Light weight pistons & rods

[JW113]

Who do you suppose makes the lightest weight pistons for Shovelheads? Same for con rods? Are those H beam style rods lighter than the stock type I beam type?

thanks,
JW

[76shuvlinoff]

No help for you JW but if I can ask. Are you putting together a high rpm mill?  Light flywheels too?

If it's top secret I understand. 

Mark

[JW113]

No secrets, just toying with the idea to turn a 74" into a 80" or so. The left side bearing insert in my cases came loose (like they do), and was repaired by the shop. But his repair does not fix the annular seam between bearing and case, so it weeps engine oil pretty bad between race and case. Driving me nuts. So probably will tear it down this winter and either replace the cases, or get the race replaced with one of those Twin Cam Timken conversion kits. But while it's apart, maybe bore/stroke too. Hey, why not, right?


My own personal theory, whether fact or fiction, is that to minimize vibration, maximize rotating weight and minimize reciprocating weight. Then use a balance factor that optimizes the "out of balance" vector in the desired RPM range. So for my case, that would be 2500 to 3500 rpm. I have a couple of stock pistons on the shelf, but damn they sure do weigh a lot! Just curious if anybody has gone through the trouble of documenting piston weight for the available aftermarket pistons. Guess I'll be contacting Wiseco, KB, S&S, etc, and see if they will share that info with me.

cheers,
JW

[Hybredhog]

     Carillo rods weigh more than stock, I have a customer that HAD to have carrillo's for his 74" Knuck top/ Shovel lower build, and I had to add a chit load of lead to the flywheels to make up for it. Total overkill, and actually created 2 masses to compensate for. But for a good bang for the $$ stock evo rods are very strong & will be just fine for a 74/80 incher. Piston wise, I believe KB's are the lightest, even under forged, and again, for relatively stock builds, more than adequate. 

[rageglide]

My 80" shovel is running an evo flywheel and rods with KB cast pistons which were honed to fit the evo pin size.

JW I still have a set of torque monster stroker wheels in my garage... just sayin.   

[friday]

guy on shovelhead is replacing pistons = Arias . good comments on weight etc

its performance motor , he toasted a piston giving it the berries up the motorway

all top stuff in there plus taper flywheels

[HotRodShovel]

Ive got T&O flywheel assembly in my Shovel. They came with the H beam type rods.  I just looked on their website at the connecting rod page and there is no mention of weight.

I would suggest a call to them. Cant hurt.  When I first installed their assembly I had a few conversations with them about technical issues and they were always receptive to those calls.

Just a suggestion, I think that would be a ground ball for them

[JW113]

Hey Bob, yeah I keep forgetting about that! Hmm... maybe I'll surf around and see if they have any 89" pistons that don't require stroker plates or raise the C/R too high. No idea why S&S favors 4-1/2 stroke over 4-5/8.

-JW

[Burnout]

When you rev up the longer stroke motors it opens up the big end of the rods.

life span shortens measurably.

I guy I know drag races with the big boys, he short shifts his junk so he doesn't have to buy a crank for every final round.

[JW113]

If this mill ever gets past 4K revs, must be a blue moon. The bike is an around town tractor, with the occasional spin down the freeway at 80, which is only 3200rpm. To make things easy, was leaning toward a 80" motor, so's not have to deal with specail pistons, cylinders, relocating oil return holes, etc. I have a set of aftermarket 74" jugs that I could bore to 3-1/2", and just round up the flywheels. I need the "heavy" wheels since this has a kicker on it, so T&O is an option, or just cruise ebay for a set of stock 80" wheels.

-JW