List,

Can someone identify an engine for me:

M28.49
8500576

Once I have conformation of what I suspect it is, then I will reveal more.

Thanks in advance,

Alex

P.S. I know it is a manual GTS engine, but I need the model year...

 

You are missing one char. There should be N, P, R or S in 85_00576.

 

See, I also thought that I am missing a character - but the engine does not have one. It was the very last manual GTS engine, which Porsche had in the museum on a pallette. I think there are pictures of it taken during EURO2002... That engine found its way into a Blue RHD GTS (seen on Jeremy Clarkson's DVD) as a warranty job, but then the car became a total loss and eventually into my possession...

According to Porsche themselves, this is the very last engine assembled by the factory and as a result it has liners and fancy conrods... I will accertain this when I strip it for inspection in the next month or so...

There is also a NB stamped on the side of the block, where the engine number is meant to be...

Strange....

 

Hi Alex,

I believe the factory stamped funny stuff on the block when they made a factory rebuild of a motor. I think Jim Bailey knows more.

marton

 

Many times rebuild blocks had ATR stamped before or after engine number. In this case it sounds more like factory didn't want to set year model to the engine at all. Maybe it was made in '94 MY or earlier already and they thought they could need it for '95 MY. Owner might not like to receive year older engine and this fact was easy to hide jyst by not puting MY into the number.

What casting week block upper half has at rear where clutch is mounted? Its very likely block was cast some years before when it was machined but this date will give lower limit for MY.

What pair number block upper and lower half have close to oil filter mounting point? I believe this number were stamped during machine work in one single sequence for all 928 blocks regardless of what specific type and market engine was build for. If this is the case pair number can be used to place each block within sequence and when other nearby numbers are known its possibly to say with fair certainty when engine was actually machined and most likely put together also. If for example number is 5555 and several '94 MY GTS have pair numbers very close to same then this block is very likely also '94 MY too.

Number of engines made in late MY's was so small that pair number didn't go through one single rotation from 0001 to 9999 during entire GTS production. It might have jumped from 9999 back to 0001 but it never reached same number again what first GTS block had. If my prediction is true on how this number was assigned its possible to place every single 928 block within one single machining sequence regardless of what type and serial number within type and MY block has stamped on top.

Together with casting number on front end on level surface just below passanger side head on LHD cars casting week and pair number form combined checklist for what is stamped on top. All three must make sense compared to stamping. This is sort of extra assurance that block is actually what it says on top. Its obviously possible to alter all of these numbers and there has been at least one case where late eighties S4 block was made to look like its from GTS. Stamping was altered very badly and it was fairly easy to see something had been done to it. Casting number was clearly S4, date also could not be for GTS block and pair number didn't fit into sequence for known period GTS block. All three other numbers also pointed to S4 and thus it was very clear serial on top had been changed.

If some 928 models get more expensive I expect this kind of forgery to become much more common. Luckily its difficult to change all numbers to match and even more difficult to change block so much that it has all GTS block features. Cars with original engines will always have more value in collector car market. Porsche have provided at least five different ways to identify what engine is, type and serial number on top, casting number at upper front corner, pair number next to oil filter mounting point, casting week at rear end and actual block features like three long holes drilled through GTS block from rear. It is practically impossible to make all these match properly so that nothing wouldn't indicate they are all changed.

 

More info on the engine:

Pair of numbers near the oil filter - 6871
Casting Week Numbers near the clutch: 35, 94, 12, P16, 14

So, Erkka, what can you tell me about my engine?

Alex

 

Are those numbers all inside boxes or is 35/94 same kind of stamping as 51/90 is in my GTS block?



I'll check few GTS pair numbers I have listed to see how far they are from yours.

 

35/94 is exactly the same as on your engine. with a big 12 next to it, whilst the rest of the numbers are in the boxes above as per your photo...

 

Alex when you say liners can you elaborate? The reason I say that is that you may be aware of an Aussie that lost a engine that had been lined. I believe those liners are not designed for the Porsche engine but are a close enough match, they suit a Mercedes, they are listed in the kolben book. Obviously I know nothing of your liners and make no comment about them.

As I said before given you have dry sump are you not tempted to increase the capacity and sell off the block to fund other adventures in 928 land?

All the best

Greg

 

If I was building a street car, then I would be tempted to do all sort of things to its engine.

I am not though and I am building a race car, where sadly engines are consumable. I would rather have a good GTS-based race engine sitting on the side, ready to be dropped in at 24hrs notice, then start the whole project again. Moreover, building the race car is a weekend hobby of mine - don't have the time to chase people and all that... I told you - 400bhp + is a goal that I am happy with. It is more than enough to propel the beast fast enough around the Ring...

 

Few '92 GTS engines I know have pair number in 3500-4000 range. This is my ROW VIN 0410:



Total GTS production for different model years was:

'92 1043 (includes early '93 MY US cars)
'93 723
'94 662 (includes early '94 MY US cars)
'95 403

Pair number 3545 was used in little before middle of '92 MY VIN in March '92 while it was cast already in 51/90. After VIN 0410 factory did abroximately 2500 GTS. 3545 + 2500 = 6045. My GTS has very early manual block so we can add maybe 500 more engines into the series to take casting number into correct range for the VIN. We need to add also all the spare engines done between these two engines. This takes number to 6500+.

Based on above I would expect absolute last GTS block cast to have pair number between 6500 and 7000. Yours is very close to last but not necessarily absolute last engine made. So besided casting week also pair number support its either very late '94 MY or '95 MY engine.

If you want further confirmation check casting week on lower half of the block. IIRR there is one in it also. Just don't ask where it is located. As lower half is separate casting and could have been done in totally different time than upper half this date can give false results. Casting is same as late S4 so date can be way off for GTS in case part was kept in warehouse for long before it was taken into use with upper half.

Early S4 have different typical 11 chars long ending with R casting number on lower block than late S4, GT and GTS. Don't know what was changed. I wasn't anything major as all significant changes were done to up upper half of the block since oil pump area changes in early eighties. Perhaps this is related to oil pressure relief valve deletion done in '89 MY. Or what was that oil valve on left front corner which was deleted at that time period? In any case lower half numbers can also support case for very late GTS if its late date too.

 

The engine was certainly not an oil burner during the time CB ran with it; of course it was unfortunately a relatively short time - it might have turned out to be an oil burner with more mileage on it; I hope not.
Will be interesting to know what Porsche did with the motor when they built it; take lots of fotos when you strip it.

Marton

 

He did 20,000 miles on that engine and he was meticulous with regards to keeping it in good knick... I would guess that if it was an oil burner, it would have shown up by now...

 

Alex, something strange re the engine number you quoted: the engine number for the 'last one' in the oldtimers department was M28.50 81S50666. see: http://amicale928.org/galeries/EURO9...s/MVC-011S.htm

(also a pic from the rear shows it was an auto)

The 'NB' appears on a rebuilt block btw. 'ATR' seems to appear when the engine was replaced under warranty.

Adrian

 

Hmm, strange indeed as the one that I have is a M28.49 and has liners - I took off the sump yesterday and took pictures. I also inspected the heads for damage - and there is no wear on the camshafts or tensioner pads - comensurate with 20k of driving and regular oil changes.