Eagle 7bolt 100mm stroker crank?

[twinkiemobile]

Hey i'm thinking about building up my motor since i need to rebuild my 120k mile stock 7 bolt block. I have not ran into any crankwalk symptoms which leads me to believe that my block is pretty stout. however, if i were to buy a brand new eagle 7 bolt 100mm stroke crank, would this ensure no crankwalk? or is the fundamental issues with crankwalk also found in the block and not just the crank? thanks for any help you guys can give to a newbie.

- Jose

[Rabbi]

i would like to know this as well

[mygsx2120]

No one knows what causes crankwalk. Some believe that it is the crank itself. Some blame it on aftermarket clutches, others such as magnus motorsports think is due the piston oil squirters. So the answer to your question is no.

My question to you is, if you are worried about crankwalk, why not do the 6 bolt swap. For the $1000 it costs for an Eagle crank and special bearings, it will be about the same. That is really the only way to elimate the chances of crankwalk. Crankwalk is overrated anyways.

[Jon Lane]

Judging by the success of both the late 2G DSM and EVO 7-bolt motors as well as certain aftermarket techniques applied to earlier 7-bolt motors to prevent them, when rebuilt and modified, from losing thrust bearing and crank integrity, the answer seems to be that increasing bearing surface, hardening cranks, and ensuring precision bearing-to-crank relationships are all key. Misaligned smaller bearings and caps seem to play a part in encouraging crankwalk.

EVO motors have improved 7-bolt bearings, as do the late-98 DSM 7-bolt engines. Both seem to have halted potential instances of crankwalk even though I believe they are using softer cranks than 6-bolts. In the NE, Overbore has great success replacing the original thrust bearings with modified units, hardening cranks, and ensuring very high precision in lower-end alignment and tolerances.

In other words, it may make sense to use the aftermarket crank in conjunction with the revised-style thrust bearings in a very well prepared block. Try Mark at Overbore.