Broken Crank, Torque Converter or ?
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Broken Crank, Torque Converter or ?
While driving about 75 in OD, I accelerated and suddenly lost power to the wheels. The engine was running but there was a lot of clatter. I pulled over and shut if off. I tried to restart but the engine would not turn over. Thanks to AAA the car is in my garage.
I pulled the valve covers and verified it did not drop a valve. I pulled the oil pan and all the rods are in place. There are no fragments or pieces in the pan. There are no signs of damage to the bottom end, but I realize the crank could be broken and I can't see it.
Does this sound like a torque converter? I've never had one go. It's a Vigilante with only 10,000 miles. The trans fluid looks normal. The transmission is a Pro-Built 700R4 with the same miles.
My next step is to pull the transmission and see how the engine turns over by hand.
I pulled the valve covers and verified it did not drop a valve. I pulled the oil pan and all the rods are in place. There are no fragments or pieces in the pan. There are no signs of damage to the bottom end, but I realize the crank could be broken and I can't see it.
Does this sound like a torque converter? I've never had one go. It's a Vigilante with only 10,000 miles. The trans fluid looks normal. The transmission is a Pro-Built 700R4 with the same miles.
My next step is to pull the transmission and see how the engine turns over by hand.
Melting Slicks
Joined: May 2014
Posts: 2,857
Likes: 583
From: New Port Richey FL
I have a few questions, First what year is the car,
you said the car wouldn't turn over, is the starter moving? are there things moving under the hood? could you have broken a flex plate around the crank bolts?
I would grab 1 of the bolts on the flex plate and turn the motor if the bottom end is snapped odds are it would show.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
I have a few questions, First what year is the car,
you said the car wouldn't turn over, is the starter moving? are there things moving under the hood? could you have broken a flex plate around the crank bolts?
I would grab 1 of the bolts on the flex plate and turn the motor if the bottom end is snapped odds are it would show.
you said the car wouldn't turn over, is the starter moving? are there things moving under the hood? could you have broken a flex plate around the crank bolts?
I would grab 1 of the bolts on the flex plate and turn the motor if the bottom end is snapped odds are it would show.
The starter was fine. If I turn the engine by hand it does move some. But there is a sound of metal parts crunching. The flex plate is fine. I'm going to try and remove the torque converter bolts (if the engine will turn enough) and see how the engine turns by hand without the tranny attached.
Melting Slicks
Joined: May 2014
Posts: 2,857
Likes: 583
From: New Port Richey FL
The car is an 85. The engine is a stroker 396 with approx. 18,000 miles on it. The crank, rods and pistons are all forged.
The starter was fine. If I turn the engine by hand it does move some. But there is a sound of metal parts crunching. The flex plate is fine. I'm going to try and remove the torque converter bolts (if the engine will turn enough) and see how the engine turns by hand without the tranny attached.
The starter was fine. If I turn the engine by hand it does move some. But there is a sound of metal parts crunching. The flex plate is fine. I'm going to try and remove the torque converter bolts (if the engine will turn enough) and see how the engine turns by hand without the tranny attached.
sounds like a plan, it just kind of itches me the car ran great, you gave it a little punch well with in its capabilities. something went crunch engine kept going making nasty noises but running, but no action to the wheels. so I tend to lean toward most of your motor is not the problem.
remove the torque converter bolts as planned give the converter a spin see if it spins freely, and give the flex plate a tug and shake too. with the halves isolated from each other hopefully the problem will show.
good hunting best of luck for this is one of those problems that make you go HUUU
Last edited by s carter; Oct 27, 2014 at 10:27 AM.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
sounds like a plan, it just kind of itches me the car ran great, you gave it a little punch well with in its capabilities. something went crunch engine kept going making nasty noises but running, but no action to the wheels. so I tend to lean toward most of your motor is not the problem.
remove the torque converter bolts as planned give the converter a spin make sure it spins freely, and give the flex plate a tug and shake too. with the halves isolated from each other hopefully the problem will show.
good hunting best of luck for this is one of those problems that make you go HUUU
remove the torque converter bolts as planned give the converter a spin make sure it spins freely, and give the flex plate a tug and shake too. with the halves isolated from each other hopefully the problem will show.
good hunting best of luck for this is one of those problems that make you go HUUU
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,062
From: altered state
St. Jude Donor '05
Ouch sorry to hear that! If it suddenly quit moving trans/converter is where Id be looking. Know if you got debris in one you got it in the other cooler too. Keep us posted.
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Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
I don't thing you have damaged bearings. That it won't run isn't a symptom IMO, you have not metal in the pan....I think it's elsewhere.
I agree w/your plan to separate the trans/flexplate and see what happens. When it cranks but doesn't start, does it have spark?
Race Director
Joined: Apr 2003
Posts: 17,697
Likes: 1,666
From: moraga ca
I disagree with most. A bad transmission or torque converter would not normally cause the motor to seize. Normally that type of failure would cause the motor to be disconnected to the rest of the drivetrain and the motor will freewheel. Weird noises may result, but not engine seizure. I would look more carefully in the motor. By the way, I have thoroughly abused a couple of Vigilante converters over the past number of years and have not had one failure.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Maybe I misunderstood this:
and...A lot of people used "wouldn't turn over" where they should have said "wound't fire". Since it was running and he shut it off, I assumed that when he retried to start it, it cranked but wouldn't fire. ("wouldn't turn over"). If the engine truly won't turn...i'd also doubt it's the trans.
OP?
OP?
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Maybe I misunderstood this: and...
A lot of people used "wouldn't turn over" where they should have said "wound't fire". Since it was running and he shut it off, I assumed that when he retried to start it, it cranked but wouldn't fire. ("wouldn't turn over"). If the engine truly won't turn...i'd also doubt it's the trans.
OP?
A lot of people used "wouldn't turn over" where they should have said "wound't fire". Since it was running and he shut it off, I assumed that when he retried to start it, it cranked but wouldn't fire. ("wouldn't turn over"). If the engine truly won't turn...i'd also doubt it's the trans.
OP?
I wouldn't have expected any of these parts to fail. This is a Jim Barth engine with a forged bottom end. The converter is a Vigilante and the trans is a Pro-Built. And the sad part is that I wasn't even racing.
Melting Slicks
Joined: Mar 2002
Posts: 3,106
Likes: 126
From: S.L.C. UT
Hey Craig, keep me posted on what you find. You will know what's going on when you disconnect the convertor and try spinning the engine. I would go ahead and start it with the convertor disconnected. I would be surprised if there was a problem with the engine. You have some good parts in there.
Last edited by tpi 421 vette; Oct 27, 2014 at 10:29 PM.
Safety Car
Joined: Nov 2009
Posts: 3,964
Likes: 337
From: Adelaide South Australia
When I said it won't turn over, I meant it won't crank. The starter engages but the crankshaft doesn't turn. If I put a wrench on the crankshaft pulley I can move the crank some counter clockwise. When I turn it clockwise there's a metal crunching sound. Now that I have the oil pan off, the sound seems to be coming from the converter or trans. I'll know more once I remove the torque converter bolts.
I wouldn't have expected any of these parts to fail. This is a Jim Barth engine with a forged bottom end. The converter is a Vigilante and the trans is a Pro-Built. And the sad part is that I wasn't even racing.
I wouldn't have expected any of these parts to fail. This is a Jim Barth engine with a forged bottom end. The converter is a Vigilante and the trans is a Pro-Built. And the sad part is that I wasn't even racing.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Safety Car
Joined: Nov 2009
Posts: 3,964
Likes: 337
From: Adelaide South Australia
Melting Slicks
Joined: May 2014
Posts: 2,857
Likes: 583
From: New Port Richey FL
I truly feel he has a Transmission by Claymore, once it goes off it throws shrapnel in all directions, and now there are parts jamming everything from front pump to planetary's .
Once the converter bolts can be pulled or the pan dropped the mystery will probably be solved.
Once the converter bolts can be pulled or the pan dropped the mystery will probably be solved.