Underboost
Mr. Dull
- Joined
- Oct 4, 2005
funny you guys should say that, I had to get my flywheel balanced. The machinist sadi it was off quiet a bit.
+1 Me too JW Wheel
funny you guys should say that, I had to get my flywheel balanced. The machinist sadi it was off quiet a bit.
I don't believe you were looking beyond the table top. The table legs against the concrete floor is the crank against the thrust bearing. The table top is the flexplate. The hammer blow, converter pressure. The bushing movement distance, an example of how much force is absorbed by the table top versus the stiffer steel plate on the concrete floor.Don,
I don't wish to debate this any further but your logic does not apply here. The table top absorbs shock through giving up momentum thus not being stiff. In the case of a crank and bearing, it is infenitly stiff and the last anchor point in the series of parts. If The block and bearing were not stiff and had a spring constant, then your logic would apply.
Don't wish to wast my breath arguing on weather a flexplate should be used as a "shock obsorber".
Yes, I've thought about Newton's Laws a few times here and there. Yes there must be an opposing force to make the flexplate flex, that was my main point in my first post. In the static case that is all there is to say, which keeps it simple, which is why I stopped there until Hutch pointed out that in the real case it takes time for those forces to be applied. The force required, and thus the force needing to be opposed, and thus the force on the crank thrust bearing, is proportional to the amount of flex. The force is given by the amount of flex, not by how fast or slowly it flexes. However, it takes some time to achieve that flex because now whatever is pushing on the flexplate has to move with the flexplate to keep pushing on it, and thus some time to achieve full deflection and thus full force on the crank, and it takes some time to unflex, as well. That means that the force on the crank rises from zero to the max value over some period of time, not instantly as you seem to be saying.
I don't believe you were looking beyond the table top. The table legs against the concrete floor is the crank against the thrust bearing. The table top is the flexplate. The hammer blow, converter pressure. The bushing movement distance, an example of how much force is absorbed by the table top versus the stiffer steel plate on the concrete floor.
I agree with that.My post mentiond nothing about instant forces. Just stating that whatever force is applied to the flexplate is going to be apposed be the crank thrust.
I think the confusion is the pressure rise vs force applied. There is a possibility that the pressure spike may never translate into a force, or at least nothing with any measurable time duration. I don't think anyone would argue that. But with this scenerio, the flexplate will not have any time to deflect and if i did, the crank thrust would have to appose it.
Allan G.
OK. Maybe I'm getting too far out there trying to explain this in layman's terms.Don,
Enough with the table top. Explain with laws of physics and free body diagrams. Show us in equations.
Allan G.
The small amount of installed T/C clearance to the flexplate is only to make sure you don't setup a mechanical preload between the engine and transmission components. If you did install the T/C jammed against the flexplate, you would end up with an equally spread mechanical preload between the engine and transmission components. The crank thrust bearing surface, and typically the inner pump gear to pump cover surface. Theoretically, both would wear in that circumstance, but typically the tranny pump gear to pump cover chews up much faster.cover these comments like a blanket?
Assuming a converter was installed to spec., Don's idea for controlling line pressures pretty much takes care of my concern for thrust bearing problems.
What else can anyone do to control bearing thrust question(s)?
If you have problems, coating/cryo treatment would be a positive unless there is excessive impact from too much clearance, which goes back to the correct TQ install and Don's idea.
Is a part of this not in understanding the why's in shimming to properly locate the TQ?
Installed TQ clearance would be interesting if anyone cares to discuss it. Is .125 the trick? :biggrin:
Just stating that whatever force is applied to the flexplate is going to be apposed be the crank thrust.
Allan G.
Wow. That's a little harsh. OK then. Bison says, thread is over. So be it.This is all the explanation needed concerning the forces a thrust bearing sees. There should be no other discussion about it unless it is concerning how to control this force. Anyone who wants to post anything different than the simple law of physics Alan explained is a babbling fool. Imo this thread should be locked.
Did Chris find anything wrong with your old pump? Assuming Chris looked at your old pump.the restricting orfice didnt solve my thrust issues.I installed one of Chris @ CKs modified pumps after trying other options such as a restricting orfice modifying the bearing and wiping 2 cranks .its been about 5 years now but i havent wiped another thrust since the new pump from chris.alway ran a stock flex plate .Im building a new set up now so we will see been out for 2 seasons
Did Chris find anything wrong with your old pump? Assuming Chris looked at your old pump.
Excessive pump gear face clearance is certainly a contributor.I'll bet it still has a lot to do with excessive gear clearence causing excessive pressure on converter hub, 400's and 350's have had these problems for years that I can remember. Chevy's wipe thrust bearings too.
Kevin.
No I haven't. I've made checks on the rack, but not during a run. I have a permanent tap set up, so it would be easy to take a measurement. I'll try to remember to get it so that I can share it.Here is a example of (at least mine) of your converter fill pressures while you go down the racetrack. There are spikes in the gear shifts for a instant. I wonder if a flex plate will help absorb this? The trans is from Rossler. We have had ZERO thrust problems with it.
Don have you logged this on your car yet? I'm curious for comparative reasons.