Suggestions with a Disgnosis on a M96.21

[Flying-Al]

Have a good friend that bought a 2002 Boxster S that the guy was considering parting out due to having a known engine issue. We were told it would run, but on the left bank only. Get it home, pull the cam plugs on the right bank and both cams are turning, but 0 compression on the right bank and only about 75 on the left bank. Pulled the oil pan, found about a 1/3 of a shot glass full of brown plastic particles, but no metal that would stick to a magnet.

We intend to pull the engine over memorial day weekend. so just thinking of things to check while its still in the car.

I thought with this engine if it jumped timing, it broke parts. Can it be so far off as to not build any compression, but not have bent valves or punched pistons ?? While turning it over with the starter and the plugs plugs out, it does not make any bad noises. Actually was expecting bad noises, could it be that far off and just (theoretically) need timing chains ?


Thanks in advance. Alan........

[BYprodriver]

[QUOTE=Flying-Al;10462561]Have a good friend that bought a 2002 Boxster S that the guy was considering parting out due to having a known engine issue. We were told it would run, but on the left bank only. Get it home, pull the cam plugs on the right bank and both cams are turning, but 0 compression on the right bank and only about 75 on the left bank. Pulled the oil pan, found about a 1/3 of a shot glass full of brown plastic particles, but no metal that would stick to a magnet.

We intend to pull the engine over memorial day weekend. so just thinking of things to check while its still in the car.

I thought with this engine if it jumped timing, it broke parts. Can it be so far off as to not build any compression, but not have bent valves or punched pistons ?? While turning it over with the starter and the plugs plugs out, it does not make any bad noises. Actually was expecting bad noises, could it be that far off and just (theoretically) need timing chains ?

Thanks in advance. Alan........[/QUOTE

The brown plastic is from the Vario-cam solenoid in the heads. The original design does that. You should install the updated new design ramp pads & chains. Ideally remove the heads & have them rebuilt.

[Flying-Al]

But would that allow to the cam timing to change enough to have no compression, but also appear to have no broken parts.

Working on a boroscope and planning on pulling the engine over Memorial day weekend.

[BYprodriver]

Originally Posted by Flying-Al

But would that allow to the cam timing to change enough to have no compression, but also appear to have no broken parts.

Working on a boroscope and planning on pulling the engine over Memorial day weekend.

Possibly

[Flying-Al]

BYprodriver, You were quite correct. finally got the engine apart and found

A) the bottom Varicam ramp on the right hand bank is missing and you can see where the chain was running across the bottom of the piston for some time. The plastic ramp is entirely gone, and so is the metal backing plate that is under the ramp. When we got the car, he gavce us the name of the shop that had worked on this for years. About 4K miles ago they had an issue and replaced the right hand chain tensioner. I believe the bottom ramp had probably failed then and the (Non Porsche) shop didn't catch it.

B) at some point later some of the debris made it into the scavenge pump which jammed it causing the drive tang to break off.

C) The resulting shock caused the right hand bank to jump a tooth or maybe 2 which was just enough to allow the exhaust valves on the right hand bank to barely touch the pistons bending all 6 Exhaust valves. It seems the left hand did not jump as much or due to the fact the timing was off with so much slack on the R side. Anyway, it only touched the valves on the right hand bank, not the left, and barely left marks on the piston tops without punching the Pistons. But with all exhaust valves open needless to say I had 0 compression R side, and only about 75 PSI on the left side.

So even with a timing failure, this will still be a good block for some Nickies and a few other fun parts....

[Flying-Al]

[Flying-Al]

[BYprodriver]

Originally Posted by Flying-Al

Yeah that's fairly standard on the 2000-2002 models. Looks like you caught it just in time