QC_MURDOC Posted February 5, 2010 Share Posted February 5, 2010 Yesterday I went to Nissan to buy the pistons for KA24E my Strocker. the guy asked me what grade. 1-2 - or 3? I know it's very important for the original engine, but is there a better grade for 3.1? Is there a stronger one?? What is the difference between them? or is it just to match the date of different parts of the engine?sorry for the noob question but I really want to make sure to have good pistons, and yes I searched. Quote Link to comment Share on other sites More sharing options...
hoov100 Posted February 5, 2010 Share Posted February 5, 2010 go forged if you have the money. (also the L31 stroker has been covered many times on this site) Quote Link to comment Share on other sites More sharing options...
Xnke Posted February 6, 2010 Share Posted February 6, 2010 as far as i know, they are not graded. He probably means what oversize do you want: i.e. stock, 20 thousanths over, or 40 thousanths over. Quote Link to comment Share on other sites More sharing options...
WEBEZEEed Posted February 6, 2010 Share Posted February 6, 2010 Back in the day when I used to get my dirt bike motor rebuilt, an over bore piston used to be described as a 1st ,2nd,or 3rd over size. Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted February 6, 2010 Share Posted February 6, 2010 Back in the day when I used to get my dirt bike motor rebuilt, an over bore piston used to be described as a 1st ,2nd,or 3rd over size. That's probably it. Quote Link to comment Share on other sites More sharing options...
QC_MURDOC Posted February 6, 2010 Author Share Posted February 6, 2010 ok, but they are exactly the same size. only different part #. I would prefer the forged, but I find no place to buy 6 without buying 2 set of 4. At the dealer it is possible to buy only one. Quote Link to comment Share on other sites More sharing options...
WEBEZEEed Posted February 6, 2010 Share Posted February 6, 2010 QC,if you went to Nissan and "the guy" asked you what grade piston, then I would think "the guy" should have your answers for you. Quote Link to comment Share on other sites More sharing options...
hoov100 Posted February 6, 2010 Share Posted February 6, 2010 ok, but they are exactly the same size. only different part #. I would prefer the forged, but I find no place to buy 6 without buying 2 set of 4. At the dealer it is possible to buy only one. If you call the company that makes them, you should be able to buy 6. Quote Link to comment Share on other sites More sharing options...
QC_MURDOC Posted February 7, 2010 Author Share Posted February 7, 2010 QC,if you went to Nissan and "the guy" asked you what grade piston, then I would think "the guy" should have your answers for you. He told me that if it was to put in a 240sx, I needed to give the VIN # of the block to know what grade to use. anyway tanks for your help Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 7, 2010 Share Posted February 7, 2010 Like VW Pistons, they are made to a specific weight range, or bore diameter depending on production tolerances of the tooling (I forget which on the KA). 1, 2, & 3 will determine which grouping they have. Its most important when you buy one piston and need to match the existing one to what you have. Putting a heavier '3' in with a light group of three other slugs may cause an imbalance situation. Having a 1, a pair of 3's and a 2 would likely cause some vibration I'm thinking. If it was bore sizing it related to, then the obvious scuffing and noise issues rear their head from incompatible tolerances piston-to-wall. "They all should be the same, and bore accordingly." This is all in the KA FSM, guys... If you are buying them one at a time, I'd buy two sets of four and have two spares of the correct matched grade in case something went wrong. It's like buying V8 pistons for the Z. You get two spares. So what? Eventually they will come in handy, as either detonation replacements, or ashtrays. Ask anybody who built an engine and then WAAAAAAY down the road broke a piston and needed to get only ONE replaced. Ask them if they would think you buying 6 'and two spares' would be a bad idea... I bet I know what they would say! Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 7, 2010 Share Posted February 7, 2010 That's what I thought, SECOND POST: http://www.freshalloy.com/forums/archive/index.php/t-132864.html Same as most Nissan Water-Cooleds. The VW was weight grouped. Damn Germans, they take tolerance to a new level. "Ze Diameter ist correct, ziss ist nat zubjekt doo debate! Zee veight is vat vee mus concentrate our efforts upon! Zee veight!" The EXACT bore diameter specifications are found under 'pistons' on this post (imagine what a 30 second google search turns up, eh?): http://www.240sxforums.com/forums/ka24de-t-ka24e/116466-anything-everything-you-want-know-about-your-ka24de.html Quote Link to comment Share on other sites More sharing options...
QC_MURDOC Posted February 7, 2010 Author Share Posted February 7, 2010 tanks for you answer! mayde i'm better with 2 set of 4, if my budget permits me Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted February 9, 2010 Share Posted February 9, 2010 Give Courtesy Nissan in Texas a call about their price for these pistons. You'll likely save a good chunk of money even with shipping cost. http://www.courtesyparts.com Quote Link to comment Share on other sites More sharing options...
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