Problems after cam swap....
Thread Starter
Team Owner
Joined: Nov 2002
Posts: 32,739
Likes: 19
From: Try not to complain so much....
St. Jude Donor '14
Problems after cam swap....
I had a new cam installed a few months ago. Car runs great with one exception, the AC belt keeps coming off. It usually comes off at normal speeds, gets chewed up by the engine and I have to cut it out. The engine builder installed a new one twice.
After the last one (Sunday) I bought a new belt and installed it myself. I cleaned everything, made sure it was free of debris and spent a great deal of time making sure everything is seated correct.
Runs fine, took it for a test drive, and when I got back, it seems both belts are moved over one rib toward the engine. The main belt is over one, and the AC belt seems to be leaning that way.
So my question: to do a cam, lifter, spring mod, you have to remove the crank pulley to get to the cover ? Its almost as if the crank pully is too far forward or all the accessories are too far back. How could the crank be too far foward ?
I want this fixed once and for all if there is a problem with the mod work....
After the last one (Sunday) I bought a new belt and installed it myself. I cleaned everything, made sure it was free of debris and spent a great deal of time making sure everything is seated correct.
Runs fine, took it for a test drive, and when I got back, it seems both belts are moved over one rib toward the engine. The main belt is over one, and the AC belt seems to be leaning that way.
So my question: to do a cam, lifter, spring mod, you have to remove the crank pulley to get to the cover ? Its almost as if the crank pully is too far forward or all the accessories are too far back. How could the crank be too far foward ?
I want this fixed once and for all if there is a problem with the mod work....
Last edited by GTrain; Nov 23, 2005 at 04:17 PM.
Racer
Joined: Jan 2005
Posts: 375
Likes: 0
From: Montreal Drive it like you test it !
Yes. The crank pulley needs to be removed. The nose of the crankshaft should be recessed .094-.176 inches in the balancer bore.
Edit. picture
Edit. picture
Last edited by vette747; Nov 23, 2005 at 04:23 PM.
Thread Starter
Team Owner
Joined: Nov 2002
Posts: 32,739
Likes: 19
From: Try not to complain so much....
St. Jude Donor '14
Originally Posted by vette747
Yes. The crank pulley needs to be removed. The nose of the crankshaft should be recessed .094-.176 inches in the balancer bore.
Thread Starter
Team Owner
Joined: Nov 2002
Posts: 32,739
Likes: 19
From: Try not to complain so much....
St. Jude Donor '14
Originally Posted by vette747
Yes. The crank pulley needs to be removed. The nose of the crankshaft should be recessed .094-.176 inches in the balancer bore.
Edit. picture
Edit. picture
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Team Owner
Joined: Nov 2002
Posts: 32,739
Likes: 19
From: Try not to complain so much....
St. Jude Donor '14
Originally Posted by vette747
If belts are moving 1 rib toward the engine, I would say that that the pulley was not pushed far (close to the engine) enough.
Thanks again...
Drifting
Joined: Jan 2002
Posts: 1,498
Likes: 3
From: Sacramento CA
I think you have a bad crank pully. did you have it replaced with a new one or did you reuse the stock one? My dad's (and a few people's here) actually seperated. The pully part came loose from the dampener and actually started to rub on the timing chain cover. This could be your problem.
Thread Starter
Team Owner
Joined: Nov 2002
Posts: 32,739
Likes: 19
From: Try not to complain so much....
St. Jude Donor '14
Here is a pic of the main belt after the test drive.
When I put it back together, I made sure it was seated on the crank and all places. After a mile, it pulled left.
If you reach in and feel the other small belt on the crank, the last rib in pushed up and heading over the edge. When I left, I also insured this was seated....
When I put it back together, I made sure it was seated on the crank and all places. After a mile, it pulled left.
If you reach in and feel the other small belt on the crank, the last rib in pushed up and heading over the edge. When I left, I also insured this was seated....
Race Director
Joined: Jul 2005
Posts: 11,308
Likes: 1
From: The Beautiful Greater Bay Area California
Originally Posted by Jackal
I think you have a bad crank pully. did you have it replaced with a new one or did you reuse the stock one? My dad's (and a few people's here) actually seperated. The pully part came loose from the dampener and actually started to rub on the timing chain cover. This could be your problem.
That, and, the crank as mentioned above, could be the crux of your dilemma. Good luck to you. Let us know how it all turns out.
Racer
Joined: Jan 2005
Posts: 375
Likes: 0
From: Montreal Drive it like you test it !
Originally Posted by Jackal
I think you have a bad crank pully. did you have it replaced with a new one or did you reuse the stock one? My dad's (and a few people's here) actually seperated. The pully part came loose from the dampener and actually started to rub on the timing chain cover. This could be your problem.
Yes it appends a lot. I got this problem on my C4 too. Most of the time the pulley goes toward the motor when situation occurs. In your case it appears that the pulley is not closed enough to the engine. If you want to check, start the car and see if the pulley wobbles.
Thread Starter
Team Owner
Joined: Nov 2002
Posts: 32,739
Likes: 19
From: Try not to complain so much....
St. Jude Donor '14
Originally Posted by vette747
In your case it appears that the pulley is not closed enough to the engine. If you want to check, start the car and see if the pulley wobbles.
Melting Slicks
Joined: Jan 2002
Posts: 2,096
Likes: 0
From: Size Does Matter CA
IN my case the belt kept coming off, the pulley was not in enough. I took care of that and didn't have any more problems. Eventually my pulley was bad and replaced it. GMdirects is the place to go for a good price. THe GM dealer charges alot more. 
Team Owner
Joined: Nov 1999
Posts: 26,679
Likes: 17
From: This vette goes to 11 Milford MA
St. Jude Donor '03-'05
You have to use a crapload of torque to seat the pulley and the torque to yield bolt is 240 lb ft. I use a big bar on an old torque wrench to get it to seat and then put in the new bolt and torque it down. Check to see if the bolt is loose. Sometimes people re-use that bolt and it backs out.
Thread Starter
Team Owner
Joined: Nov 2002
Posts: 32,739
Likes: 19
From: Try not to complain so much....
St. Jude Donor '14
Originally Posted by Fastguy
You have to use a crapload of torque to seat the pulley and the torque to yield bolt is 240 lb ft. I use a big bar on an old torque wrench to get it to seat and then put in the new bolt and torque it down. Check to see if the bolt is loose. Sometimes people re-use that bolt and it backs out.
