sorealsosurreal Posted January 27, 2009 Share Posted January 27, 2009 So I finally got my pistons actually a while ago they are from ITM Engine components and are full floating standard size with a slight dish. Part # RY6426-STD if anyone’s interested. My problem is that the stock bore on the ka24 is 89.002 mm and when I measure the piston about the middle of the skirt measures 89.4 mm also the pistons came with know information on what size to hone to or anything of the sort. So my question is what I should hone to since obviously it wont is a standard ka24de bore. Just curious on your guys input. I will be calling the company I got the pistons from later. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 27, 2009 Share Posted January 27, 2009 Take the block and pistons to a machine shop with a real hone.They can hone the block out exactly to a particular size. If you try to do this with a ball hone I don't see how you could possibly keep the bores square (you may have already known this part, I don't know). There are specs for piston clearance, and you should be able to specify with the machinist whether you want the bores "tight" or "loose". Loose makes more power but doesn't last as long. According to "How to Rebuild" .002" is standard. .009 is max allowable, but that is probably for cast pistons. Forged has different specs, I think they run tighter, or they end up with a lot of piston slap. Each bore should be fitted to a particular piston. Quote Link to comment Share on other sites More sharing options...
sorealsosurreal Posted January 29, 2009 Author Share Posted January 29, 2009 yeah i called ITM and they wouldnt tell me for some odd reason. i measures all the pistons and they all came to 3.530 in give or take a thousanth got the info to add .002 in for ring clearance so thats what im going to go with. no i would never try to beadhone the block. Ive got two hones to choose from an older sunnen and a brand new rottler that is supposed to be ready for use next week. trying to hold off to use the rottler. thanks for the help! Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted January 29, 2009 Share Posted January 29, 2009 Actually, I believe forged require more clearance than cast, because they expand more. If this is an Na build I would say that hyperutectic pistons would be best - even for a turbo'd - only IF you know how to keep the AFR and ignition under control....just ask ScottieGNZ Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 29, 2009 Share Posted January 29, 2009 Actually, I believe forged require more clearance than cast, because they expand more. If this is an Na build I would say that hyperutectic pistons would be best - even for a turbo'd - only IF you know how to keep the AFR and ignition under control....just ask ScottieGNZ You are correct, thanks for that. Quote Link to comment Share on other sites More sharing options...
josh817 Posted January 29, 2009 Share Posted January 29, 2009 Yes forged requires more clearance, they are stronger, and usually lighter. Only problem with that extra clearance is pistons slap when the motor is cold so you can't hound on it until everything is warmed up. That however, doesn't really matter though since we should all wait for a warm motor to give it a gun... If you take the piston and block to the machine shop they match up that piston with whatever bore. Under no circumstances do you say I want an 89mm bore because pistons are perfect sizes as you can see but in most cases they are .0xx of what they should be... Better hurry yourself over to Courtesy Nissan for their 90mm x 1mm metal headgaskets unless you're buying Kimeari or some other brand. Quote Link to comment Share on other sites More sharing options...
sorealsosurreal Posted February 3, 2009 Author Share Posted February 3, 2009 gonna wait till i get my head built to see how thin a headgasket i can fit with the N42 i have thats decked and possibly 1mm oversized valves. the motor is NA with hyperutectic full floating pistons possibly later ill build a p90 and turbo it later on but for now the plan is carb'd NA Quote Link to comment Share on other sites More sharing options...
josh817 Posted February 3, 2009 Share Posted February 3, 2009 If you want to make power look into all the head build threads on this forum. For an N/A motor, even a 3.1L you will need all the help you can get when it comes to flow. There is a guy on here who didn't go too hot on his head and wound up making 180HP at the wheels from his 3.1L... He's learned and is now doing 265hp I think. Don't be one of those guys, bigger displacement means bigger bucks. Quote Link to comment Share on other sites More sharing options...
sorealsosurreal Posted February 3, 2009 Author Share Posted February 3, 2009 oh no i wont be skimping on the head, pocket porting, new valve train with possible oversized valves and a reground cam with specs from the MSA stage 2 cam (streetable power range) is what's in store for the head already have a 6 to 1 header and for fuel delivery thats up in the air for now and depends on how much money i have but plan on it being carb'd. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 3, 2009 Share Posted February 3, 2009 Stage II is too small. Do some searching and buy something bigger. Quote Link to comment Share on other sites More sharing options...
josh817 Posted February 4, 2009 Share Posted February 4, 2009 Stage II is too small. Do some searching and buy something bigger. Yup I'm at Stage IV right now and thats .495"/290º however I'd like to bump up to Rebello's midrange grind since Stage IV is what I just listed and the Stage V jumps way up to like .560"/300º. Quote Link to comment Share on other sites More sharing options...
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