CombatTalon2 Posted November 13, 2007 Report Share Posted November 13, 2007 Ok, so my engine is a 66.50mm bore. Yeah i know, im pretty thin! Stock stroke, 5mm long rod. Im running the blaster pistons and as far as i'm aware everything else is standard banshee stuff. I'm in the process of talking to David Noss to get my custom domes built and he expressed some confusion on my setup. While measuring my deck height i found that my pistons don't protrude out of the cylinder, or even come close to being even with the top of the cylinder. Actually im about 1.15mm down in the cylinder. Now the standard banshee domes that i was running have a .85mm depth, giving me 2mm (.079") squish measurement. So i guess my question is this normal for a 370 Long rod running blaster pistons? David is gonna make me some domes with no gap between where the head meets the cylinder (meaning the curvature of the dome starts right where the head meets the cylinder) This is inline with what the stock milled head looks like. this will also give me a squish of about .043 which from what i read is about right. A hell of a lot better than .080 like it was. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted November 13, 2007 Report Share Posted November 13, 2007 generally...people use the 795 series pistons for the long rod motors. However, as I'm sure you know...they don't make them larger than 66.00 mm. Blaster pistons have the same pin location as the 795, but I'm pretty sure the crown is in fact different. Do you think it's worth your time and money to have a set of domes cut for a motor on it's last bore, and on borrowed time as is? I agree the squish should be tighter, but you could use thinner base gaskets to tighten it up for now, then get new cylinders or yours re sleeved properly and use 795 series and a more standard cut dome.... Just throwing ideas out there.... or you could shave .020 to .030 off the tops of the cylinders.... There's more than a few ways to skin a cat..> Quote Link to comment Share on other sites More sharing options...
PassionRE Posted November 13, 2007 Report Share Posted November 13, 2007 (edited) generally...people use the 795 series pistons for the long rod motors. However, as I'm sure you know...they don't make them larger than 66.00 mm. Blaster pistons have the same pin location as the 795, but I'm pretty sure the crown is in fact different. Do you think it's worth your time and money to have a set of domes cut for a motor on it's last bore, and on borrowed time as is? I agree the squish should be tighter, but you could use thinner base gaskets to tighten it up for now, then get new cylinders or yours re sleeved properly and use 795 series and a more standard cut dome.... Just throwing ideas out there.... or you could shave .020 to .030 off the tops of the cylinders.... There's more than a few ways to skin a cat..> Yes, this is normal ,Blaster pistons are shorter that 795's from the pin the the top edge. The crown is also different and displaces much less volume than a banshee piston so the cc's of your domes will be different than your used to running with regular banshee pistons for the same given fuel choice...Jim Edited November 13, 2007 by PassionRE Quote Link to comment Share on other sites More sharing options...
CombatTalon2 Posted November 13, 2007 Author Report Share Posted November 13, 2007 generally...people use the 795 series pistons for the long rod motors. However, as I'm sure you know...they don't make them larger than 66.00 mm. Blaster pistons have the same pin location as the 795, but I'm pretty sure the crown is in fact different. Do you think it's worth your time and money to have a set of domes cut for a motor on it's last bore, and on borrowed time as is? I agree the squish should be tighter, but you could use thinner base gaskets to tighten it up for now, then get new cylinders or yours re sleeved properly and use 795 series and a more standard cut dome.... Just throwing ideas out there.... or you could shave .020 to .030 off the tops of the cylinders.... There's more than a few ways to skin a cat..> All good points. I want to ride it obviously, and would like it to run good for whatever length of time i get out of it, so I guess spending the 70 bucks to get the right domes is really no big deal. Cutting some off the cylinder would be good if i could find someone to do it and make sure both cylinders remained the same height. The 20cc banshee domes i was running were only 66mm. Dont know if that would cause any problems with anything since im at 66.50 now? I dont know what my plans are for when its time to do my top end again. Either cheap cylinders off ebay, and paying again for porting, or just go with a cub. Who knows! Thanks for the replies! Quote Link to comment Share on other sites More sharing options...
dajogejr Posted November 13, 2007 Report Share Posted November 13, 2007 All good points. I want to ride it obviously, and would like it to run good for whatever length of time i get out of it, so I guess spending the 70 bucks to get the right domes is really no big deal. Cutting some off the cylinder would be good if i could find someone to do it and make sure both cylinders remained the same height. The 20cc banshee domes i was running were only 66mm. Dont know if that would cause any problems with anything since im at 66.50 now? I dont know what my plans are for when its time to do my top end again. Either cheap cylinders off ebay, and paying again for porting, or just go with a cub. Who knows! Thanks for the replies! I'd get a cheetah cylinder with powevalves If I were you...based on your suspension setup, you're a duner more than a drag racer... Quote Link to comment Share on other sites More sharing options...
shee rips Posted November 13, 2007 Report Share Posted November 13, 2007 seeing how the cylinders are done next time they need a bore, shaving the top of the cylinders sounds like a good idea to me Quote Link to comment Share on other sites More sharing options...
CombatTalon2 Posted November 13, 2007 Author Report Share Posted November 13, 2007 seeing how the cylinders are done next time they need a bore, shaving the top of the cylinders sounds like a good idea to me unless i get them sleeved! Cross that bridge when I come to it I suppose! Quote Link to comment Share on other sites More sharing options...
Toybreaker Posted November 13, 2007 Report Share Posted November 13, 2007 thinner base gasket or shave a stock head to bring your quench into the dimension you want. Don't forget to take into account the compressed thickness of the head gasket or O-Rings..... Quote Link to comment Share on other sites More sharing options...
jjdillon426 Posted November 13, 2007 Report Share Posted November 13, 2007 David is gonna make me some domes with no gap between where the head meets the cylinder (meaning the curvature of the dome starts right where the head meets the cylinder) This is inline with what the stock milled head looks like. this will also give me a squish of about .043 which from what i read is about right. A hell of a lot better than .080 like it was. from what my builder has told me, between .040 and .045 squish is usually the best spot. i'm running .035 squish in mine, but i drag only with 110 and nitro. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted November 13, 2007 Report Share Posted November 13, 2007 On cub motors, I try for .040 to .050... There are others that run tighter...but it really depends on a lot. Squish angle, depth, dome cc, bore size, etc.... Quote Link to comment Share on other sites More sharing options...
ohiobanshee Posted November 14, 2007 Report Share Posted November 14, 2007 WSM makes a piston in that bore with the right pin height and banshee crown. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 14, 2007 Report Share Posted November 14, 2007 Yes, this is normal ,Blaster pistons are shorter that 795's from the pin the the top edge. The crown is also different and displaces much less volume than a banshee piston so the cc's of your domes will be different than your used to running with regular banshee pistons for the same given fuel choice...Jim Yep :thumbsup: Talk with Noss Machine. He cut me a custom set of domes after I had given him a squish clearance. They are right on. Mine were for a 4mill stock cylinder running blaster pistons. Quote Link to comment Share on other sites More sharing options...
dlnoss Posted November 14, 2007 Report Share Posted November 14, 2007 Those domes shipped out today. Let me know where the squish clearance and compression come in. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.