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Original Message
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| RE: Good point. |
| By Gerry Proctor - 02/04/2005 10:05:02 AM; IP 207.133.188.254 |
But the rule of thumb is specific to the particular casting, the method used to install the sleeves, and the intended use. So, in that regard, it's impossible to apply universally.
A block with thin walls as cast using poorly installed sleeves intended to run a superchager(mechanical or chemical) or very high compression, and in an abusive environment will very likely have problems lifting the deck with adjacent sleeves.
As with anything, there are perfect ways, right ways, and Bubba ways to install sleeves. Gessford machine has a photo series on how they do sleeves. It involves heating the block and putting the sleeve in liquid nitrogen to shrink it. Once the sleeve is in, it is nearly as good as parent metal. As to the brazing method, that’s something that isn’t normally done these days with the advent of race blocks. In the 60s and 70s, it was a common(not all the common, really) to insert brazing wire into grooves in the sleeve, press the sleeve in the bore and stick the block into a very hot oven for a couple of hours. The furnace brazing method made the sleeve nearly as strong as the parent metal but cause tremendous distortions in the block. Obviously, there was a lot of post-heating stress relief and major machining to bring the block back to blueprint specifications. Very expensive and time consuming. But it was sometimes necessary.
The accepted method today is to coat the sleeve with green Loctite and press it in. The down and dirty Bubba method involves just hammering the sleeve down the bore and calling it good.
All of these methods rely on accurate machining to ensure reliability and the best method can be compromised by sloppy work.
You can’t do much about how robust the block and the cylinder walls are. If you have good parent metal in the wall after boring for the sleeve, you could run all eight with sleeves and not see a problem.
Use also has a lot to do with how well a sleeved block will survive. You can twist and lift an unsleeved block’s deck if you run enough cylinder pressure. It happens all the time with the 5.0 guys.
So just because a block has sleeves is no reason to run away. If I wasn't going to beat on the engine unmercifully, I would be fine with multiple sleeves. |
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This thread, so far...
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