Alex Posted August 30, 2002 Share Posted August 30, 2002 Just off on one.... Out of curiosity can you increase the bore size of the 2JZ? Can you turn it into a 3.2-3.4 by just increasing the bore and not touching the stroke? I realise it reduces the strength of the block. Would the liners have to be made out of anything special?? Is there "normal" stuff to make liners from and then high cost but 10x better liner material? What else would you have to concider other than getting pistons made to fit? Would the rods have to be changed purely cause the piston head is bigger? Would the crank have to be stronger (in which case getting a JUN stroker kit would be an advantage). Also bare in mind that you'd still need it to be reliable... Thanks Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted August 30, 2002 Share Posted August 30, 2002 I did ask this a little while back when everybody was talking about stroking........ I think the consensus was that not too many options due to limits of the liners and coolant channels and that the only commercially available pistons would be the Toyota oversize ones. Quote Link to comment Share on other sites More sharing options...
Alex Posted August 30, 2002 Author Share Posted August 30, 2002 I was including in my train of thought that I would commision new Omega or Cosworth Pistons (flights of fancy are great) has any one got a - to scale - top down diagram of the block?? I'd like to see where the channels run etc Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted August 30, 2002 Share Posted August 30, 2002 Why not de-stroke it down to say a 2.8, then bore it back to 3ltr, same displacement, just means you could rev it much more. I think a mixture of boreing/stroking would be best. Quote Link to comment Share on other sites More sharing options...
Alex Posted August 30, 2002 Author Share Posted August 30, 2002 You could but to shorten the stroke would require a custom crank which would cost more than a longer stroke crank already in production (like the one JUN use). It would be a fantastic experiment if you've won the lottery and are able to wast vast sums playing with different concepts. Or bored and stroked to a 3.6 he hee....that would help spin up those lazy 2835's or big singles! Just hoping for another Darren Blake special, Or one from CW Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted August 30, 2002 Share Posted August 30, 2002 Originally posted by Alex Holdroyd You could but to shorten the stroke would require a custom crank which would cost more than a longer stroke crank already in production (like the one JUN use). Your having a pipe dream anyway, so the more expensive the better Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 30, 2002 Share Posted August 30, 2002 Originally posted by Syed Shah Why not de-stroke it down to say a 2.8, then bore it back to 3ltr, same displacement, just means you could rev it much more. I think a mixture of boreing/stroking would be best. Just use the Soarer engine as the base. The 2.5 litre is such a sweet engine, for a high revver with cams and big turbos the 2.5 has the edge. As for boring a 3 litre block you could do one of several things. Cut up a scrap block on a big bandsaw and measure the wall thickness (where is this liner talk coming from, the block doesn't have liners, it's a one piece block?). Have a block sonically tested for wall thickness. Bore one until you break into a waterway and then bore another a good deal less :-) Modern blocks usually have far less meat in them than the older engines as weight was considered and computer aided design means they can be built without extra meat where it's NOT needed. You can USUALLY bore most modern blocks at least .060 oversize on the bores though. Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted August 31, 2002 Share Posted August 31, 2002 Originally posted by Chris Wilson Just use the Soarer engine as the base. The 2.5 litre is such a sweet engine, for a high revver with cams and big turbos the 2.5 has the edge. But, then you have a smaller displacement engine that NEEDS to rev higher just to spool the same turbos etc. Doing the destroking and oversize bore on the 2JZ-GTE would allow to rev nearly as high, but with more torque while also spooling the turbos at considerably less RPM. Quote Link to comment Share on other sites More sharing options...
Alex Posted August 31, 2002 Author Share Posted August 31, 2002 Not necessarily Syed. The Soarer head also flows more/better. Which will aide turbo spin up. I think what Chris is saying, is, no one knoes for sure if you can or cant but you would have to waste a shed load to find out! Quote Link to comment Share on other sites More sharing options...
Digsy Posted August 31, 2002 Share Posted August 31, 2002 I only have one pretty lousy picture of the block, but it looks quite meaty around the cylinders. I don't think there's any coolant between them in the siamesed walls, either (apart from what looks like two drillings, but the coolant flow diagram on MKIV.com doesn't show any between-cylinder flow). An extra 2mm on bore would give you 3.14litres. I think 3.2litres would be pushing it. You might need a new head gasket, depending on how close the sealing bead was to the cylinder bore. (Not as special as my cam profile post - my wrists are still aching from that one. At least I think that's what it is Chris is right, without a block to dissect, or a drawing, boring out would be a brave move!) Quote Link to comment Share on other sites More sharing options...
Alex Posted August 31, 2002 Author Share Posted August 31, 2002 2mm's wow! it's and 86mm bore stock isn't it?? So a possible max of 88mm's which would indeed need a different HG. One of the companies out there already produces 87.5mm bore pistons so maybe we should leave it at that. Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted September 1, 2002 Share Posted September 1, 2002 Originally posted by Alex Holdroyd Not necessarily Syed. The Soarer head also flows more/better. Which will aide turbo spin up. I think what Chris is saying, is, no one knoes for sure if you can or cant but you would have to waste a shed load to find out! Surely it must have been tried in the states? Some of the tuning companies over there spend massive amounts on their cars, to them, this would be small change! As for the head, that would be easier to enlarge to flow more. Quote Link to comment Share on other sites More sharing options...
Digsy Posted September 1, 2002 Share Posted September 1, 2002 Originally posted by Alex Holdroyd it's and 86mm bore stock isn't it?? So a possible max of 88mm's which would indeed need a different HG. One of the companies out there already produces 87.5mm bore pistons so maybe we should leave it at that. Stock bore / stroke is 86mm square (0.4996 litres, give or take ) 87.5 bore would give you just over 3.1 litres. Quote Link to comment Share on other sites More sharing options...
Alex Posted September 1, 2002 Author Share Posted September 1, 2002 That'll do me I guess Thanks for your help Darren....though now I need to work out why I bothered asking when I'm about to place an advert to sell my Supra. Quote Link to comment Share on other sites More sharing options...
Digsy Posted September 1, 2002 Share Posted September 1, 2002 You could sell it as an "unfinished project"... ...you don't have to mention that you haven't gone any further than working out the bore sizes! Quote Link to comment Share on other sites More sharing options...
eyefi Posted September 1, 2002 Share Posted September 1, 2002 Originally posted by Alex Holdroyd Out of curiosity can you ....... curiosity satisfied? Quote Link to comment Share on other sites More sharing options...
Alex Posted September 1, 2002 Author Share Posted September 1, 2002 Originally posted by eyefi curiosity satisfied? Never Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted September 2, 2002 Share Posted September 2, 2002 Alex I have the 87.5mm PHR JE pistons. Quote Link to comment Share on other sites More sharing options...
Alex Posted September 2, 2002 Author Share Posted September 2, 2002 Originally posted by Terry Saunders Alex I have the 87.5mm PHR JE pistons. What?! Spare ones you say...that I can have...you're too kind! :p So you have a 3.1L 2JZ with a big single and an Aftermarket ECU....hmmm what other little gems are under the hood???..... Quote Link to comment Share on other sites More sharing options...
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