FrontEngineDragsters.Org Forum

Technical => Matt Shaff's Engine Shop => Topic started by: Larry Gocha on May 31, 2016, 08:08:29 AM

Title: Balancing
Post by: Larry Gocha on May 31, 2016, 08:08:29 AM

Matt we bought a new set of pistons and there 45 grams lighter than what we had do have to rebalance the crank? We weren't expecting them to be different same part number as before.

Title: Re: Balancing
Post by: Paul New on May 31, 2016, 08:22:59 AM

In my opinion yes. Another option is to find heavier wrist-pins.

Title: Re: Balancing
Post by: Frontenginedragsters on June 01, 2016, 03:24:16 AM

Hello Larry:
 Yes 45 grams is a lot of weight. The good news is that the crankshaft will have to be lightened to balance.
Much cheaper than adding weight for heavier pistons.

Matt

Title: Re: Balancing
Post by: Larry Gocha on June 05, 2016, 06:14:00 AM

We got close by going to .250 wall pins now were only around 7 grams lighter than the original piston.

Title: Re: Balancing
Post by: dusterdave173 on June 05, 2016, 10:00:13 AM

That will work out fine
Most shops shoot for plus minus a few grams--it is well known that anything within approx 25-28 grams and no issues--think old time factory balance back in the 60's 70's  --Ford was pretty darn good but Mopar was the Worst!! I do a lot of old 440 Mopars and they can be crazy off
7 grams is within margin of error for sure I mean--we guess at 4 grams for oil etc so run them IMO
Now 40 grams/ That has to be corrected

Title: Re: Balancing
Post by: Larry Gocha on June 11, 2016, 06:01:45 PM

Thanks for the replies guys I didn't think the heavy pin would hurt as he sprays about 500 on this thing at times with two kits.