Double Roller Timing Chain
Thread Starter
Instructor
Joined: Feb 2006
Posts: 240
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From: Allentown PA
Double Roller Timing Chain
1981 Corvette..All my pulleys for belts (power steering pump,alternator,air cond.) seem off by about 1/4 inch since I installed a new cam and double roller timing chain. The crank gear and harmonic balancer have been checked and after many measurements they seem to be properly installed. Is my problem due to the new double roller timing chain being slightly thicker than the stock one? Am I going to have to figure out how to space my accessories to match up with the new crank gear width now? Any one ever had this happen? Any suggestions?
Last edited by OldCorvetteKid; May 14, 2006 at 01:10 AM. Reason: had to put in year of car
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Timing chain should not have affected any belt/pulley alignment. I would think you left out/ misinstalled a bracket in there somewhere. If the harmonic ballancer is in there correctly everything should line up
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
I put a double roller timing chain on my 81 rebuild...had no alignment problem.
However, make sure the balancer is fully seated.
Also the pulleys can go on backwards without any problem...don't ask me how I know this.
The power steering pulley will be off by a slight angle...not much but is not going to be a straight 180 degrees alignment.
If you need pictures....just let me know.
LannyL81
However, make sure the balancer is fully seated.
Also the pulleys can go on backwards without any problem...don't ask me how I know this.
The power steering pulley will be off by a slight angle...not much but is not going to be a straight 180 degrees alignment.
If you need pictures....just let me know.
LannyL81
Thread Starter
Instructor
Joined: Feb 2006
Posts: 240
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From: Allentown PA
LannyL81-mine is only off alignment by about 3/16-1/4 inch. I ran a straight edge down the flat surfaces of the timing gears for the cam and crank and they lineup perfectly...then measured the snout of the crank and deducted the width of the balancer snout and came up with 15/16, installed the balancer and measured how far in the crank snout was in the balancer...its 15/16...so I know the balancer is fully up against the crank gear....but now I have the alignment problem...I haven't installed the a/c pulley or the alternator or water pump...I figure they are going to be misaligned too....were the rest of your pulleys aligned or were they off too?
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
If you do not have the water pump or AC or alternator on....what are you saying is not aligned with the crank pulley?
Only my power steering pump pulley was a bit off angle to the crank pulley. I had a clearance problem with my water pump and timing cover (got a different cover to allow room for the double roller chain) and was going to put a shim between the block and the water pump. But if I did this, then I would have an alignment problem between the water pump pulleys and the crank pulleys. So I had to grind down the water pump housing a bit to get it to fit in front of the timing cover.
Remember the water pump pulleys mount such that they are closer to the block. This is what I could take a picture of if you need one. I first mounted the water pump pullers backwards resulting in an alignment problem.
Good luck and let us know what you find out.
LannyL81
Only my power steering pump pulley was a bit off angle to the crank pulley. I had a clearance problem with my water pump and timing cover (got a different cover to allow room for the double roller chain) and was going to put a shim between the block and the water pump. But if I did this, then I would have an alignment problem between the water pump pulleys and the crank pulleys. So I had to grind down the water pump housing a bit to get it to fit in front of the timing cover.
Remember the water pump pulleys mount such that they are closer to the block. This is what I could take a picture of if you need one. I first mounted the water pump pullers backwards resulting in an alignment problem.
Good luck and let us know what you find out.
LannyL81
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Burning Brakes
Joined: Feb 2002
Posts: 752
Likes: 31
From: Melbourne Australia
Another point of view from experience ....
I replaced the timing chain on my 69 427 and had the same problem....I was 1/10th of an inch out. The answer was that the original crank sprocket was 1/10th of an inch thinner than the double row sprocket and even though the snout of the balancer was fully seated, the balancer sat out by 1/10". This is a big mis-alignment as the inner water pump belt and its pulley are very close the balancer pulley.
I had 1/10" machined off the snout of the balancer to fix the problem.
For you to be sure, you'll need to measure the thickness of the old and new crank sprockets.
Good luck,
Joe
I had 1/10" machined off the snout of the balancer to fix the problem.
For you to be sure, you'll need to measure the thickness of the old and new crank sprockets.
Good luck,
Joe
Thread Starter
Instructor
Joined: Feb 2006
Posts: 240
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From: Allentown PA
I only had the power steering pump mounted so far and it didn't line up, it looked to be 1/4 off...I'm positive the crank gear and the balancer are all the way on...as I've almost ruined the install tool bearing tightening the nut....I talked to a guy named A.C. at the Summit Tech Line...he says its not uncommon to have to take a little off the snout of the balancer because the double timing chains are sometimes a wee bit thicker than the stock ones...so I'm taking it to the machine shop and have them take off .125....he said to be sure I had clearance with the front of the timing cover for the amount needed, which I do...however I'm going to see how the A/C and water pump pulleys line up first....Thanks for the input guys...I'll let you know how it goes....
