Quote:
Originally Posted by GTX JOHN
Thank you Gentleman for the replies.
I appreciate the help
We removed and welded up the crank in the
Superstock which is cast to get through the year
I have been told that the welded thrust will not hold up
very well. Not by the place that did it. However, told that
by my regular crankshaft guy (Castillo) who would not touch it.
I am debating running on a foot brake rather than using any
starting line two step at all.
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John, I am no expert on a 2 step by any means as have always so far been a foot brakes. But I watch a whole lot of no prep and drag and drive action on super prepped tracks also and though most of them use a trans-brake they also are almost all boosted applications and use the cut of spark or fuel and many, many...beyond belief also suffer damage from loss of crankshaft thrust bearings.
Logic just tells me that the constant pressure of coming up smoothly against the crank at a constant rpm and Trans pressure has to be kinder on forward thrust and pressure on that crank and thrust bearing, than any jack hammer type action no matter what you do using either spark or fuel cut in a T.B. or a 2 step (no matter how they may brand it as soft touch).
Many engine builders (including Steve Morris on his own and Cleetus McFarland's high dollar superb built SMX which are a fast fortune each), in the no prep world in the last few years have gone on to devise and install special bearings that we cannot add that are added to the front of the crank between the block and the timing chain covers to combat just the issue that you are seeing.
And some of them have been successful so far, many of them have yet to get enough passes on the redesigned engines yet to make a clear judgment and as said much has been blamed on and worked on transmission pressures to lessen the push pressure which is all forward, never the opposite.
I can also say that at 93K miles on my little always foot braked 4 banger of an engine, every bearing both rod and crank showed no wear whatsoever except the thrust bearing shells. And only on the outsides (no crank damage).
I have seen no prep boosted guys tear up a lot of cranks and even split and blow up the timing chain/belt covers. So we need to take a hint from the extremists that when they are popping and banging away up on the Rev limiter they have to be jack hammering that crank a bunch with on/off forward thrust. They do not have as many passes as very few do much qualifying just some testing.
It is not the old days...Newer tech always brings newer issues. It just takes a while to take its toll. Some of those guys are tearing their freshly rebuilt stuff up really fast, so rolling out and back in a new thrust bearing at maybe 75 passes to 100 might just be the new preventative maint. to avert damage.