Does This Mean Catastrophic Engine Failure?

[mca]

I am waiting for a 3.0 to be delivered so that I can rebuild it.

I don't know much about the engine except that one cylinder has 100% leakdown and zero compression. The rest of the cylinders have 140-160PSI compression and poor leakdown (no specific numbers).

Is that info enough to assume that the engine suffered a catastrophic failure?

[charleskieffner]

when you find lil itty bits of metal everywhere.................you can safely assume a catastrophic in-flight failure!

[silverc4s]

Pretty close, but not 100%. there are non-catastrophic things that could cause that. let's see how many this board can come up with. I'll go first:
1. carbon chunk stuck to a valve seat, or other non-sealing valve issue

[dtw]

Could be as simple as a bent valve not seating, or even just crud blocking the valve. Pretty much a grab bag. It could be crud, essentially free to repair. It could be a holed piston with shrapnel, which could have gone into the bottom end and destroyed the motor (though the sump screen theoretically prevents that). That's why buying stuff like this is so much fun...ya never know what you're going to get. Pulling the sump screen and/or valve covers is like Christmas morning .

The question is...do you feel lucky?

[Zeke]

Originally Posted by mca

I am waiting for a 3.0 to be delivered so that I can rebuild it.
.................................

I guess it doesn't really matter.

Let us know what you find, maybe you won the lottery.

[Fast Corners]

It could be a burnt valve. They split and do not allow the valve to seat properly. I would ask if the piston was at TDC on the compression stroke during the leak down test but the zero value on the compression test leads me to believe the leakdown figure. What ever the problem is it has to be really significant to give a 100% leakdown. When the leak down was performed where was the compressed air escaping to? Were the crank case breather, intake and exhast examined during the test of the cylinder in question? Checking these will narrow down the list of possible problems. Additionally, you may want to perform a "wet" compression test. By squirting oil into the cylinder and performing the test, you can get a better determination of what condition the rings are in.

[JeremyD]

Originally Posted by mca

Is that info enough to assume that the engine suffered a catastrophic failure?

I associate catastrophic failure with something sticking out the engine block and a big pool of oil under it.

[dtw]

Originally Posted by JeremyD

I associate catastrophic failure with something sticking out the engine block and a big pool of oil under it.

Even then you can usually still finish your session if you don't get black-flagged . Porsche engines are hard to kill

[EarlyPorsche]

Couldn't you replace the cylinder, piston, and head with some similar mileage units? Or would that not work?

[911pcars]

The leakdown test should indicate the source of air leakage. Unless there's a hole in the piston, I would guess it has something to do with the valves in that cylinder, as others have suggested.

I hope you purchased it for a good price. If the PO isn't telling you more about the leakdown test, it could be worse.

Sherwood

[obrut]

you should have heard the noise this was making when we shut it down.

makes a great desk ornament though - i have a pen in each of the stud holes.

[mca]

Thank guys. Some funny comments so far.

I bought the engine for $2k plus $320 for shipping. I certainly feel that this is a fair price for a complete engine. Here is the eBay link - http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=260215252731.

Yeah, I won't know until I tear it apart ... you guys made me much more optomistic.

[mca]

Originally Posted by Fast Corners

It could be a burnt valve. They split and do not allow the valve to seat properly. I would ask if the piston was at TDC on the compression stroke during the leak down test but the zero value on the compression test leads me to believe the leakdown figure. What ever the problem is it has to be really significant to give a 100% leakdown. When the leak down was performed where was the compressed air escaping to? Were the crank case breather, intake and exhast examined during the test of the cylinder in question? Checking these will narrow down the list of possible problems. Additionally, you may want to perform a "wet" compression test. By squirting oil into the cylinder and performing the test, you can get a better determination of what condition the rings are in.

I won't get answers to any of these questions as I am not really dealing with the PO. Thanks for the insight though.

[euro911sc]

I had 100% leakage. Blew the ring landings off #3. Cyl was fine. Rest of motor was great! Just make sure that your replacement cyl matches the height group for the rest of the cyls. Then it has to match the piston diameter group. Then the piston has to match the weight group of the rest of the pistons. If you need a rod... it has to match the rest as well.

I got caught on the cyl and piston diameter group thing, but lucked out after I measured it all up.

Enjoy the rebuild!

-Michael

[afterburn 549]

Stuck Valve !

[mca]

Remember that the others have POOR LEAKDOWN too. So I imagine that the entire engine needs refreshing ... not just one particular area.

The engine shipped out today. Should be getting it in 3-4 days!

[kodioneill]

sometimes a rocker arm nut can back off causing the adjuster to back out of the rocker.