Technical 58 Corvette Motor Advice Please.

A friend here in the UK has inherited his Father's 58 Corvette & it transpires coolant has got into the oil pan. He's been advised it could be head gasket or possibly a cracked block & they are discussing pros & cons of rebuilding the motor or a crate 350 replacement.

I am left wondering, if the sump is already off, might it be worth replacing the con rod bearings (incase coolant has caused damage), replacing the head gaskets, fill with fresh oil & coolant & run up to temperature to then do a compression test & keep an eye on the oil for coolant contamination? The mechanic advises this is a lot of work that might not be a fix, but if all is found to be good, it has been a cheap fix right?

If there is still an issue, he can then go ahead & make the decision on a rebuild or replace...

Any advice appreciated.

 

that is not that much less work than a full rebuild in my mind to make it worth possibly wasting the effort. I would maybe be willing to check head and deck surfaces, replace the head gaskets and run it like that to see if it works but you start replacing bottom-end bearings, you may as well pull the engine for full inspection/rebuild.

 

I think the first thing should be a pressure test using a cheap kit from HF or similar. This is assuming the heads are still on it. Fill the system, install the proper radiator cap from the kit and pressurize with the pump. Watch for pressure loss. With the spark plugs removed a blown gasket or bigger cracks should be obvious when the engine is rotated.
Or, one could pressurize each cylinder with shop air using a spark plug hole adapter and watch for bubbles in the radiator. Not my choice but it does work.
Either are cheaper first steps before buying parts and lots of labor.

Or my choice, just give a classic 'vette what it deserves. Pull the engine, rebuild the original and put it back. No more issues for years and years.

 

If it actually needs a full rebuild as the mechanic says then presumably he has found that the sump has literally filled with water and the crank and bores are now rusty.

Changing bearings won’t help as they don’t rust it’s the crank journals that rust.

If it’s not actually full of water then he needs a new mechanic.

Unless its already got a crate motor I’d suggest he’d needs to find another mechanic anyway.

I know a fair few people who know Corvettes. So if he needs a recommendation let me know.

PS a leaky intake will piss coolant into the block too.

 

Not to mention what changing to a crate motor will do to the value of the car (depending on what it is presently).

 

Good point, thanks.

 

Thank you, appreciated.

 

Thank you. I'm trying to find out just how much water was in the pan. Thanks for your view

 

Along with the above, take Oneball up on his offer to the corvette circles. I’ve had a couple friends who pulled engines out of C1’s and lived to regret it. Long shot, but potential for real money.

 

Right. The important thing here is: is this the original motor in a well preserved car, or something like I have, an old driver with mismatched pieces. That should influence what you do, regardless of the extent of the damage. More info and a look at what you have would be nice.

 

If the motor is together and, in the car, even if the oil pan is off. Pressure checking is a good idea. If you can get some idea of where it might be leaking from will give you a direction to start the repair.
It could be something as simple as an intake leak
Matching numbers might warrant heroics to repair to keep the car value. Not matching numbers here in the States any small block could work. As you are not in the states a rebuild may be just as cheap as a used motor.

 

Bingo^ On the early Chevy's it just needs to correct casting number / date code for the model and be in the right range date wise .
I always half ass look for a correct block or engine for my 57 . even though id really not want it in the car as it sits id like to have a correct block or engine for the day I may have to sell it .


OP
IF its the original engine Id pressure check it first and confirm its leaking some were . If it is I would pull the heads and magnaflux them for cracks as well as the block . early SBC blocks are not really crack prone or are there heads compared to other stuff but if its froze or something then who knows . IF its repariable Id then pull the short block clear out and go through it any way . It may be just a head gasket and depending on how long its been sitting with water in it may need every thing including machine work ( bored ) or may just need a new head gasket and the heads surfaced . If the bore is good and it can take a head gasket YES I would inspect the bearings and crank and likely even take a look at the cam ( keep the lifters in order ) .
Id suspect this is a very valuable car in England and the cost of the engine rebuild or replacement is a small portion of its value so do it right

If its original I would do my best to keep the original engine in it . If the car is remotely restorable or in good condition. MY 57 engine is long gone and the rest is not stock so I don't care about #s . if you go crate motor there are a lot of plus's to be gained HP and torque , hardened valve seats and all that even aluminum heads and up to over 427 CI in a SBC BUT if the engine is original Id damn sure keep it with the car even if not in it .
Got any pictures of it ?

 

Thank you everyone for your inputs, I'll run it all by my pal. Here's the car, a very nice original (other than the wheel covers) and well worth the rebuilding of the motor I reckon.

Are the Kanter engine rebuild kits still a good buy? I rebuilt the 430 in my 58 Lincoln 20 years back, with a kit from them.

 

Build the original.
If ya go crate then you’ll be making sure you keep up with the original stuff
Just keep in all in one place with the car.

 

That looks like a very original car even down to the carpets. There’s mouse droppings in there though
I think it needs more care than just shoving a crate motor in there.

 

Beautiful car. That deserves to have the original (if that's what it is) engine rebuilt. If the engine is knackered and can't be rebuilt, a correct year 283 would be what ought to go back in, or if the budget prohibits that, dress a later SBC up like a 283, keep the original engine for posterity. It would make the car worth much more if he has the original.

 

Nice car. It looks like the 1958 trunk (boot) lid moldings have been deleted. Yes, I would fill and pressurize the cooling system and determine specifically where the source of the leak is located.

 

Are we really talking about values and restoration here?!! Laaaaaaaame

Perfect excuse to hotrod the damn thing!!!

 

Yea if that was my car Id be doing my best to keep the engine or make the engine as original as possible. I'm all about hot rodding and my 57 is a ex drag car but Id not want to mess this one up due to to its more original than not and then there is the value of it vs modified. There are plenty of old heavily modified Vetts out there that can still be hot rodded .

That said if the original a engine was kept on the side then crate or replacement engine is a still a good way to enjoy the car or even improve the power a bit . Would love to see under the hood of it to know how stock it still is .
If i was going to modify anything on a stock one it would be the front brakes .

If it hasn't been sitting to long then the cylinders may be fine . A gasket set is like $50 to find out and its likely coming apart anyway .

 

Very first thing I would check is the Intake gasket like Oneball suggested. Put a length of rubber hose down the oil fill at the front off the manifold and put the other end to your ear. Have someone pressurize the radiator and listen for hissing and burbling.

 

Fill the engine with diesel all the way to the top. Manifold and all. Let it sit, soak. Give the sucker a chance to live again. Which cylinder’s had the intake valves open. Did water get in there? Did water destroy anything? Bore scope ? Look inside. Shove that scope in everything. Oil rises to the top. Maybe, just Maybe, the only thing suffering from any damage, is some goo in the bottom of the oil pan and the oil pump and pick up tube has some slimy goo. Easily removed by flushing the engine with diesel. I’ve taken many engines to the gas station and filled them up with diesel. People think I’m nuts. The biggest mistakes people make is trying to rotate the motor without soaking the cylinders with some kind of fossil fuel products. If you can fill the S.O.B. All the way to the top, it will even free up the throttle plates at the base or the carb. I went to purchase a 427 bbc , drove 4 hours. In the garage covered with a blanket, next to the washing machine. No intake manifold. Spun it over with a wrench. Water coming out of the exhaust manifolds. The guy’s like W.T.F. Turns out his wife would set her plants on top of the engine to water them. She did this for about three years. I purchase the engine at a reduced rate, just to get it out of they’re lives, might have saved they’re marriage. Getting ready to use the internals in a different block. Good luck, hoping for the best.

 

They have but thankfully they are in the trunk.