Question about repeated bearing failure

[PFC1]

What is the compression and what fuel are you using?

Bret

[stealth]

You didn't change to an msd distributor did you? They have o-rings that need to line up correctly and not damaged.

Just a thought..

[Barbapapa]

Junior, when you swapped the trans, did you install a different flexplate or balance weight?

Since you guys both have #4 problems that seems to rule out transmission thrust. If there were an imbalance on the flywheel that would have the greatest impact on #4, the crankshaft would act as a lever with the #5 being the pivot point and the #4 being the focus of the leverage.

Mr 408, was your crank balanced with the actual flexplate/cw or did they install their own weight?

[Mr 408]

If there were an imbalance on the flywheel that would have the greatest impact on #4, the crankshaft would act as a lever with the #5 being the pivot point and the #4 being the focus of the leverage.

this is exactly what i was thinking. my assembly was sent out with everything that i used to install it in the car.

I'm wondering if the balance shop was able to balance the assembly without the balance plate i supplied and me using it is throwing it way off.

How much does a 400 shake when there is no flywheel weight?? Is is noticable at low RPM [less than 3K??]

[mudracer]

stupid question for the big guys here....

would an old Fluidampner cause this type of problem?

i dunno, figured i would ask.

[junior76]

I never changed the flexplate,balancer or distributor.My stuff was balanced with the flywheel and balancer.It runs great and smooth with no vibrations but will wipe the bearings out.I took the trans out and done what was said earlier to do but the pressure only dropped 20 pounds,from 80 to 60.I'm gonna take it out again,get another pump and put a smaller hole in it this time.If i did'nt have all my money spent,i'd put the t350 back in it.I need another drive shaft.Oh the shaft in it now has lots of clearance too.

[Lucky13]

I have been looking for the info I was refering to about the extreme pressure that was pushing a torgue convertor forward. I have not found the artical I was refering to, it was a extreme case like yours and there was something out of the norm causing the pressure problems.


Some info I did find though was many people having this problem (but not as extreme as yours) and the cause was a restriction in the cooler line and or cooler. One of those coolers with the temp switch valve in it was talked about causing this, some found lines themself restricted, and some coolers restricted, and some had a oneway check valve that stoped working. When the stall was flashed the pressure would spike to extreme pressures when measured at the output that feeds the cooler system. This pressure was above/higher than what was measured at the high pressure port on the tranny. They talked about rigging a gauge on the line itself just as it leaves the tranny.


I will keep looking for the info I was talking about, but this is close to it. I may even be remebering wrong and this is what I am looking for. The very artical I am looking for I can not remember exactly where it was. But there was something very distinctive about it and I will know it when I do finally see it. I was thinking there was a internal curcuit that had leaked into another curcuit to cause the high pressure, but I may be wrong. What ever the reason or cause it was so extreme that they to went through the same problems as you with instant destruction.

Anyway the info above will be something good to check & look for and just may find something for you. You do have to much already and the rest of the reason could be the cooler curcuit as meantioned. Ofcourse all engine clearances should be checked close as meantioned. But I dont think you would have the repeated failure like you are experancing unless there was something major going on. Even though you may be the only constant involved with each build (as far as engine goes), surely you would have got it close to right out of one fo the attempts and the engine would have lasted a little longer.


Jess



Jess

[AlkyV6]

Junior 76, it seems from the pressure readings you have at your cooler line, that your on the right track.

aka DonWG

[junior76]

Yeah,i plugged the hole and redrilled it to .167.I also put the stock pr spring in it and still got high pressure.I think my next move is going to be get another pump and drill the hole smaller.Any idea on how much smaller to go?I'd like to get the pressure at 40 psi or less like recommended.

[AlkyV6]

Use a 7/64" drill bit.

[Engguy]

So does the torqueconverter move back and forth before you put the bolts in to pull it up to the flex plate?
Something is causing the problem. Missmatched bearings? Is the one with the oil hole installed into the block? Is there a gallery plug your forgetting?
Like some have mentioned journal radius running into the bearing?
Is the transmission oil cooler not plugged? How about the TC pilot, and input bearing in the trans pump? Does the transmission bolt up easy? No binding?

[Dave Koehler]

Rather than add to the mantra here are 2 Stories that may or may not supply a clue.

Balance:
Did a balance job on a 406 that was light enough to go internal. The owner, a year later, called up as he finally got it running.
"This engine vibrates quite a bit"
Me: "Are you confusing power pulses with vibration?" (It was a solid mounted dirt track car and it was his first racer.)
"I don't think so."

He was close by so I dropped by and fired it up after checking my records. Yup, he was right, this poor puppy almost jumped off the floor it shook so bad....more rpm= more shake. Have you seen a construction worker breaking concrete? Same effect!

Took a look and sure enough, internal balancer and a 400 flexplate. Changed the flexplate and problem solved. They had been running this off and on for 3 days so I suggested they back up and take a look at the bearings. They didn't.

This works the other way also. Leave the weighted parts off of an external balanced engine and it will be mucho noticeable.

Those of you that play with blower or other hi hp engines probably have experienced the same effect when 2 or more cylinders drop. Nasty vibe.

Thrust problems.
Had a regular garage customer installing a NAPA rebuilt 350 to replace one that was tired and had a bad thrust. He calls up after the third replacement engine knocked the thrust out ON THE HOIST.
My first thought was WOW, what a guy the NAPA place is to put up with 3 replacements. Anyway, we talk through the usual thing about replacing the convertor and trans cooler, yada yada. I get told that it's not a problem.
OK fine...then you have no problem, yes? I also add that he might want to take a pressure check on the cooler lines. I am told that his tranny guy says that the pump bypass won't let it get too high.
Uhhhh, OK then you still don't have a problem, yes?
At this point I give up and remind him that I have done a lot of successful things for him over the years and to humour me by testing the pressure.
grumble, grumble. OK.

Well, guess what? The pressure was sky high on the output with almost zip coming back to the trans. Long story short, and similar to what Wolf says in his oil pump post that volume has to go somewhere. In this case it was balloning the convertor every time, even at idle. Also please note that a bypass can only dump off so much gpm before the pressure either goes back up or waaaay up.

Dave Koehler