Ate main #2 rear thrust- Why?

[rodman99999]

Rebuilt the engine and had about 150mi on it. I measured .007 to .008 thrust when I assembled it. Same torque converter. Did a 160MPH blast for about 2 miles and developed a slight tick in the bottom. Pulled the engine and the above mentioned thrust(facing the trans) is missing about .035" of material, plus the crank shoulder (behind the front main journal) has been on the main. Is it possible to install a Vigilante far enough to hook up to the motor, but not far enough to keep from eating the engine? Anything else that I could have missed when I assembled it? Thanks for any tips.

 

[mygn276]

Rebuilt the engine and had about 150mi on it. I measured .007 to .008 thrust when I assembled it. Same torque converter. Did a 160MPH blast for about 2 miles and developed a slight tick in the bottom. Pulled the engine and the above mentioned thrust(facing the trans) is missing about .035" of material, plus the crank shoulder (behind the front main journal) has been on the main. Is it possible to install a Vigilante far enough to hook up to the motor, but not far enough to keep from eating the engine? Anything else that I could have missed when I assembled it? Thanks for any tips.

160mph, for two miles, on fresh motor. I dont have a clue

 

[rodman99999]

I wouldn't think Break-in should have anything to do with the crank pushing forward into the thrust. The rod and main bearings themselves are fine, except the heated up edge of #2 where the pressure was from the crank pushing on it. If my thinking is screwed up there- Someone correct me.

 

[Nick Micale]

.. ...... Pulled the engine and the above mentioned thrust(facing the trans) is missing about .035" of material, plus the crank shoulder (behind the front main journal) has been on the main. Is it possible to install a Vigilante................. .

There is that dreaded word - Vigilante.

The only thrust bearings we have destroyed [after hundreds of V-6 engine builds] have been the result of that POS. We discussed this with the owner about his converters doing damage to the thrust, but got no where.

Probably you can see a mark on your flexplate where it applied pressure?

 

[rodman99999]

Hi Nick- That was my initial suspicion, but- I wasn't certain. I thought they were supposed to be "anti-ballooning" or something. I've had that converter in the car for three years and never had the problem before. Is it only at top end they push the crank? I'll look at the flex plate more closely for signs of pressure tomorrow. Thanx for the info!!

 

[Nick Micale]

Hi Nick- That was my initial suspicion, but- I wasn't certain. I thought they were supposed to be "anti-ballooning" or something. I've had that converter in the car for three years and never had the problem before. Is it only at top end they push the crank? I'll look at the flex plate more closely for signs of pressure tomorrow. Thanx for the info!!

The normal reaction of a converter is to be "pushed" off the shaft into the engine.

Since I am not a transmission expert, what I understand is the fluid force in a Vigilante is much greater than normal, and this has to do with the fluid path and the lock up?

What I do know is we will NEVER use this converter after the damages we experienced years ago. One GN trashed 2 engines in a row after the customer was "assured" it was not the converter.

These were not street cars, but 10 and 11 sec. cars that were run hard.

 

[bison]

Measure the trans cooling circuit pressure. Under 50 psi is safe. Over 60 psi is a problem.

 

[turbofabricator]

If the thrust surface is "touched up/trued" when they grind a crank, it has the appearance of a saw blade. Was the crank ground at time of rebuild? If so, it might be the finish on the thrust surface of the crank. I hand polish the thrust surface of a crank after the crank grinder does his work. I use 600grit then finish with 1500 grit to polish out all the saw blade look. I have reduced thrust problems "significantly" since doing this.

 

[gossamer]

The only reason for your failure that I can think of would be the torque converter "ballooning" and forcing the crankshaft forward, wiping out the thrust bearing. At 160 mph, I'm sure you were in the throttle pretty hard which means the pressure in the trans/converter was probably pretty high. + 2 w/ Bison, measure the pressure in the transmission. Maybe too high?

 

[rodman99999]

If the thrust surface is "touched up/trued" when they grind a crank, it has the appearance of a saw blade. Was the crank ground at time of rebuild?

Nope! Outside of polishing the journals, the crank was left untouched. Good pointer for future reference though!

 

[rodman99999]

Measure the trans cooling circuit pressure. Under 50 psi is safe. Over 60 psi is a problem.

Does that pressure rise under WOT conditions? What can affect an automatic and cause high pressures. Nick mentioned the fluid force being greater within a Vigilante converter. Could that be verified by measuring the cooling circuit pressure? I'm clueless regarding ATs.

 

[ijames]

There are some good threads in the trans forum on this. The pressure people have mentioned is the cooling circuit pressure, the pressure in the lines going to the trans cooler, NOT the main line pressure in the trans. Bison mentioned 50 psi as a max - I think that is for TH400's. The 2004R is safe up to about 75 psi or so (again, check those old threads in the trans forum) because the input shaft is so much smaller in diameter. The internal pressure in the converter pushes on the input shaft like a piston; it is this force that pushes the crank forward into the thrust bearing, and since the fluid flow path goes pump-converter-cooler you can tee a pressure gauge into the cooler line going from trans to cooler to check this. This all assumes the body of the converter is rigid, if it also flexes and swells (balloons) then that puts a lot of extra force on the crank. It is actually pretty rare for a converter to balloon, and when they do you may have to pry them off the flexplate and may not be able to push the converter back into the trans after unbolting it (you should have 1/8-3/16" clearance between flexplate and converter with it pushed all the way into the pump). Yes, the pressures in the trans rise with throttle and are max at wot.

 

[Boost231]

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[Alky V6]

Was the cooler fitting at the transmission installed that has the restricted orifice? They usually come with the Vigilantes. Their purpose is to create a back pressure in the T/C to make TCC engagement firmer. There is a draw back to that stradegy though.

How much hydraulic push a T/C will have on the crank is related to two variables. The ID of the torque converter hub and the pressure buildup of the fluid inside the T/C. The ID is slightly smaller with the 200-4R compared to the 400, so the push is slightly less with the 200-4R, but I would try to keep T/C pressures to around 40 psi if at all possible. You really don't need anymore than that.

If you really want to know how much pressure is pushing on your crank, take the area of the inside of the torque converter hub and multiply it by the pressure of the fluid inside the T/C. Cooler line pressure is the best indicator of T/C pressure.

I wouldn't trust a cooler line pressure reading if that orificed fitting is installed. Remove it or drill it out. You don't need it.

Also, next time let your engine break in better before a high speed run like that. Holy cow.

 

[cork]

Where do you go 160 mph for 2 miles ?

 

[TurboDave]

Was the cooler fitting at the transmission installed that has the restricted orifice? They usually come with the Vigilantes. Their purpose is to create a back pressure in the T/C to make TCC engagement firmer. There is a draw back to that stradegy though.

How much hydraulic push a T/C will have on the crank is related to two variables. The ID of the torque converter hub and the pressure buildup of the fluid inside the T/C. The ID is slightly smaller with the 200-4R compared to the 400, so the push is slightly less with the 200-4R, but I would try to keep T/C pressures to around 40 psi if at all possible. You really don't need anymore than that.

If you really want to know how much pressure is pushing on your crank, take the area of the inside of the torque converter hub and multiply it by the pressure of the fluid inside the T/C. Cooler line pressure is the best indicator of T/C pressure.

I wouldn't trust a cooler line pressure reading if that orificed fitting is installed. Remove it or drill it out. You don't need it.

Also, next time let your engine break in better before a high speed run like that. Holy cow.

Don, where exactly is that orifice fitting? and how easy/hard would it be to remove it????
I'm still running the 7 disc vigilante you installed. The car is no longer raced so I'd like to "soften" things up a little.

 

[Alky V6]

Don, where exactly is that orifice fitting? and how easy/hard would it be to remove it????
I'm still running the 7 disc vigilante you installed. The car is no longer raced so I'd like to "soften" things up a little.

If I remember right, they have you install the fitting at the top location at the case. Just check both fittings. If one has the restriction, just drill it out to the same ID as the other fitting and reinstall it.

In very few cases did I install the fitting that came with the Vigilante. Mainly, because I started to understand more what they were trying to do. The problems associated with the orificed fitting are:

It creates a back pressure in the T/C. Good for getting the firmest TCC apply. Bad for crankshaft.

The orifice is rather small. Transmissions do generate debris. Even normally. If the T/C generated large enough debris to plug that small orifice, then you lose cooler and main lube circuit oil to the transmission. Very bad for transmission. In fact, long ago when I started recommending to my customers that they remove that fitting, one came to the shop for me to remove it and it was plugged. Luckily, we got to it before any permanent damage occurred. I'd almost swear it was yours Dave. It was a long while back.

Theoretically, it should lighten up the TCC apply, but I never noticed a big difference between having the restriction in and not.

 

[bison]

Does that pressure rise under WOT conditions? What can affect an automatic and cause high pressures. Nick mentioned the fluid force being greater within a Vigilante converter. Could that be verified by measuring the cooling circuit pressure? I'm clueless regarding ATs.

It will rise a little as rpm increases but it is easy enough to verify with gauges. Yes, you would measure the cooling circuit pressure with the converter unlocked.

 

[rodman99999]

Was the cooler fitting at the transmission installed that has the restricted orifice? They usually come with the Vigilantes. Their purpose is to create a back pressure in the T/C to make TCC engagement firmer. There is a draw back to that stradegy though.

How much hydraulic push a T/C will have on the crank is related to two variables. The ID of the torque converter hub and the pressure buildup of the fluid inside the T/C. The ID is slightly smaller with the 200-4R compared to the 400, so the push is slightly less with the 200-4R, but I would try to keep T/C pressures to around 40 psi if at all possible. You really don't need anymore than that.

If you really want to know how much pressure is pushing on your crank, take the area of the inside of the torque converter hub and multiply it by the pressure of the fluid inside the T/C. Cooler line pressure is the best indicator of T/C pressure.

I wouldn't trust a cooler line pressure reading if that orificed fitting is installed. Remove it or drill it out. You don't need it.

Also, next time let your engine break in better before a high speed run like that. Holy cow.

Hi Don- 1) Nothing resembling a fitting of any kind came with the Vigilante, or I'd remember it. I suppose if it had, the problem would have surfaced sooner. 2) If I do find that my trans/converter are generating higher than normal pressures: How do I get them lowered? 3) This time around, I'm unhooking the wastegate actuator rod(no self-control boost junky) for the first 500 miles.

 

[rodman99999]

Where do you go 160 mph for 2 miles ?

I was talking with a couple Neon owners about the wideband fuel/air ratio gauges they were using. I asked what speed the Neons are good for and got 160 in reply. My '87 TR wouldn't approach that with the old(original) valve springs and I was anxious to see what the new ones availed. My '85 GN had no problems with 160. I asked them to pace me. Anyway- We got on the freeway here(outside Indianapolis) and headed for the next exit(2.5 - 3mi). Neon speedometers actually register what the car is doing(imagine that)! When I slowed down for that exit, they went by with their thumbs in the air.