Gear Timing Repairs...

icanfixall

Official GMM hand model
Joined
Apr 10, 2005
Posts
25,858
Reaction score
673
Location
West coast
Sorry but no pics of this. So as I sit and think about the problems with members removing the injection pump and gear and housing as one piece and then get it out of gear time something came to mind. So the engine is now put back together wrong and it runs horrible cause its out of gear time. So why not bring the crank dampner up to top dead center on the tab. Roitwarrior has a great pic of what that looks like. It the short fat magnetic probe location on the timing tab at the crank. Now remove the small cover that has the drive gear with the three 5/16 bolts in it. The the tiny cover on the aluminum gear cover next to the fan and above the water pump. What you absolutly need to see is one of the bolts directly at the bottom. If its not there then your gear timing is wrong and the pump, gear and aluminim cover must come off. What needs to be done is remove the pump before the gear cover. Then remove the gear and reset it. If when you remove the gear cover you see the "Y" gear timing cover up top then you know one of two things. Either your 180 degrees out of proper top dead center number one or your at top dead center number 4 cylinder. No matter what, that gear must be installed with the one bolt directly striaght up and down for the gear timing to be correct. One the injection pump gear is removed you can look with an inspection mirror and flashlite to see the cam gear "Y" or feel for it with a dental pick. If you can't see of feel it then thats proof your not at number one cylinder top dead center. When the timing tab shows your at top dead center it tuff to know its number one or number four cylinder. Hope this helps some and if anyone wants to tweek this I'm ok with that. Been thinking too long and might have hurt myself a bit....:angel:
 

justinray

Contributor
Joined
Jun 24, 2011
Posts
1,141
Reaction score
2
Location
Cleveland, Tx
Thought about this while I was working... If you try this, it is also possible for you to see the 'odd-bolt-out' to be at top dead center instead of bottom dead center. Since the crank turns once for each cam/IP 1/2 turn.
 

icanfixall

Official GMM hand model
Joined
Apr 10, 2005
Posts
25,858
Reaction score
673
Location
West coast
This is true. The crank is half the size of the cam and injection pump gears. Actually both the cam and injection pump gear have to be the same size. If they weren't the injection pump would get out of crank timing on the first revolution.
 
Top