Addicted

I got a PPI recently on a turbo w/ @ 80k miles on it. The leak down test came back
Cylinder #
1 = 20%
2 = 14%
3 = 24%
4 = 4%
5 = 3%
6 = 4%

The guy that did the PPI believes one of two things is going on: 1) that the side of the engine the high cylinders are located on may not have been tuned properly, or maybe not at all, under the last service; or 2) the car needs a new top end rebuild. He is going to pull the cover off and tune the valves on that side and do another leak test. My question is really whether the engine is ok, if the results come back comprable to cylinder 4-6, or is this problematic all the way around? The car checked out good otherwise. Thanks.

mark '87 930

Could that be a timing related issue? The valves maybe properly adjusted.. but if they are not open or closed at the right time..then you have an issue. Does the engine run and sound ok?

Addicted

The owner states that he hasn't noticed anything unusual, and the mechanic said it drove solid. However, the test results were troublesome.

Geoffrey

First, the mechanic should be able to tell you if the 1-2-3 cylinders were leaking through the intake side, exhaust side, or through the crankcase. If the latter, then adjusting the valves and repeating the test is a waste of time and money.

Second, it is unusual to see a complete bank so opposite from the other bank, so it might be internal issues from running too hot on one side or something like that.

nathanUK '81 930 G50

I am wondering if the timing chain has jumped in the past and the valves are slightly bent.

Addicted

I'm not sure, but I will let you two know when the test is completed. I am not paying for the remaining tests. The seller is doing it, b/c he needs to know what he has got. I just don't want to get into a situation where I buy a car that was tweaked at the shop and gets good readings, but it really has serious engine problems. I don't mind buying if it is a situation where there really isn't a serious problem, b/c all else checked out.

DonE

Geoffrey is right - its not difficult to tell where that kind of leak is coming from. Doing a valve adjustment is truly a waste of money. I just rebuilt my motor because cylinders 1-2-3 had poor leakdown, but it really didn't feel like the car was hurting for power. However, when I pulled the motor apart, there was serious damage. You should probably move on to another car.

m42racer

I would recheck the leak down before I jumped to high here for a conclusion. The Valve Lash ma be tight on this side only from poor adjustment. If there wqs a side that was the hardess to do, it would be the 1,2,3 side. Thi is the hottest side of the engine typically as well.

First check to se you have lash. Any will allow the Valves to seat. Then listen to where the leak is coming from. If its from either Intake or Exhaust Valves, have the mechanic tap on the valves with the air connected. There will be a loud pop. Often this dislodges any carbon etc from the seat and gives a better reading. Seems odd its all on one side. If its not a Valve issue, than as its been ststed here already, you may have ring/ Piston/Cylinder issues. What it could be? A number of things.

I wouldn't walk away too soon though. If the car is a nice example and you like it, work a deal with the owner to lower the price and allow you room to repair the engine. Have him pay to open it, you pay for the repair.

DonE

That's a valid point, but wouldn't you be concerned about burned valves then? If they weren't allowed to seat properly, then they could have overheated and now you have a complete valve job. Ouch

YYC930

A valve job is usually $5K +/-.......depends what you can buy the car for......

m42racer

Yes, you could have overheated the Valves. It could be from a number of things. The Valves may have tagged the Piston(s) on that side too from the wrong Cam Timing. The only way to know is to open the engine if the tests do not show the cause and a remedy is unavailable.

Good Luck. Some of the bests cars I have ever owned were bought in this manner. I had the PO pay to have it opened and see the cause. I paid for the repair but the purchase price reflected this. Often the owner has to pay to have this done anyway, so the option to get their $ right away often give you a real good bargining chip.

Good Luck.

DonE

And then there's the "while your in there" syndrome. Suddenly $5k becomes $10k because things needed freshening up and it would be a shame to have the motor out and apart, not to finish it right. Be careful.

YYC930

Isn't that the truth.....LOL !!

turbobrat930

Yea, I am a victim of that.... I will second that statement....