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Kenny's 1990 740 GLE, goin' for 9's

Actually no apparently I did it before I fixed that. .0005 flexplate runout, and .001 converter base runout at that time. Not sure I can get a good reading now with the loose bolts.
 
linuxman51 said:
Actually no apparently I did it before I fixed that. .0005 flexplate runout, and .001 converter base runout at that time. Not sure I can get a good reading now with the loose bolts.
Click to expand...

What kind of indicator were you using? If you have changed the mounting method (an extra dowel) its worth it to remeasure.
 
mag base dial indicator. cheap stuff, but it also almost never gets used. I had it hung off the oil pan iirc last time. was comical, as I also did that on my back haha.
 
I may just shelf it for a few weeks at this point, the adapter plate GB is about to go through, the replacement shell (one way or another) is in the process of being acquired, and now that the tenants are out, I've gotta do a kitchen overhaul/facelift at the other rental and need to be in and out of that process asap.


with the pause comes the possibility of far reaching scorched earth policy stuff though, so with this new scope in mind, and based on information made available elsewhere recently (~5-6 months ago), I can sit down and maybe source better fasteners/bigger fasteners for the flexplate to crank, obviously something better to go between the converter adapter and the flexplate, I can do the empty case sight thing as well as a runout test (probably around the same time since I'll have to take the trans out to at least tighten the bolts back up to check these things)

so, shopping list (since these things work better for me this way):
m12x1.0 bolts, drill, and tap (that is, if I can't convince roger to go ahead and make mine that way to begin with, I haven't asked yet) for the plate -> adapter portion

I believe the crank bolts are m10 x 1.25 or 1.5 as well, I'll have to dig the thread up where jens and the other dude talk about those bolts breaking. the concern of course is having enough clearance at the nose of the adapter plate if I go upsize on the bolts. JVAB I believe also opined in that thread.. course, with the automagic, there's less shockload.. however I'm skeered of sayin "I ain't never seent it happen ever" so if that's what it takes..
 
Been chatting with Mike and there's some other discussions beginning on the TC plates as well, so now's the time to see what needs to be changed.

I'm disappointed though...why you no race the rustbucket chassis? Geez, where's your sense of adventure? We ALL want to see the diff get ripped out from under the car after a hard launch or three. :)
 
the axles just break, it doesn't tear anything loose. it's not as amusing as you'd think it would be, and it's really not amusing trying to fish the stub out after the fact.


besides, a station wagon drag car will be far more amusing in the long run :-D
 
blkaplan said:
Whats gonna happen at the front? The amount of vibrations it takes for a pulley bolt to come loose is much greater then what it takes for a flex plate or flywheel bolt. They also happen to be connected by a crankshaft. Vibrations love to travel through a continuous solid piece of metal...
Click to expand...
Broken crank snout?
Oval mains?
Freeze plug sized dents in your inner fender well?

The harmonic damper is for the front half of the crank. That's always been my understanding.
You have a huge mass at the back of the engine, deadening the harmonics and nothing at the front.
It's why you don't use a harmonic damper with a 70mm blower belt strapped to the snout of the crank. You don't need one. The belt drive quiets the crank.
I'm not saying you're wrong dude. Just suggesting a different viewpoint.
We're going to find out sooner or later what the problem is.
 
A significant advantage of a bolted joint over other joint types, such as welded and riveted joints, is that they are capable of being dismantled. This feature however, can cause problems if it unintentionally occurs as a result of operational conditions. Such unintentional loosening, frequently called vibrational loosening in much of the published literature, is an important phenomenon and is widely mis-understood by Engineers. It is important for the Designer to be aware of the bolt loosening mechanisms which can operate in order to design reliable joints. The information presented below is key information for the Designer on the theory of vibration loosening of threaded fasteners and how such loosening can be prevented.

Study of most Engineering magazines will reveal the multitude of proprietary locking mechanisms available for fasteners. For the Designer without the theoretical knowledge of why fasteners self loosen, this represents a bewildering choice. Presented below is key information, for the Designer, on why fasteners self loosen, and, how it can be prevented.

It is widely believed that vibration causes bolt loosening. By far the most frequent cause of loosening is side sliding of the nut or bolt head relative to the joint, resulting in relative motion occurring in the threads. If this does not occur, then the bolts will not loosen, even if the joint is subjected to severe vibration. By a detailed analysis of the joint it is possible to determine the clamp force required to be provided by the bolts to prevent joint slip.
Often fatigue failure is a result of the bolt self-loosening which reduces the clamp force acting on the joint. Joint slip then occurs which leads the the bolt being subjected to bending loads and subsequently failing by fatigue.

Pre-loaded bolts (or nuts) rotate loose, as soon as relative motion between the male and female threads takes place. This motion cancels the friction grip and originates an off torque which is proportional to the thread pitch and to the preload. The off torque rotates the screw loose, if the friction under the nut or bolt head bearing surface is overcome, by this torque.

There are three common causes of the relative motion occurring in the threads:
1. Bending of parts which results in forces being induced at the friction surface. If slip occurs, the head and threads will slip which can lead to loosening.
2. Differential thermal effects caused as a result of either differences in temperature or differences in clamped materials.
3. Applied forces on the joint can lead to shifting of the joint surfaces leading to bolt loosening.
 
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#1 speaks to me, I was actually discussing that earlier with a couple folks.

In the process of contemplating this whole thing, I started replaying the various ins and outs and problems I ran into during the whole process and remembered an issue I had with the 400 after I first swapped it in (although the th350 converter came loose once, it *could* be the same problem, or I may not have put enough ass on that)... it would push on the converter when you rev'd, which would push on the flexplate (That doesn't bottom out in the pilot bushing), and then the ears on the converter would hit the starter. made a hell of a racket, I ground on the starter initially, thinking it was just a clearance issue (not being able to be in two places at once, I couldn't observe what was actually going on). I got someone to rev the engine while I was under there watching it, and I watched it basically bend the flexplate towards the engine on accel, and then pop back flush on decel.. At the time I just made a poly 'bushing' of sorts, that would go on the snout of the converter adapter, and did the in/out several times until it would sit flush on the flexplate without pulling it out with fasteners, and I imagine a spot check at the time with the engine running yielded favorable results.

this nice phenomenon is caused partially by the th400 design, and partially by the mods I've done to it, one of which is a massive restrictor on the converter feed to prevent precisely this sort of thing. When I had it out for it's R&R last august I restricted it down even more than what it was, I reckon I need to see about going even lower or perhaps sourcing a flexplate that doesn't.. for lack of a better word, flex, eh?

this lines up favorably with the new flexplate, which is a 2 piece design vs the later 1 piece plates (you have the plate, then the washer ring thingy that goes on top, not a welded ring to the plate itself), that could feasibly allow a slight bit more flex at the crank area.
 
I had a feeling your need to play with trannies might have had something to do with your current life issues. (<- that's funny) but I figured looking at the most simple issue of why bolts get lazy would confirm or deny these "problems" that were quickly asserted. It just didn't seem right to me that others had the same pulley with no similar issues. I think mental progress is being made. Hurry up and fix this! I like it when you break ****, not just loosen ****, that's boring and not really brag worthy. Are you running a tranny blanket to save your legs from shrapnel. This is heavy stuff spinning real fast like, on top of that they seem to like to party and "get loose"
 
yes. I dunno why they're called that. it could be truth in advertising, or it could be a way to differentiate them from flywheels?

no scatter shield or blanket yet, but it's on the short list along with a roll cage.
 
cursory google search seems to concur with that.. it allows for slight misalignment and flexibility. apparently you only want this in stock applications.
 
You don't need the tone ring on that car don't you? What about a one piece adapter from the crank to the converter? They make flywheel in aluminum, why not a flex-adapt-a-plate? Could even be made in steel.

Just thinking out loud...
 
linuxman51 said:
#1 speaks to me, I was actually discussing that earlier with a couple folks.
Click to expand...

Just for the sake of blurting out answers, #1 is caused by everything we were talking about.
Vibration from a ringing crank; sliding
Bending from thrust on the flex plate; sliding
Wobbling from not being indexed accurately...
etc etc.
Narrowing it down is the trick.

:Anecdote: Big trucks use cast iron "flex plates" when auto because 1200+ft/Lb would Pringles a conventional flex plate, probably causing the bolts to back out. :e-shrug:

What throws me is the fact that you're losing flywheel bolts in the driveway.
 
poulson01 said:
Just for the sake of blurting out answers, #1 is caused by everything we were talking about.
Vibration from a ringing crank; sliding
Bending from thrust on the flex plate; sliding
Wobbling from not being indexed accurately...
etc etc.
Narrowing it down is the trick.

:Anecdote: Big trucks use cast iron "flex plates" when auto because 1200+ft/Lb would Pringles a conventional flex plate, probably causing the bolts to back out. :e-shrug:

What throws me is the fact that you're losing flywheel bolts in the driveway.
Click to expand...

I know that vibration is a plausible factor, but are you talking about massive vibration? It's just hard for me to picture as I'm possibly incorrectly assuming, that a small constant vibration is a factor in comparison to the varying speeds and jolt from the motor and fast rpm changes at shifts. What I mean is if it is super bad you should be able to feel/hear/see it? I've only messed with autos in mid hp red blocks, so things might be different here. The investigation continues.
 
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