Chewievette Posted March 8, 2006 Share Posted March 8, 2006 I recently stumbled upon two fully intact 240sx's at the local junkyard with of course KA24s under the hoods. Do I need to be looking for a specific car to get the stroker pistons from or will any ka24 pistons work. Obviously they need to match each other but if I pull all eight pistons and chose the best six should I be alright to use them? All of the parts I'm getting are going to be cleaned, inspected, and balanced before going into my engine but I need to know if it will be worth it to spend time pulling the pistons out of those engines and using them or should I keep saving and buy new ones. Also since I now have a 2.4L that is in my 240z, I can use the connecting rods out of that correct? Mine is a '72 so I dont know which rods it has but is there a serious problem with using the older rods in a stroker? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 8, 2006 Share Posted March 8, 2006 I have and would reuse pistons on a block, but I don't think you'll find too many people thinking that reusing pistons on a different block is a good idea. Cast pistons are cheap. Just get new ones. Quote Link to comment Share on other sites More sharing options...
Chewievette Posted March 8, 2006 Author Share Posted March 8, 2006 I thought that only applied to rings. Since the used pistons will be in a fresh bore with fresh rings I dont see where the problem is. It will basically be like reusing pistons in a full rebuild. If I can get a deal on new ones I'll just do that since it will save me the trouble of pulling the pistons out. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 8, 2006 Share Posted March 8, 2006 Well you have a point. Maybe I'm wrong since you're boring the block. Still, seems shadetree to me. Too shadetree. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 8, 2006 Share Posted March 8, 2006 Before you pull out those pistons ask your machine shop :how much does it cost to press out six KA24 piston pins WITHOUT DAMAGING the pstons? I gave my L26 rods/pistons to my machine shop to pressed out the pins. I asked for an estimate, they said : 28$CDN for EACH if I want to keep the pistons undamaged, 40$CDN for all six if I don't care about damaging the pistons. I said I don't care and the pistons were indeed damaged in the process. They charged me based on actual hours spent so I was only charged 22$CDN If the shop charges you a lot to press out the pins without damaging the pistons, then you wouldn't save much by going with used pistons. Quote Link to comment Share on other sites More sharing options...
Chewievette Posted March 8, 2006 Author Share Posted March 8, 2006 Good point, I knew there was a reason I didn't like pressed pins. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted March 10, 2006 Share Posted March 10, 2006 What's the difference between a ka24 piston and an l28e? I thought you could use the l28e pistons with the 240 rods to achieve a 10.5:1 compression engine roughly -Ed Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 10, 2006 Share Posted March 10, 2006 The pin height is different. L28 pistons would stick up 3mm over the deck on 240 rods. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 10, 2006 Share Posted March 10, 2006 also bore size. KA24 = 89mm, L28 = 86mm Quote Link to comment Share on other sites More sharing options...
510six Posted March 11, 2006 Share Posted March 11, 2006 You can also use VG30et pistons that are a 1mm overbore.I ran 80 10lb bottles of N20 on a set of VG30et pistons with an all stock parts bottom end with a 120hp shot to the wheels with no problems.If you are willing to have the rods prepped a set of VG30dett pistons will work and can handle 100hp per cyl. Quote Link to comment Share on other sites More sharing options...
73ZCAR Posted March 11, 2006 Share Posted March 11, 2006 Hey 510, Do the VG30dett pistons have the same pin height as the 240sx pistons? IE.. for use with 240z rods and stroker crank? Mike. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted March 11, 2006 Share Posted March 11, 2006 So then you could use the VG30et pistons with the stock 280 rods and have a stronger setup? I'm assuming the bore is bigger on the VG30et pistons. -Ed Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 11, 2006 Share Posted March 11, 2006 VG30DETT ie Z32 have a piston pin bore of 22mm (the L rods must be rebored to be able to accept the pin) VG30E & VG30ET ie Z31 have a pin bore of 21mm (same as L series) I don't know how much compression you will get with VG30ET pistons because they are dished, compared to VG30E piston that has only 1cc in valve relief. My hypothetical setup(turbo stroker) is LD28 stroke, 240Z crank, P90 head and 1mm overbore(87mm), VG30E pistons and that only give me 8.006:1 CR. With a dished VG30ET piston you might want to use N42 head, but it still won't be a high compression setup, more like a turbo setup (8.5:1 or so) Quote Link to comment Share on other sites More sharing options...
510six Posted March 12, 2006 Share Posted March 12, 2006 I used a N33 closed chamber head with VG30et pistons and ended up with a 9.2-1 compression ratio.It was perfect for the N/A nitrous motor.The VG30et and VG30dett both have the same pin heigth as the 240sx piston.What I like about the VG pistons is the 87mm bore esp. with a turbo or N20 motor a little thicker cyl. wall doesn`t hurt.The VG pistons have to be used with the 133mm 240z rods and the diesel crank. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 13, 2006 Share Posted March 13, 2006 What years of 240sx are you referring to? I got different pin height in KA24 and VG30DE/VG30DETT based on this program http://www.ozdat.com/ozdatonline/enginedesign/ The VG30DE/DETT has 31.75. VG30E not in there but IIRC 31.75 as well. KA24 has 34.00 Quote Link to comment Share on other sites More sharing options...
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