Crankshaft deflection

Hey! I've just thought of an interesting and noncontroversial one to chew on. How about crankshaft deflection?

Norm Drazy

 

yeah, and do harmonic balancers realy help distortion? and what effect could these "sfi" approved units have if you have all the rotateing mass of the blower linked to it???? now that's a lot to chew warren dauzat

[ December 11, 2004, 08:54 AM: Message edited by: NITROITCH ]

 

Jim oddy ran Fluidampers on his chevy motors for years, i ran them in the past on a blown chevy motor, couldn't really tell a difference, though they are supposed to make the mains live longer. the only problem is it moves the blower pulley further out and gives the blower more leverage was my thought on it.

 

I wouldn't want to constrain this one, because to do so might kill a new idea.

Here's a real riddle: One of the mechanics on a fuel car was showing me the wear buttons that are mounted to the motor plate to keep the flywheel from wobbling too much. The buttons are set about .10 inch from contacting the flywheel face statically. Yet when the engine is makin' it, there's some serious contact going on. He'd noticed that the wear pattern was uneven, and was especially heavy in two places that were about a quarter turn apart. Any thoughts on this?

Norm

 

Sorry! I didn't intend to stop the harmonic dampener discussion. My apology. Norm

 

norm
i noticed a several years ago when we ran a RPM sensor/prox thru the motor plate (about where a starter would go) the we had to replace it as it was worn away on its face from the flywheel rubbing it, sometimes it would quit working all together and could not figure out why till it failed
also heard Gwynn had the same problem with their fuel car back then of flywheel rubbing the motor plate, not sure where theirs was hitting

 

Norm how about 7 o'clock and 4 o'clock. Also what material was being used for a bumper?

 

Could the clutch be holding the back of the crank to the point #7 and #8 throws are retarded? This could in essence make the ignition timing advanced on these holes, allowing peak cylinder pressure too close to TDC. That pressure at TDC along with the weight of the clutch allows that journal to wishbone and give a hit? #8 results in a hit then 450 degrees later #7 results in a hit 90 degrees apart?

[ December 14, 2004, 01:41 PM: Message edited by: T.Howell ]

 

I realize this is an old thread but hey. Its a blizzard outside and we are shut in and its 1 am.

I dont think the motor plate rub is a result of flywheel distortion. But more the result of the back half winding up during accelleration. Take two playing cards hold them parallel. Pick two forward upper corners which will represent upper rail engine mounts. Now rotate them at one end clockwise and notice the left upper rail pulls back as the right upper rail pushes forward. "Therin lies the rub" as they would say. Noticed this when we tried four point mounts. Three used bent motor plates stacked up in a pile like warped pancakes each tweaked exactly the same way and amount.

 

Woodchip;
Great observation!

Back in the early 1900's with steel 426's, the switch came to aluminum blocks. Hume and Foster were building cars together. A customer was having a terrible main bearing problem. Foster, who was also tune-up talented, thought about for a couple days, called the guy and said "take the left front motor mount bolt out and throw it away!" Bearing problems were cured. Anybody that has ever seen a Foster F/C might remember that any cars he built after, there was no bolt hole period!

I'm an old Minnesota boy, so I gotta do this:
It's 74 today and I gotta go home and mow the lawn!

 

I specialize in video and computer analysis of drag race cars. In the videos I have taken of nitro cars on the starting line, the wing doesn't just squat and lean to the right, but clearly turns to the left. this really backs up what these guys are saying about the engine twisting the frame.
I'm glad to see another approach to the rear main problem as it has cost a lot of people a lot of races and parts.