I picked up a 1990 coupe automatic that will clean up real nice - body in great condition - for only $1600. The guy told me the engine is probably bad, and turns out he wasn’t wrong. Chocolate shake oil on the dipstick, and when I drained it was more water than oil. Would not turn over. Took out plugs and valve covers, and was greeted with this:



Rockers and pushrods are rusted in place - no wonder it wouldn’t turn.

I haven’t inspected pistons or crankcase yet.

Given all the rust, is it at all likely this engine is rebuildable? And if so, it is worth it vs. just finding a replacement?

 

I would pull the engine apart and rebuild it. The Block is a Roller Block, the heads are valuable 113 aluminum heads. Upgrade everything if rebuilding. a .030 or .040 over bore should clean up the block. I would buy a forged rotating assembly with good pistons, upgrade the cam, install roller rocker arms and all other new valvetrain parts. The Intake assembly is aluminum and can be cleaned and a little porting and polishing would not hurt. A well built 10.5:1 compression ratio, 355 cu inch L98 Tuned Port that comes from the factory with 250 stock horsepower as a starting point and 350lbs of torque would have a nice improvement with these upgrades. Keeping it numbers matching and original is the only way to go. IMHO
Cheers, Jarrod

 

That would be a huge waste of money and effort for nothing. At least a grand in machine work and a few in parts for not much gain. 113 heads are valuable to no one. Lol
and numbers matching means little considering most C4s are only worth about $5k

 

I have notice at car shows they are installing plug and run LS engines, easy fit and mate to the transmission.

 

I’m definitely more of a “plug and run” guy, which is why I’m more inclined (so far) to replace it like-for-like. The LS swaps I’ve seen thus far (YouTube mostly) require things like shortening the driveshaft and modifying mounts, solving computer problems, etc. But I would seriously consider it if there are kits that solve these problems. Are there?

Also I bought this car with intent to fix it up nice and sell it. It’ll never be a mint stock specimen, but should be nice. What does a LS swap do to value? I’m sure folks here will say you don’t flip these cars to make money - I get it. This is mostly for fun, but I definitely don’t want to break the bank either.

 

I'm starting the process to pull this motor out. As I mentioned it's seized - so considering I can only reach two flywheel bolts is it ok to slide it out with the torque converter still attached? I would have to move it more forward before being able to lift it, correct? Not sure if front clearance will then become a problem.

I could probably open the oil pan and disconnect pistons to spin the crank, but that seems a lot messier.

 

I’ve never seen a motor as rusted as this. What would cause this?? Seems way beyond a head gasket.

 

swimin' with the fishes?

 

A nice crate motor would be a good alternative from GM or Summit or others some have very good warranties.
Cheers

 

This was one of my first thoughts. But I can’t find any evidence of this. No water in any other fluids (transmission, brakes, steering), no corrosion of connectors or fuses, and electronics work. It’s strange.

 

Wow...yeah my 1st thought is flooding...
sounds gross, but if you still have any water in it or mixed with oil, put your finger in it and touch your tounge. If its saltwater you will know instantly.
I'm a boat guy, and it definitely looks like salt water damage. I understand you found no other evidence of flooding, but wow....only other thing could be someone did this on purpose. Did the PO have enemies?

 

I disagree about the 5k remark

 

“plug and run”

lol!!!!!!!!!

 

Yeah, I'm beginning to think it might have been sabotaged. I think I got rid of all the water, but if any more is there and I can stomach it I might taste to see if it's salty. It was very clear when it flowed out. There wasn't much coolant in the system, but that also came out clear.

Just brainstorming here, but what if it wasn't a head gasket that blew, and instead the gasket between the intake manifold and the block such that water (not proper coolant, as that would have rust inhibitor) flowed into the center chamber over the pushrods and up into the head that way? Then sat there for 5 years?

Also here is the bottom of the intake with the gaskets - is it normal that the coolant passages toward the rear of the engine to be blocked by the gasket like that??

 

If your flipping the car your best bet is finding a good used engine.

 

That could do it.

It would have had to have been straight water, though. If it were coolant, it wouldn't corrode.

That thing is ROUGH looking. Even I wouldn't try to salvage that....and I've salved some REEEEAL **** boxes!


.

 

Well my plan WAS to swap in another used L98 into this car, and then rebuild this engine as I have time for my other car, a '91, which runs pretty well but has an engine with 185k miles on it. However as you have noted this one might not be rebuildable... lol

I'm curious to see what the bottom half looks like...

 

 

What I would do with that engine, now that you have made this post, started this thread, and shared those seriously condemning photos…..in this order…
1. shop vac and scrape/chip as much rust out as possible while shop vacing all the chips and dust…(can u see where im going already?)

2. drop the pan, do the same thing. Reinstall pan with same gasket if possible and if not, a re-useable blue felpro gasket.

3. Fill the crankcase up to the absolute brim with diesel and acetone.

4. drain it all out. Filter the concoction using a few old socks, repeat with filtered fluid. Id add another bottle of acetone the second go-around. drain it out. Remove the plugs. try to break it free. Working it back and forth.

5. u will be successful, and then i would fill the crankcase with the cheapest 0w oil i could find, some of the cheapest oil filters i can find, id drizzle it all over the lifters and the valve train, and id sacrifice an old distributor and turn it into a priming tool. Spin with drill and get oil pressure.

Eventually id button it back ip and try to fire it. i bet it will run. If at any time you discover a major failure then scrap it, but recover your new felpro gaskets first.

Thats what id do. Cause it would be legendary it worked. Not much to lose other than time.

I mean you are potentially a few hours of evening work away from a running driving 1500$ vette!

 

Wow - interesting plan. Well, in order to manage my finances I was going to wait another week before choosing and buying a used engine (looking at some in Phoenix that are in the $2500-2900 range including harness, ECU, and accessories - seems wise to get some backup parts). So it does sound worth a try. I guess I'd have to get that intake back on, but I haven't taken the head off yet. Plus I wanted to take the pan off to inspect below. I just might give that a shot, cause, why not?