ghettoracer Posted May 5, 2007 Share Posted May 5, 2007 NPR, RS machine and maybe 1 or 2 other companies makes ITR replacement cast pistons. RSM also started making high comp pistons for B20B/Z. Basically it's trusty ITR dome (so it's not huge, unlike CTR piston dome) but cast in 84, 84.5 and 85 mm sizes. Link here: http://www.honda-tech.com/zerothread/1569878 price is pretty reasonable below $300. Technically I think the they would be illegal under the rules but I would love to see them get allowed. What do you guys think?! Right now, to build a B20B/Z to high comp legally, you can deck the head a lot and/or shaved the head a lot. If these pistons are allowed it would be drop in affair. Quote Link to comment Share on other sites More sharing options...
ghettoracer Posted May 5, 2007 Author Share Posted May 5, 2007 in addition on bottom ends... "9.3.1 H1 Hybrid Vehicle Engine Preparation a) This section is intended to clarify the engine preparation rules specific to Hybrid Vehicles. b) The engine, from the top (deck surface) of the engine block “down†Quote Link to comment Share on other sites More sharing options...
chad Posted May 5, 2007 Share Posted May 5, 2007 Those will never be legal....not unless the b20 weigh goes up! Quote Link to comment Share on other sites More sharing options...
Chris F Posted May 6, 2007 Share Posted May 6, 2007 Yeah, come on, OEM-only pistons in H1/H2. Otherwise we all have to get 0.040" over pistons... and higher compression... Quote Link to comment Share on other sites More sharing options...
ghettoracer Posted May 6, 2007 Author Share Posted May 6, 2007 ahh well, I thought these are affordable alternatives but extremely similar to stock OEM Honda parts... oh well. CR is unrestricted in H1 if all Honda OEM parts are used. i guess people just have to get creative... hmm, the ITR replacement from RSM, NPR... etc. should be legal according to this rule (7.1c) as I do believe they are exactly duplicates of ITR. "Factory replacement pistons or the exact equivalent shall be used. Exact equivalent shall be defined as the same dome/dish/valve relief configuration, weight, ring thickness and location, and pin location as the OEM replacement piston. Wrist pins and method of retention must also conform to OEM specifications. In the event that a .040 factory replacement piston/wrist pin is not available, the oversize pistons/wrist pins shall not weigh any less than the largest size OEM piston for that engine." if I read the rules correctly, modifying GSR girdle to fit B20B/Z block will be legal? Quote Link to comment Share on other sites More sharing options...
chad Posted May 6, 2007 Share Posted May 6, 2007 but the ITR piston never came in 84 m so how can it be a factory replacement piston??? Quote Link to comment Share on other sites More sharing options...
BrianZ Posted May 7, 2007 Share Posted May 7, 2007 ahh well, I thought these are affordable alternatives but extremely similar to stock OEM Honda parts... oh well. CR is unrestricted in H1 if all Honda OEM parts are used. i guess people just have to get creative... hmm, the ITR replacement from RSM, NPR... etc. should be legal according to this rule (7.1c) as I do believe they are exactly duplicates of ITR. you are reading the "limited prep" rules.. for H1 it says 9.3.1 H1 Hybrid Vehicle Engine Preparation b) The engine, from the top (deck surface) of the engine block “down†Quote Link to comment Share on other sites More sharing options...
ghettoracer Posted May 7, 2007 Author Share Posted May 7, 2007 would this be a legal H1 engine build? D16Z6 head, D16Z6 block, B18B rods, max over sized (1mm over?) P29 (89 D16A3) pistons?9 Quote Link to comment Share on other sites More sharing options...
BrianZ Posted May 7, 2007 Share Posted May 7, 2007 (edited) would this be a legal H1 engine build? D16Z6 head, D16Z6 block, B18B rods, max over sized (1mm over?) P29 (89 D16A3) pistons?9 in H1 you can oversize the bore, you just have to be able to get the pistons from HONDA Edited May 7, 2007 by Guest Quote Link to comment Share on other sites More sharing options...
civicrr Posted May 7, 2007 Share Posted May 7, 2007 in H1 you can oversize the bore all you want, you just have to be able to get the pistons from HONDA ...and use the stock cylinder liners bored out up to .040 over. Quote Link to comment Share on other sites More sharing options...
BrianZ Posted May 7, 2007 Share Posted May 7, 2007 in H1 you can oversize the bore all you want, you just have to be able to get the pistons from HONDA ...and use the stock cylinder liners bored out up to .040 over. opps... i stopped reading to early.. Quote Link to comment Share on other sites More sharing options...
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