928 Block repair
11-05-2005, 08:46 AM
#16
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Also so would I. Matching numbers people are totally different breed than most in this forum. That time is coming and it's nearly here already. How many 30+ years old Porsche models there are where it wouldn't matter if numbers match or not?
11-05-2005, 09:03 AM
#17
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You see, it is not even about the block... Porsche doesn't make our cars anymore, meaning there is a limited amount of cars and engines. So, we as a shark community MUST try to save all of them. And 600$ is not a whole lot more then used working block. No, I can't afford it, cause I have an engine in the garage, which eats up all my funds. And I am not equipped to do the job...But if I would be one of the "pro" guys, with the right connections, tools, I would consider it....
Klim
Klim
11-05-2005, 01:52 PM
#18
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Originally Posted by Vilhuer
On average case different block is cheaper and much easier solution. But in few years all of the sudden early '78, late '94-95 GTS and some other desirable models like CS, SE and low mileage GT will be clearly more valuable with original drivetrain than non-original similar one. This make even expensive block fix worth the trouble if it's doable.
11-05-2005, 02:26 PM
#19
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Dave,
It's true they almost never match. If they would, it would be more likely block is wrong than right one. Possibly not even factory knows for sure which body got what engine etc. But still it's possible to find out if it was even remotely feasable certain engine went into some car at the factory or not. Engine number and especially type portion of it is one good clue. Casting weeks on major parts and pairing number on block halves can also say it's impossible certain block to be original even though engine number itself would fit inside the "zone".
It's true they almost never match. If they would, it would be more likely block is wrong than right one. Possibly not even factory knows for sure which body got what engine etc. But still it's possible to find out if it was even remotely feasable certain engine went into some car at the factory or not. Engine number and especially type portion of it is one good clue. Casting weeks on major parts and pairing number on block halves can also say it's impossible certain block to be original even though engine number itself would fit inside the "zone".
11-05-2005, 04:00 PM
#20
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Erkka,
I must still be missing something. Unless you have, for example, a #25 chassis with a #200 block, there can be no certainty. Or a casting date that is after the chassis build date. I suppose that there is greater challenge in finding a block that may be considered "correct" if the chassis is one of the early ones in a series...
I must still be missing something. Unless you have, for example, a #25 chassis with a #200 block, there can be no certainty. Or a casting date that is after the chassis build date. I suppose that there is greater challenge in finding a block that may be considered "correct" if the chassis is one of the early ones in a series...
11-05-2005, 04:16 PM
#21
Originally Posted by Vilhuer
How many 30+ years old Porsche models there are where it wouldn't matter if numbers match or not?
Don't you think that high production numbers of 928s alone would do against the "matching number" potential of the 928 ?
Sad to say but there are still too many cars alive for the moment ...
11-05-2005, 04:21 PM
#22
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Originally Posted by Thom
Don't you think that high production numbers of 928s alone would do against the "matching number" potential of the 928 ?
11-05-2005, 04:30 PM
#23
Yep but these cars are way easier to keep on the road than 928s.
One can only hope the big three (or others) may reproduce ANY 928 part just like any Mustang part is reproduced today.
One can only hope the big three (or others) may reproduce ANY 928 part just like any Mustang part is reproduced today.
11-05-2005, 06:20 PM
#24
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Lets see how large certainty we can get with what we have.
All engines that have normal type and number in stamped them must have correct one for the car. This already takes care of the ATR etc. special numberings can be handled separately. ATR engine can be original also but there will always be some doubt against it.
On normal case engine should have same year as chassis VIN. This will narrow possible canditates to within single model year. Especially on last few years this is very good indication as production numbers were really small. Also if VIN is one of the first ones and engine number is much further within model year it's very likely engine was changed.
99% surely manual car should have engine with engine type saying it's for manual and automatic should have one for automatic. Especially on manual cars this is very good indication engine is probably not original. On CS, SE and '89 GT it should be easy to point out when engine is not what is expected.
Casting dates are very good in pointing out too new engine compared to cars production date. Parts 928...R casting number can also be handy way of checking if stamped engine number might be false. Sometimes it's of course possible factory used old casting to make different later style part. Early '87 S4 block with ground down intake mounting points is good example of this. If we can establish all very early S4's should have this older style block this can provide clue on checking originality of the engine on these cars.
Block half numbering is somewhat helpful also. On last model years they made so few blocks that one loop of 0001 to 9999 numbers is spread over entire nineties production. Half numbers and engine numbers certainly were not ordered compared to each other but still half numbers give at least some kind of baseline. For example on how many engines factory did compared to cars. That is if we have enough datapoints that pattern starts to show up.
Using all of the above together we should be able to get within reasonable range of engine numbers what car must have in order for engine to be original. Since production was so small as it was, number of suitable engines is also quite small. This makes it almost as difficult to find block that is close enough to pass all the tests than it is to fix original broken one.
I know one case where dishonest vendor tried to pass S4 engine as GTS engine by altering engine number stamping. This was very poorly done as old number was still partly visible and several of the above methods pointed directly to S4. Not to mention all the features of the block were clearly S4, not GTS. There will be more of these cases when cars start to gain significant value.
Not all 928 are equal. Original condition very early '78 MY is going to be much more expensive than later OB cars. Also '95 GTS would be more expensive than lets say '93 regardless of production numbers on those two years as it's last year. There being less '95 than '93 models only inreases this phenomenon but it's not root cause. Age of the car looses it's importance when car model turns old enough so 95' being few years younger don't mean anything either. Only fact that it's last one.
Difficulty or ease of finding parts is not really very important in all this. Except in what I mentioned above about small numbers produced making it harder to find close enough engine replacement. Some collectable cars are really horrible to work on because parts can't be found from anywhere. On others like some sixties British roadsters it's possible to build entire car from newly made spare parts. Still on both cases all numbers match original car is more valuable than othervise equal non matching counterpart.
All engines that have normal type and number in stamped them must have correct one for the car. This already takes care of the ATR etc. special numberings can be handled separately. ATR engine can be original also but there will always be some doubt against it.
On normal case engine should have same year as chassis VIN. This will narrow possible canditates to within single model year. Especially on last few years this is very good indication as production numbers were really small. Also if VIN is one of the first ones and engine number is much further within model year it's very likely engine was changed.
99% surely manual car should have engine with engine type saying it's for manual and automatic should have one for automatic. Especially on manual cars this is very good indication engine is probably not original. On CS, SE and '89 GT it should be easy to point out when engine is not what is expected.
Casting dates are very good in pointing out too new engine compared to cars production date. Parts 928...R casting number can also be handy way of checking if stamped engine number might be false. Sometimes it's of course possible factory used old casting to make different later style part. Early '87 S4 block with ground down intake mounting points is good example of this. If we can establish all very early S4's should have this older style block this can provide clue on checking originality of the engine on these cars.
Block half numbering is somewhat helpful also. On last model years they made so few blocks that one loop of 0001 to 9999 numbers is spread over entire nineties production. Half numbers and engine numbers certainly were not ordered compared to each other but still half numbers give at least some kind of baseline. For example on how many engines factory did compared to cars. That is if we have enough datapoints that pattern starts to show up.
Using all of the above together we should be able to get within reasonable range of engine numbers what car must have in order for engine to be original. Since production was so small as it was, number of suitable engines is also quite small. This makes it almost as difficult to find block that is close enough to pass all the tests than it is to fix original broken one.
I know one case where dishonest vendor tried to pass S4 engine as GTS engine by altering engine number stamping. This was very poorly done as old number was still partly visible and several of the above methods pointed directly to S4. Not to mention all the features of the block were clearly S4, not GTS. There will be more of these cases when cars start to gain significant value.
Not all 928 are equal. Original condition very early '78 MY is going to be much more expensive than later OB cars. Also '95 GTS would be more expensive than lets say '93 regardless of production numbers on those two years as it's last year. There being less '95 than '93 models only inreases this phenomenon but it's not root cause. Age of the car looses it's importance when car model turns old enough so 95' being few years younger don't mean anything either. Only fact that it's last one.
Difficulty or ease of finding parts is not really very important in all this. Except in what I mentioned above about small numbers produced making it harder to find close enough engine replacement. Some collectable cars are really horrible to work on because parts can't be found from anywhere. On others like some sixties British roadsters it's possible to build entire car from newly made spare parts. Still on both cases all numbers match original car is more valuable than othervise equal non matching counterpart.
