mmasse

Several months ago I replaced the CLutch and RMS on my car '02 996 C4S 3.6ltr engine. At the moment, I also replaced the IMS cover. After a couple of months I saw that the IMS was still leaking, so I decided to disassemble again and install the LN Eng bearing kit.

I just finished the installation and it seems tha I scrw it up!!! The cam timing is off !!!!!!!!!!!!
I did lock the Intermediate shaft, but this time I decided to use the method proposed by Wayne, which involves locking the Intermdiate shaft sprocket using three set screws through the holes of the IMS cover. Not sure what went wrong. Maybe I did not tight them enough, but it seem that one of the cams jumped, because the timing is off.

I started the engine and I immediately got the Check Engine light. I read the codes and I got P300, P301, P302,P303, which means missfire in cyl 1,2 and 3.

Now, my question. Is it possible to adjust the timing on a '02 3.6 996 engine while on the car? If so, can anyone explain the procedure for this?

Thanks in advance

mmasse

anyone...|PLEASE

Jake Raby

Your problem is trying to mix two different methods of camshaft timing..

Did you park the engine at #1 cylinder TDC BEFORE disassembly? if this is not done, the cam timing WILL BE compromised as #1 TDC is the ONLY position where the cams are "off lobe" with no load being exerted on the IMS tube via the drive chains.

This isn't difficult, you just can't mix methods or do things in the wrong order.

If the timing has been compromised you must not run the engine any more and it must be completely re-timed.

mmasse

Hi Jake,

Yes, it is clear to me that I screwed it up. So now my question is, what involves the re-timing procedure for my engine? I found some posts with the procedure for the 5-chain engines, but not for the 3-chain engine. Do you know what involves this procedure and if it can be done with the engine in the car?

Thanks

mmasse

Ok, just checked the timing and the Bank 1 (driver side) is off. The top camshaft is perfectly vertical at TDC, while the lower camshaft is a few degrees off (slightly turned to the left)

Bank 2 seems to be ok, both perfectly vertical at TDC.

The visual check seems to confirm the code I got...Misfire on Cyl 1,2,3

So now ....how do I fix it?????

mmasse

Jake,

What do your think about this procedure suggested by another member of the forum? Would it work for the engine with VarioCam PLus. I figure that a full re-timing would not be necessary, since only the exhaust Banks seems to have jumped and just by a few degrees.

"The relative position of the exhaust cam (lower cam) to the IMS, and there fore the crank is fixed and does not change. It is only the relative position of the intake cam (upper Cam) that changes. So if the bottom cam is not straight up and down (use a straight edge and the joint between the cover and the head to check this) than the timing of that cam is off. I can give you a fairly simple way of adjusting this. To turn the crank take off the serpentine belt and use a socket on the main pulley. The engine rotates clockwise looking from the rear of the car. Try to turn it in that direction if you are going more than a few degrees. First get the engine close to TDC for Bank1. Then rotate the crank until the exhaust cam is straight up and down. Now loosen the 4 bolts on the exhaust cam sprocket (this assumes you have removed the scavenger oil pump to have access to these bolts). Now you can rotate the crank to TDC, this should only be a few degrees, without rotating the cam. Once the crank is at TDC and the cam is still straight up and down re-tighten the bolts on the sprocket ( I tighten two of them, then put some Loctite blue on the other two and tighten them, then remove the first two and put Loctite on them and put them in. The torque for these bolts is in the manual."


I tried to draw how the timing looks at TDC for Bank1 on the image below.

cardsrule

I just checked our printed factory 996 work shop manuals and it does not cover 3.6 timing only 3.4 and GT3....Wish I could help.

I am kinda pissed that it is not in the manuals....

996cab2002

The best and only instructions I found is here:

https://rennlist.com/forums/996-foru...ml#post9069372

post #20 thanks to Porsche52

It's just half of the timing procedure, helpful anyway.

Dharn55

You need to reset the timing so that the slots on the exhaust cam line up as the first step. Then if the intake cam is off follow the manual on setting the vane assembly on the intake cam.