1971 LT-1 Engine C11S106394 V1228CGZ

[Robert E.]

Saw this on the Toronto Kijiji website

http://toronto.kijiji.ca/c-cars-vehicles-classic-cars-1971-Chevrolet-Corvette-Coupe-W0QQAdIdZ358959256

I'm not the poster nor am I affiliated with the seller.

Robert

[Kenneth H.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

So, I was wondering, what is a "high nickle block"?

Thanks.

[Michael W.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

Ah yes- the famous 010/020 myth.

[Pat M.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

Ah yes- the famous 010/020 myth.

Michael, what is this myth?

[Mike E.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

That those had a higher nickel content and were less subject to wear--that's the myth he references.

[Michael W.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

Popular lore says that 0010 casting number engine cases with the raised numbers '010' and '020' under the timing chain cover have a higher content of nickel and tin in the cast iron and hence are 'better'. It appears that these two numbers are actually pattern numbers for two concurrently manufactured cases on which they could be used interchangeably- the ubiquitous 3970010 and it's little brother the 307 cu. in. 3970020.

I think this myth was busted here several years ago by a member who may have worked in the plant at the time.

[Pat M.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

That those had a higher nickel content and were less subject to wear--that's the myth he references.

Popular lore says that 0010 casting number engine cases with the raised numbers '010' and '020' under the timing chain cover have a higher content of nickel and tin in the cast iron and hence are 'better'. It appears that these two numbers are actually pattern numbers for two concurrently manufactured cases on which they could be used interchangeably- the ubiquitous 3970010 and it's little brother the 307 cu. in. 3970020.

I think this myth was busted here several years ago by a member who may have worked in the plant at the time.

Thanks guys, interesting. What made some think there was a higher nickel/tin content in these cases in the first place? Simple rumors?

[Ron G.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

I have been around LT-1's for years and have never heard this before.

[Michael W.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

Thanks guys, interesting. What made some think there was a higher nickel/tin content in these cases in the first place? Simple rumors?

I stand to be corrected but think I remember John H relating that GM experimented with the tin/nickel content for a certain time period to see the effects on durability and manufacturing. The changes apparently made no appreciable difference.

Somehow the legend was created that the 010 020 numbers meant an extra 1% tin and 2% nickel, rather than just relating to the pattern or core numbers.

[Pat M.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

I stand to be corrected but think I remember John H relating that GM experimented with the tin/nickel content for a certain time period to see the effects on durability and manufacturing. The changes apparently made no appreciable difference.

Somehow the legend was created that the 010 020 numbers meant an extra 1% tin and 2% nickel, rather than just relating to the pattern or core numbers.

Thanks Michael, I'd never heard of this before.

[John H.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

I stand to be corrected but think I remember John H relating that GM experimented with the tin/nickel content for a certain time period to see the effects on durability and manufacturing. The changes apparently made no appreciable difference.

Somehow the legend was created that the 010 020 numbers meant an extra 1% tin and 2% nickel, rather than just relating to the pattern or core numbers.

That's correct - there was a program to evaluate an additional 0.1% tin (for improved machinability) and an additional 0.2% nickel (for improved bore surface hardness), but testing and warranty didn't support the added cost, and it was cancelled; it had nothing to do with the "010-020" cast under the timing cover, which, as Mike noted, was a core pattern number used on both 010 and 020 block castings. Many folks will spend stupid money to find a "010-020" block which they think is "stronger and harder"; some myths die hard.

[Kenneth H.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

John,

If GM experimented with this modification, and testing and warranty was involved in this experiment, how did GM track the evaluation blocks? If Terry M. is watching, I think he knows where I'm going with this, and I'm asking kinda tongue in cheek.

[Terry M.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

John,

If GM experimented with this modification, and testing and warranty was involved in this experiment, how did GM track the evaluation blocks? If Terry M. is watching, I think he knows where I'm going with this, and I'm asking kinda tongue in cheek.

Yes I know where you are going Ken, and the answer is right in your signature for all to see.

Mark Gorney (I hope I spelled that right) may have some answers as well.

[Michael M.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

I had always heard that the old Cadillac blocks (472 and 500) had a higher nickel contect. Not sure if that was myth or not or part of the same program to determine if it helped durability and then dicontinued.

[Kenneth H.]

Re: 1971 LT-1 Engine C11S106394 V1228CGZ

Terry,

You mentioned member Mark Gorney in your post. Was he involved in the testing that John mentioned above, or is he someone who might have additional info on the "M" coded blocks?

Thanks.