: Helpful hunts for dealing with timing when you have to pull the heads

10-28-10, 12:48 AM
For the benefit of others that will surely pass this way, I am going to offer a few suggestions I found helpful dealing with the timing system. This worked well for me and I offer it as a suggestion BUT do not use it without the factory manual or All Data. This is not exhaustive and you really need the manual as well. Diefinitely turn the engine through at least 2 revolutions of the crankshaft by hand before buttoning everything up and trying to use the starter. If any mistakes were made you could at the least bend a valve otherwise.

1)Remove the balancer and the timing cover.

2) Put the engine at TDC by reinstalling the balancer bolt and turning it clockwise as you look at the balancer until the primary spockets marks are both pointing to each other and the pins on the camshaft sprockets are both vertical to the head on each head. This may take several revolutions. It is really quite easy to do with a 3/8" ratchet with a 6 point 19mm socket if you pull the spark plugs first.

3)Remove one of the center camshaft bearing caps on each of the camshafts and put a long piece of paper about 3/4" wide between the camshaft and the bearing cap and resecure. Make sure it hangs out so you don't forget to remove them. This will lock the cam shafts from moving from their TDC positions making reassembly much easier.

4)Before removing the sprockets or guides, use fingernail polish to mark the sprockets (exhaust and intake on both sides) and the chain so you KNOW you have not reinstalled incorrectly. Then use a tie wrap to secure the chain to the right bank intake sprocket (the exhaust has no holes because of the camshaft sensor ramps on the sprocket) and the left bank (looking from the flywheel end od the engine) exhaust sprocket. You have to remove one of the sprockets anyway on each head from the chain to get the head off. Then using long tie wraps secure the chain between the lower sprocket and the cam sprockets just above the lower sprocket so the chain cannot lose mesh with the sprocket. This will assure the timing is maintained when reassemble if you lock the flywheel at TDC.

5)Remove the chain guides and tensioners on the chains going to the heads only (do not disturb the lower tensioner) per the manual after you removed the sprockets. Don't forget to retract and lock the tensioners (only the upper two, the lower primary chain should not have been disturbed)before reassembling.

6)When reassemble make sure the nailpolish marks line up. Put the sprockets on the chain then install them onto the camshafts. Once the guides, tensioners and sprockets are torqued down pull the pins from the tensioners and make sure they pop out to take up the slack in the chains. I also check to make sure the ratchets engaged by attempting to compress them by hand, they will probably move some but should not collapse completely. I would then turn the crankshaft through 2 full revolutions slowly by hand to make sure all is well before using the starter motor on it.

10-28-10, 03:27 PM
I copied this to the Tech Tips forum. Thanks for the write up.

10-30-10, 07:52 AM
The previous write-up is very complete. I only have a few tips to add from my own experience.
You do not need to remove the balancer. If you remove the front cover bolts, the cover will pull away from the block enough to get at the tensioners. I even replaced one of the guides with the cover just pulled away from the block like this.
With the cover left on, I could not get a tie wrap on the chains down on the lower gear. I used bungee cords to keep the chains tight. It took another person to feed the chains thru the head when removing and installing. One of the chains did slip a few teeth. The beauty of locking the engine at tdc #1 and also locking the cams is that you can readily see if a chain does slip down on the lower gearupon reassembly, and it is very easy to correct. To be sure, I not only turned the engine over by hand a few times, I compared the cranking compression on the front and rear banks to ensure the timing was correct.

10-30-10, 10:07 AM

Good input, I didn't think you could get the bottom middle bolt out of the timing cover with the balancer on, guess I should have looked closer. My engine is a yard engine with 65k on it and my blown engine is has 280k. I am putting the car in the garage today to swap the engine and transmission. My cold compression tests were between 178 and 195 after studding the yard engine. Obviously it was a cold test. What do you think of those values?

If you don't mind me asking, where do you live and how old are you? It sounds like you don't like Devilles (lol), do you fix them and sell them or just like them a lot?

Thanks for the input and you might want to add it to this post in the tech tips forum, it is the first post after the stickys.

11-01-10, 03:21 PM
Yes, I got all the bolts out with the balancer still on, and engine in the car. I seem to recall around 175 psi or so when I checked mine after I did the headgaskets Yours seem in the ballpark......I do like Cadillacs, especially Devilles. Both 2001's are identical, same color, options, etc. My son drives one and I drive one. I just picked up the 2002 for my wife. I am 50, so I guess I'm in the right age group. I also wrench and ride Harleys and built a few custom bikes.