help: timing chain w/ heads,cam
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
help: timing chain w/ heads,cam
Have any of you blown the LT1's timing chain due to too much HP?
If so, circumstances?
I am going to change the cam and re-do the LT1 heads very soon. My heads
guy said I should go to the extreme duty chain. BUT, looking at the parts
listing, this kit requires a 1996 optispark, among other parts.
If I put a new 93 LT1 chain on there, will it blow? I will autocross, drag
race, and in doing so run it up to 6100 rpm tops.
If so, circumstances?
I am going to change the cam and re-do the LT1 heads very soon. My heads
guy said I should go to the extreme duty chain. BUT, looking at the parts
listing, this kit requires a 1996 optispark, among other parts.
If I put a new 93 LT1 chain on there, will it blow? I will autocross, drag
race, and in doing so run it up to 6100 rpm tops.
Le Mans Master
Joined: Sep 2001
Posts: 7,928
Likes: 1
From: More cowbell...
St. Jude Donor '04
Re: help: timing chain w/ heads,cam (sothpaw2)
Sothpaw-
You dont HAVE to change the chain.. but, for any kind of security, you will. There are plenty of people who have done heads and cam, and busted their timing chain.. and trust me, it isnt a pretty situation.
Let me as you this-- how many miles do you have on your chain/opti?? If you have 50k+ miles on your opti, there is a good chance it is going soon anyway.. There are some advantages-
If you go with the double roller, you have even more security. However, with the double roller, you have to replace the water pump, with an electric. The new electric pump is more secure then the mechanical pump.. almost no chance of dripping coolant on your opti. It also doesnt drain HP like the mechanical pump does.
The new Opti is vented, and is much harder to destroy (You can actually sneeze on it, and it will still work..)
My own experience- when doing my mods, I had decided to go to the double roller chain.. When I got down to the old timing chain, you would not believe how loose it was!! Personally, I would get that stock chain off there ASAP.
You dont HAVE to change the chain.. but, for any kind of security, you will. There are plenty of people who have done heads and cam, and busted their timing chain.. and trust me, it isnt a pretty situation.
Let me as you this-- how many miles do you have on your chain/opti?? If you have 50k+ miles on your opti, there is a good chance it is going soon anyway.. There are some advantages-
If you go with the double roller, you have even more security. However, with the double roller, you have to replace the water pump, with an electric. The new electric pump is more secure then the mechanical pump.. almost no chance of dripping coolant on your opti. It also doesnt drain HP like the mechanical pump does.
The new Opti is vented, and is much harder to destroy (You can actually sneeze on it, and it will still work..)
My own experience- when doing my mods, I had decided to go to the double roller chain.. When I got down to the old timing chain, you would not believe how loose it was!! Personally, I would get that stock chain off there ASAP.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Re: help: timing chain w/ heads,cam (MarkLT1)
Mark,
What cam did these guys have, and how old was the chain when it blew?
My delima: I bought this car used, it was 5 yrs old, 42 kmi. Today it's 10yrs
old, 75 kmi. I don't know if the opti. /waterpump is original or not-- that
first owner may have replaced it, it was old enough.
So: why should I replace the opti and water pump if all I need is a brand
new LT1 1993 timing chain? I have a feeling that these guys blew the
chain by using Nos w/the heads cam, or else failed to change to a NEW
timing chain.
What cam did these guys have, and how old was the chain when it blew?
My delima: I bought this car used, it was 5 yrs old, 42 kmi. Today it's 10yrs
old, 75 kmi. I don't know if the opti. /waterpump is original or not-- that
first owner may have replaced it, it was old enough.
So: why should I replace the opti and water pump if all I need is a brand
new LT1 1993 timing chain? I have a feeling that these guys blew the
chain by using Nos w/the heads cam, or else failed to change to a NEW
timing chain.
Le Mans Master
Joined: Sep 2001
Posts: 7,928
Likes: 1
From: More cowbell...
St. Jude Donor '04
Re: help: timing chain w/ heads,cam (sothpaw2)
I know of one fellow, that blew his after about 5k miles, with a brand new chain, just doing a hotcam, and heads package..
The stock chain is about as hefty as a bicycle chain..
Edit- the problem is, most larger cams let you make more power, at a higher RPM.. For example, my setup makes peak HP between 4000-6500 rpms.. as ooposed to the stock cam that makes it between 3000-5500... That 1000rpm difference puts a big load on that timing chain.
[Modified by MarkLT1, 2:01 PM 4/21/2003]
The stock chain is about as hefty as a bicycle chain..
Edit- the problem is, most larger cams let you make more power, at a higher RPM.. For example, my setup makes peak HP between 4000-6500 rpms.. as ooposed to the stock cam that makes it between 3000-5500... That 1000rpm difference puts a big load on that timing chain.
[Modified by MarkLT1, 2:01 PM 4/21/2003]
Drifting
Joined: Feb 2003
Posts: 1,978
Likes: 2
From: San Antonio Texas
Re: help: timing chain w/ heads,cam (sothpaw2)
It's generally a good idea to install a new chain with any cam change, if you have mileage on your old one. I don't know about the chain your mechanic mentioned, I'm not familiar with the LT-1. Seems kinda drastic and expensive, to replace everything mentioned though. Surely someone makes a good chain for these things. JMHO
:chevy
:chevy
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Re: help: timing chain w/ heads,cam (MarkLT1)
Mark,
My cam is 212/224 dur at 050, not quite as radical as a hot cam. But still,
I will be pulling up to 6000 rpm.
What you relate is very disturbing to me, it really sounds like even a new
stock 1993 chain is not going to be enough.
My cam is 212/224 dur at 050, not quite as radical as a hot cam. But still,
I will be pulling up to 6000 rpm.
What you relate is very disturbing to me, it really sounds like even a new
stock 1993 chain is not going to be enough.
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Re: help: timing chain w/ heads,cam (sothpaw2)
My cam is 212/224 dur at 050, not quite as radical as a hot cam.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
timing chain w/ heads,cam (STL94LT1)
94,
I just talked to my heads man again, and what he tells me is that it is the
"on it, off it" acceleration demands of Road Racing or Autocrossing that
will break the chain. He said he was busting chains 12 hr into a 24hr endurance race. It was not an age problem, these were new chains.
Have you taken yours autocrossing? Road racing?
I just talked to my heads man again, and what he tells me is that it is the
"on it, off it" acceleration demands of Road Racing or Autocrossing that
will break the chain. He said he was busting chains 12 hr into a 24hr endurance race. It was not an age problem, these were new chains.
Have you taken yours autocrossing? Road racing?
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Pro
Joined: Jan 2002
Posts: 603
Likes: 0
From: LUFKIN TX
Re: timing chain w/ heads,cam (sothpaw2)
Sothpaw2, when you pull the timing cover off, and look at your timing chain, you will be :eek: ....... I know I was in shock. I only had about 8K miles on my chain also. It had so much slack in it that I could actually twist the cam a little...... Do yourself a favor and spend a little extra now and save yourself a lot later....... Even brand new, the stock chains are looser than I am comfortable with.
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: timing chain w/ heads,cam (DRAGRACR)
Replace the chain with a new one, along with new gears and sprockets. I ran my 396 for the longest time with a stock chain and gears for a '95. Not one problem from it. I went to the double roller for the solid roller that I ditched a while back.
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: timing chain w/ heads,cam (Vette92)
The stock chains are sloppy, even the heavy duty one. They do sell (More Performance I think has them) an oversized gear to eliminate the slack.
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Re: timing chain w/ heads,cam (sothpaw2)
94,
I just talked to my heads man again, and what he tells me is that it is the
"on it, off it" acceleration demands of Road Racing or Autocrossing that
will break the chain. He said he was busting chains 12 hr into a 24hr endurance race. It was not an age problem, these were new chains.
Have you taken yours autocrossing? Road racing?
I just talked to my heads man again, and what he tells me is that it is the
"on it, off it" acceleration demands of Road Racing or Autocrossing that
will break the chain. He said he was busting chains 12 hr into a 24hr endurance race. It was not an age problem, these were new chains.
Have you taken yours autocrossing? Road racing?