Engine Rebuild Horror Story
02-07-2004, 06:04 AM
#1
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Engine Rebuild Horror Story
Hold on to your seat and read this horror story.
I purchased a ’89 Carerra 3.2l coupe about 1 year ago and love the car and had no problems.
I started having loud valve clacking noise on the right side from cylinder 6. I took it to my mechanic and it appeared to have a bad rocker arm due to being far out of adjustment and it had damaged the cam. He adjusted it down the best he could but another noise was coming from within the case. I had him remove the engine and break it down.
Bad bearing wear on the crank was identified and to make a long story short, I decided to have the engine rebuilt.
I had to have the crank turned and hardened, replace the cam on the right side and the bad rocker arm. All new parts associated with a complete rebuild were installed.
The engine was put back together and my mechanic took it out for a test drive. In less than 1 mile he had to shut it down due to a horrible noise, he thought it came from the right side.
He opened up the valve covers and the rocker arm on cylinder six had broken. The engine turns fine by hand and makes no noise. A possible factory defect in the new rocker was thought to be the cause. After waiting for a week for the new rocker arm, it is finally installed and now the engine won’t turn by hand, it is locking up on no. 6.
He pulls the engine again and removes the cylinder, warning if you have a weak stomach don’t read any further, and the piston is destroyed. It appears that it broke where the wrist pin slides in and the connecting rod kept beating it to death. The inside of the cylinder is scarred and marred and the piston looks like it was attacked by a sledge hammer from below.
Now the questions:
1. What would cause this? The only things I can think of are a mistake was made during the tapping if of the wrist pin or possibly some damage was done to the piston, maybe dropped, during the teardown/rebuild.
2. Now as the rebuild continues, what should I be on the look out for and make sure is done to ensure that I don’t have further problems down the road? I am afraid that once it is rebuilt and I get 10k miles on it, metal particles or something else as a result of this damage will cause further damage.
The mechanic is a solid guy and has over 30 years experience in Porsche engines. He is not willing to state what he thinks happened until he breaks the case. I do believe that he sent some parts out for machine work.
Thanks for reading this long post and I really appreciate any input you are willing to share with me.
Scott
I purchased a ’89 Carerra 3.2l coupe about 1 year ago and love the car and had no problems.
I started having loud valve clacking noise on the right side from cylinder 6. I took it to my mechanic and it appeared to have a bad rocker arm due to being far out of adjustment and it had damaged the cam. He adjusted it down the best he could but another noise was coming from within the case. I had him remove the engine and break it down.
Bad bearing wear on the crank was identified and to make a long story short, I decided to have the engine rebuilt.
I had to have the crank turned and hardened, replace the cam on the right side and the bad rocker arm. All new parts associated with a complete rebuild were installed.
The engine was put back together and my mechanic took it out for a test drive. In less than 1 mile he had to shut it down due to a horrible noise, he thought it came from the right side.
He opened up the valve covers and the rocker arm on cylinder six had broken. The engine turns fine by hand and makes no noise. A possible factory defect in the new rocker was thought to be the cause. After waiting for a week for the new rocker arm, it is finally installed and now the engine won’t turn by hand, it is locking up on no. 6.
He pulls the engine again and removes the cylinder, warning if you have a weak stomach don’t read any further, and the piston is destroyed. It appears that it broke where the wrist pin slides in and the connecting rod kept beating it to death. The inside of the cylinder is scarred and marred and the piston looks like it was attacked by a sledge hammer from below.
Now the questions:
1. What would cause this? The only things I can think of are a mistake was made during the tapping if of the wrist pin or possibly some damage was done to the piston, maybe dropped, during the teardown/rebuild.
2. Now as the rebuild continues, what should I be on the look out for and make sure is done to ensure that I don’t have further problems down the road? I am afraid that once it is rebuilt and I get 10k miles on it, metal particles or something else as a result of this damage will cause further damage.
The mechanic is a solid guy and has over 30 years experience in Porsche engines. He is not willing to state what he thinks happened until he breaks the case. I do believe that he sent some parts out for machine work.
Thanks for reading this long post and I really appreciate any input you are willing to share with me.
Scott
02-07-2004, 12:13 PM
#2
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maybe the circlip that holds the wrist pin in the piston failed or was accidently not fully seated when installed?
or (less likely)
maybe the cam timing was off just enough that when the engine got warm a valve touched a piston, cracking the piston and the resulting damaged piston wigled just enough to hit the valve and do the rocker arm.
or (less likely)
maybe the cam timing was off just enough that when the engine got warm a valve touched a piston, cracking the piston and the resulting damaged piston wigled just enough to hit the valve and do the rocker arm.
02-08-2004, 08:11 AM
#3
Whatever caused the damage when rebuiding I would consider replacing the engine mounted oil cooler as getting all the metal parts out of there will be very difficult due to it's shape.
02-09-2004, 02:42 PM
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Speculating about the cause of an engine failure before examining the pieces is futile. If the engine guy is a 'solid' guy, you shouldn't be out any additional money. He should make the job right. I hope you know what the bill was before he took if for the test ride.
