Rob Edwards

Checking the approximate timing (ie- making sure your belt isn't a whole tooth off) is an easy DIY job. You need to pull the distributor caps and rotors, then the timing belt covers, then you need a 27 mm socket on a breaker bar to turn the engine to -O- on the balancer and see whether the rectangular divot in the front edge of the cam gear lines up with the narrow V-notch in the rear timing belt cover. Like so: (shown on the right side of the engine, the arrows just show the alignment marks for refitting the rotor)


Checking the fine timing is done exactly the same way, but then you need a 32V'r to measure the exact cam timing advance or retard:

http://liftbars.com/indexpk.htm

https://rennlist.com/forums/928-foru...its-great.html

928GTSM

Thanks very much for your reply, I'll need to get to an auto store and buy a 27mm socket as I think the largest I currently have is 23mm. If the cam timing is out it will have been for some time since the cam belt was replaced by a PO. Do you know if it's likely the valves may be damaged as a result of this. Also I'm assuming that if it's less than a tooth out I'd need to slacken the cam gear and adjust it to the reference points you mentioned.
I have the Porsche workshop manuals so presumably the whole procedure will be in these?
Thanks for the links re the tool and tensioner, if the budget allows I'll treat myself.

Hilton

Post on the 928uk mailing list - a few people will likely have the tools and experience to help out with it.

AO

I vote cam timing too for what it's worth.

John Speake

Buy a "deep" 27mm socket to reach through the pulleys to meet the bolt. Only turn the engine clockwise !

The workshop proceedure for adjusting the valve timing is very complicated, requires both cam copvers to be removed, plus a dial gauge etc. Suggest you invest in the 32v'r of Porken, available from Roger Tyson at 928sRus.

928GTSM

Thanks for the replies and advice, it would appear that my tool inventory will be increasing in the near future! John thanks for the heads up re getting a deep socket, I may be able to blag the use of one from Jason.

928GTSM

Does anyone know the answer to my question as to likelyhood of any valve damage if the cam gear is a tooth out? I've got the cam belt cover off but sadly didn't have time to pick up a deep 27mm socket so I'll have to get one tomorrow.
Would a straight forward compression test show up if there's a problem?

Rob Edwards

Nah, 1 tooth off won't hurt valves. That's 7.5 cam degrees off, +/- the keyway adjustment.

If you have the tools to do it you should check compression anyway, so you know how healthy the motor is in general.

928GTSM

Thanks for the quick reply, without spending a fortune is there any particular thing I should look for when buying a compression tester?

SeanR

Don't get a cheap Autozone one. Although, for one time use, it will be ok.

AO

Don't think they have Autozone in the UK.

John Speake

A cheap tester will be OK, you're looking for relative readings, not absolute ones. Remove all spark plugs, fit tester to each cylinder in turn, remove the fuel pump fuse, throttle wide open, crank engine for a few seconds, observe reading.

stuartph

Try this link to a sealey comp tester

http://www.sealeyonline.co.uk/ct951-...on-tester.html

Cheburator

The UK GTS got one engine under warranty because of excessive oil consumption. The second engine was fitted to the car because the Porsche mechanic did not connect the oil cooler to the car and cooked the new engine on start up. I have the 2nd engine off that GTS in my racer now. Porsche drilled 4 out of the 8 possible oil return holes in the pistons of my engine. I made sure that all 8 are drilled now.

Your biggest cost for a rebuilt will be the GTS piston rings which are Porsche only part and come at £500. ECP stocks all the other bits such as bearings/seals and gaskets. That will set you back around £850 and whatever you get charged for labour if you cannot do the work yourself.

928GTSM

Thanks for the advice, Ishall check the cam timing tonight and once I've got the distributor cap et.c back on I'll follow John's procedure and do the compression test.