Mystery Engine

SC-AL

Registered User
I bought this complete 3.8 SC engine, years ago, and I am finally going to install it in my 1989 white, 5 speed SC, with a bad rod knock. The story when I bought it, is these airplane guy's bought 6 of them on pallets, that were from the factory, and never used. I pulled all the plugs, and the pistons looked near new, except cylinder #4 piston was black. The plugs look like new, and all the same. Even have the dab of silver paint on the terminal. There is some florescent pink marking paint on the crank, and water pump pulleys, and the main engine wiring harness has been cut off also. I did a leak down test, and number 4 was 16%, and number 2 was 6%. I'm now thinking this engine failed the assembly line "Hot Test", and was rejected. Anyone ever heard or something like this? I'm going to install it anyway, and see what happens.
 
I couple of pictures.
 

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I'm not aware of them doing a "Hot Test" anywhere. Essex did a spin test for balance, oil & coolant leaks, then they were shipped to Loraine where they removed the heater port caps from spin test & they were "dressed" - added the alternator, p/s pump, a/c compressor, belts & harness's. I think the harness would then be plugged into a tester/analyzer to verify the integrity of all the circuits in the harness & ability to communicate with all the sensors.

I don't think they would've ever run it in the form you have in your pic-they would have to have p/s pump plumbed to something or it would be burnt up. Harness being cut, it must've been in a car, just not long. Maybe 1 submitted for crash testing or?
 
Great information, thanks. On a closer inspection, it has been run, but not a lot. Really makes me mad they cut the harness. I'll now have to pull the blowers on both engines, to swap them. I don't know how to identify the new engine, but it was from a 5 speed car, (has pilot bearing). Came with engine mounts, which is a plus. They didn't paint the block in those days, I see.
 

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I don't know how to identify the new engine
Looks to be an early engine. EGR bits, and pass. side early style exhaust manifold (late is better if you can find one).

Can you tell if the intake/plenum-to-supercharger port is...

Early:
1667343911894.png

Late:
1667344081740.png
 
That is strange that the block wasn't painted? I think early engines had the rear cam cover painted blue so Essex workers could identify it was built for a 5 speed & put on a flywheel, instead of a flexplate. Different cam, although I dont know what was different about it.
 
The intake port is the early oval one. I have an extra supercharger off a 91-92, SC, automatic car, but doesn't have the intake/supercharger plenum, not that it would help. Thanks for the input. I also plan on just leaving the trans in the car when I pull the old engine, and drop this one in complete.
Should I take the mounts off the block, and put them on the K member?
 
Does anyone know how to read engine date codes. I know I have to pull this engine back out because of a rattle@ 2,500rpm, along with a vibration at the same rpm. I'm thinking this might have a duracast crank. It came without a flywheel, so I used the one off the original 1989 engine with a vin of 100597.
PA110005 (2).JPG
 
Interesting and likely an early one? 9K503 indicates it's a 89 engine for a 5-speed configuration. The AA indicates the first version of such. No date on that label is not what I have seen in dozens of these motors. A 'K506' indicates the engine would be mated to an Auto transmission. The 9 digits in groups of 3 are some sort of serial number but I can't confrm how the sequence is indicated. On an '89 engne the other valve cover should have a label with same info on the top of the valve cover but the digets maybe larger font and it may have the engine build date in (MM/DD/YY). Hope that helps you somewhat?
 
@XB-70. Thanks for the information. I don't doubt this engine is an early production, and might even have a duracast crank. I haven't pulled it out of the car yet, but will know for sure, when I do. Also, the harmonic balancer/pulley assembly has part number, E9SE-6312-CA, that I assumed was the early balancer used with the duracast crank. The strange thing is, the original, ( spun bearing), engine that came with the car has the same E9SE-6312-CA part number on the pulley, but isn't counter weighted. The production date of this SC is 2/89, but appears to have a forged crank.
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@XB-70. Thanks for the information. I don't doubt this engine is an early production, and might even have a duracast crank. I haven't pulled it out of the car yet, but will know for sure, when I do. Also, the harmonic balancer/pulley assembly has part number, E9SE-6312-CA, that I assumed was the early balancer used with the duracast crank. The strange thing is, the original, ( spun bearing), engine that came with the car has the same E9SE-6312-CA part number on the pulley, but isn't counter weighted. The production date of this SC is 2/89, but appears to have a forged crank.
View attachment 97947
@SC-AL. I agree that very much looks like a forged crank in that picture.
 
The harmonic balancer is going to be the giveaway. If it has the cast crank, then the balancer will have less material on one side to give it the proper imbalance. That would be the easiest way to tell, without pulling the oil pan off to physically look at it.
 
I'm going to be pulling the engine back out because of a rattle/clatter, that I'm suspecting is a bearing issue. I wish I knew then, what I know now. I would have inspected everything a lot more. Maybe I will try and take a peek at the balancer today, and confirm my suspicions.
 
Well here is a update on my 89SC 5spd. resurrection. This week I finally got around to removing the replacement, (mystery engine). Took a gamble, and lost, as the supposedly near factory new engine ran good, but was very mechanically noisy. Can really hear much better with the belts off.
I did find out it has a forged crankshaft, and the correct zero balancer, just like the cars original engine, that has a engine date code of 02/06/89. Also, both engines have the exact same casting date of 88 K 12, (October 12th 1988). How many blocks did they cast that day?
Anyway, I pulled the pan, and it looks brand new in there, but the bearings are wiped. Check it out.
 

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It certainly is a early casting. Strange that is same date as your or other engine.

They sure are wiped!! Do you suspect lack of oil, or debris in oiling system or hard to tell?
I had one fail within 500km's after rebuild that looked very simular. The 2nd shop suspected the oil cooler &/or galery's were still full of crap from the first failure( spun rod bearing from coolant in oil) that first shop didnt flush.
 
I decided to get serious, and tear the whole thing apart. The crankshaft was dropped off at the machine shop today. They said at least three weeks. The mains journals look pretty good. Hoping for just a polishing. The rod journals will probably need a .010" turn. One good thing was the shop foreman walked up, and knew about 3.8 SC cranks. Recommended I get it magnafluxed, ($85). Said they crack a lot, and are hard to find. I asked about welding the really bad rod journal in the original engine, and he said no problem. I just hope after waiting three weeks, they don't tell me it's not good, I will clean up, and paint the block, this time. But, it came apart, nice, and smooth. Including the timing cover. My hands don't even get dirty, working on it. When is the last time you have seen a 34 year old, never apart engine, this clean inside?
 

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Just an update, and question on my engine repair. The crankshaft only needed polishing, and is still in standard spec. The camshaft had some chatter marks, so I pulled the cam out of the original spun bearing engine, and had them polish it, instead. Came out nice. It is also a 1989 manual pink cam. I will use the lifters from the org. engine, also. I finally got my crank bearings. I wanted all Kings, but was sent Clevite CB1283A std. for the rods. From another ebay seller, I ended up getting one set of King MB4034SI standard, and one set of MB4034SI .25(.010") undersize, for the #4 main. My question is on the Harmonic Balancer. The one off this engine is near new, and this is the first time it has ever been removed. The hub is tight, and round, when measured. Also, the shop manual doesn't say anything about replacing the bolt. Yes, I've read the horror stories. Does anyone know the order that the failure happens? What happens first, the bolt breaks, comes loose, or the hub cracks? My 1990 SC has 168K miles, and original balancer, and head gaskets. Maybe just dumb luck on that one.
 
That is a nice surprise!! I thought with the condition of the bearings, the crank would've required more then that.
I wonder why the cam had those kind of marks with such low mileage? Really dry start or lack of lube during assembly?
 
As for your harmonic balancer questions, the failures I have had on involve the bolt snapping first. Also in tougher time in my youth, I reused a balancer w a new bolt and again had the same end results.

If it were me I'd replace both the balancer and the bolt while you're there. Piece of mind is worth any dollar amount.

-Tim
 
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