One whine, two questions

[Dave Barbieri]

First, the whine:
Here in Texas, we have a real finance disaster unfolding. Our legislature has based future funding on a continuing rise in sales tax that simply hasn't occurred. People are becoming more conservative/worried and are choosing to save money rather than spend it. This concept is unfamiliar territory to politicians, so it was never considered in budget forecasts. Result: a shortfall that reaches into the billions of dollars. Since education accounts for 46% of the state budget, it takes the hardest hit when shortfalls occur. Bottom line - I'm losing 20% of my budget and will not be able to replace any of my teachers that are retiring. Add to that the fact that our enrollment continues to grow. We'll be doing a lot more with a lot less. Salary reductions are a very real consideration for next year. Said all that to say this: Since Thanksgiving, I've been mostly lurking and contributing nothing. I've been doing the very thing that I accuse some of my students of doing: Contributing nothing while sucking up oxygen and air conditioning. Sorry about that, folks. :nonod:

So, here I am, asking for help and advice. I will be replacing my engine and transmission at some point this Spring or Summer. Figure I better get my ride in top shape, since there's not gonna be time or money to do it any time in the future.

First question: I need advice on choosing a torque converter. I want something that is slightly stronger than OEM. I use my truck to tow and haul, but not heavy - no track loaders, barrels of scrap, etc. I'm getting frustrated because according to my GM shop manual, the diesel torque converter uses a double stator for greater torque multiplication. Well, none of the replacement units have this. They all talk about the number of clutches that are used in their lock-up, but that's not the issue for me. I'm looking at the other end of the operating range - the 'getting started' part. Folks seem to get around this by juggling fin angles and stall speeds, but no one addresses the fact that we're working with only one stator. Any ideas out there?

I've successfully bid on a GEP motor in San Antonio. I'll be picking it up sometime in the next month or so, once the government checks me out (again) and realizes I'm not a terrorist, just a grouchy old fart with a lot of financial worries. I'm gonna keep running my GL4 chip from Bill Heath. It's been an incredible help in getting me great fuel mileage, keeping my tranny together, and giving me more power than I'll ever (responsibly) need.

So here's the second question: Anyone using the ATT setup in a vehicle similar to mine? (94 one ton dually, approx 7,000# empty) My ARP studs arrived yesterday, but I'm wondering what kind of boost pressures I'll see. Since the turbo isn't waste gated, is over boost a problem? Remember, this is a 6.2, which means no coated pistons. Getting the pistons coated is an option, but the money needed to do that, would have to come form the ATT fund. Course, it's easier to add an ATT later than to go back and coat pistons. :hihi:

I'm open to ideas and suggestions folks.

Mods - If any of this is inappropriate, feel free to edit as necessary.

 

[bk95td]

I work at a school also and have had my wages froze for the next 2 year minimum. I haven't gotten squat for raises in the 11 years I've worked there. There is nothing that costs less than it did 11 years ago. I feel your pain.
If you've only been lurking ,that could be a good thing in that you haven't had some rare odd problems going on. You should feel lucky.
I did enjoy your thread on your paint job. It's good to see a quality work being done by the next generation of craftsman.
If you aren't towing heavy and money is short why not find a high quality stock reman torque converter. I can't see spending huge $ on a suncoast or other big $$$$ converter like the modern diesels need just to hold together.
I wouldn't assume that the engine you are getting is a stock bore 6.2 untill you actually measure the bores. The military has their engines rebuilt as often as some of us change oil.
Good luck on your project. Barry

 

[Dave Barbieri]

Thanks for the thoughts Barry! Yeah, raises in education are pretty much non-existent. Like I said, the legislature is considering 'regressive raises'. Gotta love it! Ya know, I'd love to see these guys start applying some of the stuff they pass to themselves! Now THAT would be a hoot! If their salaries start getting cut each year, I wonder how many would stay in politics simply for love of country?

I like your idea about the quality rebuild. Any recommendations on supplier? The replacement converter is listed as a B-81. When I look up specs for that, I come up with two choices: 'low stall fin angle; single stator' for big blocks and diesels, or 'high stall fin angle, dual stator' unit for the small block motor. No low stall, dual stator option available. I checked with our local transmission shop and they gave me the number for their rebuild vendor. I'll call them next week and see what they say.

As far as the engine goes, the pics show the exhaust manifolds with unused donut gaskets in place, no trace of carbon on the inside of the manifold opening, and the cardboard box of support pieces unopened. I can hardly wait to actually see this sucker! What a huge blessing it would be to be able to start with a brand new engine!

 

[ak diesel driver]

Some of the rebuild shops are starting to use 1000rpm stall convertors and staying away from the multidisc clutches as they are having warranty issues with them

 

[Burning oil]

Try Brittan Parts Service INC 713 694 0712 in Houston. They do all in house. Did my TC for the 4L80E.

 

[Matt Bachand]

Some of the rebuild shops are starting to use 1000rpm stall convertors and staying away from the multidisc clutches as they are having warranty issues with them

I never understood what stall speed means on a convertor, can someone please explain?

 

[ak diesel driver]

my understanding is the rpm that it engages at

 

[JiFaire]

I never understood what stall speed means on a convertor, can someone please explain?

http://www.bankspower.com/techarticles/show/10-Understanding-Stall-Speed

Basically, it's the rpm speed that the converter starts to engage. Lots of info on the web about this, most of it is about racing or street-rodding, you need to look for towing or diesel applications to get the info you need.

http://www.campbellenterprises.com/...e-converters/high-stall-torque-converters.htm

 

[Dave Barbieri]

Matt -

Stall speed is when the stator quits rotating and spins at the same speed as the turbine.

You've seen diagrams showing a torque converter like two halves of a grapefruit, right? One half of the grapefruit is bolted to the engine flywheel/flex plate (pump), the other half is bolted to the tranny input shaft (turbine). The idea is that fluid is flung from the fins of the engine half towards the fins of the tranny half. The force of the fluid causes the tranny half to start rotating. That is actually a fluid coupling. What makes a torque converter special is the addition of a stator. This looks like a second mini-turbine set tin the middle of the turbine/pump assembly. After the pump blades bounce the fluid off the turbine blades, the stator takes the fluid and redirects it again towards the turbine blades. This redirection actually causes the fluid to accelerate before it hits the blades again. This redirection and acceleration cause torque multiplication. Most good OEM converters give a 1.6 - 1.7 multiplication factor. 100 foot pounds of torque at the flywheel becomes 165 foot pounds of torque at the tranny input shaft. Like getting 15 pounds of sugar out of a 10 pound bag! Very cool! Here's a great overview:

http://auto.howstuffworks.com/auto-parts/towing/towing-capacity/information/torque-converter2.htm

 

[buddy]

And like Barry mentioned, what you get might not be a 6.2, seeing as I dont think AMG casts a 6.2, and we have seen 506 blocks as 6.2 replacements. However, people are seeing them with bearings that don't squirt when the piston oil squirters are in place and low flow oil pumps like a 6.2 would have had with no oil squirters.

For the ATT, it works much better than a GMx turbo under load. Dont know if you have to climb any grades, but anytime you can think of when you might be straining to get power out of the engine, the ATT will make it seem like its not straining at all. DetroitDan has one like yours.

States all over are having to cut budgets and employees. Hopefully teachers can bear through it, unlike the UAW that drug their corporations down to Bankruptcy without batting an eye. If everyone can sacrifice a little might be able to save some jobs. Here in CA, teachers get paid pretty well for actual "on the clock" hours, and then they "get laid off" and collect unemployment over the summer months if not teaching. CA is all sorts of messed up compared to other states. If only politicians could apply their methods to their own wages, then we may respect them.

 

[ak diesel driver]

politicians wages ought to be determined by the avg wage for their area. and gov ought to take a reduction like everyone else

 

[Woody35]

texas is starting to sound as bad as IL

 

[Dave Barbieri]

And like Barry mentioned, what you get might not be a 6.2, seeing as I dont think AMG casts a 6.2, and we have seen 506 blocks as 6.2 replacements. However, people are seeing them with bearings that don't squirt when the piston oil squirters are in place and low flow oil pumps like a 6.2 would have had with no oil squirters.

Yeah, I remember reading that thread. Installing the late model 'squirter' main bearings in all the mains fixed that. I never did understand the logic behind using squirter main bearings in only the rear mains. That's one reason I plan to disassemble it completely - check for internal problems and be sure it's truly good to go. Gotta tell ya, it'd be a real hoot not to have to deal with any cracks in the block or heads.

For the ATT, it works much better than a GMx turbo under load. Dont know if you have to climb any grades, but anytime you can think of when you might be straining to get power out of the engine, the ATT will make it seem like its not straining at all. DetroitDan has one like yours.

I keep coming back to that. Plus the fact that there's a serious reduction in back pressure, which ends up helping mileage. Anything that makes the engine more efficient makes it cheaper to keep over the long run. With diesel fuel prices increasing by the week, the time to hit break even gets shorter. Add to that the fact that the engine isn't working as hard, longevity increases as well. At least, that's the rationale I'm going with. Frankly, I just want one under the hood!

Here in CA, teachers get paid pretty well for actual "on the clock" hours, and then they "get laid off" and collect unemployment over the summer months if not teaching.

Texas ranks in the bottom quarter. Not a lot of fluff to begin with. Most of the teachers in my group spend a portion of their summer break (two months off) working in their classroom getting ready for the coming year. I'm really fortunate because I work with some outstanding people. I just wish we had better news for them.

 

[Dave Barbieri]

Try Brittan Parts Service INC 713 694 0712 in Houston. They do all in house. Did my TC for the 4L80E.

Thanks Leroy! :thumbsup: :thumbsup:

I'll call them Monday. Houston is less than four hours from the house. I could actually drive down there and take a look around. What exactly did they do to your TC? How's it set up? How long have you had it and what differences do you notice from stock?

 

[Burning oil]

Thanks Leroy! :thumbsup: :thumbsup:

I'll call them Monday. Houston is less than four hours from the house. I could actually drive down there and take a look around. What exactly did they do to your TC? How's it set up? How long have you had it and what differences do you notice from stock?

You know its been so long ago I don't remember the details, but they increased the stall speed. It has held up well. Its behind a 680 hp 700 #torque 540 CID engine.

 

[Dave Barbieri]

Some of the rebuild shops are starting to use 1000rpm stall convertors and staying away from the multidisc clutches as they are having warranty issues with them

I didn't know that. What kind of issues? As I dig around on the web, I'm seeing some common trends for OEM replacement:
1. Furnace brazed fins
2. Single disk lock up clutch, different materials depending on supplier
3. Balanced
4. Stall speed 1300 - 1400 rpm
5. Single stator
6. Price $250 - $325

It would be good to know about any trouble spots.

 

[Matt Bachand]

So if you have a stall speed of 1500 rpm, the transmission wont start transferrring power to the drivetrain until the engine is at 1500rpm?

Thus a 2800rpm Stall high performance race converter lets the engine get up to 2800rpm (possible HP peak range) before power begins to go to the rear wheels?

 

[ak diesel driver]

as was explained to me to use multi discs in the same space requires thinner clutch and mat which don't seem to last as long

 

[ak diesel driver]

Thus a 2800rpm Stall high performance race converter lets the engine get up to 2800rpm (possible HP peak range) before power begins to go to the rear wheels?

not necessarily peak HP but most high revving engines have gutless low rpm power

 

[Dave Barbieri]

So if you have a stall speed of 1500 rpm, the transmission wont start transferring power to the drive train until the engine is at 1500rpm?

Thus a 2800rpm Stall high performance race converter lets the engine get up to 2800rpm (possible HP peak range) before power begins to go to the rear wheels?

Stall speed is the rpm point at which the little stator quits doing it fluid redirect act. Any time you're accelerating or needing power, the stator lags behind, redirecting the fluid against the turbine a second time (torque multiplication). As the need for power drops off (top of the hill, cruise, etc), it catches up with the turbine and effectively 'stalls' in relation to turbine speed. At this point torque multiplication stops. Stall speed is basically the rpm point at which the magic stops inside the torque converter. You're back to 1:1 torque multiplication. 10 pounds of sugar out of a 10 pound bag.

Stall speed is all about torque multiplication. It has nothing to do with when a vehicle starts moving forward. This relies on the fin configuration inside the turbine and pump. Example, once warmed up, my truck will move forward at 5mph with the engine idling at 650rpm. The stall speed is actually around twice that rpm.

Here's a quick 'n dirty test to determine stall speed for your specific power train:

1. Bring the engine and tranny up to operating temps.
2. Lock the brakes. Set the parking brake, place wheel chocks, chain it down, etc. Whatever you need to do
to make sure that sucker will not move.
3. Place the trans in Drive.
4. Hold the brakes down and floor the accelerator pedal.
5. The engine will accelerate to a certain rpm and hold there. That's your stall speed.

WARNING: DO NOT RUN THIS TEST FOR MORE THAN 15 SECONDS ! !

Because you're really stirring up the fluid in the torque converter, it generates a LOT of heat. 15 seconds gives you a chance to take an accurate reading and stop well before the fluid gets hot. If you want/need to retest, let the engine idle in park for several minutes before retesting.

Rule of thumb:
Higher than normal RPM: weak torque converter (or modified engine)
Lower than normal RPM: weak engine