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78 Euro #579 OB Blog

 
Old 07-09-2012, 08:11 AM
  #121  
mikeb7
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Yes, just did the cam seals on the 78 here. All those o-rings were like hard brittle plastic. Would never know they were once rubber.

Watch the big o-ring. Depending on how early the car is, it may be a different size than what 928intl (for example) will send you. If it seems too big going back in, it probably is. The ETM will give you the correct size. I just ordered some from McMaster Carr.
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Old 07-09-2012, 09:26 AM
  #122  
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Originally Posted by mikeb7 View Post
Yes, just did the cam seals on the 78 here. All those o-rings were like hard brittle plastic. Would never know they were once rubber.

Watch the big o-ring. Depending on how early the car is, it may be a different size than what 928intl (for example) will send you. If it seems too big going back in, it probably is. The ETM will give you the correct size. I just ordered some from McMaster Carr.
Thanks for the tip! What is ETM?

This is an early car (#579 RoW, which predate most US 78's). Do you happen to have a McMaster P/N?
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Old 07-09-2012, 07:15 PM
  #123  
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That is good info for us EARLY OB guys!
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Old 07-09-2012, 07:33 PM
  #124  
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ETM- "engineering technical manual"?

The spec book?

http://members.rennlist.com/sharkski...-80-928-TS.htm
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Old 07-10-2012, 08:17 AM
  #125  
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Actually, I mis-spoke. I really meant like a parts microfiche.

I cheat and use a re-seller's site that has all the exploded view parts diagrams.
This is infinitely helpful - http://www.autoatlanta.com/porsche-p..._928_parts.php

If you go to the camshaft page, you'll see item #10 is an o-ring that's either 52x4 or 50x5.
I think the 50x5 is the more common one 928int sent me. My very early car needed the 52x4 I eventually figured out, after going crazy trying to get the cam bearing back in (it will NOT go with the 5mm thick o-ring on there). http://www.autoatlanta.com/porsche-p..._928_parts.php

I've probably got 48 left from the bag of 50 I got from McMaste-Carr if turns out you need them. Or 928int has them if you know you need them when you order.
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Old 07-10-2012, 08:35 AM
  #126  
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Change was done in early part of '79 MY.

Camshaft O-ring thickness has been changed from 4mm (0.160 in.) to 5mm (0.196 in.), as of Engine Numbers:
829 0252 (5speed)
829 5131 (automatic)

Part Numbers
Old Part Number 999 701 425 40
New Part Number 999 701 602 40

0-Ring Replacing
Order new 5mm thick O-ring for replacement.
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Old 07-10-2012, 09:07 AM
  #127  
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Originally Posted by mikeb7 View Post
Actually, I mis-spoke. I really meant like a parts microfiche.

I cheat and use a re-seller's site that has all the exploded view parts diagrams.
This is infinitely helpful - http://www.autoatlanta.com/porsche-p..._928_parts.php

If you go to the camshaft page, you'll see item #10 is an o-ring that's either 52x4 or 50x5.
I think the 50x5 is the more common one 928int sent me. My very early car needed the 52x4 I eventually figured out, after going crazy trying to get the cam bearing back in (it will NOT go with the 5mm thick o-ring on there). http://www.autoatlanta.com/porsche-p..._928_parts.php

I've probably got 48 left from the bag of 50 I got from McMaste-Carr if turns out you need them. Or 928int has them if you know you need them when you order.
Thanks for another source of updated PET parts diagrams. This helps me avoid the hassle of trying to update PET7.2 to Pet 7.3.
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Old 07-10-2012, 11:05 AM
  #128  
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>>0-Ring Replacing
>>Order new 5mm thick O-ring for replacement.

Don't order 5mm thick o-ring if your car had the 4mm. You won't get that cam bearing back in the head.
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Old 07-10-2012, 07:20 PM
  #129  
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Use a bigger hammer?
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Old 07-10-2012, 07:23 PM
  #130  
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Factory says 5mm thick should fit but if its too thick and 4mm will not leak then there is no reason to use it.
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Old 07-11-2012, 07:14 AM
  #131  
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I couldn't get the 5mm to go in. Could not "pound" it in regardless of hammer size, and if it did go in it would have been pinched/damaged on the way.
Tried drawing it in by slowly tightening mount bolts. Cam bearing would hang up a mm or two short of seating with cam bolts torqued to spec. Tried variety of lubes and methods.
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Old 07-11-2012, 09:00 AM
  #132  
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This is great dialogue! First time doing this job, so I'm relatively clueless.

Roger has hooked me up with what appears to be both orings.

999 113 282 40 2 Cam Shaft Seal - Driven - 77-95
999 701 425 40 2 Cam Shaft O Ring 78 to 79 large
999 701 592 40 2 Cam Shaft O Ring 77-86 small

Should be in today. Will report back with my observations.
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Old 07-15-2012, 01:10 PM
  #133  
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Default Update: camshaft seals

The large oring was the easy part. P/N 999 701 425 40 (4mm thick) did the trick there. Went in easy with a touch of silicone, and seated it by lining it up then drawing in the 3 bolts in an even pattern.
Reference point: the original oring was also 4mm thick.

The head-scratcher was the small oring. P/N 999 701 592 40 (23mm X 2mm) was wrong for the job. Should've done my homework to get the right part, P/N 999 701 452 40.
EDIT: Per TSB-03, small oring is 18.4 X2.4mm, see attached TSB. Change occurred for engines s/n from 8280082 (for manual trans), 8289026 (for auto trans)

A couple things to note:
If you don't want to reset your ignition dist., remove it with the cam seal housing. Just make sure to line up the indexing mark with you reassemble (with crank at TDC).

The right side, lower bolt to remove the plastic cover from the cam seal housing is a bugger to get to. I'd suggest installing the plastic cover before pressing back on the seal housing, so you don't have to fiddle with getting the bolt back in.

And don't forget to replace the oil galley seal P/N 928 105 184 00





Attached Images
File Type: pdf
Technical Bulletins - 78-03.pdf (226.2 KB, 106 views)

Last edited by Jadz928; 09-25-2012 at 09:02 AM.
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Old 07-15-2012, 01:30 PM
  #134  
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Default 78 engine harness p/n 928 612 002 00

Another reference point:
Early main engine wire harness p/n 928 612 002 00

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Old 07-16-2012, 02:45 AM
  #135  
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Keep up the great work Jim!!!
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