HELP! --- Timing chain issues... 1996 ODBII
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From: Manassas VA
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St. Jude Donor '14
HELP! --- Timing chain issues... 1996 ODBII
Guys.. I'm having issues with my 383 rebuild. The new issue is when SDPC line bored the block for the billet caps the centers were .02 or .2 higher then the outer caps. This caused damage to the crank and bearings. The crank was so tight that it couldn't be spun by hand without loosening the center caps. To fix this issue the engine builder line bored the block to even everything out but now the crank is sitting higher up, closer to the cam which makes the timing chain very loose. He wants to use a cloyes double roller "short" chain to solve this issue but I have to remove the reluctor ring to do this...
anyone know of a "short" stock type timing chain or know of a way to use a cloyes double roller "short" chain and the reluctor ring. I need to keep the ring because of ODBII emissions testing. I've read a few threads and several people have ground down the ring to keep it from hitting the chain. ARe there any other problems if this is done?
anyone know of a "short" stock type timing chain or know of a way to use a cloyes double roller "short" chain and the reluctor ring. I need to keep the ring because of ODBII emissions testing. I've read a few threads and several people have ground down the ring to keep it from hitting the chain. ARe there any other problems if this is done?
Last edited by Bluewasp; Oct 20, 2006 at 04:09 PM.
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
I would think someone would make one because these issues could come up on even a stock rebuild. Have you checked with Cloyes? They actually make the Extreme Duty set and I believe even the standard one for GM.
I'm curious because I'd like to get an LT4 car one of these days. And if I did, I too would be subject to emissions testing on a '96. Are you saying that if the crank sensor is programmed out, it will flunk the test on the state's computer? I guess it stands to reason, I just never thought about it. We have the same thing here in NC on OBDII cars.
I'm curious because I'd like to get an LT4 car one of these days. And if I did, I too would be subject to emissions testing on a '96. Are you saying that if the crank sensor is programmed out, it will flunk the test on the state's computer? I guess it stands to reason, I just never thought about it. We have the same thing here in NC on OBDII cars.
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From: Manassas VA
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St. Jude Donor '14
Originally Posted by Corvette Kid
I would think someone would make one because these issues could come up on even a stock rebuild. Have you checked with Cloyes? They actually make the Extreme Duty set and I believe even the standard one for GM.
I'm curious because I'd like to get an LT4 car one of these days. And if I did, I too would be subject to emissions testing on a '96. Are you saying that if the crank sensor is programmed out, it will flunk the test on the state's computer? I guess it stands to reason, I just never thought about it. We have the same thing here in NC on OBDII cars.
I'm curious because I'd like to get an LT4 car one of these days. And if I did, I too would be subject to emissions testing on a '96. Are you saying that if the crank sensor is programmed out, it will flunk the test on the state's computer? I guess it stands to reason, I just never thought about it. We have the same thing here in NC on OBDII cars.
He asked me to find out what other people are doing when this issue comes up. He has a LT1 short chain double roller setup on the self and wanted to use it but he was unsure how to deal with the reluctor ring. When a LT1 comes in for rebuild they've all been ODBI engines. He doesn't see many ODBII LT1/LT4 engines. He said he could machine the ring but the ring would move foward by .100 of inch and he wasn't sure if the sensor would be able to read the ring if it was .1 foward. He is looking for tried solution..
I did a search and there appears to be two ways to handle the issue.
1. delete the ring and install a 95 pre hub - Program out the CP sensor or go to ODBI
2. machine the reluctor ring so it doesn't hit the double roller chain.
There is a lot of info on this issue on the Camaro forum. Here are some of the links I found:
http://web.camaross.com/forums/showt...eluctor+cloyes
http://www.google.com/search?hl=en&l...ble+roller+LT4
http://www.ls1.com/forums/archive/index.php/t-8679.html
http://impalassforum.com/cgi-bin/ult...=1;t=010239;p=
http://forums.ufba.org/index.php?PHP...ic=787.msg5118
http://web.camaross.com/forums/archi.../t-243473.html
http://web.camaross.com/forums/showt...eluctor+cloyes
http://impalassforum.com/cgi-bin/ult...=1;t=010239;p=
http://www.google.com/search?hl=en&l...ble+roller+LT4
http://web.camaross.com/forums/showt...eluctor+cloyes
http://www.cloyes.com/images/CloyesH...rmCat-2002.pdf
http://web.camaross.com/forums/showthread.php?t=135105
As for the emessions... In N. VA they just started PCM testing on 1996 and newer ODBII cars. I'm unsure if the State's testing software can detect if the CP sensor is disabled. Since the sensor is there for emissions they could fail me. I would rather not take the chance since the engine is out of the car now.
Last edited by Bluewasp; Oct 20, 2006 at 08:15 PM.
Le Mans Master
Joined: Jul 1999
Posts: 8,683
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From: Phoenix AZ
I'm running the Cloyes double-roller chain without the reluctor ring. I tried running it on the lathe to remove some material, but by the time I was done I didn't trust it to stay together. I can pass the OBDII emissions test with no problems without the ring. Oh, and I am running a shorter chain as well in my engine for similar reasons as you. Just a fore-warning, you may also need to oval some of the holes on the timing cover to slide it up a little so it matches as well. 
Le Mans Master
Joined: Oct 2004
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From: CLT, North Carolina
You have two figures (.02 and .200) in your first post that are 180 thousandths apart, what are these numbers? If they moved the crankshaft either of these distances the block is not usuable now. Have you considered the transmission input shaft alignment with crankshaft centerline which will be another issue to deal with through bellhousing alignment? A good shop can install steel caps without moving the crankshaft more than .001. Did they have trouble installing aftermarket caps with the three center cap parting lines in the block at different heights than the outer cap surfaces? The line boring operation requires a lot of skill to do properly. They should have set the block up in the machine to bore material out of the caps with a "zero" referrence cut in the block to establish round holes about .0015 tight. This leaves a small amount of stock for removal through line honing to finish size. Finish bore diameter size within limits is decided after measuring crankshaft main journal diameter and knowing what oil clearance you are shooting for.
Last edited by Greg Gore; Oct 21, 2006 at 11:48 AM.
Burning Brakes
Joined: Nov 2005
Posts: 848
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From: 1992 LT1 6 speed Cayman Islands
Originally Posted by Greg Gore
You have two figures (.02 and .200) in your first post that are 180 thousandths apart, what are these numbers? If they moved the crankshaft either of these distances the block is not usuable now. Have you considered the transmission input shaft alignment with crankshaft centerline which will be another issue to deal with through bellhousing alignment? A good shop can install steel caps without moving the crankshaft more than .001. Did they have trouble installing aftermarket caps with the three center cap parting lines in the block at different heights than the outer cap surfaces? The line boring operation requires a lot of skill to do properly. They should have set the block up in the machine to bore material out of the caps with a "zero" referrence cut in the block to establish round holes about .0015 tight. This leaves a small amount of stock for removal through line honing to finish size. Finish bore diameter size within limits is decided after measuring crankshaft main journal diameter and knowing what oil clearance you are shooting for.
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
Originally Posted by Greg Gore
You have two figures (.02 and .200) in your first post that are 180 thousandths apart, what are these numbers? If they moved the crankshaft either of these distances the block is not usuable now. Have you considered the transmission input shaft alignment with crankshaft centerline which will be another issue to deal with through bellhousing alignment? A good shop can install steel caps without moving the crankshaft more than .001. Did they have trouble installing aftermarket caps with the three center cap parting lines in the block at different heights than the outer cap surfaces? The line boring operation requires a lot of skill to do properly. They should have set the block up in the machine to bore material out of the caps with a "zero" referrence cut in the block to establish round holes about .0015 tight. This leaves a small amount of stock for removal through line honing to finish size. Finish bore diameter size within limits is decided after measuring crankshaft main journal diameter and knowing what oil clearance you are shooting for.
Time to look for a new block. We have a local machine shop do them for us all the time. We have 2 blocks there now being converted to splayed 4 bolts. If you move the crank up .020 its time to junk the block. Even after line BORING the crank shouldnt move up more than .001 or 2. line boring is specialty shtuff, the shop that does it here isnt even an automotive machine shop.PS The crank sensor is just for misfire counting. It shouldnt be an issue with the emission test, I wouldnt think. If all they're doing is scanning it for emission related codes, the missing reluctor wont set any codes, as long as the sensor itself is plugged in it will pass the comprehensive component monitor. Sent you a PM
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