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Rosco_NZ
 
Join Date: Aug 2017
Location: Melbourne, Australia
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Quote:
Originally Posted by targa72e View Post
you can run any 2.2 or 2.4 P&C combo as piston pin is in same location. The difference in stroke was accommodated in the rods. t,e,s, pistons differ in compression ration and clearance in valve pockets. S pistons are forged. 2.2 compression will be stock with 66mm crank. 2.4 with 66MM crank will be about a 1/2 point lower and 2.2 with 70.4mm crank will be about 1/2 point higher. Port size relates more with cam selection. If using E cams you don't need to do anything with ports (T and E were same). Will probably need to rework carbs for new configuration for best power.



john


My ‘72 TE had 29mm inlet ports vs 32 for E I think
Old 04-02-2019, 07:56 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #21 (permalink)
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Richey did you use the 10.5:1 pistons and a 0.5 mm shim to get down to 9.5:1? where you using the standart T head?

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Originally Posted by Richey View Post
From my experience the Wossner pistons were not actually 10.5 to 1 . I think I only needed to add .5 mm of cylinder base shimming to get a ratio of 9.5 to 1 . You must of course do the math . Wossner has the dome volume specs , my 84.5 mm piston was
29.4 cc .
Old 04-03-2019, 07:06 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #22 (permalink)
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I used the 10.5 to 1 pistons and added a .5mm shim . I had S heads but all heads have the same volume . I think the issue will be a ratio of 9.5 to 1 with T cams . The actual CR will be too high .
Old 04-03-2019, 06:31 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)
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Thanks Richey.
for what I understand is that if I use the T heads, E cam, the Wössner 10.5:1 pistons a 0.5 shim
the 85mm S cylinders, E cam. the CR will be 9.5:1, which will make it posible to use single plug. Does it have some side effects to use the 0.5 shim?
Old 04-04-2019, 01:28 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #24 (permalink)
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Yes , this is want I did with no side affects . Every engine is a little different , so take measurements and do the calcs for your application .
Old 04-04-2019, 07:35 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #25 (permalink)
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Thank you very much. It seems to be the simpel solution and not having the pistons machined, to meet the 9.5:1 CR.
Does any have a guide to do the CR calculations?
Old 04-05-2019, 02:01 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #26 (permalink)
 
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Do any of you guys know a good zenith rebuilder?
Old 04-11-2019, 09:06 AM
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Rosco_NZ
 
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He’s using a 66mm crank with 10.5:1 pistons so final CR will be around 10:1 .. add spigot land spacers as required to bring down further. High compression 2.5E should be a sweet engine!
Old 04-13-2019, 01:21 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #28 (permalink)
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Rosco. Do you mean that with the 0.5 shim the 66 crank and the 10.5:1 I will end up with around 10.1:1? And dont know the spigot land spacers, can you elaborate a bit?
Thanks Rasmus QUOTE=Rosco_NZ;10425453]He’s using a 66mm crank with 10.5:1 pistons so final CR will be around 10:1 .. add spigot land spacers as required to bring down further. High compression 2.5E should be a sweet engine![/QUOTE]
Old 04-14-2019, 11:35 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #29 (permalink)
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