The Ford Barn

Kurt in NJ · 06-08-2025, 03:23 PM

I have a smoking problem but hardly any blowby and when the head was off no cylinder damage or wear was evident,the pistons are .040 oversized.
It was sitting for many years and at first there was puffing blowby until it ran a while then it stopped,the compression is even and all cylinders get oil on the plugs but not enough to foul them the ceramic is deep up in the X plugs and burns a light brown,the valve guides are not loose so I figure it is a oil ring problem.
I don’t see any listings for the aluminum jahns pistons.

J Franklin · 06-08-2025, 07:47 PM

search for OTTO Machine. He would have rings I bet.

redmodelt · 06-09-2025, 05:15 PM

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If the Jahns pistons take the narrow compression rings and wider oil control rings, the Hastings or Grant will work. Just different material between the two brands.
Langs Snyders and other supplier should have them but check before you order, there are some sizes that have been out of stock for a while.

06-08-2025, 03:23 PM	#1
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,672	Piston rings for Jahns pistons I have a smoking problem but hardly any blowby and when the head was off no cylinder damage or wear was evident,the pistons are .040 oversized. It was sitting for many years and at first there was puffing blowby until it ran a while then it stopped,the compression is even and all cylinders get oil on the plugs but not enough to foul them the ceramic is deep up in the X plugs and burns a light brown,the valve guides are not loose so I figure it is a oil ring problem. I don’t see any listings for the aluminum jahns pistons.

06-08-2025, 07:47 PM	#2
J Franklin Senior Member Join Date: May 2010 Location: Oregon Posts: 6,581	Re: Piston rings for Jahns pistons search for OTTO Machine. He would have rings I bet.

06-09-2025, 05:15 PM	#3
redmodelt Senior Member Join Date: May 2010 Location: Portland OR Posts: 6,458	Re: Piston rings for Jahns pistons Sponsored Links (Register now to hide all advertisements) If the Jahns pistons take the narrow compression rings and wider oil control rings, the Hastings or Grant will work. Just different material between the two brands. Langs Snyders and other supplier should have them but check before you order, there are some sizes that have been out of stock for a while. __________________ I know the voices aren't real but damn they have some good ideas!