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93 LT1 timing chain /set options
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,674
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From: NEwhere Ohio
93 LT1 timing chain /set options
Ive got my 93 lt1 yanked aprt for a cam change (getting rid of hotcam in favor of a 'blower cam'.).
I want to see what my timing chain options are.
I remember the LT4 uses an 'extreme duty' gear set.
However, I remember its not directly interchangeable and I would need additional parts (raising the costs to do this).
Im not planning on spinning my supercharged stock bottom end past 6000 RPM anyways, so if the costs of a timing chain upgrade are too excessive, Im not going to do it.
However, in the mean time, Id like to know what my options are to 'beef up' the timing chain / gear setup while I have it apart.
heres a pic of the one thats on my 93.
I want to see what my timing chain options are.
I remember the LT4 uses an 'extreme duty' gear set.
However, I remember its not directly interchangeable and I would need additional parts (raising the costs to do this).
Im not planning on spinning my supercharged stock bottom end past 6000 RPM anyways, so if the costs of a timing chain upgrade are too excessive, Im not going to do it.
However, in the mean time, Id like to know what my options are to 'beef up' the timing chain / gear setup while I have it apart.
heres a pic of the one thats on my 93.
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,674
Likes: 751
From: NEwhere Ohio
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,674
Likes: 751
From: NEwhere Ohio
I did some research:
*****This extreme duty timing chain kit is for 1995 and newer model "Gen II" LT1 and LT4 engines. To convert 1993 and 1994 engines, you must use camshaft P/N 10224242, distributor P/N 1104032, timing cover P/N 12552426, vac harness P/N 12554395, and vac fitting P/N 14082470. Included in this kit are the following steel gears: water pump gear, a camshaft sprocket, crankshaft sprocket P/N 14088784, and timing chain P/N 14088783. These parts are not the production replacement components, but this roller chain kit is a great performance upgrade. Use with pin drive camshaft only ****
The issue is some of the parts I need are prob hard to find and/or will make this project extremely expensive.
Like why do I need a new optispark for this? I have my 93 lt1 optispark 'mod'd with a late model vented cap and it works great. I have the base mod'd (i drilled out one of the weep holes) to accept a vacuum input and epoxied the other 2 holes shut. I dont want to replace this expensive part that is working great right now.
Also, What is this camshaft p/n 10224242? Is this just the waterpump drive pin?
Why in the world would I need a new timing chain cover?
I imagine that is really hard to find...
*****This extreme duty timing chain kit is for 1995 and newer model "Gen II" LT1 and LT4 engines. To convert 1993 and 1994 engines, you must use camshaft P/N 10224242, distributor P/N 1104032, timing cover P/N 12552426, vac harness P/N 12554395, and vac fitting P/N 14082470. Included in this kit are the following steel gears: water pump gear, a camshaft sprocket, crankshaft sprocket P/N 14088784, and timing chain P/N 14088783. These parts are not the production replacement components, but this roller chain kit is a great performance upgrade. Use with pin drive camshaft only ****
The issue is some of the parts I need are prob hard to find and/or will make this project extremely expensive.
Like why do I need a new optispark for this? I have my 93 lt1 optispark 'mod'd with a late model vented cap and it works great. I have the base mod'd (i drilled out one of the weep holes) to accept a vacuum input and epoxied the other 2 holes shut. I dont want to replace this expensive part that is working great right now.
Also, What is this camshaft p/n 10224242? Is this just the waterpump drive pin?
Why in the world would I need a new timing chain cover?
I imagine that is really hard to find...
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
Like why do I need a new optispark for this? I have my 93 lt1 optispark 'mod'd with a late model vented cap and it works great. I have the base mod'd (i drilled out one of the weep holes) to accept a vacuum input and epoxied the other 2 holes shut. I dont want to replace this expensive part that is working great right now.
Also, What is this camshaft p/n 10224242? Is this just the waterpump drive pin?
Why in the world would I need a new timing chain cover?
Also, What is this camshaft p/n 10224242? Is this just the waterpump drive pin?
Why in the world would I need a new timing chain cover?
The Gen II opti is driven by the camshaft dowl pin. It is a longer pin than the first gen non vented opti. If you use an aftermarket camshaft with your early opti make sure the dowel pin is cut to fit.
The vented opti uses a different timing cover than the early version.
Instructor
Joined: Jun 2004
Posts: 190
Likes: 0
The center of the extreme duty timing gear doesn't have the splines that drives your early distribuitor. You have to get a later style distribuitor that is driven by the cam dowel. Then you have to get the 95 or 96 timing cover to work with the later style distribuitor.
I just did this exact conversion myself. I was able to find a member in the for sale/wanted section that listed he was selling three 95 timing covers. The listing was old so I sent him a pm to see if he still had them. Turned out he did.
I just did this exact conversion myself. I was able to find a member in the for sale/wanted section that listed he was selling three 95 timing covers. The listing was old so I sent him a pm to see if he still had them. Turned out he did.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
Without converting to a 95-96 timing cover and opti your timing chain options are:
1. Run the stock one. Melling and Lunati sell replacement timing sets.
Will
1. Run the stock one. Melling and Lunati sell replacement timing sets.
Will
Last edited by rklessdriver; Jan 6, 2012 at 05:51 PM.
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,674
Likes: 751
From: NEwhere Ohio
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Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
I've used both of them back in the day (when LT1's were popular to modify) and honestly I don't think so... Melling probally mfgr's both of them (as well as the stock GM's).
I did have a Lunati boxed one break on a 93 Firebird that we did heads/cam on back in the 1995/6ish time frame.... really sucked as I had to replace a few valves after that deal (not to mention eat the labor to pull the heads again on that SOB). Kinda my fault because that car was a 6spd, had (for the time) a pretty big cam (226@.050) and NO2 and the owner really turned it hard on the bottle.
I should have known better than to use that crappy link chain stuff - but honestly the GEN II opti stuff was brand new that year, nothing else was availiable and we flat didn't know any better back then. I want to say Lunati gave us a new chain for our trouble but honestly I don't remember.
I do remember after that failure, I did a lot of research on LT1's and every LT1 that came in the shop for ANY performance work after that got the 95 up GEN II pin drive opti conversion - or we refused to do the work.
I want to say around a year later we figured out that with an elect water pump we could use a real double roller chain and I've never done anything but that since.
Will
I did have a Lunati boxed one break on a 93 Firebird that we did heads/cam on back in the 1995/6ish time frame.... really sucked as I had to replace a few valves after that deal (not to mention eat the labor to pull the heads again on that SOB). Kinda my fault because that car was a 6spd, had (for the time) a pretty big cam (226@.050) and NO2 and the owner really turned it hard on the bottle.
I should have known better than to use that crappy link chain stuff - but honestly the GEN II opti stuff was brand new that year, nothing else was availiable and we flat didn't know any better back then. I want to say Lunati gave us a new chain for our trouble but honestly I don't remember.
I do remember after that failure, I did a lot of research on LT1's and every LT1 that came in the shop for ANY performance work after that got the 95 up GEN II pin drive opti conversion - or we refused to do the work.
I want to say around a year later we figured out that with an elect water pump we could use a real double roller chain and I've never done anything but that since.
Will
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Cloyes makes a stock replacement part number C-3228.
No HD unit however. I would think RPM's and how much you are up in them would determine how long one lasts. Under 6k in my opinion it should be fine for a very long time.
No HD unit however. I would think RPM's and how much you are up in them would determine how long one lasts. Under 6k in my opinion it should be fine for a very long time.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
FWIW, it's not really rpm that breaks timing chains. It's the force the chain experiences due to rapid acceleration of the crankshaft. A good example is what Will mentioned....hitting the engine with a shot of NOx is a heck of a jolt.
Lots of hp will do the same...slam the loud pedal to the floor in 1st gear and it's a shock to the system.
Lots of hp will do the same...slam the loud pedal to the floor in 1st gear and it's a shock to the system.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
FWIW, it's not really rpm that breaks timing chains. It's the force the chain experiences due to rapid acceleration of the crankshaft. A good example is what Will mentioned....hitting the engine with a shot of NOx is a heck of a jolt.
Lots of hp will do the same...slam the loud pedal to the floor in 1st gear and it's a shock to the system.
Lots of hp will do the same...slam the loud pedal to the floor in 1st gear and it's a shock to the system.
