XLR8NSS

iTrader: (4)

I just noticed on Eagles website that they have a 4.25" stroke LS series crank available. It states that it is for tall deck blocks only and is to be used with their 6.560" rod.

My question is to any engine builders who have seen/used this crank already. Is there a specific physical reason it has to be used on a tall deck block and with the longer rods? I know on a stock LS block a stroke that long is not the best do to the short sleeves but, is there any reason it couldn't be run on a sleeved block or the LSX block with the longer sleeves and standard deck height?

I put this in here mainly because this forum seems to deal with some of the newer bigger bore/longer sleeve blocks.

ls1408cp

iTrader: (37)

I asked about it in a lsx block a while back and never got an answer.

SLED28

iTrader: (7)

I have run a 4.250 stroke crank on a 9.240" deck sleeved block. It is only for N/A and the motor is more designed for race. It will burn more oil then a 4" or 4.125" crank. There is some pretty good sideload and the rings are very thin to make it work on the short piston. It can be done, but the tall deck will allow a taller piston, thicker rings and ringlands and less sideload with the longer rod.

Uthinkso

Of course the physical problem as well that the counter weights are too tall for use with a 6.125" rod like most LS builds. The pin tower of the piston would crash against the counter weight preventing the engine to complete a revolution.

427

iTrader: (3)

X2 on that reply.
It will never balance once you cut the pendulum down to clear that rod length until you do massive re-work (read expensive). The piston pin needs to be very narrow to get the reluctor wheel to spin also.

Kurt

XLR8NSS

iTrader: (4)

Good stuff guys!

Thanks for the responses.

SLED28

iTrader: (7)

I run longer then 6.125 rods in these combo's. AT least a 6.200 or even 6.250. I still have the custom piston spec sheets here, it would be easy to order!

Beast96Z

iTrader: (21)

I don't think the sleeves are long enough on the LSX, but the new "longer" Darton sleeves can accomodate that stroke. It's been done is a stock LS1 block, so there's no reason that it can't be done with the longer sleeves. It will require a few custom parts, but would make an awesome N/A motor when coupled with a 4.180" + bore.