green aftermarkit engine blocks

[randy77zt]

if a person was to buy a aftermarkit bbc tall deck block would or should it be heat treated or cryo treated before machining?i have somebody asking me about an engine and had a problem with main bearings on a green engine before.what do the big time engine builders do ?

[78Eliminator]

Putting a block in the oven does nothing to strengthen the block. The cleaning ovens are heated to 700F. The temperature in the cylinder is around 3000F. So, a measely 300F isn't going to do anything.
FYI: If you take the block and sit it in the sun in the desert, you can get it to 300F.
Justin

[Fiat48]

I've heard some good things about the cryo treating but haven't ever done it. But main bearing problems don't play in here. Whoever you heard had a main bearing problem probably had an incorrect line bored block either in sizing or straightness or both. Or could have been an oiling or clearance problem.

[DORIGHT]

How maney blocks are produced by MFG's and put in new cars and released to the public? Millions over the years they dont Cryo or heat treat their blocks.
Wanna do some thing Trick though?
Try getting your cylinders Nitrited.
(This will require heat treating to do though)
Simular to the coating that chevy puts on their cranks, But when used in the Cylinder bores it makes the bores harder and aids in Preventing cylinder wear, Aids ring seal most important.
Better than chrome cylinders.
They use it in Aircraft engines, Neat stuff
Most pepole dont know what the heck im talking about
I have found one shop that will do it, And its in Tulsa OK

[TIMINATOR]

We cycle the blocks in the cleaning oven to 550 deg to ambient over a 24 hour period for 4 days, this relaxes the internal stresses before machinework. It is recomended by GM, MOPAR and FORD, you can measure the differences in the machinework before and after. The old standard of letting all castings remain outside in the weather for 2 YEARS before any machining (back east) works too, but who wants to wait that long? IF the current crop of aftermarket stuff has relaxed somewhat before you get it, its possible to see how far off it is. Take a set of new iron heads and put the decks together, and look towards the light, if they have been around a while you can see how far off they are. Think about the valvejob and guides! TIMINATOR :) :eek!:

[cstraub]

On a green block with a fresh bore and hone the cylinders will move around after just a few hours. If you were to take it apart the cylinder walls would look blotchy. . .movement of the walls. As stated it is common to use the furnace cleaning machines to heat cycle the blocks.
Chris

[78Eliminator]

Originally posted by cstraub69
On a green block with a fresh bore and hone the cylinders will move around after just a few hours. If you were to take it apart the cylinder walls would look blotchy. . .movement of the walls. As stated it is common to use the furnace cleaning machines to heat cycle the blocks.
Chris
How do the cylinder walls move?

[Infomaniac]

Originally posted by DORIGHT
How maney blocks are produced by MFG's and put in new cars and released to the public? Millions over the years they dont Cryo or heat treat their blocks.
Wanna do some thing Trick though?
Try getting your cylinders Nitrited.
(This will require heat treating to do though)
Simular to the coating that chevy puts on their cranks, But when used in the Cylinder bores it makes the bores harder and aids in Preventing cylinder wear, Aids ring seal most important.
Better than chrome cylinders.
They use it in Aircraft engines, Neat stuff
Most pepole dont know what the heck im talking about
I have found one shop that will do it, And its in Tulsa OK
Imagine that, Okies up on the latest and greatest.
There are several general aviation engine component repair shops here. They provide the maket for the heat treat process shops as well.

[cstraub]

Nicaseal. . .common in german and italian engines in high HP.
78, the cylinder change shape and you will have areas that shift in and out so you have loose and tight spots up and down the cylinder walls.
No you don't have to do this to OEM engine. . .but you are not pushing the block to its limits. This is done by professionals to reach maximum HP levels.
Chris

[TIMINATOR]

The SAE standards for machinework of castings recomended that they be left outside for 2 years to stabilize before machinework was done. We did that at ALLIS-CHALMERS at least up until I left their employ in 1977. It was related to me that that practice fell into disuse during WW II, due to the need to get war materials into the front lines. The engines, etc. were overbuilt as to H.P. to make up for the losses. After the war all the returning soldiers had out of country pay to spend and wanted cars, so the carmakers haven't seasoned the blocks etc. since to keep up the demand. P.S. Allis-Chalmers was bought out by Fiat many years ago(high manufacturing costs?). We are trying to maximize the performance of what we have so thats why we go the extra steps. If you dont think I'm right, get some instant gun blueing, apply it to the walls of a new block, and make a light hone pass with 600 grit stones and LOOK! Try it on the heads with a skin cut too. We have a CBN diamond tooled head mill and can skin cut .001, what a revalation to you naysayers! This is why we have to charge more for precision machinework. ITS NOT ALL THE SAME!!! TIMINATOR :) :D