marc a
06-11-2009, 04:38 AM
This is from the other board and I did not want it to disappear . . .
I wanted to do this write up to make sure that those who are in the process of doing conversions and maybe those who do the conversion in the future have the benefit of my issues. I am not including engine issues only those related to the kit and the conversion.
For the most part the conversion has been bulletproof, but I have had two unfortunate issues that relate to the torque tube requiring the replacement of two.
I did a write up in April of '08 when I had to replace the RH clutch and torque tube. The clutch disc was not bad, but the hub had been stripped out because the drive shaft was not far enough forward to engage the entire hub. This caused the end of the drive shaft to be stripped as well.
The position of the drive shaft in the torque tube is set by the factory. At the rear end of the torque tube the drive shaft is notched, as is the main shaft of the transmission, and the two joined by a coupler. The gap between the drive shaft and main shaft from the factory is less than a match book cover wide. I originally installed the clutch and pressure plate on the flywheel of the LS1 without even thinking to check whether the drive shaft was going to be positioned properly into the pilot bearing. This was my first mistake and caused the clutch hub/drive shaft failure mentioned above.
LESSON #1 - Install engine WITHOUT clutch and pressure plate FIRST and then bolt up bell housing with torque tube connected. This way you can see the position of the drive shaft "nose" as it relates to the pilot bearing. If you find the same thing that I did the drive shaft will have to be gently tapped forward (from the rear of the torque tube) until the nose of the drive shaft is fully engaged in the pilot bearing. I had to move my drive shaft about 1/4" forward. Moving the drive shaft forward requires the drive shaft to be "notched" so that the coupler can be installed with the new location of the drive shaft. The drive shaft is not hardened so a drill can be used to make the notch.
At this point connect the transmission to the bell housing, properly tightening the four mounting bolts. Slide the collar onto the drive shaft until the notch in the main shaft is aligned with the rear through hole of the coupler and install the allen head bolt all the way. Now check the position of the drive shaft nose to make sure it is still in the proper location. MAKE SURE THE CAMFER BEHIND THE NOSE DOES NOT TOUCH THE PILOT BEARING.
If all is in order, drill the drive shaft using the coupler as the die. Do not drill too far as you will hit the threads on the top side of the coupler. Once drilled install the allen head and check the nose one more time.
Now remove the transmission and back the torque tube out of the bell housing. Install the clutch and pressure plate and then re-attach the torque tube and transmission.
The other solution is to take the adapter plate to a machine shop and have it milled enough to have the nose of the drive shaft properly engage the pilot bearing. If this is done the transmission mount holes will have to be notched so the transmission can move forward the same distance as the adapter plate is milled.
LESSON #2: - Do not use the needle pilot bearing supplied with the RH kit. There has been much written on this, but now I have unfortunate proof. The simple solution is to take the bushing to a machine shop and have them remove the needle bearing and install the same double sealed ball bearing that Porsche uses on the 944/951/968. The ball bearing cost about 14 bucks.
The unfortunate proof started as a slight vibration (more than normal) through the shifter (shifter is mounted directly on torque tube). Then an occasional squawking sound when the clutch was let out in first. Then finally a major vibration through out the car. The latter is probably when the pilot bearing grenaded. When I removed the torque tube the end was rounded off. There was no sign of the needle bearings anywhere.
LESSON #3: - For track cars a transmission cooler is mandatory. I cooked a "non cooler" 951 transmission last summer. My particular fix is documented in my gallery.
LESSON #4 - Wrap your starter with a heat resistant blanket. Again, this has been mentioned in the past, but after my first starter went bad in fairly short order, the blanket has kept the second one alive already twice as long.
LESSON #5 - Oil pan clearance. Make sure that you grind away enough of the crossmember so that the oil pan does not hit it when the engine torques.
Well that's really all that I have. The first two are the most troubling and hopefully my experiences will prevent someone from having the same problems.
I wanted to do this write up to make sure that those who are in the process of doing conversions and maybe those who do the conversion in the future have the benefit of my issues. I am not including engine issues only those related to the kit and the conversion.
For the most part the conversion has been bulletproof, but I have had two unfortunate issues that relate to the torque tube requiring the replacement of two.
I did a write up in April of '08 when I had to replace the RH clutch and torque tube. The clutch disc was not bad, but the hub had been stripped out because the drive shaft was not far enough forward to engage the entire hub. This caused the end of the drive shaft to be stripped as well.
The position of the drive shaft in the torque tube is set by the factory. At the rear end of the torque tube the drive shaft is notched, as is the main shaft of the transmission, and the two joined by a coupler. The gap between the drive shaft and main shaft from the factory is less than a match book cover wide. I originally installed the clutch and pressure plate on the flywheel of the LS1 without even thinking to check whether the drive shaft was going to be positioned properly into the pilot bearing. This was my first mistake and caused the clutch hub/drive shaft failure mentioned above.
LESSON #1 - Install engine WITHOUT clutch and pressure plate FIRST and then bolt up bell housing with torque tube connected. This way you can see the position of the drive shaft "nose" as it relates to the pilot bearing. If you find the same thing that I did the drive shaft will have to be gently tapped forward (from the rear of the torque tube) until the nose of the drive shaft is fully engaged in the pilot bearing. I had to move my drive shaft about 1/4" forward. Moving the drive shaft forward requires the drive shaft to be "notched" so that the coupler can be installed with the new location of the drive shaft. The drive shaft is not hardened so a drill can be used to make the notch.
At this point connect the transmission to the bell housing, properly tightening the four mounting bolts. Slide the collar onto the drive shaft until the notch in the main shaft is aligned with the rear through hole of the coupler and install the allen head bolt all the way. Now check the position of the drive shaft nose to make sure it is still in the proper location. MAKE SURE THE CAMFER BEHIND THE NOSE DOES NOT TOUCH THE PILOT BEARING.
If all is in order, drill the drive shaft using the coupler as the die. Do not drill too far as you will hit the threads on the top side of the coupler. Once drilled install the allen head and check the nose one more time.
Now remove the transmission and back the torque tube out of the bell housing. Install the clutch and pressure plate and then re-attach the torque tube and transmission.
The other solution is to take the adapter plate to a machine shop and have it milled enough to have the nose of the drive shaft properly engage the pilot bearing. If this is done the transmission mount holes will have to be notched so the transmission can move forward the same distance as the adapter plate is milled.
LESSON #2: - Do not use the needle pilot bearing supplied with the RH kit. There has been much written on this, but now I have unfortunate proof. The simple solution is to take the bushing to a machine shop and have them remove the needle bearing and install the same double sealed ball bearing that Porsche uses on the 944/951/968. The ball bearing cost about 14 bucks.
The unfortunate proof started as a slight vibration (more than normal) through the shifter (shifter is mounted directly on torque tube). Then an occasional squawking sound when the clutch was let out in first. Then finally a major vibration through out the car. The latter is probably when the pilot bearing grenaded. When I removed the torque tube the end was rounded off. There was no sign of the needle bearings anywhere.
LESSON #3: - For track cars a transmission cooler is mandatory. I cooked a "non cooler" 951 transmission last summer. My particular fix is documented in my gallery.
LESSON #4 - Wrap your starter with a heat resistant blanket. Again, this has been mentioned in the past, but after my first starter went bad in fairly short order, the blanket has kept the second one alive already twice as long.
LESSON #5 - Oil pan clearance. Make sure that you grind away enough of the crossmember so that the oil pan does not hit it when the engine torques.
Well that's really all that I have. The first two are the most troubling and hopefully my experiences will prevent someone from having the same problems.