GMark1

I have a 1985 928 32v car , it has a small valve in the hollow bolt that screws into the cam chain tensioner that connects the oil feed pipe , newer model 928 cars don't have this valve , I can't blow air threw the valve either way, can I put a later bolt in with no valve

davek9

Hi and Welcome (First Post

The hollow bolts are commonly called "Banjo" bolts and the Fittings on the oil pipes are "Banjo" fittings.
I don't recall a "check" valve in the bolt of that oil line can you please post up a pic?

Anyway, early on '85 / '86 32v the chain tensioners had a tech bulletin, due to inconsistent oil pressure and causing the Tappets to clatter, they changed the flat disk inside to one shaped like a cup (most likely less chance of binding).

As the chain replacement pads are NLA, and due being 30 year old plastic, I'd highly recommend giving 928 International a call and Upgrading yours to S4 chain tensioners w/ new plastic pads.

This is a critical part of the engine and if one fails it will cost thousands of dollars to repair the damage to the valve train.

Dave K

GMark1

Thanks for the info Dave, I couldn't find anything on the tech bulletin from porsche anywhere, I looked up the part # for s-4 tensioners and they where the same part # as the 1985 ones yet I know they are different, , can I use the same chain and just put a new tensioner in , my car was making a rattle and ticking sound in the valve cover passenger side when hot plus running rough , the cam gear teeth have some wear a little sharp feeling I can't tell if the chain is worn, Gregg

davek9

Hi, Yes you can use the same chains, just need:
S4 Tensioners
S4 mounting bolts
S4 Oil Banjo pipes
S4 Banjo Bolts and 8 "new" crush washers

You may need to reform (not bend) one of the pipes a bit to fit under the cam IIRC.
I just ordered the above for a recently acquired '85 I'm refreshing as the Pads were quite warn out.

GMark1

I had an passenger side s-4 tensioner and banjo oil feed pipe I tried and couldn't make the the oil feed pipe fit the 1985 head

Snark Shark

I wonder will the tensioners lack oil on startup after the s3 to s4 tensioner upgrade? Because the s3 appears to lack the check valve that installs in the head. It only has the one installed tensioner itself as far as I can tell. Unfortunately I didn't think about this until I upgraded my driver's side. Still have the cam covers off though.

The s4 pipe fit in mine just fine. Is this a difference from 85 to early 86?

davek9

Nope, the engine started right up and all was quiet in less than 3 seconds (engine was apart for several months).
Many have done this upgrade over the years, I own three with the S4 tensioners, one of them used for DE's at the track, with no issues over the years.

And both oil feed pipes will require reshaping (1-4 more so than 5-8) to adapt the S4 tensioners.

85 and early 86 tensioners are different, all S3 heads are different from S4.
Even the Banjo bolts are different sizes (S4 uses the same size for head and the tensioner).

Rob Edwards

TSB on the S3 chain tensioner issue, for posterity:

davek9

Thanks Rob, that is the TSB I was thinking of, the original part was a "disk" at the top of the spring, the "new spring guide" is a Cup that the spring fits into.

However all this is moot as you can no longer get replacement Pads for the old tensioners, the S4 tensioners have an upgraded piston and spring design and pads are readily available.

At one time I thought of making up some pads for the old S3 tensioners but IMO not worth the risk of experimenting with a failure on such a critical part.

Dave K

Snark Shark

Thanks for the peace of mind. Installing the passenger side later today. Looks like I got lucky and the used tensioners I bought came out of an upgraded S3.

My engine is a bit of a mystery since the entire engine was replaced long before I bought it. I have an 86.5 block number, but I think the heads are older. I had the later S3 tensioner with the spring guide on the driver side.

davek9

Your welcome, the 5-8 head is the easy oil pipe to modify, it is 1-4 that requires a twisting of the Banjo almost 90degs. I did not use any heat just slow and steady and many test fits as you want it to lay flat and not bolt down under tension.

Dave

Snark Shark

Have you been installing them with all 4 crush washers, or just 3? My old S3 tensioners were lacking one where it attaches to the head. I think I read in one of your other posts that this is typical.