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-   -   Timing 360 Degrees Off. What is the quickest way to correct? (http://986forum.com/forums/performance-technical-chat/70106-timing-360-degrees-off-what-quickest-way-correct.html)

martsink 11-19-2017 09:48 PM

Timing 360 Degrees Off. What is the quickest way to correct?
 
Hey Guys,

I need help with the most appropriate and fastest procedure to fix my mistake. I was replacing a bad lifter on bank 4-6, but I set the engine to the wrong TDC (the index cam was pointing outward instead of inward). I only realized when I put it all back together and went to check the timing.

What I was thinking of doing is:

- Remove the 4 bolts on the exhaust cam sprocket (see below) to allow it to rotate 360 degrees
https://i.imgur.com/Qm65MlN.jpg
- Undo the chain tensioner to relieve some pressure from the sproket
- Lock the cam in position with the cam holding tool
- Rotate the engine 360 degrees
- Check the timing (should be correct now)
- replace and torque the 4 bolts on the exhaust cam sproket

Edit: this is a 5 chain engine

Let me know if I'm missing something or if my procedure doesn't make sense.

Thanks!

Jamesp 11-20-2017 02:55 AM

The year of the engine might make a difference, 5 chain versus 3 chain after 2003.

I would not attempt this until one of the more experienced members chimed in. Ok, I would, but I view mechanical disasters on my own stuff as "learning experiences". It might be safer to take to long route by did assembling and reassembling.

martsink 11-20-2017 07:49 AM

Quote:

Originally Posted by Jamesp (Post 555822)
The year of the engine might make a difference, 5 chain versus 3 chain after 2003.

I would not attempt this until one of the more experienced members chimed in. Ok, I would, but I view mechanical disasters on my own stuff as "learning experiences". It might be safer to take to long route by did assembling and reassembling.

Haha I'm on the same page as you. Where's the fun if you don't completely f something up once in a while...

Its a 1999 car, so a 5 chain. I figure its already at TDC, so turning the engine should not cause any damage, granted I hold the exhaust cam locked in position.

Gilles 11-20-2017 01:59 PM

Quote:

Originally Posted by martsink (Post 555841)
Haha I'm on the same page as you. Where's the fun if you don't completely f something up once in a while...

Its a 1999 car, so a 5 chain. I figure its already at TDC, so turning the engine should not cause any damage, granted I hold the exhaust cam locked in position.

Since our engines are "interferience motors" I doubt that you will be able to rotate the crank 360deg without the piston hitting the valves...
Perhaps you may be able to 'walk the cam' while rotating the crank to avoid interferience. (I did it a couple of months ago on the Alfa Romeo because forgot to lock the tensioner and the timing belt
jumped a theeth but was able to set the timing without removing the cams.

JFP in PA 11-20-2017 02:41 PM

The correct way to do this is to remove the cams from both cylinder heads, closing all the valves. Then rotate the engine to true TDC, and start over reallocating the cams.

martsink 11-20-2017 03:06 PM

I thought about this some more and yeah, I guess i have to start over... Thanks for the help!

Gelbster 11-21-2017 07:01 PM

It is very easy to get confused or disoriented doing this. Just follow the entire FSM sequence. If you want a toe-curling example of what a mess you can get into and the color charts + tools + advice to get out of it, hop over to Renntech 986 Forum.
You have to be absolutely sure you get TDC+valve overlap.
This is not a job to re-do ! Access is horrid.
https://www.renntech.org/forums/topic/51555-cranks-but-no-start-misfire/


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