TH350 Clutches / Modifications - Page 2

Mark Yacavone · 05-15-2011, 08:32 PM

Quote:

Originally Posted by Bob Mulry

Hi Alan,

Got to be careful about not running the wavy steel on the intermediate clutch pack because sometimes the flat steels interfere with the apply piston return spring retainer. This will also give you an incorrect clutch pack clearance...

Just a heads up,
Bob

I put a spacer under the int. piston so it doesn't return as far , thus tightening the clearance and quickening the apply.

Alan Roehrich · 05-15-2011, 08:40 PM

Quote:

Originally Posted by Chad E532

Alan,
Thanks for the info on the clutch/plate counts and also the tip on replacing the wave plate with flat steels.
What is the theory behind drilling the holes out on the direct clutch? It is just a cooling enhancement for street driven cars?

This is a race only car that is slowly inching it's way to I/SA as I save up the funds to replace the bracket engine with a legal stocker.
Thanks again.

Chad, I've seen that modification done, but not seen any real gain.

Honestly, the transmission for Stock will be very different. In fact, for your car, in I/SA, I'd be looking at a 200 Metric from McClay or Arnett. To convert your 350 to a class transmission, you'll need to replace both drums with aluminum drums, as well as having some other stuff lightened. The difference between what you're building now and what you'll need for Stock is about a tenth.

Daran Summerton · 05-19-2011, 07:51 PM

http://www.truckinweb.com/tech/0510t.../photo_03.html

What do ya'll think???

ss3011 · 05-19-2011, 08:19 PM

One of the reasons for drilling out the "cooling holes" in the OD of the clutch housing is to allow trapped oil to escape. The oil could build up on the OD of the clutch plates, when the housing spins and drag the clutch on. By drilling holes in the correct areas of the splines, the oil will exhaust and won't apply the clutch. Usually this trick only is done on the direct clutch housing.

Alan Roehrich · 05-19-2011, 08:48 PM

Quote:

Originally Posted by Daran Summerton

http://www.truckinweb.com/tech/0510t.../photo_03.html

What do ya'll think???

Daran, that is exactly what I described up thread. It yields a 2.75 low gear, because the front planetary remains unchanged.

That photo is merely a picture of a stock TH350 rear planetary carrier next to a stock 700 R4 planetary. That's not what it looks like when ready to install.

Mark Yacavone · 05-20-2011, 02:07 AM

Quote:

Originally Posted by Daran Summerton

My latest brillant idea, 1966 Impala SS/NA 283/220 low budget!!!! 5.86 gear stocker radials, footbrake stock t-350 with 8" converter approx. 4500.
60 ft 1.86
1/4 12.80 on a 12.15 index
mph 106

My U/SA left harder

Car will never be a killer, just looking for consistancy 2-3 under.

Daran, You're way under geared and about a thousand short on the stall speed for openers.

Alan Roehrich · 05-20-2011, 02:15 AM

Mark, I was thinking 6.17 gears, if it's a 12 bolt, and about 6000 stall, if he's got a Super Stock engine that will spin anything like it should. Not sure a 2.75 low will work because of the drop between 1st and 2nd. That extra point and a half of gear is a big deal to a small engine with no torque, especially in a heavy car.

Going from 2.52 in 1st to 1.52 in 2nd is not the same as going from 2.75 in 1st to 1.6 in 2nd, even though the 1st is low, the extra 0.15 gear drop makes a bigger difference than some think, because they forget the car is going SLOWER when it comes out of low gear with a 2.75 than it is with a 2.52, that amplifies the drop.

Mark Yacavone · 05-20-2011, 02:29 AM

Quote:

Originally Posted by Alan Roehrich

Mark, I was thinking 6.17 gears, if it's a 12 bolt, and about 6000 stall, if he's got a Super Stock engine that will spin anything like it should. Not sure a 2.75 low will work because of the drop between 1st and 2nd. That extra point and a half of gear is a big deal to a small engine with no torque, especially in a heavy car.

Going from 2.52 in 1st to 1.52 in 2nd is not the same as going from 2.75 in 1st to 1.6 in 2nd, even though the 1st is low, the extra 0.15 gear drop makes a bigger difference than some think, because they forget the car is going SLOWER when it comes out of low gear with a 2.75 than it is with a 2.52, that amplifies the drop.

I imagine Daran is trying to pick up the 60' with the low gear change.
If he had the right rear gear, he wouldn't need the low gear set.
We used about 5300 stall in a 283/220 SS car, about 30 years ago.
He needs a 6.40 ford or a 6.50 Dana to do it right.

Alan Roehrich · 05-20-2011, 02:33 AM

We've got a 6500 in the SS/EA car. I've got a 2.75 low in it because I can't get the 5.57 they say I need, the closest I can get is a 5.38, they don't have a 5.57 for a Dana 60. I'm not sure the RPM drop won't hurt me a little. But I need the car to move harder, and I think between the stall and the big block, I can pull that drop okay.

Daran Summerton · 05-21-2011, 09:28 AM

Just installed a light T-350 2.75 low with brake this time. On the brake the converter is going 5200. Heading to Gainesville tonight to try. Hoping for a 1.5 something??? 60 ft. I have a 12 bolt in it with 9x30 radials. Perhaps a 6.14 and a ET 29.5 will be next.

05-19-2011, 07:51 PM	#13
Daran Summerton Senior Member Join Date: Jun 2003 Location: Las Vegas nv Posts: 598 Likes: 18 Liked 65 Times in 36 Posts	Re: TH350 Clutches / Modifications http://www.truckinweb.com/tech/0510t.../photo_03.html What do ya'll think??? __________________ 72 cutlass

05-19-2011, 08:19 PM	#14
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: TH350 Clutches / Modifications One of the reasons for drilling out the "cooling holes" in the OD of the clutch housing is to allow trapped oil to escape. The oil could build up on the OD of the clutch plates, when the housing spins and drag the clutch on. By drilling holes in the correct areas of the splines, the oil will exhaust and won't apply the clutch. Usually this trick only is done on the direct clutch housing.

05-20-2011, 02:15 AM	#17
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,915 Likes: 996 Liked 1,043 Times in 274 Posts	Re: TH350 Clutches / Modifications Mark, I was thinking 6.17 gears, if it's a 12 bolt, and about 6000 stall, if he's got a Super Stock engine that will spin anything like it should. Not sure a 2.75 low will work because of the drop between 1st and 2nd. That extra point and a half of gear is a big deal to a small engine with no torque, especially in a heavy car. Going from 2.52 in 1st to 1.52 in 2nd is not the same as going from 2.75 in 1st to 1.6 in 2nd, even though the 1st is low, the extra 0.15 gear drop makes a bigger difference than some think, because they forget the car is going SLOWER when it comes out of low gear with a 2.75 than it is with a 2.52, that amplifies the drop. __________________ Alan Roehrich 212A G/S

05-20-2011, 02:33 AM	#19
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,915 Likes: 996 Liked 1,043 Times in 274 Posts	Re: TH350 Clutches / Modifications We've got a 6500 in the SS/EA car. I've got a 2.75 low in it because I can't get the 5.57 they say I need, the closest I can get is a 5.38, they don't have a 5.57 for a Dana 60. I'm not sure the RPM drop won't hurt me a little. But I need the car to move harder, and I think between the stall and the big block, I can pull that drop okay. __________________ Alan Roehrich 212A G/S

05-21-2011, 09:28 AM	#20
Daran Summerton Senior Member Join Date: Jun 2003 Location: Las Vegas nv Posts: 598 Likes: 18 Liked 65 Times in 36 Posts	Re: TH350 Clutches / Modifications Just installed a light T-350 2.75 low with brake this time. On the brake the converter is going 5200. Heading to Gainesville tonight to try. Hoping for a 1.5 something??? 60 ft. I have a 12 bolt in it with 9x30 radials. Perhaps a 6.14 and a ET 29.5 will be next. __________________ 72 cutlass