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Engine Liner Re-Bore  Rate Topic 
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 Posted: 04-19-2005 12:27 pm
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Nigel Abrahams (UK)
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Joined: 03-17-2005
Location: Taunton, United Kingdom
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My engine rebuild strategy is to use JE Flat top Pistons (+0.030" oversize) and get the cylinder liners re-bored and honed to suit. What is the standard practice for this machining operation ? Should the liners be kept clamped in the block for the re-bore or removed and done indvidually ?

My guess is that they should be kept in the block to avoid liner/nip problems etc..

Also, I have tried to remove the bearing studs in the bottom of the block but I have only managed to remove only one of the ten studs (using the double nut method and a 3ft breaker bar). I have a stud extractor tool I can use, but this will damage the studs and I don't want to go to the expense of buying new ones. 

Any advice on how to remove these studs, and should they be removed if the liners are re-bored in the block to give access to the bottom face of the block to serve as a datum for machining purposes?

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 Posted: 04-19-2005 02:41 pm
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Judson Manning
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Joined: 03-14-2005
Location: Atlanta, Georgia USA
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Nigel,

Your initial strategy is correct, however, many have found it necessary to hone all .030" rather than bore ~0.025" and hone the last 0.005".  The liners tend to warp and wiggle under the stress of a boring bar.  Delta stocks  0.005" o/s pistons as well as the 0.030".

The overwhelming consensus is to leave the liners in the block as any jig or clamp would oblong the liner during machining.  A number of people have machined a torque plate to hold eveything in place, and I know of a few people who have even heated the block with a 180^F water bath while completing the honing process.

We found that with a few pieces of scrap aluminum we were able to hold the liners in place during the ridiculously long honing process.  As for the 180^ water-bath...how perfect is practical?

With 30 years of corosion, I can understand how difficult it can be to remove the studs.  The double-nut method works fine for me, however, my machinist was able to work around the studs and I only remove the studs when the block needs to be decked.

Judson

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 Posted: 04-19-2005 05:27 pm
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Jensen Healey
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Joined: 03-11-2005
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Barry Spencer pulled my liners and clamped them into a custom made jig for boring. He said the jig cost him lots of $ to have manufactured. Sadly, he has closed his shop but your local Lotus shop may have a similar setup. 

 

Kurt

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