Cylinder wall thickness vs. Longevity.... Tuesday, 21-Mar-2000 00:17:03 Message: 188.8.131.52 writes: We were doing some clean-up around the shop today & I realised I had had every Mahle Cyl. So I whipped out my mic. & measured cyl. wall thickness.This is at the head end,the results are pretty conclusive to engine or cyl. life,I'll list them from thinnest to thickest. .115 (88mm Slip-in) .120 (92mm) .135 (87mm Slip-in) .140 (94mm) .150 (90.5mm) .165 (85.5mm) .170 (88mm Machine-in) James Lutz
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Re: James I`ve also noticed... ( Mark H) (21-Mar-2000 00:33:28) I've a set of machine in 88's that had over 70K hard miles on them, there was NO steps in cylinders, ball hone/new (soft iron) rings and still in service :-) (n/t) (Steve B) (21-Mar-2000 16:51:37) were these numbers taken at the top of the cylinders? (n/t) (bergboy) (21-Mar-2000 00:37:19) good info Jim (n/t) (John Pagnanelli) (21-Mar-2000 01:15:19) If Cima were to make 92s with the same OD as 94s, then we'd have a wall thickness of .180"! (Bruce Tweddle) (21-Mar-2000 01:52:21) I think that the cut to length century 94's are even thicker (n/t) (max, Der Bahnstormerz) (21-Mar-2000 02:40:04) i just had my thick wall 90.5's (92 o.d.) sent to rimco and sleeved the top of the barrel to 94 o.d. dude thats thick!!! (n/t) (bergboy) (21-Mar-2000 11:47:37) James, do you have any 911 cylinders laying around your shop? (John Plow) (21-Mar-2000 12:25:01) Yes I do John but the 911 style cyl. is WAY different,it dosent extend into the head like a VW Cyl. & it has a replacable seal that fits into a groove cut into the very top,Neat stuff man.I have a set of 97mm Turbo pistons ready for my modified wasser street engine,All I need is 4 more 97mm barrells to do the swap (ouch).I may use bored Type 4 cyls. haven't decided yet,too may projects!! (n/t) (James Lutz) (21-Mar-2000 20:55:24)
That the cylender thickness at the fin area verys quite a bit. Most cylenders get thicker at the top fin and then they get thinner in the mid section of the cylinder and then the thicken up again at the base of the cyl. at the last fin.
These thicknesses don`t always corrispond to the
spigot thickness(the head part) of different cyls. And its weird that the larger 94 cyl. is thicker than the 92. When I use 94s on a driver I have Rimco sleeve them to 96 size. Its too bad that all these cyls. are based on old technoligy.
They could all be built along the same lines as the thick wall 90.5. Of coarse then theres the pistons being super thin compared to the old cimas but thats another story. Cool info.