993 Cam Timing - Stuck between a rock and a hard place..
 

I have a 96 993 engine and of course have the wonderfull "friction-fit" camshafts that Porsche decided to use on these engines. The valve guides need to be done and I have been building out a costing spreadsheet with the parts/tools/labour/machining etc. to get a handle on the cost of the valve job (as an aside holy cr** these engines are expensive!).

Anyways I appear to have two choices regarding the cam timing. I either get the factory tools and do it according to the manuals or change out the sprockets/camshafts and do it the old fashioned way.

The factory tools seem to run about $1200-$1400. I am not sure of the sprockets/camshafts but I bet its close to that.

So this put an additional big chunk of cash that has to be outlayed if its going to be a DYI. In fact, after I factor in all the custom tools and how much time it will take getting a good shop to do it is becoming more attractive all the time, nevermind that the car will only be down a few weeks and will have a warranty. BTW I also factor in reselling some of the tools as well in my sheet.

Will anyone who has backdated the cams/sprockets care to comment on the end cost? Did you replace the chains as well (an additional cost again) given the sprockets are new?

Anyways just griping away while I watch my costing spreadsheet grow and grow...

Cheers,

Mike

When I did mine I changed to new 964 sprockets and new chains.

<pre>1 3.8 RS cams new 900.00 900.00
6 993RS Intake Valves 600.00 600.00
12 993 Phosphorous Bronze Guides 9.00 108.00
2 964 Cam Drive Gear/Spacer/Shim Assys 50.00 100.00
2 Competition Upgrade Timing Chains 50.00 100.00

</pre>

I'm sure prices have chnged considerably

I highly recommend the cam and valve changes "while you are in there"

Excuse my ignorance...

What are the 'Competition Chains'??? Is that a Porsche part? Do they go any faster?

Are the 993RS valves different to the normal ones?

Thank you.

Thanks Bill,

Will the 3.8RS cams work with a 3.6 engine? I certainly do not have the money to upgrade the barrels/pistons to a 3.8. How about emmisions (since we have some of the toughest testing here in Canada)? You also have one Cam, are they $900 each or for both?

Are the RS valves larger? And if so I guess you have to either replace the heads or change the seats on the exising heads.

I have not heard of "Competition" timing chains. The pricing appears to be the same as "normal" chains...

Thanks for your help!

Cheers,

Mike

Those cams will work geat. SHould still get you through aircare without any trouble as well.

Jeff

A s far as I know, I have looked at several cars that purport to have them

Emissions I havn't a clue about, WAG they are ok. That was for the set from WebCam, new billet only available w/ the old style drives.



Yes, by 1.5 mm yes, new seats, valve job and guides were being done anyway. The valves were the expensive apart @ $100/ea.

I was told that there were 2 grades of endless chain, I went w/ the upgrade. I don't believe that they are a normal 993 part, no faster just supposed to be more dureable

Find someone with a mill, buy the correct keyway cutter and cut the key slot. Not a big deal for a good machinist.

Thanks Jeff,

I understand that to take advantage of the RS cam's you should replace both the cams and valves, and to really help update to 3.8 pistons/jugs and other goodies. I can't afford that but doing RS cams/valves might be interesting. I need to price this option out.

I also like the cheaper option of machining the keyway out on the existing camshafts. Anyone know the size of that keyway?

Cheers,

Mike

Talk to John (camgrinder) about the cam and keyway issue, he should have the answer. You could always pick up core set of cams cheap and have them reground. I think I might have access to low price billetts locally as well..... The cams will work with the stock valves but from what I understand those motors really like the bigger valves but I do not have experience with that to back it up. I would probably only do the bigger valves if yours are worn and need replacing and costs are a concern. But if you need valves anyway..... 3.8 P/C are a pricey if you go with Mahle, but are a lot more reasonable if you get a bored cylinder and JE piston from someone like EBS, some just don't like JE, but I have no problem with them, infact a set should be at my door this morning! There has been lots of discussion on pistons (je vs mahle) on this board that makes for some good reading.

If you need any tools or help or ?????? let me know, lots of stuff I have extras of like engine stand etc....

Jeff