sotaorava Posted June 4, 2012 Share Posted June 4, 2012 hi all i know there are many post about these builds and i have read most that i can find but there are few questions still remaining... my bottom end is -n42 89mm bore -ld28 crank -9mm 240z rods -240sx pistons with 2.8cc dish i have read that compression with those parts and 2mm head gasket is 10.14:1 i am planning to use 1.5mm head gasket and then piston to head would be 0.9mm which would be better according my head builder? any danger that valves hits pistons? can anyone calculate what would compression be using 1.5mm head gasket? and what camshaft (and where to buy) would be best for that compression? car is for daily driver occasionally little race so i am looking wide powerband max rpm 7000-7500?? first i am planning to drive my ztherapy su:s with sm needles and when budget allows go to tribles i have msa 6-2-1 header also ready with 2.5" exhaust Quote Link to comment Share on other sites More sharing options...
ctc Posted June 4, 2012 Share Posted June 4, 2012 Piston to valve clearance will depend on camshaft selected. There is an engine calculator out there for the Datsun L engines that let you change gasket thickness and other parameters to calculate compression. Engine cal Search around here for what others have done regarding cams, it will depend on what you want the engine to do and what comprimises you make. For your target RPM band, are you using cast or forged pistons? Also, APR rod bolts I assume? Quote Link to comment Share on other sites More sharing options...
steve260z Posted June 4, 2012 Share Posted June 4, 2012 What head? steve Quote Link to comment Share on other sites More sharing options...
sotaorava Posted June 4, 2012 Author Share Posted June 4, 2012 (edited) thanks for that calculator! it says compression is 10.77 with 1.5mm gasket i think that would be ok for pump gas or is there possibility to increase compression to 11.5 or somenthing if i use correct cam... and what would be correct cam for wide powerband and that compression? we have here in finland 98 octane i believe its ron? is that about 93 octane us gas? my headbuilder said that exhaust valve should be increased a bit to 37mm intake should be fine at 44mm +basic porting of course.What you people think about that? pistons are standard 240sx believe those are cast not forget and head is n42 Edited June 4, 2012 by sotaorava Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted June 4, 2012 Share Posted June 4, 2012 I understand cast pistons will not be reliable over 7000 rpm. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted June 5, 2012 Share Posted June 5, 2012 There has been a lot of discussion here if the extra power/efficiency gained from raising the CR offsets the loss of power/efficiency when timing has to be retarded due to detonation. I suspect you will not be able to run full advance with 11.5:1 CR on 93 pump gas with an open chamber head such as the N42. The conservative approach would be to get the CR into the 10:1 range, maybe even lower, with your configuration. Quote Link to comment Share on other sites More sharing options...
sotaorava Posted June 5, 2012 Author Share Posted June 5, 2012 yeah been reading those i think i go with that 1.5mm head gasket that gives me 10.77 compression and for cam i was thinking http://www.thezstore.com/page/TZS/PROD/PEM01/10-2000 and there 10-2002 or 10-2003 any ideas or recommendations? Quote Link to comment Share on other sites More sharing options...
josh817 Posted June 6, 2012 Share Posted June 6, 2012 Resources Enter in custom numbers, you are not restricted to what is in the drop down panels http://www.atlanticz.ca/zclub/techtips/calcs/engine%20builder/index.html'>http://www.atlanticz.ca/zclub/techtips/calcs/engine%20builder/index.html http://www.atlanticz.ca/zclub/techtips/ And of course this place is filled with info if you are diligent. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted June 6, 2012 Share Posted June 6, 2012 I would be very cautious about going with a Schneider cam. Search and you're going to find many who have had cam failures - I'm one who "did everything right" including using ZDDP religiously. For less money you can have a cam reground by Isky or Delta Cams that is customized for your application. You'll have to source the balance of the parts yourself (it's not a kit), but you'll be using a Nissan blank which has proven to be more reliable than the Schneider. Most tedious task for me was to determine the correct lash pad size and then find them. But I believe Z Car Customs now has them available. Spend some time searching here and then you can make an informed decision about a cam. Quote Link to comment Share on other sites More sharing options...
steve260z Posted June 6, 2012 Share Posted June 6, 2012 Are you dead set on an open chamber head? Better way to go is a P90..... Quote Link to comment Share on other sites More sharing options...
sotaorava Posted June 6, 2012 Author Share Posted June 6, 2012 i allready have e31 and n42 heads so yes atleast for my first build Quote Link to comment Share on other sites More sharing options...
sotaorava Posted July 14, 2012 Author Share Posted July 14, 2012 recommendations about carbs weber or mikuni any difference? if webers dcoe 40 or 45? will 40 be good for 3.1 and 300hv? there are few sets on ebay every now and then Quote Link to comment Share on other sites More sharing options...
sotaorava Posted July 25, 2012 Author Share Posted July 25, 2012 i got my hands on F.E.T intake manifold for triples carburetor side is ok 45mm for my 45 dcoe webers but head side is only 30mm in diameter is that good or should i machine that a little bit bigger? Quote Link to comment Share on other sites More sharing options...
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