Turbo-Hydro 350 operation

bill dedman · 06-26-2007, 04:24 AM

I have a friend who wants to run a TH350 in a street car with no vacuum signal available for the modulator (he'll be using a mechanical, Hilborn port- injector that has no manifold, just 8 individual stacks.)

He searched for a mechanical modulator, unsuccessfully, and has decided to just put a full-manual valve body on it and run NO modulator. This is a street car, basically; a home-built street roadster.

I was asked to get some information for him RE: What is necessary to do to the transmission to allow the use of a full-manual valve body (but not a reverse-pattern.)

I know that the modulator will not function at all, and can be removed and the hole plugged. Someone else told me that there is a "kickdown cable" on these transmissions. I am an ignoramous when it comes to these TH350's and don't know why, if it had a modulator, ir would NEED a "kickfdown cable:, but I am asking... Does a TH350 HAVE a kickdown cable at all, and should it come off in the case of a full-manual (probably Turbo-Action) valve body being installed?

Should the governor be removed, since it won't be used any more?

Is there any other modification that should be performed during the installation of a full manual valve body?

ANY information will be greatly appreciated.

Thanks in advance...

Bill

Mark Yacavone · 06-26-2007, 05:24 AM

Bill, The passages to and from the governor need to be plugged and a little piece of the wall between the two passages needs to be removed to create a loop for the governor pressure to the shift valves. There are other ways to do it but this will work.

Bob Mulry · 06-26-2007, 05:42 AM

Hi Bill,

Yes TH-350's have a "kick down cable" for a forced downshift at wide open throttle ONLY. You will have NO automatic 1-2, 2-3, 3-2 or 2-1 shift without a modulator or substitute for the modulator.

You can't drive in a normal maner without a modulator or a modulator replacemrnt such as the kit that B&M used to make. I think it was called a Modulink System and it worked like a TV (throttle valve) cable that senses throttle position and would allow automatic operation.

TH-200, TH-700, TH-355-4L etc use a TV cable rather then a modulator and it works fine.

If this is STREET CAR leave the trans alone and buy a Modulink set-up and let the throttle position working against the modulator and the govenor to control the shifting, because tranmissions are smarter then people.

Bob

bill dedman · 06-26-2007, 11:42 AM

Mark,
Thanks for the advice RE the governor passages. We'll take your advice on that, for sure!

Bob, we've looked pretty extensively for a B & M Modulink kit to replace the vacuum modulator and cannot find one. There IS a kit available for a 700R-4, but it won't work on a TH350.

This car is a hand-built, all-aluminum replica, loosely-based on a "Model A" roadster, and won't be a daily driver, so lots of cruising won't be a part of its operational life. It will not get driven a whole lot. We were told that the manual valve body shift kits wouldn't "jar your bones" when manually-shifted at part-throttle settings, especially, with a fairly loose converter, and if shifts were made in the 2,000 rpm range.

This car will be raced very rarely, if ever.

The owner is aware that every shift will be, of necessity, made by the driver, just like would be necessary with a Borg-Warner T-10, which is the alternative.

This way, he just avoids the use of a clutch.

Am I missing something here? Is there some reason this won't work? And will the transmission function okay without the kickdown cable? I realize he'd have to manually pull it into 2nd-gear for a downshift, but that alone, is no problem. I was wondering if the kickdown lever boosted main-line pressure to the servos/clutches when it was activated by a "floored" throttle.

Thanks for any information; It's MUCH appreciated!!!

Bill

Mark Yacavone · 06-26-2007, 12:03 PM

Bill, It will downshift to second without the cable hooked up,...off the modulator. Just won't go all the way down to low. What it will probably do also, is shift fine, 1st to second at WOT, off the governor, and then go right into third shortly after.

bill dedman · 06-26-2007, 01:42 PM

Mark,

I am not sure we're on the same page here.

What I was trying to find out is whether the kickdown cable needed to, or if it even SHOULD be hooked up and operational if this transmission has NO modulator or governor.

It's impossible to get a vacuum signal from the engine, due to the lack of an intake manifold (Hilborn mechanical port fuel injection; old-style), and we can't seem to find a mechanical modulator for a Turbo 350, so it will have:'
1. No modulator of any kind
2. No governor
3. No kickdown cable

That will work okay with a full-manual valve body, if I understand everything... it just means that for the transmission to shift up OR down, he'll always have to move the shift lever, which is no big deal, as the car won't be driven very much.

That being the case, I don't think it's EVER going to downshift on its own, will it? No governor; no kickdown cable; no modulator.... what could effect a dowshift? There's no reason for it to get into another gear.

lease correct me if I'm wrong... and, thanks for your time and advice!!!

Bill

Alan Roehrich · 06-26-2007, 02:04 PM

If you convert to a forward pattern FULL manual valve body, you will not need the detent (AKA "kickdown" or "passing gear" cable) cable nor the vacuum modulator.
The valve body will run the line pressure up to near maximum all the time to prevent slippage. The shifts will be very firm, especially if the transmission is built for performance anyway. MOST full manual forward pattern valve bodies will bolt on to a stock transmission. The will retain engine braking when downshifting to second. PLEASE remember that the transmission WILL go INSTANTLY to whatever gear you put it in. If you accidentally shift to first gear at 100 MPH, it WILL go, and lock the rear tires while spinning the engine way up.

bill dedman · 06-26-2007, 02:17 PM

Thanks, Alan, for the info.

What you said confirms everything I had assumed.

I think that is what we'll do. Possibly, order a Turbo Action full manual valve body, remove the govrnor and vacuum modulator and kickdown cable, and have essentially, a "clutchless three-speed" semi-automatic transmission.

I have some friends who have this setup in their Stockers and they all say that the shift quality is firm, but not bone-jarring at low (2,000) rpm's.

I'm hoping that that proves to be true in this case. It will have a fairly loose converter, so that will absorb some of the driveline shock that results from running 100-percent main-line pressure, 100-percent of the time.

I appreciate the time you took to respond to my question.

BTW, I am also very much in favor of a 7.5 pound per horsepower AA/Stock class... Too many cars sitting idle that could race under that parameter.

Bill, in Conway, AR

Bob Mulry · 06-26-2007, 03:47 PM

Bill,

Give me a call at 650 922 0407 I have a fix

Bob

Glenn Briglio · 06-26-2007, 05:27 PM

Another way to skin the cat would be a common vacuum source off of the 8 stack setup. If you want details call me at the shop (516) 599-7182 Glenn.

06-26-2007, 04:24 AM	#1
bill dedman VIP Member Join Date: Feb 2002 Location: Conway, AR Posts: 1,739 Likes: 0 Liked 6 Times in 4 Posts	Turbo-Hydro 350 operation I have a friend who wants to run a TH350 in a street car with no vacuum signal available for the modulator (he'll be using a mechanical, Hilborn port- injector that has no manifold, just 8 individual stacks.) He searched for a mechanical modulator, unsuccessfully, and has decided to just put a full-manual valve body on it and run NO modulator. This is a street car, basically; a home-built street roadster. I was asked to get some information for him RE: What is necessary to do to the transmission to allow the use of a full-manual valve body (but not a reverse-pattern.) I know that the modulator will not function at all, and can be removed and the hole plugged. Someone else told me that there is a "kickdown cable" on these transmissions. I am an ignoramous when it comes to these TH350's and don't know why, if it had a modulator, ir would NEED a "kickfdown cable:, but I am asking... Does a TH350 HAVE a kickdown cable at all, and should it come off in the case of a full-manual (probably Turbo-Action) valve body being installed? Should the governor be removed, since it won't be used any more? Is there any other modification that should be performed during the installation of a full manual valve body? ANY information will be greatly appreciated. Thanks in advance... Bill __________________ Bill Last edited by bill dedman; 06-26-2007 at 04:35 AM.

06-26-2007, 05:42 AM	#3
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,017 Likes: 57 Liked 321 Times in 101 Posts	Hi Bill, Yes TH-350's have a "kick down cable" for a forced downshift at wide open throttle ONLY. You will have NO automatic 1-2, 2-3, 3-2 or 2-1 shift without a modulator or substitute for the modulator. You can't drive in a normal maner without a modulator or a modulator replacemrnt such as the kit that B&M used to make. I think it was called a Modulink System and it worked like a TV (throttle valve) cable that senses throttle position and would allow automatic operation. TH-200, TH-700, TH-355-4L etc use a TV cable rather then a modulator and it works fine. If this is STREET CAR leave the trans alone and buy a Modulink set-up and let the throttle position working against the modulator and the govenor to control the shifting, because tranmissions are smarter then people. Bob __________________ Bob Mulry 7516 STK A & M Motorsports

06-26-2007, 11:42 AM	#4
bill dedman VIP Member Join Date: Feb 2002 Location: Conway, AR Posts: 1,739 Likes: 0 Liked 6 Times in 4 Posts	Mark, Thanks for the advice RE the governor passages. We'll take your advice on that, for sure! Bob, we've looked pretty extensively for a B & M Modulink kit to replace the vacuum modulator and cannot find one. There IS a kit available for a 700R-4, but it won't work on a TH350. This car is a hand-built, all-aluminum replica, loosely-based on a "Model A" roadster, and won't be a daily driver, so lots of cruising won't be a part of its operational life. It will not get driven a whole lot. We were told that the manual valve body shift kits wouldn't "jar your bones" when manually-shifted at part-throttle settings, especially, with a fairly loose converter, and if shifts were made in the 2,000 rpm range. This car will be raced very rarely, if ever. The owner is aware that every shift will be, of necessity, made by the driver, just like would be necessary with a Borg-Warner T-10, which is the alternative. This way, he just avoids the use of a clutch. Am I missing something here? Is there some reason this won't work? And will the transmission function okay without the kickdown cable? I realize he'd have to manually pull it into 2nd-gear for a downshift, but that alone, is no problem. I was wondering if the kickdown lever boosted main-line pressure to the servos/clutches when it was activated by a "floored" throttle. Thanks for any information; It's MUCH appreciated!!! Bill __________________ Bill Last edited by bill dedman; 06-26-2007 at 11:52 AM.

06-26-2007, 01:42 PM	#6
bill dedman VIP Member Join Date: Feb 2002 Location: Conway, AR Posts: 1,739 Likes: 0 Liked 6 Times in 4 Posts	Mark, I am not sure we're on the same page here. What I was trying to find out is whether the kickdown cable needed to, or if it even SHOULD be hooked up and operational if this transmission has NO modulator or governor. It's impossible to get a vacuum signal from the engine, due to the lack of an intake manifold (Hilborn mechanical port fuel injection; old-style), and we can't seem to find a mechanical modulator for a Turbo 350, so it will have:' 1. No modulator of any kind 2. No governor 3. No kickdown cable That will work okay with a full-manual valve body, if I understand everything... it just means that for the transmission to shift up OR down, he'll always have to move the shift lever, which is no big deal, as the car won't be driven very much. That being the case, I don't think it's EVER going to downshift on its own, will it? No governor; no kickdown cable; no modulator.... what could effect a dowshift? There's no reason for it to get into another gear. lease correct me if I'm wrong... and, thanks for your time and advice!!! Bill __________________ Bill

06-26-2007, 02:04 PM	#7
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,915 Likes: 996 Liked 1,043 Times in 274 Posts	If you convert to a forward pattern FULL manual valve body, you will not need the detent (AKA "kickdown" or "passing gear" cable) cable nor the vacuum modulator. The valve body will run the line pressure up to near maximum all the time to prevent slippage. The shifts will be very firm, especially if the transmission is built for performance anyway. MOST full manual forward pattern valve bodies will bolt on to a stock transmission. The will retain engine braking when downshifting to second. PLEASE remember that the transmission WILL go INSTANTLY to whatever gear you put it in. If you accidentally shift to first gear at 100 MPH, it WILL go, and lock the rear tires while spinning the engine way up. __________________ Alan Roehrich 212A G/S

06-26-2007, 05:24 AM	#2
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,417 Likes: 2,582 Liked 4,453 Times in 1,694 Posts	Bill, The passages to and from the governor need to be plugged and a little piece of the wall between the two passages needs to be removed to create a loop for the governor pressure to the shift valves. There are other ways to do it but this will work.

06-26-2007, 12:03 PM	#5
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,417 Likes: 2,582 Liked 4,453 Times in 1,694 Posts	Bill, It will downshift to second without the cable hooked up,...off the modulator. Just won't go all the way down to low. What it will probably do also, is shift fine, 1st to second at WOT, off the governor, and then go right into third shortly after.

06-26-2007, 02:17 PM	#8
bill dedman VIP Member Join Date: Feb 2002 Location: Conway, AR Posts: 1,739 Likes: 0 Liked 6 Times in 4 Posts	Thanks, Alan, for the info. What you said confirms everything I had assumed. I think that is what we'll do. Possibly, order a Turbo Action full manual valve body, remove the govrnor and vacuum modulator and kickdown cable, and have essentially, a "clutchless three-speed" semi-automatic transmission. I have some friends who have this setup in their Stockers and they all say that the shift quality is firm, but not bone-jarring at low (2,000) rpm's. I'm hoping that that proves to be true in this case. It will have a fairly loose converter, so that will absorb some of the driveline shock that results from running 100-percent main-line pressure, 100-percent of the time. I appreciate the time you took to respond to my question. BTW, I am also very much in favor of a 7.5 pound per horsepower AA/Stock class... Too many cars sitting idle that could race under that parameter. Bill, in Conway, AR __________________ Bill

06-26-2007, 03:47 PM	#9
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,017 Likes: 57 Liked 321 Times in 101 Posts	Call Me!!! Bill, Give me a call at 650 922 0407 I have a fix Bob __________________ Bob Mulry 7516 STK A & M Motorsports

06-26-2007, 05:27 PM	#10
Glenn Briglio VIP Member Join Date: Nov 2002 Location: Massapequa Park,NY Posts: 1,206 Likes: 1,729 Liked 822 Times in 264 Posts	T350 Operation Another way to skin the cat would be a common vacuum source off of the 8 stack setup. If you want details call me at the shop (516) 599-7182 Glenn.