The Ford Barn

bobH · 12-20-2019, 05:34 PM

If you have a broken piston on an engine with that few miles/time, I wouldn't be taking a chance on simply replacing ONE piston/rings. As a minimum, I'd likely pull the other 7, and inspect. Perhaps dye-penetrant, or at least something similar. I've had too many 'bad piston' experiences. And, if ONE is bad, I'd figure the rest are 'suspect'. How may times have I heard a 'knock in the crankcase' audible externally, and especially audible if you put an ear to the oil-fill tube. And, the 'knock' turned out to be from hearing the combustion through a cracked or broken piston. And, almost always, on flathead Fords. One exception, I once correctly guessed a broken piston on a Porsche six cylinder (almost new car at the time). The dealer who tore it down/fixed it, was amazed at my guess, and I told him it was based solely on flathead ford experience.

Ggmac · 12-20-2019, 07:26 PM

I've seen breaks in that area when w new piston , with a higher ring location , is installed in blocks that haven't had the ridge removed or removed properly .
Glad you found it , check others or at least find the problem. Hopefully it's not a piston manufacturing issue . If it is ,other Pistons may soon fail .
On another note , an overzealous installer could have forced the piston in with the rings not fully compressed .
I would check ring gap and look carefully at other cylinders for similar scratch marks .

deuce5wndw · 12-21-2019, 08:45 AM

I would check piston to cylinder clearance also. I don't think that crack is the cause of the piston dragging in the cylinder.

12-20-2019, 05:34 PM	#21
bobH Senior Member Join Date: May 2010 Location: so cal, placerville, vegas Posts: 1,394	Re: Replacing rings on 1 piston on 8ba If you have a broken piston on an engine with that few miles/time, I wouldn't be taking a chance on simply replacing ONE piston/rings. As a minimum, I'd likely pull the other 7, and inspect. Perhaps dye-penetrant, or at least something similar. I've had too many 'bad piston' experiences. And, if ONE is bad, I'd figure the rest are 'suspect'. How may times have I heard a 'knock in the crankcase' audible externally, and especially audible if you put an ear to the oil-fill tube. And, the 'knock' turned out to be from hearing the combustion through a cracked or broken piston. And, almost always, on flathead Fords. One exception, I once correctly guessed a broken piston on a Porsche six cylinder (almost new car at the time). The dealer who tore it down/fixed it, was amazed at my guess, and I told him it was based solely on flathead ford experience.

12-20-2019, 07:26 PM	#22
Ggmac Senior Member Join Date: Jul 2016 Location: Lake worth Florida Posts: 1,088	Re: Replacing rings on 1 piston on 8ba I've seen breaks in that area when w new piston , with a higher ring location , is installed in blocks that haven't had the ridge removed or removed properly . Glad you found it , check others or at least find the problem. Hopefully it's not a piston manufacturing issue . If it is ,other Pistons may soon fail . On another note , an overzealous installer could have forced the piston in with the rings not fully compressed . I would check ring gap and look carefully at other cylinders for similar scratch marks .

12-21-2019, 08:45 AM	#23
deuce5wndw Senior Member Join Date: May 2010 Location: Liberty, KY Posts: 900	Re: Replacing rings on 1 piston on 8ba I would check piston to cylinder clearance also. I don't think that crack is the cause of the piston dragging in the cylinder.