Picking a new torque converter

[carrman]

Now that I've got the new rear gear put in, the engine vibration this 440 has always had is a bit more prevelant. I'm suspecting a torque converter for an external balanced engine got installed. What I have is a 440 forged crank, 727 auto, 3.23 sure grip rear gear with Dr. Diffs Sure-Trac II center section. Car weighs about 4400 lbs. Low compression 440 built in late '72 from an RV with Stealth close chambered heads. I have this Lunati hydraulic roller cam in it:


"Retro-Fit Hydraulic Roller. Great mid range torque and power. Likes 2000 RPM stall converter and works great in towing applications with lower gearing. Largest for inboard/outboard performance marine use. ;Advertised Duration (Int/Exh): 270/278 ;Duration @ .050 (Int/Exh): 219/227 ;Gross Valve Lift (Int/Exh): .515/.530 ;LSA/ICL: 110/116 ;Valve Lash (Int/Exh): Hyd/Hyd ;RPM Range: 1800-5800."

Trying not to break the bank, but don't want junk either. I'm not racing, I just use it as a cruiser, and spirited runs on the freeway, not wasting time getting up to speed...;-). i've found couple of converters so far:

A727 High Stall NON-LOCKUP torque converter 2000-2200 w 11" Bolt Circle Diameter | eBay

Hughes Street Rod Torque Converter Fits Chrysler Torqueflite 727 2000 Stall | eBay

And then there was a B&M listed on Summits page but it says not to use behind a big block. Anyone have any experience with picking a converter for a heavy car like I have?

 

[CBODY67]

If you are going to replace the converter due to stall speed issues, then look to see if the converter has two weights tacked onto it. If it does, then remove them and see if the vibration changes. Might an external balance converter be needed with the heavier 6-pk rods?

 

[carrman]

If you are going to replace the converter due to stall speed issues, then look to see if the converter has two weights tacked onto it. If it does, then remove them and see if the vibration changes. Might an external balance converter be needed with the heavier 6-pk rods?

I was always told forged crank 440's need a neutral balance TC and flex plate. I think the guy who built the engine used an external balanced "heavy duty" converter.

 

[RemCharger]

If it has a neutral balance balancer on it.. ( and you know the crank is indeed forged..) I would knock the weights off and try it

 

[carrman]

If it has a neutral balance balancer on it.. ( and you know the crank is indeed forged..) I would knock the weights off and try it

If it has a neutral balance balancer on it.. ( and you know the crank is indeed forged..) I would knock the weights off and try it

Yes I know it's forged, I verified it as we thought it might be cast but the crank and harmonic balancer indicated forged. It's a late '72 engine.

 

[carrman]

Took it for a long drive Saturday. Did great but the engine vibration is defnitely more pronounced. The rear view mirror vibrated so much it's hard to see out of. Kick it into neutral and the vibration stops.

 

[FURYGT]

Now that I've got the new rear gear put in, the engine vibration this 440 has always had is a bit more prevelant. I'm suspecting a torque converter for an external balanced engine got installed. What I have is a 440 forged crank, 727 auto, 3.23 sure grip rear gear with Dr. Diffs Sure-Trac II center section. Car weighs about 4400 lbs. Low compression 440 built in late '72 from an RV with Stealth close chambered heads. I have this Lunati hydraulic roller cam in it:


"Retro-Fit Hydraulic Roller. Great mid range torque and power. Likes 2000 RPM stall converter and works great in towing applications with lower gearing. Largest for inboard/outboard performance marine use. ;Advertised Duration (Int/Exh): 270/278 ;Duration @ .050 (Int/Exh): 219/227 ;Gross Valve Lift (Int/Exh): .515/.530 ;LSA/ICL: 110/116 ;Valve Lash (Int/Exh): Hyd/Hyd ;RPM Range: 1800-5800."

Trying not to break the bank, but don't want junk either. I'm not racing, I just use it as a cruiser, and spirited runs on the freeway, not wasting time getting up to speed...;-). i've found couple of converters so far:

A727 High Stall NON-LOCKUP torque converter 2000-2200 w 11" Bolt Circle Diameter | eBay

Hughes Street Rod Torque Converter Fits Chrysler Torqueflite 727 2000 Stall | eBay

And then there was a B&M listed on Summits page but it says not to use behind a big block. Anyone have any experience with picking a converter for a heavy car like I have?

Why do you think that you need more than a stock torque converter? You have a low compression RV 440 with more cam than you need and a 3.23 rear gear. Just because the cam manufacturer suggests a 2000 stall speed doesn’t mean it’s what you need. Note the comments about a low gear, which you don’t have. Given everything including how you will drive the car I think a stock converter would be fine.

 

[73Coupe]

Took it for a long drive Saturday. Did great but the engine vibration is defnitely more pronounced. The rear view mirror vibrated so much it's hard to see out of. Kick it into neutral and the vibration stops.

Most of the converter mass is still spinning in neutral, so perhaps you have a driveshaft or u-joint issue and not the TC....or loose bolt somewhere.

Trying to piece together the story from these posts...

I was always told forged crank 440's need a neutral balance TC and flex plate. I think the guy who built the engine used an external balanced "heavy duty" converter.

Does this mean that your machinist balanced the rotating assembly with a random TC and flex plate bolted onto it? This doesn't make sense. A machine shop would wouldn't bolt on a TC, only a flywheel and clutch housing for a manual car. TCs are balanced at the factory, I don't believe that you could balance them after the fact anyway because of the moving parts inside.

Also, I assume that your harmonic balancer is the correct type for an internally balanced crank....

And lastly, check your motor/trans mounts.

 

[carrman]

All the mounts are good. This was an rv 440 with super low mileage but got new rings, rods and mains. Driveline all new with 1350 u joints. No machine work or balancing done as no hardware was changed. There was a random tc installed.

 

[carrman]

I have the cam Lunati recommended for my setup.

 

[CBODY67]

Engine balance will not be affected if the trans is in neutral or not, but any time the engine is running. If it is in the engine, the vibrations should get worse with rpm, not road speed. If it is in the drivetrain, behind the flywheel (and torque converter), the vibration should happen with road speed increases.

Wondering if it might be a burnt valve causing the vibration due to compression imbalance, under load? More vibration under load than at idle.

The other thing that seems a bit out of whack, to me, is the presence in an automatic transmissioned vehicle in 1972. Per the Chrysler parts book, I discovered that steel cranks existed into the 1974 model year for manual transmission B-bodies, as everything else was cast cranks. IF the engine came out of an RV, was it a genuine MHC (motor home chassis) 440, with a TF transmission? How was the forged crank identified as such?

Just some curiosities,
CBODY67

 

[carrman]

Heads were fresh when put on the engine. Verified forged crank and proper forged crank harmonic balancer. Engine was a late '72 and there were still forged cranks being used then. Vibration is RPM, not road speed related. Letting it drop to idle by kicking into neutral the vibration is mostly gone. Put it back in gear and it comes back.

 

[volksworld]

think i'd send out the driveshaft to have it balanced and make sure its straight...when i got my car someone installed a cast crank engine and left the neutral balance converter...it shook bad enough at idle that i assumed it had a dead cylinder...check for dumb stuff like a tire that threw a belt...if you pull the lower inspection cover i think you should be able to see if the converter has the 2 balance weights on the front...worse case remove the converter bolts to move it into a position where you can see them

 

[pioneer]

In 1972 and maybe even later Chrysler was using 6 pack rods on forged cranks in 440s and they definitely needed external balancing. If the motor has the original front damper it will have a offset weight cast in to it and the torque converter should have 2 small weights totaling 6.5 oz. I think most 72 440s had 6 pack rods, they were using up rods when they stopped 6 pack production.

 

[carrman]

 

[carrman]

I see my problem.

 

[pioneer]

That is a weight for a 360 cast crank the damper is neutral balanced, try knocking the weight off with a chisel. you might get lucky

 

[carrman]

That is a weight for a 360 cast crank the damper is neutral balanced, try knocking the weight off with a chisel. you might get lucky

I forgot I had a pic of the converter taken as the 440 was getting set in there...

 

[Gerald Morris]

Took it for a long drive Saturday. Did great but the engine vibration is defnitely more pronounced. The rear view mirror vibrated so much it's hard to see out of. Kick it into neutral and the vibration stops.

You need to REMEDY this PROBLEM BEFORE it becomes a DISASTER. Don't drive it again until you have a stock TC, sans cast crank weights. If the flex plate is like that one from B&M which is made for any sort of TC, it should be fine for this.

 

[carrman]

You need to REMEDY this PROBLEM BEFORE it becomes a DISASTER. Don't drive it again until you have a stock TC, sans cast crank weights. If the flex plate is like that one from B&M which is made for any sort of TC, it should be fine for this.

No it's not going out until I can get the weight knocked off of it.