1970 chrysler 300 converter picture?

[CBODY67]

IF you want to chase factory part numbers, the heavier 6-Pak rods will need a crank that is balanced to match their heavier weight, which will generate a different factory part number for the crank. I suspect the factory 6-Pak pistons, having a taller compression distance, will be heavier than the normal 440 pistons of that model year, which will need a different crankshaft balance to be correct, too, AND a different factory part number for the crank.

The basic crankshaft item will be the same, ONLY the labor operation to do the balancing of it will be the difference, I suspect.

The torque converters are "generic", when built. Those that went with an external balance motor got the additional TWO weights on either side of the drain plug (of where it used to be) on the torque converter. Direct Connection used to sell the weight kits, I believe. I know one of the old Race Manual sections detailed the converter weight issue.

Of course, the external balance crankshaft damper is specific to the "external balance" motors only.

I'd always believed that the steel cranks stopped with the'71 model year . . . UNTIL I was looking through a '74 and a '75 Chrysler parts books I'd purchased from a dealer (as surplus items). That's when I noticed that it listed a STEEL 440 cranks ONLY with 4-speed B-bodies in both '74 and '75 model years' 440HO engine. Automatics had a different crankshaft part number.

From what I remember reading in the '80s or so, the factory 6-Pak rods were "overkill", but needed for the stock classes. Not unlike a '67 Camaro Z/28 with a 780cfm carb on a 302 cid engine, in that respect. I seem to remember reading why those same rods ended up in some 440 "U" motors, where they would have been even MORE overkill, but they did.

LOTS of weight in those B/RB pistons/piston pins!

CBODY67

 

[Davea Lux]

IF you want to chase factory part numbers, the heavier 6-Pak rods will need a crank that is balanced to match their heavier weight, which will generate a different factory part number for the crank. I suspect the factory 6-Pak pistons, having a taller compression distance, will be heavier than the normal 440 pistons of that model year, which will need a different crankshaft balance to be correct, too, AND a different factory part number for the crank.

The basic crankshaft item will be the same, ONLY the labor operation to do the balancing of it will be the difference, I suspect.

The torque converters are "generic", when built. Those that went with an external balance motor got the additional TWO weights on either side of the drain plug (of where it used to be) on the torque converter. Direct Connection used to sell the weight kits, I believe. I know one of the old Race Manual sections detailed the converter weight issue.

Of course, the external balance crankshaft damper is specific to the "external balance" motors only.

I'd always believed that the steel cranks stopped with the'71 model year . . . UNTIL I was looking through a '74 and a '75 Chrysler parts books I'd purchased from a dealer (as surplus items). That's when I noticed that it listed a STEEL 440 cranks ONLY with 4-speed B-bodies in both '74 and '75 model years' 440HO engine. Automatics had a different crankshaft part number.

From what I remember reading in the '80s or so, the factory 6-Pak rods were "overkill", but needed for the stock classes. Not unlike a '67 Camaro Z/28 with a 780cfm carb on a 302 cid engine, in that respect. I seem to remember reading why those same rods ended up in some 440 "U" motors, where they would have been even MORE overkill, but they did.

LOTS of weight in those B/RB pistons/piston pins!

CBODY67

The part number for the externally balanced crank seems to be the same for all the applications in '70. Part number is: 3512036. The standard internally balanced crank part number 2526983.

Dave

 

[CBODY67]

It's been years since I found those things in the parts book. The referenced "35___" part number should be possibly the last iteration of that particular crank for the '75 model year. The "25____" number would have been for the '65 model year? But only 413s in '65, although the first 440 production would have been in about August, 1965?

CBODY67

 

[Davea Lux]

It's been years since I found those things in the parts book. The referenced "35___" part number should be possibly the last iteration of that particular crank for the '75 model year. The "25____" number would have been for the '65 model year? But only 413s in '65, although the first 440 production would have been in about August, 1965?

CBODY67

Parts book was always something of a pain. Try www.moparts.org they have the cranks listed in the archives section. www.darkside.ca also has the numbers in the tech section.

Dave

 

[max1196]

Here's the need for the external balance, it's that porky stuff hanging on the journal, at a 100 grams more per hole. Some regular "LY's" for a comparison.

 

[Clover]

If the “six-pak” crank was balanced differently, it wouldn’t have needed external weights. I always heard that they were hand-selected, given extra journal chamfering and also flame-hardened.

 

[ceebuddy]

The SFGT's all had the 440 HP, with the 6-Pak being optinal in 1970.

 

[Big_John]

The SFGT's all had the 440 HP, with the 6-Pak being optinal in 1970.

1970 had the 350hp 4bbl and the 390hp 6bbl.
1971 had the 375hp 4 bbl.

 

[ceebuddy]

1970 had the 350hp 4bbl and the 390hp 6bbl.
1971 had the 375hp 4 bbl.

True! I am sorry for the mistake.

hp = horsepower
HP = High Performance
I need to remember...

 

[commando1]

Lol

 

[ayilar]

Resuscitating this thread to confirm my thoughts about balancing on a 1970 Polara/Monaco 383-4: internal? @CBODY67 and @saforwardlook, both of you own 1970 C-bodies with that engine so I am tagging you, but others may have the answer too?

 

[fury fan]

70 383-4 should be internally balanced.

If you look at my post #10 here, it conflicts with my post in your Snow White thread.
Over there I said that the converter didn't have the weights when I took it apart, but post #10 above (which is older and has a better IIRC-factor) said the weights WERE there.

As I remember this more, the converter I took out had a few teeth missing from the ring gear, which I think I could hear when starting the engine (an aha, that's what that subtle noise was).
While not much weight in those teeth, they are at the OD of the converter, so the radius makes the largest effect.

Perhaps check the ring gear on Snow White?

 

[Davea Lux]

Resuscitating this thread to confirm my thoughts about balancing on a 1970 Polara/Monaco 383-4: internal? @CBODY67 and @saforwardlook, both of you own 1970 C-bodies with that engine so I am tagging you, but others may have the answer too?

'70 383's were all internally balanced.

Dave

 

[saforwardlook]

When an engine gets rebuilt, having someone really knowledgeable is important. If the engine is being rebuilt by a novice or a chain of rebuilders, there is no telling what they might do incorrectly and not be aware of it.

I have discussed the engine rebuilder I am using for one of my vehicles currently under restoration in another thread about camshaft replacements for both the 383-4 and 440HP engines in another thread:

Replacement Aftermarket Camshaft for 383-4 and 440HP engines

My rebuilder called me just a few days ago and said that because my original engine to the car had already been rebuilt in the past before I bought the car and that since the original engines used fairly heavy cast pistons, these engines were externally balanced using weights on the torque converter. He noticed, however, that the rebuilder had replaced the pistons from the factory original ones and used more modern lighter ones, so the weights on the torque converter should have been reduced or removed but were not. Since my rebuilder is also going to use lighter more modern cast pistons (he usually goes only with forged ones except I told him I do not "beat" my cars, so good cast ones would be fine with me - he also wanted me to go with a more aggressive cam for higher horsepower but I told him that was not what I wanted since I only was striving to reproduce the original feel of the car as built - especially a smooth idle). He also knows I am rebuilding the transmission to my car myself and he called to tell me that in view of the change of weight of the pistons, that when I send out the original torque converter for rebuilding, he wants me to have those extra weights removed in order to maintain proper engine balance when I send the original torque converter out to rebuilt by a shop I trust to do that aspect of the transmission rebuild - so I am going to do what he said. He said that the original rebuilder didn't do that and he indicated that was probably why the previous rebuild didn't last as long as it should have and that the engine probably had a vibration to it as well.

Now mine is a 440 HP engine and yours is a 400-4 so in your case there wouldn't have been really heavy pistons in that engine so it was internally balanced, unlike my 440HP.

So when your engine was previously rebuilt, I wonder whether the rebuilder took into account any changes in piston weight when doing the rebuild so that there might need to be adjustments for the change in piston weight that was not done and so you now have this vibration taking place.

I believe when I was talking with Wyatt in the not too distant past now that he had an association with an engine rebuilder and Wyatt was considering whether he should go down a path of working with that rebuilder to learn how to do this himself but I do not know whether he did that or not, so maybe that contact for him might have some thoughts on what step to take next. Maybe a good engine rebuilder might be able to feel the vibration if you take the car to one and ask them for advice whether your situation feels like a balance problem or something else and get their input on what to do next.

Like you, I know for sure having a vibration problem would annoy me a great deal.

 

[Clover]

Resuscitating this thread to confirm my thoughts about balancing on a 1970 Polara/Monaco 383-4: internal? @CBODY67 and @saforwardlook, both of you own 1970 C-bodies with that engine so I am tagging you, but others may have the answer too?

1970 383s were all internally balanced from the factory. However, it is well worth the extra money to take the rotating assembly to a reliable engine balancer and have it balanced. They will likely add external weights and your engine will run smoother and quieter, plus it will rev faster and higher.

 

[Big_John]

When an engine gets rebuilt, having someone really knowledgeable is important. If the engine is being rebuilt by a novice or a chain of rebuilders, there is no telling what they might do incorrectly and not be aware of it.

I have discussed the engine rebuilder I am using for one of my vehicles currently under restoration in another thread about camshaft replacements for both the 383-4 and 440HP engines in another thread:

Replacement Aftermarket Camshaft for 383-4 and 440HP engines

My rebuilder called me just a few days ago and said that because my original engine to the car had already been rebuilt in the past before I bought the car and that since the original engines used fairly heavy cast pistons, these engines were externally balanced using weights on the torque converter. He noticed, however, that the rebuilder had replaced the pistons from the factory original ones and used more modern lighter ones, so the weights on the torque converter should have been reduced or removed but were not. Since my rebuilder is also going to use lighter more modern cast pistons (he usually goes only with forged ones except I told him I do not "beat" my cars, so good cast ones would be fine with me - he also wanted me to go with a more aggressive cam for higher horsepower but I told him that was not what I wanted since I only was striving to reproduce the original feel of the car as built - especially a smooth idle). He also knows I am rebuilding the transmission to my car myself and he called to tell me that in view of the change of weight of the pistons, that when I send out the original torque converter for rebuilding, he wants me to have those extra weights removed in order to maintain proper engine balance when I send the original torque converter out to rebuilt by a shop I trust to do that aspect of the transmission rebuild - so I am going to do what he said. He said that the original rebuilder didn't do that and he indicated that was probably why the previous rebuild didn't last as long as it should have and that the engine probably had a vibration to it as well.

Now mine is a 440 HP engine and yours is a 400-4 so in your case there wouldn't have been really heavy pistons in that engine so it was internally balanced, unlike my 440HP.

So when your engine was previously rebuilt, I wonder whether the rebuilder took into account any changes in piston weight when doing the rebuild so that there might need to be adjustments for the change in piston weight that was not done and so you now have this vibration taking place.

I believe when I was talking with Wyatt in the not too distant past now that he had an association with an engine rebuilder and Wyatt was considering whether he should go down a path of working with that rebuilder to learn how to do this himself but I do not know whether he did that or not, so maybe that contact for him might have some thoughts on what step to take next. Maybe a good engine rebuilder might be able to feel the vibration if you take the car to one and ask them for advice whether your situation feels like a balance problem or something else and get their input on what to do next.

Like you, I know for sure having a vibration problem would annoy me a great deal.

It isn't the pistons. The heavy rods are the reason for the external balance. That's pretty common knowledge.

Changing the piston weight may bring the piston/rod weight down enough to an internal balance without the addition of weight to the crank, or at least minimalize it.

When we would have the heavy rod, steel crank engines (70 6pk) internally balanced, weight had to be added to the crank. It was expensive and... well... added weight on the rotating assembly that I always figured was counterproductive to the goal of going fast, but it wasn't my car and we had to keep in the NHRA stock rules.

 

[saforwardlook]

It isn't the pistons. The heavy rods are the reason for the external balance. That's pretty common knowledge.

Changing the piston weight may bring the piston/rod weight down enough to an internal balance without the addition of weight to the crank, or at least minimalize it.

When we would have the heavy rod, steel crank engines (70 6pk) internally balanced, weight had to be added to the crank. It was expensive and... well... added weight on the rotating assembly that I always figured was counterproductive to the goal of going fast, but it wasn't my car and we had to keep in the NHRA stock rules.

In my case, the change in weight of the pistons caused my rebuilder to want to remove the balance weights on the torque converter - he is not changing the rods, so are you essentially saying the same thing - he did seem to be on the fence about it so I am not sure at this point. I accept your point about the heavier rods being the reason for the extra weights and not the pistons alone however.

 

[Big_John]

In my case, the change in weight of the pistons caused my rebuilder to want to remove the balance weights on the torque converter - he is not changing the rods, so are you essentially saying the same thing - he did seem to be on the fence about it so I am not sure at this point?

I'm not sure how it works to rebalance an externaly balanced engine other than turn it into an internally balanced engine. I would image that it would be a matter of removing some of the weight from the converter, but I can't see removing all of it and keeping the external balance.

What about the harmonic balancer? Did he say anything about that? That is also weighted for the external balance.

 

[saforwardlook]

I'm not sure how it works to rebalance an externaly balanced engine other than turn it into an internally balanced engine. I would image that it would be a matter of removing some of the weight from the converter, but I can't see removing all of it and keeping the external balance.

What about the harmonic balancer? Did he say anything about that? That is also weighted for the external balance.

He is not changing the harmonic balancer. I personally am clueless about what to do in this case so I just am relying on him. All I know for sure is that if there turns out to be any issue such as vibration, he will correct it. He usually replaces all pistons in his rebuilds with forged ones but in this case I told him I didn't think that was needed, so maybe I should have just kept my mouth shut. I am old enough that I do not have a need to floor it from every stop or practice burnouts.

 

[Big_John]

He is not changing the harmonic balancer. I personally am clueless about what to do in this case so I just am relying on him. All I know for sure is that if there turns out to be any issue such as vibration, he will correct it. He usually replaces all pistons in his rebuilds with forged ones but in this case I told him I didn't think that was needed, so maybe I should have just kept my mouth shut. I am old enough that I do not have a need to floor it from every stop or practice burnouts.

Forged pistons have their place, although with a basically stock 440, there's no reason to use them. Myself, I would probably use the KB Hypereutectic pistons. It's a strong piston that lets you run tight clearances like a stock cast piston. Then it doesn't rattle when cold like a forged piston might.

Is he rebalancing the rotating assembly?