Factory Mixing Engine and Model Years

[Chub]

I have a question for the experts out there. During the last few production runs at the end of a model year, was it possible that parts from model years were mixed? I ask this question because my '95 SC2 appears to have a '96 head even though the previous owner changed nothing on the engine, as far as I am aware. My SC2 was produced in late February of 1995, which seems like it would have been one of the last SC2's produced for that model year, but I don't know the exact time that they actually would switch over. Another factor that added confusion to my engine's year is that it has a synthetic valve cover, and I thought all '93-'95 DOHC cars came with aluminum ones. The wiring harness has an ECTS and relay sensor, so I know it has a '95 harness / PCM, but what gives about the head and valve cover? Should I assume that it is possible this could have happened from the factory, or should I try to dig a little deeper?

[pampas56]

The short answer is "Yes". If the supply chain starts delivering the new style and the factory runs short of the older parts they will use what is available. Conversely, if the new parts are held up the old parts can and do show up in the early cars of a model year.

My 1980 Plymouth Sapporo (a brand new model) came with the engine from a 79 Arrow. The oldest daughter's 94 SL has the later style radiator because it was late in the model year.

The best I can tell you is go to your FLAPS (NOT AZ, O Rielly's or some other consumer parts chain. Think Carquest, NAPA or the places the pros get their parts) and ask the counterman to help you figure out what you have. Most of them will be glad to help you out if thing aren't too busy.

Thank them by buying some of your parts there.

[fetchitfido]

Originally Posted by Chub

Another factor that added confusion to my engine's year is that it has a synthetic valve cover

Same style as the aluminum cover? Most '94s got that one. Check the engine VIN, it's just below the coil packs I believe. Not out of the realm of possibility that someone swapped in a '96-'99 engine.


It's more likely to use left over parts at the beginning of the model year, not the end. My '96 and '97 are more likely to have previous year parts then your '95 as they both left the factory by mid September (Sept 23, 1995 for the SC2 according to Compnine, haven't VIN checked the SW2 but the delivery date on the dealer paperwork says Oct 11, 1996 so probably left the factory in September as well). Not that they can't or won't use whatever's handy late during the run, but early model year cars are far more likely to be Frankenstein from the factory. Your's being an actual 1995 made car is "late" in the model year.

[Chub]

I figured as much for the car being produced "late" in the model year. I will definitely take your suggestions and look at the VIN on the engine, as I know that the car is a 1995. I thought of doing something like this, but I just didn't know where to look for the VIN on the engine itself. The head is definitely a 1996 or later because it has a T that the ECTS and the temperature sender are on and there is only one hole in the head for these sensors, combined with the plastic valve cover.

[Chub]

I found the VIN number on the block below the coil packs after some scrubbing, but this number is only 9 digits long. Did I miss part of it, or does it only match partially to the car, starting from the engine code?

Well, if the VIN on the engine starts at the engine code and goes through to the end of the serial number, then my car is definitely a frankencar with a very strange past. The engine's VIN was 8TZ162136, indicating that my block is from a 1996 SOHC with a serial number of 162136. So then I guess this means that my engine is an SOHC block with a DOHC head on it from somewhere else. Does anyone know if the heads have the VIN on it, and if so, where is it?

If these numbers are correct, this definitely comes as a surprise to me, not that it is a 1996, but that it was originally an SOHC block, so it was definitely swapped in. Weird.

I am currently trying to guess the missing pieces of the VIN to see what kind of car it came off of. Too bad there isn't a way to look up cars by just the serial number alone once you specify body type and that it was a saturn.

[PlasticCarsRock]

Originally Posted by Chub

I found the VIN number on the block below the coil packs after some scrubbing, but this number is only 9 digits long. Did I miss part of it, or does it only match partially to the car, starting from the engine code?

Well, if the VIN on the engine starts at the engine code and goes through to the end of the serial number, then my car is definitely a frankencar with a very strange past. The engine's VIN was 8TZ162136, indicating that my block is from a 1996 SOHC with a serial number of 162136. So then I guess this means that my engine is an SOHC block with a DOHC head on it from somewhere else. Does anyone know if the heads have the VIN on it, and if so, where is it?

If these numbers are correct, this definitely comes as a surprise to me, not that it is a 1996, but that it was originally an SOHC block, so it was definitely swapped in. Weird.

I am currently trying to guess the missing pieces of the VIN to see what kind of car it came off of. Too bad there isn't a way to look up cars by just the serial number alone once you specify body type and that it was a saturn.

Not positive what the format of the number on the engine is, but if it is the last digits of the (17 digit) vin, it starts with the 9th digit, which is a check digit (engine would be the 8th digit, which isn't there). That makes sense, as the 10th digit is the model year, and T corresponds to '96.

February of '95, while certainly not the beginning of the model year, is not the end of the model year, either.

My best bet is that it either it received a '94 composite valve cover that had been sitting out of the way somewhere for a little while, or a composite cover was swapped on by a previous owner. Many people prefer the aesthetics and noise reduction characteristics of composite valve covers, so it's plausible that someone who wasn't aware of the warpage issue could have swapped it on.

[Chub]

Originally Posted by PlasticCarsRock

Not positive what the format of the number on the engine is, but if it is the last digits of the (17 digit) vin, it starts with the 9th digit, which is a check digit (engine would be the 8th digit, which isn't there). That makes sense, as the 10th digit is the model year, and T corresponds to '96.

So, if 8 is the check number, then it is not the engine code saying it is an SOHC block? If that is the case, it answers some more questions for me, but the serial number of the block and my car are definitely different. I would like to see if anyone else out there has checked their engine VIN and whether or not it starts with the check number and then goes on. Either that or if it starts with the engine code and skips the check number.

Also, since the code is hard to read, I checked it again and found it to be 8TZ183155.

[rowdydog]

auto manufacturers start their new model yr build half way through the yr or mid yr, so a car built late 95 will be a actual 96 yr model, this is called change over, we have a couple weeks off in July usually and that is when we start build the next yrs models, I worked at the plant and after 3 million + cars had to remember lol, Iknow the 95 sl2's had the 96 interior so anything is possible , as for ur block sound like it was changed, the blocks are the same single or twin cam its the heads that are diff.

[fetchitfido]

Originally Posted by rowdydog

Iknow the 95 sl2's had the 96 interior so anything is possible

Such as every '95 sedan/wagon having most of the updated '96-'99 interior and '95-'96 SC's having the updated '97-'99 interior? lol

8TZ183155
8 = check digit
T = model year (1996)
Z = Assembly plant (Spring Hill)
183155 = Serial number of the car the block is from.

Sad to say, that's not the original engine if the car's VIN checks (or Different Racing's manual VIN check) out to 1995.
Never read of anything on the head's having any sort of VIN ident, but if the 2nd ECTS isn't in the standard '91-'95 location then it's most probable that someone swapped in an entire engine from a '96.

[Chub]

Originally Posted by fetchitfido

Such as every '95 sedan/wagon having most of the updated '96-'99 interior and '95-'96 SC's having the updated '97-'99 interior? lol

8TZ183155
8 = check digit
T = model year (1996)
Z = Assembly plant (Spring Hill)
183155 = Serial number of the car the block is from.

Sad to say, that's not the original engine if the car's VIN checks (or Different Racing's manual VIN check) out to 1995.
Never read of anything on the head's having any sort of VIN ident, but if the 2nd ECTS isn't in the standard '91-'95 location then it's most probable that someone swapped in an entire engine from a '96.

So I think the consensus is that the engine was swapped in since the serial numbers between the block and the body are off. The 2nd ECTS is not in the usual location, but on a T, suggesting a newer head, so the engine is probably just a 96 somebody swapped in along the line. Truthfully, I have no idea how many owners this car has had before me, just that it was first bought in Indianapolis and is now in extreme eastern Pennsylvania. Thank you to all of those that responded for your insight. I guess my car is going to go back to its roots once I finish rebuilding the '95 engine I pulled from the yard.

[1993]

would you please post a good pic of the 'T' you mention got yhe 2 ects sensors? I need to do this also and need ideas..
thanks

[1993]

Please post pics

[1993]

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