Advice needed for torque converter fluid

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Hi, folks! Noobee here. To keep my first post short I'm going to not give a lot of background. If we need some 'splaining, let me know as the topic progresses and I'll do my best. [edit] It got long anyway.

I am running a motorcycle trike with no gearbox. It's an experiment, based on the theory that given enough engine torque and a torque converter, a mechanical gearbox is unnecessary. With my final drive ratio and the proper tire diameter I've been able attach the torque converter from a Moto Guzzi Convert to a 1200cc Guzzi engine (native shaft drive) and in effect run a drive shaft directly from the t/c driven turbine to the differential -- no mechanical gear reduction, no clutch, and only a transfer case to get powered reverse. It gets up and moves from a stop like a volvo, and does 90+ mph. Keeping up at highway speeds and passing are not problems.

What is becoming an increasing problem though is low speed and stop-and-go/construction/accident/urban rush hour stuff. 9,000 miles ago it was peachy, and I was in Alaska, where nobody ever got heatstroke. Now the trike is in AZ, and it is suffering.

The fluid heats up quickly and pressure drops in an inverse relationship until at idle rpm I have zero pump pressure and temps pushing 200f. I need to hold the idle up to keep pressure, but when stopped, the fluid coupling slippage makes the fluid hotter, faster. The result is that the trike becomes very reluctant to start rolling from a stop, and it shudders badly with poor lockup/acceleration until pressure has been back up for a few minutes. It can take several miles before pressure and temperature are back within operating parameters. It feels as though there is no fluid circulting through the t/c.

The torque converter was spec'd for DEXRON II. I did not like the performance of the new and improved DEXRON substitutes, especially for their operating temps and foaming, so I settled on 5606A. The 5606A is what it has been running for the trip from Alaska through the lower 48, but I think it is failing in this hotter Arizona weather. The symptoms began in Kansas and got steadily worse as I ran old route 66 to AZ. At this point I'm concerned for safety and a complete meltdown in hot city traffic.

Sooooo. . . . I'm once again looking for alternative fluids to feed my experimental hydrauic drive. Key details are

engine-camshaft-driven fluid pump.
flow and pressure feeds a torque converter/fluid coupling

(5606A when working good)
Pressure relief at 28#
low pressure no less than 10#
nominal urban pressure ~18#
nominal highway pressure ~24#

nominal highway temp ~20-40f above ambient temperature, rising slightly on grades and hills. Road speed itself has no direct relationship to temp above 40mph.

nominal urban temp 150f. Stop-and-go is augmented with electric radiator fan.

(5606A currently)
low idle pressure 0
nominal urban pressure 4-8#
nominal highway pressure 15-18#
nominal highway temps unchanged - 20-40f above ambient.
nominal urban temps 180 - 220f.

I am inclined to try some sort of tractor hydraulic fluid, like a 10/30 or iso 46, with minimal additives for slip and valve lubrication, and a lot of antifoam. But I see nothing about how these perform in a fluid coupling/torqueconverter as the drive fluid.

What would you folks suggest?
 
Does the oil end up in the Guzzi gearbox for scavenging back to the pump ?

i.e. I would imagine that's the easiest way to ensure that the converter gets fed, and scavenged.

Start again...can you explain the oil circuit, and how it does everything with one pump ?

I don't think it's a viscosity issue, I think that the pump is either having trouble (slippage) on the thinned oil, or there's an air leak on the suction side.

The converter carrying on and surging until it refills is what I think is happening.

Mobil Agri 424 is a thick multi purpose fluid with Dexron (III???).

My thoughts are
* air leakage (you mention foaming as an issue, but not a symptom)
* worn pump (no pressure and foaming)

If you have some pics of the hydraulic circuit, I'd really like a look...I can find squat on line.
 
Originally Posted By: rodekyll
If we need some 'splaining, let me know as the topic progresses and I'll do my best. [edit] It got long anyway. ....What would you folks suggest?


WHERE'S The fluid COOLER???!?!?!???!??
 
You may need to use a different pump configuration. It's your relying on engine rpm to build pressure on the cam which is half your engine rpm. Your torque converter is also slipping at start out alot generating a ton of heat.i would try a belt driven dry sump pump and over drive it to provide the pressure you need at idle. The pressure relief valve on those pumps work great. At higher rpm is should be well enough to not over pressure the system. And yes a cooler is in order especially for your setup with no gearbox. I can't believe that your only seeing 200 as your temp. Stock car products makes a wetsump belt driven pump that works extremely well. Talk to them to see what ratio you will need to get the pressures you want. What engine is this all running off of anyways?
 
Originally Posted By: Linctex
Originally Posted By: rodekyll
If we need some 'splaining, let me know as the topic progresses and I'll do my best. [edit] It got long anyway. ....What would you folks suggest?


WHERE'S The fluid COOLER???!?!?!???!??
You beat me to it. My '77 IH hydrostatic has a fan. Something on a cruiser, probably over weight, I'd plumb in a cooler bigger than needed, regulate with a thermostat of some sort. Give the system a little more capacity. I'm not big on mods. Too cheap and lazy. The tin foil cooler that AMC and Chrysler used in the Grand Wagoneer was a dangerous POG. A 40$ cooler kit from NAPA was installed on every one of the 5 GWs I had.
 
Last edited:
Thanks for the repllies so far.
smile.gif


I have had poor luck with redline products. I think the oil shears early (I have 10/60 in the engine now and watch the hot idle pressure degrade at 2000 miles), and the shockproof oozes past the seals in my newly re-geared differential. I went back to regular dino in the diff and have 10/60 Motul on the way for the engne. So I'm not real excited about even more redline.

The engine here is a 1200cc Moto Guzzi 2-valve mill, fresh from the crate 2500 miles ago. The torque converter was originally used on Moto Guzzi 1000cc "converts" back in the mid 1970s. I've owned several. The torque converter pump lives in a casting in the engine front timing cover and drives from the end of the camshaft.

The cooler/reseviour is a radiator about 8x12x2.5". It has about 16x the surface of the oem cooler. It has a scooped airflow channel.

Fluid loop maps like this:
fluid out the bottom of radiator -> 5/16 (oem size) transmission cooler hose to the pump intake. fluid must rise about 8" to the pump intake.

pump is a double-gear setup. I don't know the proper term for the pump design. It has an internal 5-lobed paddle that spins inside another lobed, spinning body. Fluid leaves the pump via 5/16 hose and travels to a banjo fitting on the side of the fluid drive housing.

The fluid drive housing is a bellhousing similar to a standard automatic transmission. Fluid enters it at the banjo fitting and breaks into two galleys in the casting. One galley feeds the output shaft bearing. The other communicates with the torque converter itself.

fluid flow and pressure circulates and cools the t/c and exits throuugh another banjo fitting in the fluid drive housing. Fluid from the bearing lube side exits the bottom of the fluid drive housing. Both return lines attach to the top tank of the radiator, but by separate hoses and ports. They dump returning oil above the level of the fluid in the radiator to reduce foaming and not backpressure each other.


Up till the last couple thousand miles, this setup has been successful (see stats in previous post). It idled 12-14# at 950rpm. Now I'm getting 0 at 1200rpm.

I have ordered 3/8 banjo fittings to increase flow. They have not arrived yet.

I am also suspicious about the pump. When I installed the 1200 engine last month I Grabbed a timing cover and pump of unknown parentage off the shelf. I replaced the o-ring (common air leak) and shaft seal (the only other consumable), but I did not do any volume or flow testing before buttoning it up. It could be a clapped-out pump. I have another used assembly in shipment. I'd like to follow this topic through before treating myself to the partial engine teardown required to replace the timing cover.

Just an observation -- in the past when the pump o-rinng has failed, the fluid foams badly. I am not seeing foam.
 
I am familiar with that type of pump. There are clearances that you need to check and or modify. You can also port the pump and do a little mod to prevent cavitation. When you receive your used pump please post some good pics and I can point you to areas that you should address.
 
An alternative pump would not be out of the question. My alternator lives on the drive shaft, so the nose of the crankshaft, where an alternator would normally be installed, is bare. It would be very cool if I could find something that worked in the temp/flow/pressure limits and also could couple directly to the crankshaft instead of belt driven. Anyone know of anythinng like that?
 
You could couple anything to the crank given the rotation of the pump is right. I'm sure you could just fabricate a keyway coupling. If considering that I really urge you to check the wetsump pump out on stock car products. Not sure on rotation but they are small and pack a [censored] of alot of volume. Adjustable pressure relief as well.
 
Aviad external wet sump. 1" body reverse rotation to be cam driven. Part number
001-11000

That's the smallest body pump I've found. Should be more than ideal for your application. Aviad makes very high quality trick stuff.
 
http://www.guzzitek.org/gb/ma_us_uk/Haynes_750-850-1000Convert_Atelier(GB).pdf

Page 79 on the PDF
 
UPDATE:

I changed the intake hose from the cooler to the pump from 5/16 to 3/8. I drilled two more holes in the banjo bolt at the pump. Running pressure has improved in the short distance I've ridden (was 17-18# now 22#-ish), and the temperature is rising more slowly. However the idle pressure when hot is still eventually dribbling to zero.

Side note: I had to drain 5606 from the radiator in order to change the hose connection. Fluid has shinies in it. I only have two moving parts in the fluid loop -- pump and torque converter. Looks like one or the other is shedding itself. I can't make out the color of the flakes yet, so I don't know if it's brass or steel. But they're microscopic.
 
Also -- and back to my originl question -- I'll need to refill the fluid completely. Can I use a tractor hydraulic fluid (non-AW) in place of ATF in a torque converter/fluid coupling application? I'm hoping a multi-vis like 10/30 hydraulic fluid will substitute.
 
I've been asked to post pics, and I'm going to try. In the meantime, think "motorcycle trike" and "Mad Max meets Model A". Stay tuned!
 
Let's see if I'm smarter than the buttons! This is the 3V'L TWIN. It was the EV'L TWIN when it was a 2-wheeler. Lacking imagination, I just flipped the E to be a 3. Alaska built from the ground up, and driven via WA, OR,UT . . . . MI upper penn, LA, TX, KS, to its current location in Kingman, AZ. Headed to Seattle if I can solve this problem. If you want me gone (and don't we all?) please help!





 
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