Aftermarket stereo-caused major issues.
11-21-2010, 10:11 PM
#32
Burning Brakes
Thread Starter
Sounds like you may have learned WHY your GTS was for sale...... The question about the flex plate is because some of the symptoms sound much like the dreaded thrust bearing failure which ruins the engine......It is time to have a mechanic check the crankshaft end play.
Hopefully this wiring problem was the cause of the starting problem.
11-21-2010, 10:45 PM
#34
Burning Brakes
Thread Starter
11-21-2010, 11:16 PM
#35
Rennlist Member
Well, It sounds like you have yourself good car that will be a great car someday soon. Once the bugs are worked out, you will love this car. I have been driving 928's for over 20 years and I have never seen one that didn't have some electrical grimlins when first purchased. I am here in Raleigh and am glad to learn about Brad and Glen.
Best of luck,
Best of luck,
11-21-2010, 11:20 PM
#36
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Checking the flex plate for preload is not the same as checking crankshaft end play......more than one 928 has had the flexplate preload released and then the car gets SOLD while it will still start and run......for a while ! I hope it is not the problem and not very likely but before spending any more money it might be good to KNOW ! Just confirm with the mechanics that they checked the crankshaft end play.
11-21-2010, 11:24 PM
#37
Burning Brakes
Thread Starter
Well, It sounds like you have yourself good car that will be a great car someday soon. Once the bugs are worked out, you will love this car. I have been driving 928's for over 20 years and I have never seen one that didn't have some electrical grimlins when first purchased. I am here in Raleigh and am glad to learn about Brad and Glen.
Best of luck,
Best of luck,
Mr. Bailey; I will be sure to ask him about it...I'm pretty sure that my other mechanic checked it out, but I'm not 100% sure.
11-22-2010, 06:16 AM
#39
Plus +10 on James and Landseer comments.
On reading this post I cannot see what model year or weather Auto or Manual GTS and thrust bearing kept 'looming it head'.
To undertake end play measurement of thrust bearing, the forward flexplated clamp bolt need to be released and the crank shaft need to be moved forward and aft until it bumps/stops with a clunk. The best way to do this is with a dial indicator measuring the movement backwards and forward by moveing the crankshaft with a small pry bar on the flywheel ring gear. Measure the distance in mm or thousands of inches to see whether it is within specifications tolerance limits.
Specifications for clearances on a new thrust bearing are:
0.110 to 0.312mm with max clearance of 0.40mm
If the bump clearance of the thrust bearing is within limits, before tightening the forward flexplate clamp, check that the rear flexplate clamp is tightened up to specified torque plus 10%. This clamp has a recess in the drive shaft that the clamp bolt passes though, so there should be no migration of the after flexplate clamp, however the clamp bolt has been known to come loose.
If the bump clearance is outside the maximum limit do not run the engine until the thrust bearing has been investigated and whether the crankcase bearing pocket sides in way of the web has been damaged.
If the TB is within limits, always tighten the forward flexplate clamp bolt last and it can he torqued up to 10% in excess of the specified to try and stop migration of the clamp. Note the drive shaft splines and the clamp splines can wear in way of the movement of the clamp and it get harder to stop migration.
It is suggested that you investigate installing a PKlamp available from Roger at www.928srus.com or fit a Constantine super clamp.
For more information do a search on thrust bearing failures as there is lots of information including numerous photographs to help you.
It is advisable to include in your signature the MY and what gear box is fitted, so the forum members can immediately help you with your problems.
Tails 1990 928S4 Auto
On reading this post I cannot see what model year or weather Auto or Manual GTS and thrust bearing kept 'looming it head'.
To undertake end play measurement of thrust bearing, the forward flexplated clamp bolt need to be released and the crank shaft need to be moved forward and aft until it bumps/stops with a clunk. The best way to do this is with a dial indicator measuring the movement backwards and forward by moveing the crankshaft with a small pry bar on the flywheel ring gear. Measure the distance in mm or thousands of inches to see whether it is within specifications tolerance limits.
Specifications for clearances on a new thrust bearing are:
0.110 to 0.312mm with max clearance of 0.40mm
If the bump clearance of the thrust bearing is within limits, before tightening the forward flexplate clamp, check that the rear flexplate clamp is tightened up to specified torque plus 10%. This clamp has a recess in the drive shaft that the clamp bolt passes though, so there should be no migration of the after flexplate clamp, however the clamp bolt has been known to come loose.
If the bump clearance is outside the maximum limit do not run the engine until the thrust bearing has been investigated and whether the crankcase bearing pocket sides in way of the web has been damaged.
If the TB is within limits, always tighten the forward flexplate clamp bolt last and it can he torqued up to 10% in excess of the specified to try and stop migration of the clamp. Note the drive shaft splines and the clamp splines can wear in way of the movement of the clamp and it get harder to stop migration.
It is suggested that you investigate installing a PKlamp available from Roger at www.928srus.com or fit a Constantine super clamp.
For more information do a search on thrust bearing failures as there is lots of information including numerous photographs to help you.
It is advisable to include in your signature the MY and what gear box is fitted, so the forum members can immediately help you with your problems.
Tails 1990 928S4 Auto
11-22-2010, 07:19 AM
#40
Burning Brakes
Thread Starter
Plus +10 on James and Landseer comments.
On reading this post I cannot see what model year or weather Auto or Manual GTS and thrust bearing kept 'looming it head'.
To undertake end play measurement of thrust bearing, the forward flexplated clamp bolt need to be released and the crank shaft need to be moved forward and aft until it bumps/stops with a clunk. The best way to do this is with a dial indicator measuring the movement backwards and forward by moveing the crankshaft with a small pry bar on the flywheel ring gear. Measure the distance in mm or thousands of inches to see whether it is within specifications tolerance limits.
Specifications for clearances on a new thrust bearing are:
0.110 to 0.312mm with max clearance of 0.40mm
If the bump clearance of the thrust bearing is within limits, before tightening the forward flexplate clamp, check that the rear flexplate clamp is tightened up to specified torque plus 10%. This clamp has a recess in the drive shaft that the clamp bolt passes though, so there should be no migration of the after flexplate clamp, however the clamp bolt has been known to come loose.
If the bump clearance is outside the maximum limit do not run the engine until the thrust bearing has been investigated and whether the crankcase bearing pocket sides in way of the web has been damaged.
If the TB is within limits, always tighten the forward flexplate clamp bolt last and it can he torqued up to 10% in excess of the specified to try and stop migration of the clamp. Note the drive shaft splines and the clamp splines can wear in way of the movement of the clamp and it get harder to stop migration.
It is suggested that you investigate installing a PKlamp available from Roger at www.928srus.com or fit a Constantine super clamp.
For more information do a search on thrust bearing failures as there is lots of information including numerous photographs to help you.
It is advisable to include in your signature the MY and what gear box is fitted, so the forum members can immediately help you with your problems.
Tails 1990 928S4 Auto
On reading this post I cannot see what model year or weather Auto or Manual GTS and thrust bearing kept 'looming it head'.
To undertake end play measurement of thrust bearing, the forward flexplated clamp bolt need to be released and the crank shaft need to be moved forward and aft until it bumps/stops with a clunk. The best way to do this is with a dial indicator measuring the movement backwards and forward by moveing the crankshaft with a small pry bar on the flywheel ring gear. Measure the distance in mm or thousands of inches to see whether it is within specifications tolerance limits.
Specifications for clearances on a new thrust bearing are:
0.110 to 0.312mm with max clearance of 0.40mm
If the bump clearance of the thrust bearing is within limits, before tightening the forward flexplate clamp, check that the rear flexplate clamp is tightened up to specified torque plus 10%. This clamp has a recess in the drive shaft that the clamp bolt passes though, so there should be no migration of the after flexplate clamp, however the clamp bolt has been known to come loose.
If the bump clearance is outside the maximum limit do not run the engine until the thrust bearing has been investigated and whether the crankcase bearing pocket sides in way of the web has been damaged.
If the TB is within limits, always tighten the forward flexplate clamp bolt last and it can he torqued up to 10% in excess of the specified to try and stop migration of the clamp. Note the drive shaft splines and the clamp splines can wear in way of the movement of the clamp and it get harder to stop migration.
It is suggested that you investigate installing a PKlamp available from Roger at www.928srus.com or fit a Constantine super clamp.
For more information do a search on thrust bearing failures as there is lots of information including numerous photographs to help you.
It is advisable to include in your signature the MY and what gear box is fitted, so the forum members can immediately help you with your problems.
Tails 1990 928S4 Auto
Again, I'm quite sure that my mechanic checked it out correctly....I wasn't there when he did it, as I don't know anything about how to work on cars. I will call him today and talk to him just to make sure.
11-22-2010, 07:58 AM
#41
Burning Brakes
Thread Starter
I can now confirm that my mechanic has checked the flex plate with the correct figures, and everything is as it should be. The timing belt was just replaced with a PK tensioner, so I know that nothing is wrong there. Between what the previous owner had done, and what my father and I have had done, the entire car has practically been rebuilt in the past year!
Last edited by Range Rover; 11-22-2010 at 11:20 PM.
11-22-2010, 07:58 PM
#43
+1 on Chris's post #92.
As an engineer the bump clearance measurements are more definative than a statement from your mechanic as you said " I can now confirm that Ray (my more mechanical mechanic) has checked the flex plate with the correct figures, and everything is as it should be". We are not looking at the flexplate we are looking at the crankshaft thrust bearing bump clearance which requires the front flexplate clamp to be loose to get the freedom of movement of the crankshaft to get the correct measurement.
MY of car and whether auto or manual can be of assistance with our help, as if we have to look further to fault find the problem this information will help us to help you.
Tails 1990 928S4 Auto
As an engineer the bump clearance measurements are more definative than a statement from your mechanic as you said " I can now confirm that Ray (my more mechanical mechanic) has checked the flex plate with the correct figures, and everything is as it should be". We are not looking at the flexplate we are looking at the crankshaft thrust bearing bump clearance which requires the front flexplate clamp to be loose to get the freedom of movement of the crankshaft to get the correct measurement.
MY of car and whether auto or manual can be of assistance with our help, as if we have to look further to fault find the problem this information will help us to help you.
Tails 1990 928S4 Auto
11-22-2010, 08:08 PM
#44
Team Owner
Range rover if you click on user CP at the top of the page,
then click on edit signature,
you can add year model and trans type to your signature
then click on edit signature,
you can add year model and trans type to your signature
11-22-2010, 08:13 PM
#45
Burning Brakes
Thread Starter
I really appreciate your help. If you don't mind, I'd like to print off your post, or at least read it to Brad, just to make sure that he could check that for me. Obviously, I'm not a mechanically inclined person...nor is my father (he's a stock broker) so I basically have to go by what my mechanic says. Hopefully the wires were the cause of the problem. Almost the entire wiring system behind the dashboard was frayed and has been replaced.
Again, thank you very much for your help, as I'm sure it will come in handy sometime during my ownership of the car.
-Andrew
Again, thank you very much for your help, as I'm sure it will come in handy sometime during my ownership of the car.
-Andrew