Block align bored alot, now timing chain loose, any options?
03-22-2006, 04:25 PM
#1
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Block align bored alot, now timing chain loose, any options? Motor just came out of machine shop that had a spun main bearing.
The whole thing is now done with good h-beam rods, forged pistons, arp main studs and all the good parts. Picked the shortblock up fully assembled from machine shop.
When I was putting it together (cam,timing chain etc)
I noticed the new rollmaster timing chain was a bit loose. I checked everything out and its from the crank being about 8 thousandths closer to the cam (from the align bore/hone job to fix the spun bearing).
If this was a small block chevy/ford this would be easy, just order a 10 thou' shorter timing chain. Is this possible for an LS1 car? does anyone know if I can order a custom length chain or somehow get a 10 thou shorter chain.
I am a little concerned about the timing chain slack.
Any suggestions would be appreciated.
The whole thing is now done with good h-beam rods, forged pistons, arp main studs and all the good parts. Picked the shortblock up fully assembled from machine shop.
When I was putting it together (cam,timing chain etc)
I noticed the new rollmaster timing chain was a bit loose. I checked everything out and its from the crank being about 8 thousandths closer to the cam (from the align bore/hone job to fix the spun bearing).
If this was a small block chevy/ford this would be easy, just order a 10 thou' shorter timing chain. Is this possible for an LS1 car? does anyone know if I can order a custom length chain or somehow get a 10 thou shorter chain.
I am a little concerned about the timing chain slack.
Any suggestions would be appreciated.
03-22-2006, 08:02 PM
#2
I dont know, but I bet the guys at katech would know. Since they specialize in billet cap replacement, I'm shure they do a fare share of fixing this problem. Hope you dont mind me sharing a worse situation with you 
but anyhow.... I had the reverse problem. A speedshop in Cali sold me a chain set for a 10thou align bore block only I was unaware of it. Mistaken pn#. Being 18 and rather ignorant, I thought "it goes on tight but it'll stretch" . Oh boy, that motor made it 50 miles before it dropped a valve on I-10 in the fast lane doing 80. What a ride!!! Ah the experience and education that comes with disintegrating engines. 
but anyhow.... I had the reverse problem. A speedshop in Cali sold me a chain set for a 10thou align bore block only I was unaware of it. Mistaken pn#. Being 18 and rather ignorant, I thought "it goes on tight but it'll stretch" . Oh boy, that motor made it 50 miles before it dropped a valve on I-10 in the fast lane doing 80. What a ride!!! Ah the experience and education that comes with disintegrating engines.
03-23-2006, 11:11 AM
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Does anyone make an idler/slack adjuster/rub block to install on the non-pulling side of the chain (right side of engine). If so, that would take care of this issue. The cam phasing needs to be set with the engine turning in its normal direction of rotation (clockwise as viewed from the front).
BTW, I don't know of any aftermarket LS1 chain that is shorter than standard. Call Rollmaster or Cloyes or some company like that.
Steve
BTW, I don't know of any aftermarket LS1 chain that is shorter than standard. Call Rollmaster or Cloyes or some company like that.
Steve
03-23-2006, 01:05 PM
#6
When you have a block line bored it moves the crank deeper into the block or closer to the cam shaft , witch will make the timming chain loose and there is nothing you can do for it, There is machaine shops that can weld up the aluminum main jernal and then just replace the steel main cap with a new one,and then line bore ,to keep the crank at the right depth in the block.
03-23-2006, 05:04 PM
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when your engine was align bored the new bearings should keep the crank centerline and deck height the same. special bearings with a thicker backspacing will fill the void that was bored out, which shouldnt be alot anyway.
your machinist should not have cut deep into the block in the first place, if thats what he did, the main caps should have been milled and honed back to the
proper bore.
if not then you need to find a new machine shop. any respected engine builder should know that timing chain play will end up in valvetrain failure
your machinist should not have cut deep into the block in the first place, if thats what he did, the main caps should have been milled and honed back to the
proper bore.
if not then you need to find a new machine shop. any respected engine builder should know that timing chain play will end up in valvetrain failure
Last edited by ODB; 03-23-2006 at 05:14 PM.
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03-23-2006, 07:05 PM
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When you have a spun main bearing, you cannot avoid the crank moving slightly toward the camshaft. The problem on this block is that the first machine shop screwed up twice on the align hone and I had to take it to another shop to fix the screw ups of the first shop.
The motor is built and done now, so my only option is finding a shorter chain or something to tension. I called Katech today and they recommended calling cloyes and seeing if they can do something custom for me.
The motor is built and done now, so my only option is finding a shorter chain or something to tension. I called Katech today and they recommended calling cloyes and seeing if they can do something custom for me.
