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



jimsbox
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 heads 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.