• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

polishing a turd / aw70-71 build up

n xntrx volvo said:
greenbook says otherwise.
16v's have less torque to multiply to start with. so if it felt the same, there was a difference.

as long as the data comes from somewhere other than superstition...

in any case, i was refering to the stall reached with a brake stand.
 
n xntrx volvo,

Looks like you are doing your research.

I have an AW72L in my 740 +T. Like others have stated the very slipery 2-3 shift is the killer. I have rebuilt this trans once but not due to the +t but the previous owners neglect. Even with a rebuilt valvebody, the 2-3 shift was still soft and slippery. I'm just living with it now.

I say go for it. We need an AWXX pioneer. Those other Brand X transmissions mentioned were turds for hot rodding till someone polished those.

I like those fire proof socks.

Good Luck
 
I cant really explain the 5500rpm thing. My 1st aw nuked its self about a week after I got my MS setup running well. The stock EZK and LH start to pull timing hard at 5500rpm and throw alot of fuel at the engine above 5500rpm to smooth the shift and ease the transmission shifts.. After i was able to tune my car to pull strong to 6300rpm or so the car was faster but the trans was noticeably struggeling to keep the power contained. My first aw took a crap about 1 week after i was MS's and i dont think it was due to some enormous power gain total just the fact that the car was still making power later in the power band. My next AW got the valve body mod during SE3.0 and dident make it threw the weekend.. I have since tuned 1 MS'ed car with an AW trans and me and kenny both decided it would be wise to pull some timing up top to spare the trans..

Keep us posted and if you find any valve body diagrams i would be very intrested in seeing them..

Sam
 
n xntrx volvo said:
philip- i'd love to open that valve body open to see what was done and find a way to replicate it for other people. i hear the nose of the conv is weak, but have yet to see proof. the higher stall of the 72 guts should be sufficiant. i'd worry about going any higher on stall due to heat. that said, if i could dig it up, i'd be on it, if just for the learning experience. any pictures of the improved rear bush? also, shouldn't a 93 be a aw71L?

I don't have any pictures of the improved tailshaft bushing location, but I have seen it because I have removed the tailshaft cone in both my 89 AW71 and my 93 AW71. The bushing is moved out to the end of the cone instead of at the beginning of the cone relative to the trans body. This may allow the cone to provide more structural support for the shaft. The mechanics I use say they have not replaced nearly as many bushings on the later trans. I think this change occurred around 92 or 93, but was short lived because the AW71 was used only on the 940 Turbo at that point and that model was discontinued in the US a couple of years later.

The converters are definitely very different for the lock up and non lockup trans. You will have to decide which way to go. Theoretically a lockup is weaker, but some domestic ones have held decent power stock and been modified for more. I think the Buick GN is one example.

I think you could go higher stall than the MVP if you used synthetic fluid and a large heat exchanger -- possibly one with an electric fan. People measure stall differently, but the best method is the zero boost method. Run the engine up to 0 vaccum and 0 boost while holding the brake until, if applicable, the wheels spin. That will be the true stall. The same converter can yield different stall speeds on different motors, depending on the torque the motor produces.

On the AW71, the governor inside the tail shaft housing does not control shift point rpm. I don't know why, but when I was at Level 10, they added 5 ounces with no effect. The change was internal to the valve body. They said something about the rpm shift point at full throttle being controlled by the "ramp." Again, I don't know what that means.

If I can get the trans out of my car and sell it in the next couple of months and it ends up out west, maybe you can get pictures or have a look.

Philip Bradley
 
Do look to what Toyota did with this transmission so that it is able to live behind the six....
I have had good sucess in the past with adding clutches and steels in place of the really thick spacers in the clutch packs.
 
re: 2-3 shift. looks to be the only change is the release of the 1st brake. the #1 and #2 only have 12 springs, where as #3 has 16. the cluthes also have a higher number (18 springs). this would appear to be a great weekness in the release force on the brakes, causing failures there. the main reason that imho one would do this is to allow for smoother shifts. just raising the valve body's line pressure, w/o fixing this, would still lead to problems. since if the springs where weak under stock pressures, at higher pressures, it def wouldn't get better.
in early versions of these trannys, the modified the clutch springs aswell, leading me to believe this is def a problem.
i'll try to see if i can use the plate off c1 or b3 to get aleast 16 springs onto it, if not a full 18.
 
Are you sure that the springs are there to release the clutch or to slow application of it?
My fifty cents in a bet has the clutch holding NOTHING the instant that pressure is released......
Think of how it operates....... The springs MUST be there to slow application of the clutch for smoother shifting....... Exactly opposite of what we are looking for.
I'd try it with half the springs removed and see how it behaves. Heck you may be able to fit another clutch and steel (or more) with the springs removed..... more clutches is more fun for longer......

'Power interruption' is evil. I remember EZK having a pair of wires that talked with Fuel..... Was there also a trans brain involved? EWE!!

I've absolutely beat the hell out of the AW-70 in the Hornetkar and it has been (knock on wood) utterly without issues........ With many miles and having been ignored. This is a good trans....... one we can ignore and it goes about it's business......

John Lane
 
this is in the brake, not the clutches. the brake is the same concept as bands in a domestic application. the springs increase release pressure. what i'm seeing is it slowly switching to 3rd, increasing the overlap of both.
more plates/ clutches will def try to be stuffed in there.
opinions on thinner steels to accomplish this? one schoool tells me "extra clutches good no matter what" another "thinner steels will not dispate enough heat and warp".
the whole ezk thing doent matter, i'm on a standalone & edis
 
The EZK is not even in the picture when we are talking about the trans.
 
I have not encountered what you describe with the brake being slow to release.

When replacing the steels I replace the real thick ones on the inside and outside of the clutch packs with more of the already thin steels used elsewhere. Thinner steels then those? I've not seen such an animal. I can speak from experience in saying that more clutches+more steels makes for firmer shifts......More material should make it easier for the trans to work.

The brake is bled off via the valve body. Look for the restriction to be partially blocked.

EZK is evil......Only cuz it bit me in the ass years ago with a 'mystery stall' issue.
 
Aside from bumping line pressure, do not forget to add in coolers. One of the things I've found is that they seem to run a bit better with a thicker fluid. Back when Aw7x trannies were being made, transmissions ran on Dexron 1 fluid. Most places now, you can only find Dexron 3. HOwever, you can still find Dexron 1 at the honda dealer. Try running that (much thicker) on your trans, and see how the reliability holds.
 
FWIW my trans in the Hornetkar is doing really well running on the synthetic ATF that Mercedes pours into their junk........... Shifts are still crisp even in that old junk.
 
JohnLane said:
FWIW my trans in the Hornetkar is doing really well running on the synthetic ATF that Mercedes pours into their junk........... Shifts are still crisp even in that old junk.

I just went to synth as well. Royal Purple. I'm noticing very nice crisp shifts as well. I'm not complaining. :)
 
stevemd said:
Great info in this thread though wtf is the HornetKar of John Lane's?

The Hornetkar is a POS 242turbo that is built to the rules for Evergreen Speedway's 'Hornets' flavor of racing that is certain to have tears running down your face the first time you try it due to laughter.

Have a look-see at www.evergreenspeedway.com and find the page (yes; one page!!) of rules for Hornetkars.
I've not been racing it this year due to dealing with my 'Seattle issues' though I hope to be back at it soon.

The AW70 in the Hornetkar is the same age as the car AFAIK, which is to say an utterly neglected POS thing. The engine was worn such that the ring ridge was oh..... .020" deep or so. Yeah......fill the oil and check the gas...... I gave the old trans Mercedes' flavor DuJour of synthetic ATF and it has been just fine, getting manually shifted cuz we are all savages and we can...... and is generally treated with the lack of respect you would expect for such a fine specimin of a 242 turbo. Pics of it are to be found in the 'Turbobricks Welding competition' thread. Certainly NOT serious racing but good times.

I'm also curious as to how it goes with the AW buildup as the trans in the Hornetkar is just bound to fail AT SOME POINT and I will want to build one that will be wayyyy bitchener as we did with the motor that is....... *wink 'Stock' inside. Heh heh heh heh heh..... To match all the Honduh boyz with their H-22 CRX things that are 'SSSSSSTToocckkkk' and it actually makes it through tech. Who am I to question?
 
I'll be keeping an eye on thsi thread, I want to make a AW71 last behind a modified b280, because Manual is going to be too much cost initially.
 
Ah yes, the T56, that's on the list, but is there a bellhousing to mount it? that's definetly going to be my limiting factor for a while.
 
Back
Top