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modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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 Posted: Thu Jun 01, 2023 11:06 pm Post subject: Re: Piston Pins Too Tight? |
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| tcoop1100 wrote: |
| Just to clear one thing up, though- right now I'm working with brand new AA 83mm 40hp p&c's. The pins are too tight for push fit at room temperature. |
I think that's not right.
Maybe you can send them back or have them honed out.
I'd be curious to try a good quality 22mm pin and see if that slides free.
IMO it's a bad sign when the pins come in sealed baggies instead of arriving in the pistons.
They are skipping a lot of QC by not checking the pin fits in the piston.
Not just the clearance, sometimes the end play of the pin is zero or too much.
KB/silvolite/uem I have NEVER had a problem with any of that, so good job.
Maybe china will figure it out someday. 
But would it work as is? I think it would work ok, if it slides free at 130F. |
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tcoop1100
Samba Member
Joined: August 12, 2004
Posts: 197
Location: Hilo, Moku O Keawe, Moana Pakipika
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| Posted: Fri Jun 02, 2023 1:02 am Post subject: Re: Piston Pins Too Tight? |
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Too late to return them. I suppose I could try to hone the pistons. Iʻve already run them, but the motorʻs apart again to fix other problems. Couldnʻt say what temp theyʻre at but it doesnʻt take long to heat them enough for the pins to slide in- my guess is less than operating temp. 40 horse- 20mm pins, rebuilt rods w/new bushings.
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Aloha,
Tim
January '57 Sedan, April '64 40hp big bore |
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RWK
Samba Member
Joined: June 24, 2009
Posts: 1349
Location: S.W. MI
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| Posted: Fri Jun 02, 2023 5:36 am Post subject: Re: Piston Pins Too Tight? |
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Bently 61-65 manual references using a piston heating tool or heating in oil for piston assembly, "when pin doesn't slip fit into piston" kinda sounds like it's ok either way.
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73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
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VWporscheGT3
Samba Member
Joined: September 01, 2006
Posts: 2076
Location: Gardnerville, NV
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| Posted: Fri Jun 02, 2023 2:53 pm Post subject: Re: Piston Pins Too Tight? |
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| modok wrote: |
| tcoop1100 wrote: |
| Just to clear one thing up, though- right now I'm working with brand new AA 83mm 40hp p&c's. The pins are too tight for push fit at room temperature. |
I think that's not right.
Maybe you can send them back or have them honed out.
I'd be curious to try a good quality 22mm pin and see if that slides free.
IMO it's a bad sign when the pins come in sealed baggies instead of arriving in the pistons.
They are skipping a lot of QC by not checking the pin fits in the piston.
Not just the clearance, sometimes the end play of the pin is zero or too much.
KB/silvolite/uem I have NEVER had a problem with any of that, so good job.
Maybe china will figure it out someday.
But would it work as is? I think it would work ok, if it slides free at 130F. |
The owners pet projects is pin bore. we have spent a lot of time and effort into making our pin bores perfect with our new honing machines so I glad you appreciate them Modoc.
Tcoop I would definately have the pin bores honed, maybe your local machine shop has the correct mandrel for their old sunnen... worth a shot
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Schnell, SCHNELL!
I like being wrong, Because, it is another opportunity to learn. If you stop learning from your mistakes than what is the point?
If you have any questions about Forged ICON 4032 VW pistons just shoot me a line. |
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