View Full Version : WIll a 98 vin 9 motor go into a 94 STS

08-31-09, 11:00 PM
which had a vin 9 motor. I found a low mileage vin 9 motor out of a 98 Deville that I want to use while I have my motor rebuilt. I still have the tapping in my original motor and really don't have the time anymore to play with it. I need a car and a mechanic told me he could start in the morning and probably would have it running the Wednesday. For the tioem being, that's the best for myself, does anyone know if a 1998 vin 9 motor will go into my 1994 STS vin 9 motor without to many problems. I know it'll physically bolt into my STS, it's the sensors, computer etc. that I'm wondering about.


09-01-09, 07:57 AM
The heads will have to come from the '94 as well as the intake, bolted on the '98 block. The 98 doesn't have the EGR provisions in the head- they can be drilled and cut into the heads but I wouldn't go that route.

Also the knock sensor will have to be moved to where the '94 had it, and I believe the hole is there and threaded for it.

09-01-09, 09:54 AM
Thanks, in a hurry, doctor appt. will get back later, once again, thanks!

09-01-09, 11:54 AM
Wait a minute. A Deville and an STS do not both have a VIN 9 motor. I keep forgetting which is which, but one has a VIN Y.

09-01-09, 03:25 PM
If youre going to go that route and have to take heads off anyway you might as well replace the head gaskets. I would put Jake's studs in there at same time and make that thing bulletproof.....

09-01-09, 03:49 PM
The motor in my STS is a vin 9, I had the service man read the vin # to me yesterday and that motor which he said is from a 98 Deville, is also a vin 9. I'm not going to purchase that motor because I'm not going to pay someone to go through all that work, changing heads, intakes and who knows what! My thinking is to buy a motor that runs okay for a quick install and I'm back on the raod. It doesn't have to be in perfect condition because in the mean time, I'm going to have my motor taken apart to find out what the tap is. My motor needa a rear seal anyway so I might as well take a look at the bottom end while the seal is being changed. If all is okay, that leaves the piston pins or a lifter that I missed. More than likely I'll have my motor rebuilt and if some cams become available in the near future, I'll wait for them and add the cams! Anything I can I add that is high performance will be added, so I won't mind it taking awhile as long as I can drive my car with a spare motor for the time being.

I found a mechanic who will change the motor for $400, in my opinion, that's pretty reasonable and I don't mind paying it twice.

All that aside, if I can find a motor that'll bolt right in, that's what I'm going to do for now. I believe I just found one a fwe minutes ago, they're getting back with me to let tme know the vin # and I'll be on my way, for now!

Wait a minute. A Deville and an STS do not both have a VIN 9 motor. I keep forgetting which is which, but one has a VIN Y.

09-01-09, 04:09 PM
I've found a couple of vin y motors that are both 94's. I assume that a vin y should bolt right in and the only difference is giving up a few HP for the time being. If that's the case and I don't find a vin 9 in the next day or two, I'll just have them install a vin y while my motor is being repaired/rebuilt.

09-01-09, 05:37 PM
:tisk: DO NOT do that. You MUST stick with a VIN 9. Like I said, they have different PCM's and final drive ratio's. It's more than just 25 horses. You will have problems and you won't be happy.

09-01-09, 09:42 PM
Ranger, I'm not to worried about the final drive ratio with mine being 3:73 to 1 I believe and a vin y being something like 3:11 to 1. I don't recall you mentioning that the PCM is different or should I say programmed differently. I certainly don't want something that won't run but at the same time, I'm only looking at using the replacement motor to get around town for a few weeks.

You can bet my original vin 9 motor is going back in along with a few other new parts. At that point, my car should be in top mechanical shape for another 5 years if not more.

Appreciate the input!

09-01-09, 10:24 PM
don't recall you mentioning that the PCM is different or should I say programmed differently.
Yeah, shift points and such. If you are only looking for it as temporary transportation for a few weeks, it should work. I thought it was to be permanent.

09-02-09, 11:04 PM
Actually I've done the VIN 9 to Y swap before, driveability was unaffected, didn't seem to make much of a difference. Seemed like it had a bit more top end pull, and no loss in bottom end torque. So it seemed. I'm still running a 4.0 in my Eldo. The engines are amazingly interchangeable, but I have to agree with Ranger. Stick as close to what it originally had as possible.

Now that N*Caddy is doing the LED interior and Bose conversion in my Eldo (with the aux. audio input jack) I've got to swap it back to the 4.6. The 4.0 is great on fuel and pulls hard in the upper RPMs but it is lacking down low with the 3.11's.

And some Devilles had the vin 9 engine- well the Cadillac Concours, but to me, it's still a Deville. More/less a DTS! :D I'm still looking for one of those to add to my collection.

09-04-09, 09:43 PM
I found 2 motors and looked at them today. On the crossover one had a 1994 stamp on it and the other 1995. Loking at them, the 94 had the same intake as mine which is a 94 and the 95 had an intake that looked a bit different, the cover was off and I could see the FPR was different than mine which is a 94 so they p[robably are what the crossover say's they are.

There was a number on an aluminum tag on the front right side of the block on the 94, the number was 6RU298600, couldn't find any other numbers.

The 95 had the number in the same area but it was scribed into the block, the number was 6SU8069895, there was a second number, can't remember where it was but that number was T10L693996.

I was about ready to buy the 94 motor when I decided to lookat it again, that's when I noticed the idler pulley for the belt missing. I looked close to where I believe it should bolt on and there is a small boss that hangs out on the corner of the block, it was broken. I would say that 2/3's of the hole was still there with about 1/3 missing, a problem but probably not terminal to the block. An idler pulley may hold with the hole that's there but to make it right, that corner would have to be welded up, drilled and tapped!

If anyone can identify those numbers it would be most appreciated, comments please!

09-04-09, 10:01 PM
Forgot to mention, I never go on that side of town but when I left from where I looked at the motors, I saw an STS for sale and as it turns out, it's a 97 SLS and they were asking 2200 cash. I drove it and it's in very good condition, the motor and trans were tight 110k, only problem a banged in back door, like somebody's behind got banged into the door! I thought they were asking $2200 down and then some small payments but it was cash take out. I may make them an offer for 1700 and if they take it, I'll probably just have my STS repaired and not change the motor. I can dirve that 97 while my car is being repaired and then sell it when mine is fixed.

The problem getting mine fixed is that the engine repairs shops are on the othe rside of toiwn. I don't know any of them and don't know anyone who's done business with any of them. Once thay have your car and take it apart, your pretty much at their mercy. I've been hearing numbers like 3900, 4100, 3750 and all of them is for the motor, rebuilt with a 3 year or 36k mile warranty. They all say, that they don't know what it'll cost toreplace and don't know what they may have to replace along the way. Of course they don't know, they've only changed hundreds of motors and they don't know, lolol!

I'm sure by the time I walked out of one of those shops, I would be spending over 5k.


09-06-09, 02:13 PM
Come to my shop. I'm a bit behind in the cars right now but I'm usually within $200 of the quoted price, most of the time dead on.

09-07-09, 03:19 AM
Appreciate the offer and I may just take you up on it. If you were within a few hundred miles I would for sure. I know the garages that I've talked with, know within a couple hundred bucks what it'll take but they're pretty good at taking someone who may be a bit naive. I would say they are in the testing stage, once they talk to you face to face and realize that you know something about an engine, then they'll be up front. If they see you know nothing, I'm afraid you would be replacing the monkey bearing and by the way, there are like 8 monkey bearings!

Something has to give in a few days, I need a car..........