16V cam timing issue

[JD159]

OK so lets see if we can solve my problem.

Here is the before picture: *Car has had a flywheel lock installed the entire time. Crank has not moved.




Thats the only pic I have of the timing before disassembly. Note that TDC was determined using the cam gear as I couldn't for the life of me find the OT marks. With the head removed, it did appear that the cylinders were at their top most position.

Current picture:




I THINK that the cams look to be in the same orientation. The indicators measure 113mm so thats correct. But something tells me that they need to rotate just a touch in the clockwise direction. So that the first exhaust lobe moves downward and the intake lobe moves upwards. Just a little.

When I put the cam gear on and the timing belt on, when I go to remove the 3 temporary retaining bolts from the gear, one of them becomes too difficult to remove because the gear is being forced clockwise. That can't be right, as I wouldn't be able to attach the rotor. When its in the TDC position, the cam gear is moved as far clockwise it will go when attached to the cam. I can however move it about 2 teeth counter-clockwise.



One more thing to keep in mind is that my mechanic said that he runs my car SLIGHTLY advanced to give me a bit more bottom end. Not sure how this would effect the cam gear. Any questions or more information needed just let me know! I'll be calling my mechanic tomorrow and send him the pics. If I can't get it figured out at home I'll end up trailering it to him to do but I think I'm pretty close.

[Panzer909]

You're current pic looks fine as far as the cam timing goes but that's only half of it. When you removed the bolts per what you said, the timing is WAY off.

Don't let the belts do "slightly" anything. Some might suggest this before you release the auto tensioner but we won't ignite that debate here.

For now, I'd remove the belts again and grab a good light. Theres two ways to determine crank TDC. One (the easier) is to get under the car and look for the flywheel mark. To see this, lay down and crawl under the car feet first. You'll see an open notch at the bottom where the flywheel spins.

The second way is to literally lay on top of the engine bay facing the passenger side and do "the superman". Look directly down the bellhousing past the firewall into a timing opening about 6cm wide. It's only timed prpoerly when you see an "OT" marking. (I'm sure if you google this you'll get a better description). You MUST ensure both top (cam) and bottom (crank) are lined up perfectly. Look into this first.

Oh - and while you're at it - change out the chain tensioner pad(s). Is that an original one!?!?

[JD159]

I'm not quite sure how I would of gotten way off. I only JUST removed the bolts and turned the sprocket left and right just a touch to see what it would do. I watched the position of the plate behind the sprocket and it is in the same position it always was in.

The crank hasn't moved at all the entire time. I just want to re-assemble exactly the way it was before. Keeping the 3 bolts on the cam gear ensured my timing. I didn't remove the bolts, take off the sprocket and mess around with the plate on the back. Its still in the same position
And yes that job was done a longgg time ago. Long as in under 10k miles.

[Panzer909]

Hmm. Did you remove the belt as well? Dumb question: is the flywheel lock still sitting in there? What about finding TDC via the bottom end? Sounds like those bolts were holding tension of their own which isn't supposed to be right.

[JD159]

Yup flywheel lock has always been in. Head was off, cams off, changed belts and waterpump. Bolted head on, cams in with 113mm and both front lobes pointing slightly up, and kept the 3 retaining bolts in the cam gear to hold the position of the plate behind it. All belts, rollers, and WP bolted back up as well.

Now onto those 3 bolts. The pressure is only on one of the bolts, and its only when I have the belt on and the big cam bolt tighten down to 50.

[Panzer909]

Okay. what about bottom end TDC marks?

[JD159]

Again I couldn't find TDC OT marks. I've got Webcam's and a modified head so he ran the car slightly advanced. I couldn't find the OT mark's despite looking for a whileeee lol. When the head was off the pistons looked like the were at TDC.

With the flywheel lock in place, pictures of my previous setup, and the plate behind the sprocket held with the 3 bolts I figured I could just put it right back to the way it was.

[Panzer909]

You must find the marks.

From yours truly years ago. Hope this helps:
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/313976-cant-find-tdc-mark-s.html

[JD159]

Haha when I first started the project I found that page. Looked forever for those marks. Couldn't find the flywheel marks at all. Not sure if every year had it. In step 3 those bolts are inserted to prevent the cam gear from turning. But with a flywheel lock and a timing belt on the cam belt, its not going anywhere when you remove the bolt.

I'm just trying to wrap my head around this its been a long day lol! How would knowing crank TDC help in being able to easily remove the last of the 3 retaining bolts from the cam gear when the cam bolt and belt are applied? Maybe my cams need to move a tooth so that the front lobes are even.

Either way, my mechanic has offered to check everything over and fine tune the timing included in the price i paid for the machine work. To save myself money i figured if i could at least put the cams in properly, wp, belts and intake, he will do the rest if i cant figure it out.