cleaning cosmoline off of NOS block

[mightyohm]

Hey all,

I picked up a new old stock 1725 block from SS. The block, crank, rods, etc are all covered in a thick layer of cosmoline. What's the best way to clean this stuff off? I'm thinking about having the block hot tanked to avoid the mess of cleaning it in my garage. However, as I understand it, I'd have to remove the cam bearings and freeze plugs in order to do this. It seems like a shame to remove fresh parts and have to replace them.

I've also heard that there can be casting sand left inside the block from manufacturing, and that's another reason to really flush out the block before using it. Again, is it worth pulling the freeze plugs on a brand new block to do this?

 

[RootesRacer]

Hey all,

I picked up a new old stock 1725 block from SS. The block, crank, rods, etc are all covered in a thick layer of cosmoline. What's the best way to clean this stuff off? I'm thinking about having the block hot tanked to avoid the mess of cleaning it in my garage. However, as I understand it, I'd have to remove the cam bearings and freeze plugs in order to do this. It seems like a shame to remove fresh parts and have to replace them.

I've also heard that there can be casting sand left inside the block from manufacturing, and that's another reason to really flush out the block before using it. Again, is it worth pulling the freeze plugs on a brand new block to do this?

Brake cleaner will dissolve it right off but you will have to repaint the block.

The only other thing I can think of to avoid the respray would be to use a hot water pressure washer perhaps with a "engine cleaner spray" prewash.

 

[Bill Blue]

Don't mineral spirits or kerosine do a good job with cosmoline? They are not instantaneous in action, but easy on paint.

Sand inside the block sounds like it would be in the water jacket. If so, it would be contained and at worse, end up in the radiator. Not good, but not catastrophic. If the build was so careless that sand might be left in the mechanical area of the block, I would take it down to bare block and rebuild.

Bill

 

[Tom H]

The problem area for sand in the black has been at the rear, behind the #4 cyl. Might be worth removing just that rear freeze plug. Then run a coat hanger wire down there to loosen any sand residue. Hopefully you'll find none, indicating that the shop that cast these blocks were more careful than the original factory. This seems to me a good compromise of some small extra work to have confidence.

Tom

 

[mightyohm]

Brake cleaner will dissolve it right off but you will have to repaint the block.

The only other thing I can think of to avoid the respray would be to use a hot water pressure washer perhaps with a "engine cleaner spray" prewash.

Is there any advantage to retaining the original paint? The block is blue. I was planning on painting it black anyway.

 

[RootesRacer]

Is there any advantage to retaining the original paint? The block is blue. I was planning on painting it black anyway.

No and the partly dissolved paint that brake cleaner leaves behind is as good as primer as far as painting on.

 

[Jay Laifman]

FWIW, I just had to remove cosmoline off of the rocker shafts I got from SS. I looked online and found people suggest boiling water. I figured it was the least damaging possibility. I have to tell you, it was like magic. I put them in a tin, poured boiling water over them and it just flowed off. I wiped a little more with hot water after and they cleaned up perfectly.

So before you spend too long smelling those strong solvents, just use some water.

 

[DanR]

QUOTE: .... However, as I understand it, I'd have to remove the cam bearings and freeze plugs in order to do this. It seems like a shame to remove fresh parts and have to replace them.

I've also heard that there can be casting sand left inside the block .....Unquote

++++++++++++++++++++++++++++++++++++++++++++++

If you have to remove the cam bearings....? That is getting into the oil passages ?

If that is the case I'd suggest you be very cautious and not contaminate the other bearings and surfaces (rod&mains)...

Doesn't sound like a great idea tearing into the engine unless you are going to tear down all the way.

There has to be a better way to resolve your problem with the cosmoline!

DanR

 

[mightyohm]

I'm completely tearing down the engine. Not only has it been sitting in storage for who knows how many years (35?) but i'm swapping out the low compression pistons for high compression ones.

 

[DanR]

Jeff, That is a smart move!!

I would highly recommend you disassemble the entire engine freeze plugs and any other plugs then rod out any area you can.... scrap and scratch the complete inside of the engine block....

You'll never regret!

DanR

 

[mightyohm]

I can report that mineral spirits and WD-40 work well in conjunction with each other. I wound up spraying the block down with WD-40 (inside and out) and let that sit overnight, then removed the resultant slurry with mineral spirits and a set of brushes. A stiff toothbrush worked best for the hard to reach areas. I also used a plastic razor blade to scrape away the thick spots. Without this step it would have taken much longer.

 

[tony perrett]

I would be inclined to follow DanR's advice and remove all of the freeze plugs in order to thoroughly flush out any casting sand. When I replaced the rusted plugs I was surprised to see how much sand was present and it had become compacted. At least with a new block it should be dry and easy to remove.

 

[ALPINE5GT]

Now is definitely the time to take the opportunity to remove any sand behind #4. My series V Always runs hot, and I am sure it is caused by this problem.
I just have had no reason to pull the Motor, and don't drive it enough to justify the tear down.