|
|
|
|
| Author |
|
|
Registered
Join Date: Oct 2005
Location: Mahwah, NJ
Posts: 314
|
Rocker Arm Shaft Question
How much wear is considered acceptable for the rocker arm shafts? I was disassembling my heads last night and was surprised at the amount of scoring that I noticed on my shafts. Is this considered "normal" wear? Thanks in advance.
__________________
Mark 1987 Carrera 2018 GMC Sierra Denali 2500 Duramax 2012 Harley Davidson FLHX Street Glide |
||
02-15-2007, 05:40 PM
|
|
|
Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,123
|
I am thinking anymore then a shadow would be too much
__________________
D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
||
|
02-15-2007, 08:52 PM
|
|
|
Registered
Join Date: Apr 2006
Location: Newcastle, WA
Posts: 966
|
You can measure the outer diameter with a caliper. I recall mine were 18.02 mm, surprisingly all of them were. There are tolerances mentioned in Wayne's book.
__________________
James 1969 911E Slate Grey 1981 911SC Wine Red 1997 911C4S Ocean Blue |
||
|
02-15-2007, 11:13 PM
|
|
|
Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,123
|
I would be concerned for reason for the "wear"
__________________
D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
||
|
02-16-2007, 04:42 AM
|
|
|
Registered
Join Date: Feb 2004
Location: California
Posts: 926
|
I consider more than .0003" unacceptable.
__________________
John Dougherty Dougherty Racing Cams |
||
|
02-16-2007, 02:05 PM
|
|
|
Registered
Join Date: Apr 2006
Location: Newcastle, WA
Posts: 966
|
Wow, 3 10thousandths! My micrometer isn't that good, but no wonder they were all 18.02. Thanks camgrinder.
__________________
James 1969 911E Slate Grey 1981 911SC Wine Red 1997 911C4S Ocean Blue |
||
|
02-16-2007, 02:12 PM
|
|
|
|
Moderator
Join Date: Dec 2001
Posts: 9,569
|
Well, I don't have a spec book for an '87. You should absolutely have one, or the factory workshop manual, to guide you through all mechanical work.
My old book for the '65-68 cars says the specs are: Rocker arm shaft: 17.992-18.000 mm So the difference is 0.008mm, or 0.00031496063" (which is exactly what Camgrinder said, 'cept in "English."  )The rocker shaft bore in the cam housing is listed as 18.000-18.018.
__________________
'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
||
|
02-17-2007, 11:58 AM
|
|
|
Registered
Join Date: May 2003
Posts: 3,346
|
Some scoring seems to be common on the shafts. That doesn't mean they are worn out. You can check with a micrometer. I install them with the scored surface on the "outside" so the smooth surface wears for the second life of the engine. Worn out rocker arm shafts and bushings will be noisy. Not dangerous but annoying.
-Andy
__________________
72 Carrera RS replica, Spec 911 racer |
||
|
02-17-2007, 04:27 PM
|
|
|
Registered
Join Date: Oct 2005
Location: Mahwah, NJ
Posts: 314
|
Thanks for the input. I'll "mic" them tomorrow and see where I am at.
__________________
Mark 1987 Carrera 2018 GMC Sierra Denali 2500 Duramax 2012 Harley Davidson FLHX Street Glide |
||
|
02-17-2007, 06:14 PM
|
|
|
Registered
Join Date: Nov 2000
Location: Dallas
Posts: 3,593
|
Anything wrong with Eagledriver's process? Aren't these under pressure from the "bottom" only?
Thanks
__________________
Buck '88 Coupe, '87 Cab, '88 535i sold, '19 GLC 300 DD Warren Hall, gone but not forgotten |
||
|
04-07-2008, 12:33 PM
|
|
