IP Timing

[ngoma]

We've been needing an IP Timing sticky for some time. Here is my first draft quick'n'dirty, just some links to individual posts that give good info (mostly from v8volvo-- thanks!). Really needs to take the best from each and make a more readable prodecure, but for now, here they are:

http://www.d24t.com/showpost.php?p=6253&postcount=16

http://d24t.com/showpost.php?p=10418&postcount=2

http://d24t.com/showpost.php?p=8451&postcount=6

"First start by taking the pump plug out and re-checking basic timing with the dial indicator again. You are sure you got the zeroing procedure right? I'm not familiar with your method -- it's not the one that I use. My method is to insert dial indicator before setting engine to TDC, then using a 27mm or 1-1/16" socket on the crank dampener bolt, rotate engine while watching dial indicator and go until the needle reaches its lowest point. Set your zero point there. Forget the 2mm setting. Then rotate by hand all the way around until you are approaching #1 TDC. (Your hint for this is by feeling/watching the back if the IP drive pulley, which has a notch in its rear flange. When the notch aligns with the marks at the outside of the IP and bracket, that is roughly #1 TDC, so as the pulley comes around and the notch nears that point, get ready to start watching through the bellhousing hole for the flywheel marks. Make sure you are reading the right flywheel mark as well -- it is not a notch, but a "0" marked into the flexplate, which can be tricky to see especially if there is a little surface rust on the flexplate rim.) As the notch approaches TDC, bring the flywheel slowly around until the 0 aligns with the pointer inside the bellhousing. Once it is there, look at the reading on the dial indicator. Anywhere in the neighborhood of .90-.98 will be a good reading. If you overshoot, you have to either back way, way off (greenbook says 1/4 turn but with an older, slightly sticky IP you need a lot more than that), or, as I do, just go all the way around again, 2 full crank rotations.

If your reading after measuring this way is off, then readjust static IP timing using method of loosening and turning rear cam pulley.

If your reading appears to be on after measuring this way, your next step is to set to #1 TDC and remove the vacuum pump from the cylinder head. This is the quick trick for figuring out whether the cam is at TDC or not without removing the valve cover. If the vacuum pump seems to be coming out under a lot of spring tension, even after you have wound its mounting nuts a significant way off, then you are timed 180 degrees off on the pump. If the vacuum pump is under slight spring tension as you first remove it but after loosening the nuts a bit, it sits loosely on its mounting studs, without tension from the drive rod pushing against it, then you were phased correctly. (The cam lobe that drives the vac pump is bottomed when the cam is at #1 TDC and at full height when the cam is 180 off #1 TDC -- a useful and clever move by the Audi engineers!)

If you find you are timed 180 off, you know what you have to do."

From http://d24t.com/showpost.php?p=5038&postcount=8

http://d24t.com/showpost.php?p=2651&postcount=7

[ngoma]

Again, thanks to v8volvo for this explanation of the preferred method of IP timing:

- ensure cold start device is disengaged and rotate the pump a bit afterwards to let the IP timing parts settle to the "warm" position

- rotate engine until it approaches #1 TDC, using the notch in the IP sprocket as your guide for when you are getting close, but stop before reaching the TDC mark

- using the cam sprocket counterhold tool and the offset wrench, loosen and remove the rear cam sprocket bolt, the sprocket, and the belt

- install the new belt, clean up the mating surface between the rear cam sprocket and the back of the cam to ensure it is dry, apply a light coat of oil to the threads of the rear cam bolt and between the bolt head and washer, and reinstall the rear cam sprocket inside the new belt. Install the bolt until it is finger tight but still allows the sprocket to move freely on the cam.

- bring the engine up to TDC by turning the front of the crankshaft and using the flywheel marker. Make sure you only turn in the direction of engine rotation. If you go past TDC and need to go back, turn the engine back a ways then come back to TDC in the direction of rotation. This is to ensure there's no slack in the drive side of the front timing belt, which would throw your timing setting off.

- install the dial indicator and holder in the IP and zero it. Using the 5199 counterhold tool on the rear cam sprocket, rotate the rear sprockets and belt until the notch on the IP sprocket is on approach for the TDC mark on the IP bracket, and continue to slowly rotate until you reach your desired timing setting plus .02mm or so. Then tighten the rear cam sprocket bolt, ensuring the timing setting and engine position don't move as you tighten it (use the counterhold and wrench together).

- turn the engine two full rotations and confirm your timing setting is correct. If so, finish tightening the rear cam bolt to spec if necessary, remove the dial indicator, reengage the cold start cable, and you're good to go.

Sounds a little complicated to explain but once you have done it this way a couple of times it's quick and painless, much better than wrestling the IP sprocket off, and guarantees correct timing and successful work. Using the method you described would work but is less exact and more difficult, especially if you find you need to make a timing adjustment afterwards. Rotating the IP on its mount to adjust timing is a pain compared to the method given above.

Note -- all of this assumes you are certain before beginning that the cam timing setting is correct, which requires removing the rear cam sprocket (and valve cover) anyway