944S 16V Cam Timing help please

[asudds]

OK, I have the head work done 16 new valves, but now I need to install it to the car. I put on the head (without the cams) and I have 2 dial indicators. I also have a set of factory manuals, however they are a little vague.

It is my understanding that I rotate the crank 45 degrees from TDC#1, install the cams with the cast arrows pointing up (arrows line up to dark links on the cam chain). Bolt in the saddles and the oil pipe. Assemble the new tensioner and done...

NOW.... where do I go from here to time the cams to the crank.

Porsche engineering at it's best...

Thanks for the help,

Aaron
1987 944S 16V
atsudds@cogeco.ca

[dugcat11]

I don't know a thing about it but I believe 'Overkill' on this forum just went through the whole thing and did a running documentary for us .... pics along with questions/answers.

See his posts.

[AFJuvat]

here is what has worked for me:

Install camshafts at TDC #1. Tool 9226 (replaces tool 9448 in workshop manual) is helpful here but not 100% necessary.

Cams are at TDC when the lobes lift off the tappets +1.4mm.

Will check the books again after work..

AFJuvat

[overkill]

Ok, this is serious **** so don't take this lightly. I did not use the dial calipers seeing that I did not have them noe the speacial rail to mount them to the head. I used a dial caliper I had bought from home depot.

Make sure your car is in PERFECT TDC!!! When piston for cylinder #1 hit the top of the cylinder I turned it just a tad more pas that point. You'll notice that the piston has what looks to be some dead movement as the rod closes in on the top of the crank. The idea of TDC is the the rod is perfectly vertical. When the pistons appears to hit the top of the cylinder, turn it just a TAD more to straighten out the rod. This is merely estimation, use your best judgement. When the crank is in TDC, install the chain onto the cams. I think there has to be like 7 links inbetween the cast arrows or 113mm of chain. Install the cams with the cast arrows facing up. The lobes for cylinder #1 should be facing up and towards each other(intake and exhaust). DONT GOUGE THE BEARINGS!!! Evenly tighten the bearing bridges down until they are to torgue spec. Install the cam gear and DO NOT tighten it down. MAke sure your timing belt is ready to go. Now you need a wrench big enough to fit over the hexed portion of the cam. Only turn the cam that gets bolted the the gear. You turn this cam to take any slack out of the chain. Using your dial caliper your going to use the needle portion that sticks out the back. You can messure deepth with this part of the caliper. Before you move the cams your are going to messure the distance between the surface of cylinder #4 intake tappet and top of the intake lobe. touch the tappet with the tip of the needle and ush to body of the caliper until it touches the top of the intake lobe. MAKE SURE YOU MESSURE DOWN THE CENTER OF THE LOBE FOR REASONS OF ACCURACY. Eye ball it to the best of your ability. Once you have a confident value, your are going to zero the guage. Now, turn the cam with the cam gear just a little bit until the cylinder #4 intake lobe pushes the intake tappet down apporx. 1.4mm. Once you have that down 1.4mm, bolt you cam gear in the tdc position, that is with the marking facing towards the marking on the housing. MAKE SURE YOU DO NOT MOVE THE CAMS!!! Once you have the gear bolted down good, check the distance again. If you did not move it, you can install the timing belt. Tension your timing belt and then by had hand crank the engine over. If you feel anything stop and turn back. If you do not feel anything keep going and sett it back to TDC. Messure again with caliper. THEN DO IT AGAIN JUST FOR THE HELL OF IT. If the value stays then your set This method scares some people no names but it worked very well with me so it's up to you. I am here to help you.

[overkill]

How did you do? Did you nail it?

[fletch944t]

There's a section in here on cam timing:

http://www.clarks-garage.com/shop-manual/cam-04.htm

Regards,
Clark