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Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: BPBP440] #1371335 01/18/13 11:44 PM 01/18/13 11:44 PM
Joined: May 2004 Posts: 5,123 Warrenton, VA RoadRunnerJD master
RoadRunnerJD master Joined: May 2004 Posts: 5,123 Warrenton, VA	You probably will not be able to match the weight of the cast pistons exactly. I would spend the money to rebalance the whole reciprocating mass. It will be worth it in the long run. If you are replacing bearings, it will be also worth building in the extra clearance in the bearings and the piston to wall. It won't cost any extra. It will make the motor in your street cruiser zing!

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: RoadRunnerJD] #1371336 01/19/13 06:22 AM 01/19/13 06:22 AM
Joined: Aug 2006 Posts: 2,144 junction city oregon V viperblue72 top fuel
viperblue72 top fuel V Joined: Aug 2006 Posts: 2,144 junction city oregon	Quote: Quote: They are definitely right around 875g without the pin. I wouldn't dwell on the weight. You can find lighter pins and remove some metal under the pistons to lighten them some if you want but unless you are trying to wring that one extra tenth of a second out of it and race every weekend, the weight is not going to make that much difference. Otherwise, but lightweight pistons and rods and go all out. I don't think horsepower is the reason for concern about the weight. I think the stress that it puts on the rest of the bottom end is imo. Although these old trw's are very prevalent and have been used for years with success.

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: BPBP440] #1371337 01/19/13 11:19 AM 01/19/13 11:19 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Since you will be talking to Best Machine, let them balance the assm... Chrysler was bad enough on a stock balance that if you want a smooth running engine I would have them balance it.. no matter if you found pistons with equal weight

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: viperblue72] #1371338 01/19/13 12:25 PM 01/19/13 12:25 PM
Joined: May 2004 Posts: 5,123 Warrenton, VA RoadRunnerJD master
RoadRunnerJD master Joined: May 2004 Posts: 5,123 Warrenton, VA	Quote: Quote: Quote: They are definitely right around 875g without the pin. I wouldn't dwell on the weight. You can find lighter pins and remove some metal under the pistons to lighten them some if you want but unless you are trying to wring that one extra tenth of a second out of it and race every weekend, the weight is not going to make that much difference. Otherwise, but lightweight pistons and rods and go all out. I don't think horsepower is the reason for concern about the weight. I think the stress that it puts on the rest of the bottom end is imo. Although these old trw's are very prevalent and have been used for years with success. No problem for a street machine. You want to talk about weight of the reciprocating mass, what about the heavy rods in the 70-71 6-BBL cars or a 426 Hemi? I broke an LY rod in an original A12 motor once but it was at 8200 RPM's with over 200 runs on a 13.6:1 race only motor. I would not worry about the weight but I would definitely get it balanced if you are changing pistons!

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: RoadRunnerJD] #1371339 01/22/13 11:03 PM 01/22/13 11:03 PM
Joined: Nov 2012 Posts: 264 Farmington Hills, MI B BPBP440 OP enthusiast
BPBP440 OP enthusiast B Joined: Nov 2012 Posts: 264 Farmington Hills, MI	Thanks for all the great input guys, I am grateful for the advice. I think I may not have included all the info, and led some folks to think of the older TRW vintage 2355's, whereas these are the newer Speed Pro 2355's. Is the opinion that I am still OK at .0045 PWC (despite the input of .002-.0025 that speed-pro verbally but reluctantly provided), without having a bunch of piston noise and premature wear??

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: BPBP440] #1371340 01/22/13 11:33 PM 01/22/13 11:33 PM
Joined: Aug 2003 Posts: 44,085 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 44,085 Bend,OR USA	Quote: Thanks for all the great input guys, I am grateful for the advice. I think I may not have included all the info, and led some folks to think of the older TRW vintage 2355's, whereas these are the newer Speed Pro 2355's. Is the opinion that I am still OK at .0045 PWC (despite the input of .002-.0025 that speed-pro verbally but reluctantly provided), without having a bunch of piston noise and premature wear?? I haven't ran my new motor with the coated Speed Pro likes yours yet but .0045 worked fine on all the old motors I did with the non coated 6 pak pistons Go for it No piston slap or noise at .0045 either Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: Cab_Burge] #1371341 01/23/13 04:26 PM 01/23/13 04:26 PM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	We ran into the same issue with SpeedPro and not getting a solid answer.We have seen a lot of their pistons scored at the skirt on engines that were set at .0015/.0025 for street use and many machinest would rather set it at .004/.005.We have set the forged hi-silicone pistons at .0025 to.0035 on race applications with synthetic oils and found no problems. [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: B G Racing] #1371342 01/23/13 08:06 PM 01/23/13 08:06 PM
Joined: Feb 2005 Posts: 4,349 Prospect, PA BSB67 master
BSB67 master Joined: Feb 2005 Posts: 4,349 Prospect, PA	Quote: We ran into the same issue with SpeedPro and not getting a solid answer.We have seen a lot of their pistons scored at the skirt on engines that were set at .0015/.0025 for street use and many machinest would rather set it at .004/.005. Bob - that is what I remember. The first set I bought about 25 years ago actually came from SpeedPro with the 0.0015" - 0.0025" spec in the instructions, and guys that ran them at that would tear-up the skirts. My machinist and I decided to put them in at 0.0035". I still have them (in a box now) and they look perfect. I would not think about putting them in at anything less. Of course, today's metallurgy is probably way different.

Re: Piston to Wall Clearance for 2355 "Six Pack" pistons?? [Re: B G Racing] #1371343 01/23/13 10:28 PM 01/23/13 10:28 PM
Joined: Nov 2012 Posts: 264 Farmington Hills, MI B BPBP440 OP enthusiast
BPBP440 OP enthusiast B Joined: Nov 2012 Posts: 264 Farmington Hills, MI	Quote: We ran into the same issue with SpeedPro and not getting a solid answer.We have seen a lot of their pistons scored at the skirt on engines that were set at .0015/.0025 for street use and many machinest would rather set it at .004/.005.We have set the forged hi-silicone pistons at .0025 to.0035 on race applications with synthetic oils and found no problems. Moving forward with the Speedpro pistons. Thanks to all for the great advice.

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