TH400 Tailshaft Roller Bearing and Pressure Feed?

[Speed of Heat]

I’m collecting parts to rebuild the TH400 for my Sanger Mini. Blown 900HP. Upgrading to stronger parts for insurance against carnage. I’ve heard peeps in the past mention using roller bearing tailshaft housing with pressure feed. It’s been said that because of the angle and the trans being backwards, that the bushing type starve for fluid? Anyone know anything about this and how the mod is done? -Thanks in advance.

 

[Outdrive1]

I’m collecting parts to rebuild the TH400 for my Sanger Mini. Blown 900HP. Upgrading to stronger parts for insurance against carnage. I’ve heard peeps in the past mention using roller bearing tailshaft housing with pressure feed. It’s been said that because of the angle and the trans being backwards, that the bushing type starve for fluid? Anyone know anything about this and how the mod is done? -Thanks in advance.

Alexi @BoostPower can set that up for you. I had a bearing fail in one of mine and wipe the trans and housing out.

 

[welldigger00]

I’ve heard about this as well. I tore my trans down in my RC, and it was surprisingly in good shape for a standard t400 with 1000hp and at least 250 hrs(since I’ve owned it) who knows how many more. I’ll be interested to hear how this thread develops.

 

[monkeyswrench]

There is this option, but there is no other pressurized feed setup.

TH400 Output Thrust Bearing Conversion Kit 400-34601BC

TH400 Output Thrust Bearing Conversion Kit 400-34601BC

www.tsr-racing.com

It's an easy swap out for this deal with no machining.

 

[lenmann]

Not the best pic, but here is how the pressure feed line was plumbed on my RC. I have since replaced the stainless hardline with #4 braided lines. I have also seen them plumbed from the cooler fittings instead of the pressure port as shown.

 

[monkeyswrench]

Not the best pic, but here is how the pressure feed line was plumbed on my RC. I have since replaced the stainless hardline with #4 braided lines. I have also seen them plumbed from the cooler fittings instead of the pressure port as shown.

View attachment 1100874

Ok, so they run line pressure, not just lube pressure? Or do you know if they run a restrictor orifice inline?

Nevermind... just blew up the pic and saw the valve

 

[Speed of Heat]

Not the best pic, but here is how the pressure feed line was plumbed on my RC. I have since replaced the stainless hardline with #4 braided lines. I have also seen them plumbed from the cooler fittings instead of the pressure port as shown.

View attachment 1100874

Any idea who makes the valve or regulator used in the lube feed line? I assume that’s what is on the end of the hard line?

 

[Boat Anchor]

Any idea who makes the valve or regulator used in the lube feed line? I assume that’s what is on the end of the hard line?

From the logo on top of the adjustment knob, it appears to be a Nupro/Swagelok valve. Check on Ebay for one.

 

[rivermobster]

Ok, so they run line pressure, not just lube pressure? Or do you know if they run a restrictor orifice inline?

Nevermind... just blew up the pic and saw the valve

That's a pretty cool set up, and smart! I would think if they just pressed a needle bearing in there, and ran it off the cooler line, it would self restrict? Pretty interesting idea.

 

[monkeyswrench]

That's a pretty cool set up, and smart! I would think if they just pressed a needle bearing in there, and ran it off the cooler line, it would self restrict? Pretty interesting idea.

If you ran it off the cooler line output, you'd end up about lube pressure, but cooler fluid. With adjustable feed pressure though, it would ramp with throttle angle/RPM...so both have their advantages I'd think.

I've only done the roller bearing deal on drag cars, and off road cars. Shock and load are big, but not sustained like a boat. The feed line is something different for me, but now goes in the rolledex of stuff in my head.

 

[rivermobster]

If you ran it off the cooler line output, you'd end up about lube pressure, but cooler fluid. With adjustable feed pressure though, it would ramp with throttle angle/RPM...so both have their advantages I'd think.

I've only done the roller bearing deal on drag cars, and off road cars. Shock and load are big, but not sustained like a boat. The feed line is something different for me, but now goes in the rolledex of stuff in my head.

I would think to do it right, you'd need a pressure regulator. Looks like they just used a brake line adjustable proportioning valve? Seems like it would real easy to blow that output shaft seal out with line pressure! Bigger drain back hole to offset?? Would definitely need some thought! Pretty cool idea though.

 

[lenmann]

I would think to do it right, you'd need a pressure regulator. Looks like they just used a brake line adjustable proportioning valve? Seems like it would real easy to blow that output shaft seal out with line pressure! Bigger drain back hole to offset?? Would definitely need some thought! Pretty cool idea though.

As mentioned above the hardline set-up is a Swage Lock valve. When I re-plumbed it with hose I used one of these:

SDMVR | 316 SS Needle Valve | Titan Fittings

Product Details 6 000 psi pressure rating

www.titanfittings.com

Now I am wondering just how much pressure is going to be in the line and if braided hose will be adequate. How much pressure comes out of that port?

 

[rivermobster]

As mentioned above the hardline set-up is a Swage Lock valve. When I re-plumbed it with hose I used one of these:

SDMVR | 316 SS Needle Valve | Titan Fittings

Product Details 6 000 psi pressure rating

www.titanfittings.com

Now I am wondering just how much pressure is going to be in the line and if braided hose will be adequate. How much pressure comes out of that port?

Like monkeys mentioned, it changes constantly depending on RPM, load, gear, ect..

You have a built in restriction with that hard line you are using, and another restriction with the proportioning valve.

If you Are using a needle bearing, instead of a bushing, the oil Should flow pretty freely though it?

With all this in play, the pressure in that hose shouldn't be anything to worry about.

But I'm mostly just guessing here. I don't know off the top of my head what kinda line pressure YOUR transmission puts out.

It's an interesting discussion for sure.

 

[rivermobster]

And on another note...

Is that feed bleeding off internal line pressure, making it less than it should be??

Lots of questions here!!

 

[coolchange]

If I remember right at least on a PG if you run the shorty roller bearing tail shaft no feed line is needed. For stock tail shaft I have seen them with just a very small hard line. Never seen the valve set up before.

 

[monkeyswrench]

As mentioned above the hardline set-up is a Swage Lock valve. When I re-plumbed it with hose I used one of these:

SDMVR | 316 SS Needle Valve | Titan Fittings

Product Details 6 000 psi pressure rating

www.titanfittings.com

Now I am wondering just how much pressure is going to be in the line and if braided hose will be adequate. How much pressure comes out of that port?

I think the most I've seen out of a 400 on the pressure gage was a little over 300psi. That was on a "garage" shift, park to reverse. Reverse, being a lower gear, and not having to shift to another, ramps full line pressure. That said, never messed with one in a boat. Weird differences, like no torque converter, and the output always being in "slip"...I have no idea how they set up the valve bodies or governors

And on another note...

Is that feed bleeding off internal line pressure, making it less than it should be??

Lots of questions here!!

If it's a fixed bleed when set up, I think it would be no different than the lube or control circuits. They just constantly "bleed". On the other hand, I can also see screwing it up like a 700 TV cable if you didn't meter it down.

 

[rivermobster]

I always thought a boat transmission used a full manual valve body?

Pretty sure they are highly modified transmissions? I have no clue what kinna pressures one of those trannys would put out.

 

[coolchange]

I know a guy who used a modulator on his turbo 21. It would auto down shift to second and up shift for pulling skiers. Also had a shift button (electric kick down) to hold it in second for the shift. No need to move the shifter.

 

[obnoxious001]

It seems like there was a bus tailshaft housing that worked out well. I never had an external line in the trans in my Schiada that got ski raced as well as running on the river. Never an issue with mine, but few years back rode in a race with the Coin Toss boat and we had to keep slowing down due to smoke choking us. I will check with him tomorrow and see how that was fixed.