OBD2 LT1 w/ double roller timing set?
OBD2 LT1 w/ double roller timing set? Ok, so I've been looking around for information on converting an OBD2 LT1 w/ vented opti over to a double roller setup and ewp. Now, I can't seem to find what exactly the problem is, but have narrowed it down to 2 general ideas:
either:
1) the timing set itself interferes/rubs the crank position sensor (if this is the case, I don't think it'd be worth my time to make it work, and I'd have to just get the GM severe duty LT4 set, which I really don't wanna do)
or,
2) the reluctor wheel will not slide on the crank snout far enough due to interference w/ the double roller timing chain/crank gear. (if this is the case, then couldn't you just put a washer/spacer behind the reluctor for enough clearance with the timing chain, assuming there's room to move it forward without hitting the timing cover or getting out of range of the crank position sensor, and then just machining a little bit off the crank hub to maintain belt alignment?)
Anyone with experience in this area please shed some light on the subject, as I really prefer a double roller setup over the GM heavy duty LT4 set but don't want to give up the crank position sensor or convert to OBD1. Suggestions are also welcome.
Thanks
-Josh
either:
1) the timing set itself interferes/rubs the crank position sensor (if this is the case, I don't think it'd be worth my time to make it work, and I'd have to just get the GM severe duty LT4 set, which I really don't wanna do)
or,
2) the reluctor wheel will not slide on the crank snout far enough due to interference w/ the double roller timing chain/crank gear. (if this is the case, then couldn't you just put a washer/spacer behind the reluctor for enough clearance with the timing chain, assuming there's room to move it forward without hitting the timing cover or getting out of range of the crank position sensor, and then just machining a little bit off the crank hub to maintain belt alignment?)
Anyone with experience in this area please shed some light on the subject, as I really prefer a double roller setup over the GM heavy duty LT4 set but don't want to give up the crank position sensor or convert to OBD1. Suggestions are also welcome.
Thanks
-Josh
Last edited by beast69camaro; Feb 20, 2007 at 05:25 PM. Reason: revised wording
I take it you're not willing to give up the crank position sensor? It's only use is for cylinder misfire detection.
You can eliminate the check from the PCM and just take out the reluctor and call it a day.
You can use the 96/97 timing cover w/o an issue, just leave the CPS in there, it doesn't rub or anything.
You can eliminate the check from the PCM and just take out the reluctor and call it a day.
You can use the 96/97 timing cover w/o an issue, just leave the CPS in there, it doesn't rub or anything.
If you already have an electric water pump, 95+ style opti and 95 or 96-97 cover, then there is no problem with running a double chain.
On the stock cam sprocket, it has a gear in the back that drives the stock water pump. The double roller chain sprocket does not have room for that gear, so you need the switch to an electric pump in order to remove the mechanical drive parts.
On the 93-94 Opti, it was turned by a splined dowel coming out of the cam sprocket. Since the double roller chain sprockets have a larger center opening, there is nothing to turn that splined dowel, which prevents use of the older style opti with a double chain.
On the stock cam sprocket, it has a gear in the back that drives the stock water pump. The double roller chain sprocket does not have room for that gear, so you need the switch to an electric pump in order to remove the mechanical drive parts.
On the 93-94 Opti, it was turned by a splined dowel coming out of the cam sprocket. Since the double roller chain sprockets have a larger center opening, there is nothing to turn that splined dowel, which prevents use of the older style opti with a double chain.
Javier: I didn't know that was the only purpose of the crank position sensor. But no, as I said in the first post I do not want to get rid of the sensor (misfire detection could be very helpful to me during tuning...). It also looks like you answered my interference question.....any interference issues are caused by the reluctor wheel, not the sensor. Thanks!
BaD AZz: Thanks, but I already had all that information....
BaD AZz: Thanks, but I already had all that information....
To reiterate my only unanswered question so far:
Couldn't you just put a washer/spacer behind the reluctor for enough clearance with the timing chain (assuming there's room to move it forward without hitting the timing cover or getting out of range of the crank position sensor) and then just machine a little bit off the end of the crank hub to maintain belt alignment?
Has anyone done this?
Couldn't you just put a washer/spacer behind the reluctor for enough clearance with the timing chain (assuming there's room to move it forward without hitting the timing cover or getting out of range of the crank position sensor) and then just machine a little bit off the end of the crank hub to maintain belt alignment?
Has anyone done this?
Last edited by beast69camaro; Feb 21, 2007 at 05:21 PM. Reason: rewording
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
No... An additional spacer would have the reluctor wheel too far forward. At which point you'd lose the clearance between reluctor wheel and cover. I deleted the codes outta my pcm and called it a day... Misfire detection is not as important to me as a double roller chain is.
so fire67, what you're saying is that there's just not enough room to space the reluctor forward? That sucks....Not even with some clearancing/modification of the timing cover? I've got my mind set on making it work if possible.
Staging Lane
Joined: Oct 2005
Posts: 86
Likes: 0
From: Atlanta, Georgia
Since everyone needs an advocate, I'll be the devils' 
...
Is there a particular reason one would need a double roller timing chain? What has happened with a single chain that a double roller would prevent? I know chains stretch... will a double roller stretch less?
Maybe extreme applications with a solid roller cam and major spring pressure need a double roller? 8000rpm?
I put a double roller on my solid roller 406, but I can't on my '94 LT1, but I'm not sure its a problem.
...Is there a particular reason one would need a double roller timing chain? What has happened with a single chain that a double roller would prevent? I know chains stretch... will a double roller stretch less?
Maybe extreme applications with a solid roller cam and major spring pressure need a double roller? 8000rpm?
I put a double roller on my solid roller 406, but I can't on my '94 LT1, but I'm not sure its a problem.
I have a96 LT1 and i have a cloyes double roller in mine. i took the crank sensor out and bought an OBD1 computer and an electric water pump. the reason i took my crank sensor off was because the reluctor wheel was rubber the double roller timing chain.
Originally Posted by beast69camaro
so fire67, what you're saying is that there's just not enough room to space the reluctor forward? That sucks....Not even with some clearancing/modification of the timing cover? I've got my mind set on making it work if possible.
Beast, on my old build I installed a Pete Jackson silent drive and had to clearance a specific area on the block for the pass side idler shaft (standard stuff on any LT1 year). But since mine was a 97 (vented, CPS, blahblahblah) I had issues with the gear thickness, CPS, Reluctor Ring & Timing Cover. First I had to shave about 1/16" off the crank seal alum shoulder on the inside of the timing cover (just a tad to clear the RelucRing properly). It's just a tiny bit to dremel off and don't go lower than the steel shoulder of the oil seal (left mine installed so I could clearance just enough on the Timing Cover w/o interfering with the seal). Second I located a spacer (around 1/4" thick, forget the exact specs OD/ID, etc) but it spaced the Reluctor Ring perfectly and cleared the TimCov while being functional. I had to put the little square (woodrif key) notch on this spacer to fit the crank. I found it at SEARs Hardware interestingly enough and it was a perfect OD/ID & thickness, but you could always get a bronze one made at a machine shop. Although this was a Gear Drive & not a D-Roller the thickness on the crank is the issue to contend with. I'm just not sure if the D-roller clears the top of the timing cover, Gear Drive had no issues being a simple gear on the cam snout.
My new build has a Cloye's Single Roller that is good for 850+rwhp. I'm currently changing some stuff (non-nitrous) to bump my 500rwhp to my original goal
. Another benefit of the Single is it's less rotating mass (lighter). This would save you a lot of headache. Staging Lane
Joined: Oct 2005
Posts: 86
Likes: 0
From: Atlanta, Georgia
Originally Posted by chree
Is there a particular reason one would need a double roller timing chain?
http://www.z28.com/forum/showthread.php?t=77983 (LT4 timing set, with photos if you log in)
http://impalassforum.com/noncgi/ulti...c;f=1;t=007228
Hmmm... not alot of options for the spline-drive / non-vented opti people (like me... with an MSD Opti about to go in)
...and I can't run a electric water pump. My LT1 is in a daily driver / family car and if an electric pump crapped out in podunk I'm out of luck.
That's why you get a warning relay system for $80 and then you will always know if an E-WP is about to go out on you. If anyone wants info PM me.
Do you really have to do all of that just to get a double roller chain to fit on a 97? That sucks.
Do you really have to do all of that just to get a double roller chain to fit on a 97? That sucks.
