blazing928

firstly its not my car , but at my mechanics business.
The car drove in for a service, the mech went to start it to move into a service bay and it went 'clang'. The crank was seized, no movement!
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edit; I have highlighted the above comment, as some comments below allude to the car having sat for a long time. This car was used every week, i often saw it as he lives in my area. It has been serviced by this mech for just over 10,oookm, and had a fully documented main dealer service history.
So please no more comments about the mech should've done this and that before. , thanks
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The initial thought was a dropped valve seat, but it was all a guess until the head [RH] was removed and this was found.

Its a good condition car, full service history, around 150,000km.

Anyone got a spare block for sale???? M2850 motor from 92 GTS

the head will be stripped to see if the valves are bent, they all seem flush in their seats.

Any one seen anything like this before?


note how three three of the cyl have a shiny section at the top where the carbon build up has been hitting

that's a bump of corrosion , a bit hard to see.

edit;
SORRY i HOPE NOW FIXED, PICS BELOW

danglerb

None of the images show up for me, its says sorry the person moved or deleted this image.

aviography

Same here, can't see any images.

blazing928

Ok I see them, Ill post again

blazing928

Dave928S

I can't see the pics either but can't see anything wrong with your insertion of the photobucket url's, so I'm thinking it might be the same problem I've been having with photobucket in the last day or so.

They are trialling a new version of their software, and if the pics have been created in the old version they won't show up when they are arrived at via a link, as the site defaults to the new version to display them.

Edit: Now I see them .. weird!

Maybe a leaking head gasket was left for long enough to hydrolock the motor after shut down, then turning the motor over split the bore?

Landseer

Engine appears to have sat for years with water in the bores.

Hilton

Pull it apart.

If the pistons/crank/rods are ok, they can track down an S4/GT block which had the same piston tolerance group in it, and use that.

Or they can try to fit a replacement liner (IIRC the liners can still be had from Porsche) for that cylinder. The factory liners used in some GTS engines are alusil.

Looks like massive carbon buildup - this is probably a GTS engine which drank oil?

blazing928

Hi Hilton,
motor is slowly being dismantled, Don is looking at the liner option as he would like to keep the engine number.
He thinks it was just never given a good hard drive to blow out the carbon now and then, the owner has several cars. There was a bit of oil in the intake runners.
It certainly has not sat for years as suggested. There was no water in the bores, or oil in water etc. A boroscope was used but no damage was seen!

17prospective buyer

Seafoam would have cleared all that **** out. Remember that if his knock sensors were old and not working correctly, the huge amounts of carbon in there could have caused knocking by effectively raising the CR.

danglerb

Preserving the number isn't going to preserve anybodies wallet. Looks like its toast to me. Has anybody ever really gotten liners to work in a 928?

SeanR

Yup, my thought also.

G8RB8

Looks like sugar in the gas tank to me. I'd drain it.

WallyP

There are no "liners".

The 928 block is made of Reynolds 490 high silicon (not silicone) aluminum
alloy. It is precision cast, with controlled cooling for the bores, so as
to bring the silicon to the surface. After boring and honing, the block is
chemically honed to remove a very thin layer of aluminum from the surface
of the bores, leaving a very hard, slightly porous layer of silicon for the
pistons and rings to rub on. Since aluminum does not function well rubbing
against this silicon surface, the aluminum pistons receive a very thin
coating of iron as a wear layer.

Interesting that the bores are cracked, but the pistons look undamaged.

Sharkbody

Looks like sugar to me too. G