How to clean a block
 

Hello all
I recently pulled the engine in my yellow 1968 L89 corvette due to poor compression.
Heads are in the shop being rebuilt and the block has been completely taken apart.
Prior to me buying the car, it sat for a long time and there is a bunch of crude inside the block.

I called up a couple of machine shops and they will put the block in to essentially an engine dishwasher. None have the ability to tumble it with shot (not sure what the machine is called) to clean the water passages and completely clean the inside of the engine.
How are you guys cleaning engines prior to rebuilding?
The block needs no machine work. Mump the engine builder will hone the cylinders, new bearings and rings.

My other question is if I do find someone that has a rotating shot cleaner, will this affect the engine pad stamping?

Thank you

Flip it
 

A

I would not shot peen the block.i would power wash it and put it in a barrel and fill it with evaporust and leave it in for a day or two.buy 20-25 gallons and do one side of block and flip the engine and do the other side. Would cost you $500 in chemical but would be clean.

Here is an example of my experience having a block shoot peened.
https://www.yenko.net/forum/showpost...6&postcount=11

That VIN stamp does not look like it was stamped with a gang stamper the last 5 numbers look like a heavier stamp, looks like you destroyed your concrete driveway

Ha ha, I’m hoping that mess will clean up Ralph. I got carried away pulling the engine, and completely forgot to put down a large piece of cardboard I have for this exact reason.

Re: vin stamp…
Of course it was stamped with a gang stamp. Were they done any other way?
You’ve been around long enough to know there can be nuances with stampings.
I had the stamping certified by Corvette Validation Services( aka Jonathan Herrick)as original.
The original drivetrain was in the car and the transmission has part of its vin lightly stamped also.
And of course I have the tank build sheet.

Interestingly, I had concerns about the block casting date (3-25-68)being so close to the assembly date (4-18-68), which was also close to the car’s assembly date(4-25-68).
I called Jonathan ( he has the L89 registry and owns Corvette Validation Services and he had several cars in his data base that was very close to my car.

If I remember correctly a couple of L89’s whose vins were close to my car had the same exact Tonawanda assembly date as my car. Apparently these L89’s were batch built.

Re: block cleaning… My plan is to take it to a local machine shop and have it run thru the pressure washer with solvent and hot water. Hoping this will remove the oil and grease and anything else.
Then buy some bulk Evaporust and put the block in plastic with water surrounding it to compress the Evaporust.

I've noticed on several TH400 Vin stampings that the last 3 or 4 digits are not even with the first digits. My guess is that the factory stamped the first two or three digits knowing the car would be in a certain range of a thousand cars and left the last three or four digits until later in the assembly.

Maybe that's the case here? The digits fonts are all good.

Block
 

HI i would and i have bolt the oil pan on and sand blast the block and oil pan with the block up side down . Then wash thee hell out of it .

One of the local machine shops bakes them. The invoice say's "thermal clean". They come out clean and rust free. Just a thought.

I'd probably just fill the water jackets with evaporust (or similar) - shouldn't need much. I don't see a speck of rust anywhere else on this block.

I don’t know what Ralph is talking about to be honest.
It looks good to me, broach marks are present, characters match other 68’ L89 blocks that are built close to the vin. And it’s been validated by the same guy that does all of Corvette Mike’s C3s.
I don’t really see the need to defend it.