|
|
|
|
| Author |
|
|
Registered
Join Date: May 2008
Posts: 48
|
Rocker arm bushes
I'm in the UK and none of the regular Porsche parts shops over here stock replacement bushes for the rocker arms. My engine is a 7R case '72 2.4 that I'm in the process of rebuilding into a 2.8. Although Pelican list a rocker arm bush they cannot advise me what material it is made of. I need bronze - at least, so can any of you good people tell me are there any US companies making a good replacement bush I can order for back home. Thanks Guys.
|
||
01-27-2023, 11:32 AM
|
|
|
Registered
Join Date: Jul 2005
Location: Cleveland, OH
Posts: 1,367
|
Email or call John Dougherty
John@drcamshafts.com 530-672-2286 |
||
|
01-27-2023, 11:43 AM
|
|
|
Rosco_NZ
|
If you order cam and rockers together, they’re often welded up, rebushed and refinished. William Knight or Henry at Supertec can supply parts.
|
||
|
01-27-2023, 07:40 PM
|
|
|
Registered
Join Date: May 2008
Posts: 48
|
It freeks me out a bit to hear that Pelican cannot tell me what their replacement bushes are fabricated from. Has anybody bought a set and inspected them? My 2.4 is going to have some nice stuff in it - 2.8 hi comp barrels and pistons, Wossner rods, ported heads G40 cams but it will only be a street engine so I dont need all the hi-tech components. So if I can avoid paying for a set of new rocker arms and feet this would greatly help my budget. BTW the engine is going in this . . .
|
||
|
01-28-2023, 04:10 AM
|
|
|
Registered
|
At the start of my rebuild I thought this was a simple item to rebuild, so I bought replacement bushings. PN 90110534101
Problem is they are undersized, and require reaming or boring to correct size after installation. Then the face of the rocker must be resurfaced so that it's curved face has the correct curve, correct surface finish RMA value, and its "paralle"l to the centerline of the rocker bore. If it's canted at all the rocker will ride on one edge and wipe out the cam. I went so far as to measure a new rocker arm on a optical comparator, and make a sketch of it, and it's critical dimensions. Buy and restore a valve grinding machine with the plans to use it to rebuild and regrind my rocker arms I could have kept on this path and rebuilt my own rockers, but finally decided it was safer and cheaper to just buy a set already rebuilt. Want a nice rebuilt Kwik-Way vale grinding machine? David Performance EngiNerding  Sometimes even though you know you can do it yourself, it's just not worth the effort or risk. Last edited by reclino; 01-28-2023 at 06:33 AM.. |
||
|
01-28-2023, 06:24 AM
|
|
|
Registered
|
 Raw x y coordinate data from optical comparator  First wack at pencil sketch of rocker face in relation to pivot center. I have another sheet somewhere where I did all the measurements again and then compared the 2.... At this point I was less interested in finding the bottom of this rabbit hole. None of this data is what I consider final measurements to build a fixture from, but just an example of the process one goes through to determine how to make a tool to do a job. I would say plus or minus .001" was the measure tolerance I was hoping for, but the angle the rocker is sitting in the comparator can screw with your numbers if it's not exactly in line..... David Performance EngiNerding Last edited by reclino; 01-28-2023 at 09:27 AM.. |
||
|
01-28-2023, 09:23 AM
|
|
|
|
PCA Member since 1988
|
You won't save money by doing it yourself. Just buy rebuilt ones from a reputable shop that already has all the machinery set up to do it right. Then measure to be sure...
__________________
1973.5 911T with RoW 1980 SC CIS stroked to 3.2, 10:1 Mahle Sport p/c's, TBC exhaust ports, M1 cams, SSI's. RSR bushings & adj spring plates, Koni Sports, 21/26mm T-bars, stock swaybars, 16x7 Fuchs w Michelin Pilot Sport A/S 3+, 205/55-16 at all 4 corners. Cars are for driving. If you want art, get something you can hang on the wall! |
||
|
01-28-2023, 09:56 AM
|
|
|
Registered
Join Date: Mar 2022
Posts: 23
|
Can anyone suggest the best places to buy rebuilt ones, the price of new rockers are terrible.
|
||
|
02-01-2023, 05:55 AM
|
|
|
It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,703
|
I believe most cam grinders like Dougherty, Web, Elgin, etc. can do them. As to Ollies and some Porsche shops like Supertec. I'm sure there are others.
|
||
|
02-01-2023, 07:17 AM
|
|
|
Registered
Join Date: Feb 2019
Posts: 184
|
We sell a lot of these at 911 Vintage parts
Supertec rocker rebuild process: We remove the old bushing and adjuster (if present) Clean adjuster threads with 8x1.0 forming tap. Ream the bushing hole Black Oxide the rocker Press in the new DP4 bushing and burnish Surface the contact pad Coat the contact pad with Moly dry film (TLML 2) Treat the rocker to a Cryogenic conversion process   Supertec Performance 445 Golden Road, Fallbrook, Ca. 92028 Ph (760)728-3062 Fax (760)728-3063 Email supertec1@earthlink.net |
||
|
02-02-2023, 06:36 AM
|
|
|
PCA Member since 1988
|
Dick Elverud, Northwest Machine Products, in Hillsboro, OR does them for a reasonable price. If you are nearby, go visit him. He's one of the oldest guys in the business and a great source of engine building and racing knowledge. 503-502-1609.
__________________
1973.5 911T with RoW 1980 SC CIS stroked to 3.2, 10:1 Mahle Sport p/c's, TBC exhaust ports, M1 cams, SSI's. RSR bushings & adj spring plates, Koni Sports, 21/26mm T-bars, stock swaybars, 16x7 Fuchs w Michelin Pilot Sport A/S 3+, 205/55-16 at all 4 corners. Cars are for driving. If you want art, get something you can hang on the wall! |
||
|
02-03-2023, 11:40 AM
|
|
1986 Porsche 911 turbo
