks guys.
piston to wall clearance for std. bore 302
- Thread starter nickp
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Wallzy
New Member
If you are just cleaning up the motor i would say that you are fine with your piston to wall clearances - Just make sure you gap your new rings correctly. I think that you'll be fine milling off 0.020" as well, just make sure that your pushrod length is fine when you put it all back together.
Walz
Walz
Cobra_Dusten
Member
its not that at all, infact i just finished my motor recently. no one wants to lend advice on a cheap ass build like that. To many variables to consider to feel comfortable lending advice. However, best of luck
Black1987Stang
Active Member
its called a budget rebuild for a reason. i dont see all the variables you found in the original post. i asked a simple ? about piston to wall clearance & milling the heads, not very complicated to answer either of them.
if you dont want to lend advice on a cheap ass rebuild, then dont reply.......its that easy.
rd
Founding Member
I concur with milling the heads, I did that, .020 on my last build.
I don't have guidance for the piston clearance issue. I would take the measurements you have and compare them to the new recommended clearance, and then see if you can find the Ford description of allowable piston to bore clearance. Compare these and decide.
It may work but I have not put an engine together yet that was not bored and finish honed.
I think Car Craft did exactly this about 18 months ago, so you could search there.
I don't have guidance for the piston clearance issue. I would take the measurements you have and compare them to the new recommended clearance, and then see if you can find the Ford description of allowable piston to bore clearance. Compare these and decide.
It may work but I have not put an engine together yet that was not bored and finish honed.
I think Car Craft did exactly this about 18 months ago, so you could search there.
