Another thrust bites the dust

[1320n10]

Well i pulled the motor this evening and if we were panning for gold we would be rich. I pulled all the main caps and the crank looks really good for all the bearing materal in the pan. I only pulled one rod and it also looked good but the bearings were starting to show some copper. From the looks of things i may find a rod journal that is shot when i pull the rest. My engine builder says he can have the crank sent out and have the thrust metalized with some sort of powerdized metal procedure. Anyone ever had this done !!! If the crank checks out other than the thrust this would be a lot better than balancing a different crank.

 

[FJM568]

Someone offers an oversized thrust bearing, you just need to grind the thrust on the crank to match and keep on going...If it's already oversized and shot, then I would think about having it spray-metallized...But that needs to be done right...We used to do a lot of that at work repairing jet engine parts by spray-metallizing, but the parts need to be cleaned and prepped right for the spray to stick to the parent material...When it's done, the sprayed-on metal will in some cases be harder than the parent material...

On second thought, I probably wouldn't do the spray metallizing to a crank...There is actually a heckuva lot of heat involved in the process and I'm not sure what that would do to the crank...It might cause it to warp...

I would try the oversized thrust bearing route if that's still possible with your crank...Maybe have the thrust surfaces hard-chromed and reground...I think that Lonnie Diers had a 455 crank's journals hard chromed and after that he never wore a journal out...But you would probably be better off trying to locate another crank....

 

[1320n10]

Thanks The thrust was stndard so the oversize bearing should work. He said he has sent several cranks out to have this done. I am just looking at all my options right now.

 

[laz]

I recomend that you find the cause of the thrust problem. I had the same problem on my t-type it turned out to be an art carr 9 inch conv. I bought on oversized thrust clevite 77 bearing machined the crank to 3 thousants endplay and its lasted 4 years so far. Laz

 

[1320n10]

Laz it seems to be the t400 with a tci trans brake that has caused the same probled in bob slussers and chuck leapers motors and a orfice in the front pump needs to be installed to prevent this.

 

[PaulRV6]

With all this talk of thrust brg failure.... is there any way to make a check to see if there might be a problem before this occurs? Maybe not even a concern with street driven GN/2004R trans?

paul

 

[Ormand]

Pressure

I just read another post (somewhere- TurboBuicks?) that confirmed what Walt says above. Excessive pressure pushes the pump forward, a hole drilled/enlarged prevents this from happening. Don Wang in California knows the details, I'm running (almost) all stock, high mileage, haven't looked at the this problem. Don't think it would happen with a stock transmission, though.

 

[PaulRV6]

Is there someonr that could post this "Don Wang" fix on the board so it is there for future use. Maybe in the tech section in GNTTYPE.ORG.

PAUL

 

[GRNDNL]

Walt, Paul @ Jax may have a crank if your looking for a replacement, call me if you need the number. You can use that extra short block I've got if you need to get it running this weekend....Keith

 

[BobbyBuick]

OK,Im not a tranny expert or have I tried this yet but here is what Ive learned since last weekend.after reading an article by ATRA about thrust failure I found that the the thrust surface on a big block chevy can withstand 210 pounds.now the sq in of the convertor hub x the line pressure = force and after I spoke with tci they said the line pressure all the time is 180-200psi non modulated on a 200 its modulated with the detent.now if you do the math thats somewhere around 318-422 pounds.Even on the low side its twice as high as it shoud be. I spoke with Chuck Leeper and he said it cost him a few cranks for he got ahold of Don Wang.After making the Mod Don sugested Chuck has had no more problems with the thrust I mean SOO I called Don ,he said you need 40 psi at the cooler line and all the fluid the convertor needs is 1 qt in 20 seconds thats a rule of thumb they go by.now for the mod. On the pump cover their is a passage straight down from the stator that runs at an angle up by the pressure regulater.at the opening by the regulater tap the passage with a 1/8"pipe tap and drill a 7/64 hole in the pipe plug.this mod will releave the amout of fluid that is pushing the convertor off the stator support.Now I havnt done this yet .and if a tranny guru can help out here Im open to listen .I am interested in this metalizing as I may be past the over sized bearing Thanks Bob Slusser

 

[Tim Cucci]

Stock engine and tranny here. Just rebuilt my engine. Crankshaft had .040" endplay. I had pulled the engine just to do the rear seal and install another set of heads when I found Thrust Bearing Failure. Had the crank machined for an oversized thrust bearing. Engine has about 250 miles on it now and seems to be just fine.
I still don't have a clear answer on the failure of the bearing.
Tim

 

[fc227]

I lost my last two engines from thrust bearning failure . Each engine had 4 years on it , with four full race season's . (about 800 1/4 mile passes).

I was told it's just wear & tear from loading and unloading the crank from racing & building boost against the brake al the time.

Now this over sized thrust bearing , Is it over sized on both sides? I wish I new this two years ago When my present engine was going togethere.

Oh well maybe in two years we'll look into it again.

 

[BobbyBuick]

In beleive that 4 years might be only wear and tear.If you are making any power I would think you would want to tear it down at least every 2 years and freshen it up.I also beleive that if the convertor dosnt balloon and the ,pressure doesnt exceed the limit assuming everything is correct the thrust should last a long time

 

[fc227]

Thats my game plan for this winter.