Broken Torque Converter

Greg Gay · 05-25-2015, 08:50 AM

My S/S car will normally leave with the wheels up about 3 feet. This year, when I let off the transbrake button, the car stumbles out about 3 car lengths, then runs strong to the finish line. MPH is about normal, but et is off .5 seconds. I tried leaning the primary, leaning the secondary, float height adjustment, different rpm. The car responds to the changes, but both mph and et adjust together. The same .5 delay remains. One racer described it as sounding like it stays on the 2 step for awhile after the leave, but I can't see anyway that is possible. Does the broken torque converter idea fit? Any other ideas?

Danny Ashley · 05-25-2015, 09:27 AM

If it's a Q-Jet car, make sure the secondary rods are sealed. Sounds like a spill-over problem. Regards, Danny.

MR DERBY CITY · 05-25-2015, 12:15 PM

If it drives off like a STREET Car,then runs strong to the finish line, I would definitely change converters. Been there ...Done that.....M.J.

Alan Roehrich · 05-25-2015, 01:07 PM

A converter will not cause a stumble. At least I haven't seen one do it in about 35 years or so. It will make one lazy, but not a real stumble.

As Danny said, it sounds a lot like a carburetor problem, both the Q-Jet and the Holley carburetors do it, but for different reasons.

It can also be one of any number of electrical problems, a connection, a loose ground, I've even seen a battery do it because a plate came loose. I've seen an oil filled coil do it, too.

Mark Yacavone · 05-25-2015, 01:57 PM

Hold the T brake on or put it in manual 3rd and hold the foot brake, and flash the converter.
If it goes up to near where it should be.. most likely not a converter issue.

Bob Gullett · 05-25-2015, 02:39 PM

A few years ago when we had my wife's stocker we had the same issue. Started stumbling real bad. Changed everything but the MSD two step module. Took the one out of my car problem fixed. Put her's in my car same problem. Just a suggestion if you have one of these modules.

Stock4106 · 05-25-2015, 06:14 PM

Could be a broken stator support.

Mark Yacavone · 05-25-2015, 07:13 PM

Owen ,Not if it stalls up where it should be.

Greg Gay · 05-25-2015, 08:35 PM

Thank you for the responses, everyone. A couple more pieces of information: The engine is a 400 Chrysler with a Thermoquad. The carb had set for virtually 15 years while I ran a different combination in the car. Last fall, we ran it on Jeff Roell's chassis dyno. I would bring it up to 3000 rpm, then stab it and hold it to 7000. It seemed to run well. I took it to the track and on the first run, it was about a tenth slow in 60 feet, ran hard to about 150 feet from the finish line, and nosed over. The next run, I turned the two step (dial) up from 3400 to 3800. It ran about .3 slow in 60 feet, then ran more strongly to the finish line, and nosed over again. The last run, I put it up to 4400 rpm. It pushed through the beams, ran .3-.4 slow in 60 feet, ran strong again to about 150 feet from the finish line, and broke up a bit.

Over the winter, I raised the float levels and made a few other changes that the small T-Quad liked on the 318. That puts me to where I am today. I can't say that I watched the tach off the line, but I would say that the rpm stays low (3500-4000) before it comes to life. I DID watch the fuel pressure, and it remained steady.

MR DERBY CITY · 05-25-2015, 09:05 PM

After further review, I would definately change the carb....Been there ..Done that...Lol.!! M.J.

05-25-2015, 08:50 AM	#1
Greg Gay Member Join Date: Aug 2003 Location: Vermont Posts: 383 Likes: 21 Liked 278 Times in 68 Posts	Broken Torque Converter My S/S car will normally leave with the wheels up about 3 feet. This year, when I let off the transbrake button, the car stumbles out about 3 car lengths, then runs strong to the finish line. MPH is about normal, but et is off .5 seconds. I tried leaning the primary, leaning the secondary, float height adjustment, different rpm. The car responds to the changes, but both mph and et adjust together. The same .5 delay remains. One racer described it as sounding like it stays on the 2 step for awhile after the leave, but I can't see anyway that is possible. Does the broken torque converter idea fit? Any other ideas?

05-25-2015, 09:27 AM	#2
Danny Ashley Member Join Date: Nov 2001 Location: Marion,In. Posts: 266 Likes: 58 Liked 108 Times in 28 Posts	Re: Broken Torque Converter If it's a Q-Jet car, make sure the secondary rods are sealed. Sounds like a spill-over problem. Regards, Danny.

05-25-2015, 12:15 PM	#3
MR DERBY CITY VIP Member Join Date: Feb 2014 Location: Derby City, USA Posts: 3,565 Likes: 1,058 Liked 7,584 Times in 1,462 Posts	Re: Broken Torque Converter If it drives off like a STREET Car,then runs strong to the finish line, I would definitely change converters. Been there ...Done that.....M.J.

05-25-2015, 01:07 PM	#4
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,066 Likes: 1,487 Liked 1,630 Times in 378 Posts	Re: Broken Torque Converter A converter will not cause a stumble. At least I haven't seen one do it in about 35 years or so. It will make one lazy, but not a real stumble. As Danny said, it sounds a lot like a carburetor problem, both the Q-Jet and the Holley carburetors do it, but for different reasons. It can also be one of any number of electrical problems, a connection, a loose ground, I've even seen a battery do it because a plate came loose. I've seen an oil filled coil do it, too. __________________ Alan Roehrich 212A G/S

05-25-2015, 01:57 PM	#5
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,742 Likes: 2,845 Liked 5,002 Times in 1,902 Posts	Re: Broken Torque Converter Hold the T brake on or put it in manual 3rd and hold the foot brake, and flash the converter. If it goes up to near where it should be.. most likely not a converter issue. __________________ "We are lucky we don't get as much Government as we pay for." Will Rogers

05-25-2015, 02:39 PM	#6
Bob Gullett VIP Member Join Date: Mar 2002 Posts: 1,099 Likes: 56 Liked 461 Times in 111 Posts	Re: Broken Torque Converter A few years ago when we had my wife's stocker we had the same issue. Started stumbling real bad. Changed everything but the MSD two step module. Took the one out of my car problem fixed. Put her's in my car same problem. Just a suggestion if you have one of these modules. __________________ 68 Chevy11 327 F/S

05-25-2015, 06:14 PM	#7
Stock4106 Member Join Date: Aug 2005 Location: Covington, LA Posts: 99 Likes: 0 Liked 10 Times in 4 Posts	Re: Broken Torque Converter Could be a broken stator support. __________________ Owen S. Birkett Stock/Super Stock 4106

05-25-2015, 07:13 PM	#8
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,742 Likes: 2,845 Liked 5,002 Times in 1,902 Posts	Re: Broken Torque Converter Owen ,Not if it stalls up where it should be. __________________ "We are lucky we don't get as much Government as we pay for." Will Rogers

05-25-2015, 08:35 PM	#9
Greg Gay Member Join Date: Aug 2003 Location: Vermont Posts: 383 Likes: 21 Liked 278 Times in 68 Posts	Re: Broken Torque Converter Thank you for the responses, everyone. A couple more pieces of information: The engine is a 400 Chrysler with a Thermoquad. The carb had set for virtually 15 years while I ran a different combination in the car. Last fall, we ran it on Jeff Roell's chassis dyno. I would bring it up to 3000 rpm, then stab it and hold it to 7000. It seemed to run well. I took it to the track and on the first run, it was about a tenth slow in 60 feet, ran hard to about 150 feet from the finish line, and nosed over. The next run, I turned the two step (dial) up from 3400 to 3800. It ran about .3 slow in 60 feet, then ran more strongly to the finish line, and nosed over again. The last run, I put it up to 4400 rpm. It pushed through the beams, ran .3-.4 slow in 60 feet, ran strong again to about 150 feet from the finish line, and broke up a bit. Over the winter, I raised the float levels and made a few other changes that the small T-Quad liked on the 318. That puts me to where I am today. I can't say that I watched the tach off the line, but I would say that the rpm stays low (3500-4000) before it comes to life. I DID watch the fuel pressure, and it remained steady.

05-25-2015, 09:05 PM	#10
MR DERBY CITY VIP Member Join Date: Feb 2014 Location: Derby City, USA Posts: 3,565 Likes: 1,058 Liked 7,584 Times in 1,462 Posts	Re: Broken Torque Converter After further review, I would definately change the carb....Been there ..Done that...Lol.!! M.J.