inline6 Posted May 29, 2011 Share Posted May 29, 2011 I dropped off most of the engine parts with my engine builder today. The block is an N42 from a 77 Z (had round port head). Quick measurements on the bore thickness in a couple of accessible areas make me think I won't be able to do the 89mm overbore. This is going to be a NA engine... but we measured .175" in one spot on the front cylinder (freeze plugs are removed). Back cylinder, where accessible was in the .2 something territory. It will be sonic tested in the coming days. From some threads I found here, the guidance seems to be .125" thickness for cylinder walls. Anyone have thoughts on this? I hoped to go 89mm on the bore with this block. Now, I'm thinking 88.5 will be more likely. And that might put me at .115". G Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 29, 2011 Share Posted May 29, 2011 Wet sleeves is always an option... Quote Link to comment Share on other sites More sharing options...
inline6 Posted May 30, 2011 Author Share Posted May 30, 2011 Wet sleeves is always an option... Any idea of approximate cost? I'm thinking the block would have to be shipped there (where the machining and liners can be done) and back? Am I better off (time and cost) searching for another N42 block... say from 75? Theory being that with production variances or more regular changing of coolant, perhaps I can find one with thicker (enough) walls? G Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 30, 2011 Share Posted May 30, 2011 Sinking wet sleeves is one step beyond boring. Most shops that bore also sleeve the cylinders when needed. Can check with Darton or L.A. Sleeve for pricing on sleeves and dimensions. Quote Link to comment Share on other sites More sharing options...
SKiddell Posted June 2, 2011 Share Posted June 2, 2011 When we built my steel motor last year we took the opportunity to measure the wall thickness in several areas across all bores (ultra sonic unit), my plan was to only go to 88mm on a stroked billet crank, and boring out to this left between 150 and 160 thou of wall thickness. Personally this is a minimum for me as I am running around 12:1 compression and didn’t want any barrelling of the bores. Recently it’s made close to 290 FWHP on the rolling road with 242 ft/lbs of torque (not bad from a 3 litre that has to be driven on the road to comply with club rules), with that I don’t see the value of scraping out the bores further for what would amount to small power gains and potential reliability issues (personal choice) Re sleeving (Tony D) another block we did ran into porosity issues at 88mm and we had to sleeve one cylinder (fast road engine), the company we used did a cracking job and its hard to see why its not done more often (cost sure). If I had the budget and needed to go to a big bore then I would sleeve the whole damn thing given half the chance, and leave nothing to chance, nothing to stop you using some of the more exotic materials on the liners and rings then. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 2, 2011 Share Posted June 2, 2011 "If I had the budget and needed to go to a big bore then I would sleeve the whole damn thing given half the chance, and leave nothing to chance, nothing to stop you using some of the more exotic materials on the liners and rings then. " Now you're gettin' smaaaaata! Quote Link to comment Share on other sites More sharing options...
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