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mcjweller
Samba Member
Joined: October 05, 2022
Posts: 73
Location: Kitchener Ontario Canada
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 Posted: Thu Jul 10, 2025 5:25 pm Post subject: Piston ring land clearance |
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Ok, so AA 90.5 cylinders and pistons. Bently says .003" to .004" piston ring to land clearance. On my AA pistons I have .002" 1st ring, less than .002" 2nd ring. Exactly the same all pistons. I have to say "less than" because I have no way to measure less than .002" as a feeler gauge.
I called AA and enquired, they said their spec is .001" to .002"
That seems tight! Although, all rings can be spun in the groove easily even if dry. And they all fit well for depth, also.
AA says run them...yet I'm paranoid... |
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daveblank
Samba Member
Joined: November 07, 2024
Posts: 131
Location: TX
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| Posted: Thu Jul 10, 2025 6:19 pm Post subject: Re: Piston ring land clearance |
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| mcjweller wrote: |
Ok, so AA 90.5 cylinders and pistons. Bently says .003" to .004" piston ring to land clearance. On my AA pistons I have .002" 1st ring, less than .002" 2nd ring. Exactly the same all pistons. I have to say "less than" because I have no way to measure less than .002" as a feeler gauge.
I called AA and enquired, they said their spec is .001" to .002"
That seems tight! Although, all rings can be spun in the groove easily even if dry. And they all fit well for depth, also.
AA says run them...yet I'm paranoid... |
The Bentley manual is referring to the original cast aluminum pistons that would have came in the car. The AA pistons are cast hypereutectic & they wont expand as much as standard aluminum ones will so the gap doesn't need to be as big.
I'm not the expert & I'm sure someone will come along & Tell me how wrong I am. |
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jim martin
Samba Member
Joined: January 14, 2004
Posts: 341
Location: Vancouver, BC
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| Posted: Thu Jul 10, 2025 8:24 pm Post subject: Re: Piston ring land clearance |
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Your good to go
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modok
Samba Member
Joined: October 30, 2009
Posts: 27662
Location: Colorado Springs
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| Posted: Thu Jul 10, 2025 8:25 pm Post subject: Re: Piston ring land clearance |
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.001-.002 is good
.004" is the wear limit IMO |
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Rob Combs
Samba Member
Joined: December 30, 2020
Posts: 529
Location: South Bay LA, California
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| Posted: Fri Jul 11, 2025 9:07 am Post subject: Re: Piston ring land clearance |
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Do make sure to check them for piston-to-cylinder clearance, then check your ring gaps afterward!
My AA piston to wall clearances were really tight as boxed and needed to be honed. |
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mcjweller
Samba Member
Joined: October 05, 2022
Posts: 73
Location: Kitchener Ontario Canada
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| Posted: Fri Jul 11, 2025 2:44 pm Post subject: Re: Piston ring land clearance |
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Thanks everyone, for the sanity check! Looks like I am good to go on all counts.
Thanks,
Matt |
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