I have a 1997 850 GLT with 132k on the engine. AsI was passing on the freeway the turbo engaged and the engine began to knock very loudly. Did not seem to loose any power and there was no smoke. I took it to my machanic and he diagnosed it as lifters wore out do to a bad oil pump. he replaced the oil pump and lifters and still the knocking persists. Now he says he was wrong and that when they looked deeper they found the cam scratched and the rods bent. he wants to try to shave the cam to give it more room and said short of a rebuild that he doesn't want to do or putting in another engine, thats the besthe can do. help

 

I miss spoke its the crank shaft that has the scrapes

 

I would do an engine.
He must not really be a good Mechanic that he can't tell the diffrence between lifter and crank noise.

 

I was thinking the same thing. Is the noise coming from the top or the bottom? Does not seem too hard to figure out does it?

 

+1.

Severe knocking/pinging can damage an engine. It was probably due to the turbocharger's over-boosting, ignition timing control malfunction, incorrect octane rating fuel or just inferior fuel, or neglected maintenance.


JPN

 

As for the maintenance I followed owners hand book on fluid changes and regular maint. I use the top octain fuel and dont drive the car hard (commute 100 miles daily). The mechanic may not be a great machanic but sadly he is the best ive been able to find so far. If you can recomend a mechanic in the 92503 area I would greatly appreciate it. The mechanic has shaved the crank and the noise is gone but I am concerned this is not the proper solution. Do I need to rebuild the entire bottom end? Is there a berring that would allow the crank to hit the block if it was bad or would it be bent rods?

 

I see, your car was kept in great shape as far as the servicing goes, in which case something else went wrong, most likely the turbocharger or the electronic ignition control. Or, if it was happening in hot climate, there may have been abnormal combustion in one or more of the cylinders, or the knock sensor didn't do its job.

As to finding a good technician, please note that recommendations from those who don't know much about cars is almost always useless. Since I'm stuck across the Pacific at the moment, I cannot help you find a competent technician in Riverside area, but I would at least look for:

- ASE-Certified Master Technician.
- An independent shop that specialises in Swedish/Euro makes.
- Dealer (you must know your car or they'll make sure to take advantage of you)
- Carefully listens to your description of the problem.

If the engine is running without unusual behaviour, noise, fuel consumption, fluid losses, or exhaust gas, you have nothing to lose and can keep running it until it ceases, then you can either look for another car, or another engine, either used or fully rebuilt.

I apologise that I may have been a bit rude in my 1st reply; nooffense was meant.


JPN

 

Thank you all for the advice, I will put it to use. Selling the car is out of the question since I dont feel comfortable with the engine in its current condition (turned down crank) although it seems to drive fine. Ill use it for my sunday driver since the rest of the car is in great shape or maybe a project for whenI have more time. Thanks again and JPN honesty should never be mistaken for rudeness.

 

The oil pump failed most likely as you stated in the original post.
That inturn burned up the bearings. If something hit the block on the bottom that would be a bent rod.
If it was all bearing damage and minor crank damage there is nothing wrong with having and oversize crank. The bearings would have been bought to match it. As long as it was all done correctly then you will be 100% fine.
Most racing engines have all oversized parts in them.

I hope I didn't sound to rude originally either.
It just makes me so upset to see how People out in the world get treated when it comes to tech's and shops fixing cars.
Anyone can have book Knowledge but being able to fix a car properly the first time and knowing what you are doing only comes from working on them for years and knowing them.

I just get so aggrivated hearing how people get treated.