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I am building a 427 with the LSX block. but my builder went to bore it yesterday, and the main caps are a .001" too high. the rod slides when he tightened it down to bore it. is this normal. he said i had to cut the mains down .002 and then line bore it. are the main bearingsany bigger on the lsx stuff. oh and he is a sbc and bbc builder. not ever mess with the lsx stuff. is there any special machine work that has to be done that he wouldnt normally know about. he is my neighbor and is a great builder but, i am a little scared since he doesnt do ls engines. any info would be great
 

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LS stuff does not require special tools or black magic as far as building them. Machine work is machine work so if he puts it within tolerance, it will all be fine. We have seen brand new cranks that need to be ground and brand new blocks (BB, SB, all kinds) that need align bored and decked. Sounds like he knows enough to check everything. You would be surprised the amount of people that think just because it is brand new that they don't have to check anything. Good for him for checking and good for you for double checking.
 

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he is saying, the bar that they put in the mains to hold it for boring is loose..It has little rings that get tightend by the main caps, well the main caps will not tighten all the way up on the rings... so the guy is worried that it wont hold the block steady and bore it straight...

anyone seen this problem before on a new block?? LSX block
 

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PM me his contact info so I can have someone give him a call tommorow.


I will forward this to one of the production managers at GMPP.

The mains should not be that loose in my opinon.

Robin

Oops, need to read the clearences thread to learn a bit......
 

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he is saying, the bar that they put in the mains to hold it for boring is loose..It has little rings that get tightend by the main caps, well the main caps will not tighten all the way up on the rings... so the guy is worried that it wont hold the block steady and bore it straight...

anyone seen this problem before on a new block?? LSX block
What boring machine is this?
 

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he is saying, the bar that they put in the mains to hold it for boring is loose..It has little rings that get tightend by the main caps, well the main caps will not tighten all the way up on the rings... so the guy is worried that it wont hold the block steady and bore it straight...

anyone seen this problem before on a new block?? LSX block
O ok. I have not seen or heard of this problem on these blocks.
 

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Here is what I was told.

The main bores should be 0.002" small. The blocks are not shippped ready to assemble. They require a line hone.

If the block mains are too big then they should return the block to the dealer they purchased it from and get another.

For your knowledge or if you want to inquire, the main bore specification is 69.829 +/-0.009 mm.

Let me know what you find.

Robin
 

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Discussion Starter #8
billy the machine is at a nascar shop, i am not sure what kind it is. I took the block to a machine shop today to have them cut the mains and line bore it.
 
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