510SSS Posted July 23, 2012 Report Share Posted July 23, 2012 Ok so I'm trying to get my (1971 Datsun 510) back on the road after she started smokin like a chimney from worn rings. Now I figure this is my oppurtunity to upgrade, so I am building a LZ motor to replace it, here is my set up: L20b Block Bored .50 over, LZ22 crankshaft, LZ20E long connecting rods, Rebuilt W53 Peanut Head Shaved Very Low, L20b stock cam, Custom Headers, Dual SU Carbs. I was wondering if anyone can estimate for me what kind of compression I will have. I am trying to keep the compression low enough so that I can run on 91 pump gas since it is my daily driver. What type of pistons do you think would be good to use in order to lower the compression ratio? ring reccomendations? Any other techniques to keep the compression ratio reasonable? Thanks everyone. Quote Link to comment
NKrader Posted July 23, 2012 Report Share Posted July 23, 2012 http://www.ozdat.com...e/enginedesign/ im playing with what Frankenmotor I want to build at this moment aswell.. Quote Link to comment
datzenmike Posted July 23, 2012 Report Share Posted July 23, 2012 L20B block with Z20E rods and Z22 crank will require a piston pin height of just under 30mm and there are none ready made by Nissan. Custom ones are too expensive. Also a .5 overbore L20B with a Z22 crank is only 2136cc max. If you have an L20B block bore it to 87mm and slip a Z22 crank and pistons into it using your L20B rods... 2.2 liter, all Nissan used parts from a wrecking yard. Even easier is a good running Z22 motor and swap an L head, timing cover and oil pan on... done LZ22 Quote Link to comment
510SSS Posted July 23, 2012 Author Report Share Posted July 23, 2012 Would I be able to run an a stock L20b crank and utlize the L20E long connecting rods? Will this help to keep my compression down at all? My block is already bored and I cannot afford to rebore it, I am just going to have to hone it as is. Quote Link to comment
ggzilla Posted July 23, 2012 Report Share Posted July 23, 2012 So the L16 didn't blow, it was smoking. The L-series engines are very tough and rarely blow. Quote Link to comment
datzenmike Posted July 23, 2012 Report Share Posted July 23, 2012 Would I be able to run an a stock L20b crank and utlize the L20E long connecting rods? Will this help to keep my compression down at all? My block is already bored and I cannot afford to rebore it, I am just going to have to hone it as is. A block should be bored to match pistons not the other way round. If this was over bored where are the pistons for it? You can use the L20B crank and the Z20E rods only if you find Z20E pistons that are .5mm oversize to fit the block. These will be flattop and have a 9.6 compression with an open chamber head. 1 Quote Link to comment
510SSS Posted July 23, 2012 Author Report Share Posted July 23, 2012 I am using a closed chamber peanut head (W53), with my combination of .40 (87mm) overbore. Could I run L20b connecting rods in order to lower my compression? What piston/rod combination would allow me to best run on 91 pump gas? Quote Link to comment
sssr20det510 Posted July 23, 2012 Report Share Posted July 23, 2012 Get vg30e pistons and mill the tops down to 29mm piston hight Quote Link to comment
sssr20det510 Posted July 23, 2012 Report Share Posted July 23, 2012 Then you can still retain the z20e longer rods to keep the rod stroke ratio good for high rpm Quote Link to comment
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