Hah! I haven't pulled my tranny yet but after reading through my powerglide manual, I'm pretty sure my poor 60' times are related to a bad torque converter now. After doing that stall test without the 2 step, I was able to see the rpms increase. I assumed the low band wasn't holding. I have a spare Kevlar band which isn't hard to change. It's right behind the pump. However this is what the manual says.

Symptom: Engine will exceed normal stall speed when the transbrake is on

Fault: Converter stator one-way clutch not holding. This condition will be exhibited by a flare-up of engine rpm when transbrake is applied and you are "on the converter". If you run a 2-step or similar rev limiter when on the transbrake, you may misdiagnose the problem as transmission slippage. To confirm that the stator clutch is slipping, disable the rev limiter and test stall. If the rpm exceeds the normal stall of the converter, the one-way clutch is not locking up.

That's exactly what's happening in my car. My converter has been apart once before a couple of years ago and there isn't enough metal in the case to cut it open and reweld a second time. The one way clutch is the converter sprag. Sounds like mine has failed. The aluminum sprags fail often.

Playing with Desktop dyno/drag 2000, I could never get the proper results from my data. When I bought my converter years ago, I phoned the manufacturer to find out what the torque multiplier was for drag 2000. I was told 2.5x. The only way I could match my track results with the software was to drop the multiplier down to 1.5.

Looks like I get a new converter in my car within 2 weeks. While the tranny is out, I'll put in a new low band also.

 

There's a good high performance converter manufacturer here in Canada. tcsproducts.com . I've seen their decal on a few cars at the track including many supergas cars. They give a 2 year warranty on their race converters and a lifetime warranty on their in house produced steel stators. I guess I give them a call tomorrow and put a dent in my credit card bill.

 

glad to see you figured something out about your crappy 60', hopefully this fixes it quick and you can hit some 1.3s

 

converter is super important. that is one area to not skimp on whatsoever. i would drop $600+ on it..... neal chance or something like that.

 

Converter prices is one thing where you get what you pay for. Quality parts are not cheap. A $300-$500 is still a street converter with OEM parts inside it.

I ordered my new race converter this morning. It should arrive early next week and maybe by the end of this week. $1300 for a new race converter built for my engine. My last one was $1000 and it lasted quite a few years but it was also behind a few failed engines so it's not in the best of health.

Now I need to yank my tranny to get the old converter off and to pull the pump so I can change the low speed band. I race again in 2 weeks providing the converter arrives in time. Probably a good opportunity to make a removable floor section to access the tranny while it's out. Depends on how much sheet aluminum I have left over.

 

kickass! it will be interesting to see how she picks up with the new 'verter!
what kinds of information did you have to supply them with? just curius, as i have not had to order a brand new one yet. i am VERY lucky to have a combination that works as well as mine does with a used converter.

 

The first thing they would like is an engine dyno sheet. That's the absolute best way to buy a converter. Since I've never had the engine or the car on a dyno I could only give rough estimates on performance.

Stuff he wanted to know.

3060 pound race weight car running 140 mph at altitude. Based on the power to weight ratio, it's putting out around 650 hp to the wheels. Altitude corrected would be around 750 hp. Shift at 6800, go through the traps at 7400. Cam specs and I knew my Comp Cams grind number. Induction is a tunnel ram with alcohol carbs. When I switch to Toilets, the torque converter should be changed but as far as I'm concerned, I'm not a stock eliminator type car where every bit of HP is required. I just need something that works well enough. He wanted to know if I use a transbrake, yes. Gear ratio, 4.86. Powerglide tranny with turbo splines and 1.76 first gear. Rear suspension is 4-link. Engine size 540 with no mid plate. Compression ratio, around 14:1. Heads with flow numbers if possible. I said I had unported Canfield 310 heads with 2.25 intakes. They're a little small for this engine but work fine for what I want.

I said I wanted something that stalled in the 5500 - 6000 range and he agreed with me. He said I know my stuff and knew what I needed.

Here's a PDF of a typical race converter order form.
http://tcsproducts.com/images/storie...5_pub_0001.pdf

Well my tranny is out. The converter is off and I can't find anything obviously wrong with it. After unbolting it from the flexplate, I spun the converter and didn't hear any noises. After taking it off I shook it and still didn't hear any noises. Still doesn't mean it's still good. I wonder if that's what the buzzing type noise I heard earlier in the year coming from the back of the engine? I should take it into the local tranny rebuild shop and have them cut it open so I can have a look inside it again. It can't be welded back up again but I'd like to know if there really was damage inside.

Pulled the pump then pulled out the low band. Oooh, that wasn't pretty. The low band is actually 3 bands in one because of the way the design is to activate it. The servo piston pushes on the center band and the 2 outside bands sit on the adjustment fork on the other side. Sort of like an anchor. The center band was black and the other 2 didn't look much better. I have a new band sitting in tranny oil overnight before installing it. Proper and frequent band adjustments may have prevented that. The burnt band could have been part of the problem. PG band adjustment is to tighten the adjustment screw to 70 inch pounds the back it off 3-1/2 - 4 turns and tighten down the jam nut. It's accessible from the outside of the tranny but I had to cut a hole in my floor to do it.

Time for another shower. I stink of tranny oil.

 

Got a call from TCS today. My new converter is ready to ship. I think it's going out tonight so I may have it tomorrow. If not then Thursday. Looks like I'll be putting my tranny back into the car by the weekend.

 

I ran one of their street converters in the 700 behind my old engine for a while. It was a solid piece, and their service was good. I've got a converter from the "other" TCS now.

 

I got the low band replaced tonight. I also changed the filter. Yuck. Lots of friction material. Good to know I have another PG if I ever needs spare parts. I never did get around to building up the second one.

Just waiting for the new converter now and I can put it all back together.

 

do you need to flush out all your lines, etc due to so much junk in the trans?

 

I just let the lines and cooler drain. The path of oil flow is from the pan, through the filter, through the pump to the cooler than back to the tranny to be used as hydraulic pressure which is dumped back into the pan along with any contaminates. Any big particles coming out of the tranny that can cause problems are first trapped by the filter and should never get back into any critical passages.

I drained the oil from the pan yesterday before removing the tranny. Today when I pulled the pan off to change the filter, I got about a liter more oil out of the tranny that had drained down from the valve body. The entire tranny oil system is now as dry as it's going to get.

 

just thought i'd mention it, since when converter let go, stuff gets tossed into the passages IIRC. I've flushed out daily driver lines with brake cleaner, then clean fluid and garbage has come out.

 

i just orderd a spragless for the race car, $795 4800 to 5000 stall, i also had a wasted converter very inconsistant especially with nitrous (yeah i know rough on parts) so to fix the problem i built a 383 that desktop dynos says 690 hp and new conveter bout the same power without having to use the bottle, I got the converter from www.transmission-specialties.com (might be spelled wrong) they can convert a sprag to spragless for @400 including overhaling the rest of converter, they also have other parts maybe you could find out what a core saver ring is and if that would make yours rebuildable? just an idea

 

The converter never really let go. It still works but with the inconsistent 60' times and a full stall on the converter didn't hold. I think most of the junk sitting on top of the filter is friction material from the low band. Maybe some aluminum from the sprag.

I saw the previous damage inside my converter. It was repaired a couple of years ago. I know if it failed again, it wouldn't be worth fixing.

I've considered spragless but didn't get one.

 

Converter arrived today. I should be able to get the tranny back in the car tonight. Maybe go get some hits at the track tomorrow night.

 

Tranny is back in the car but it's too late to fire it up to check the fluid level. My neighbors might not appreciate a race car firing up after 10 pm during the week.