forged or cast torque converter??

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cli55er

cli55er

Tem Greene's Nephew
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i'm pretty sure this is a torque converter for a forged crank, but I wanted you guys to look at it and confirm.

there are no balancing weights anywhere on it. Also there is no drain plug. I thought it would have been on the outside ring of the converter, but there is not one.

I think the drain plug was sealed up....look at the imperfection on the face, I think that is some kinda putty junk filled into the hole. see red circle. that is the only place I can see that maybe had a drain plug in it at one point.

is there a way to put an externally balanced bolt on flexplate on here to save money on a new torque converter?

thanks for the help and input guys.
 

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There is no forged or cast converter. Only internally or externally balanced. That appears to be an externally balanced converter somebody knocked the weights off of to make it internally balanced, but since we can only see one side, that's just a guess. And yes, you can get one of many different brands of flex plate to make whatever work.
 
i'm sorry the title is a bit off. I didn't mean if the TC is forged or cast, but more along the lines of its application....for a forged or cast crank.

i'm 99.9% sure its an internally balanced unit....for forged crank.....reason is because there are no weights anywhere on this thing. there is also no drain hole....I rotated the motor all the way around and checked....which as another member has pointed out...could mean it is aftermarket.

the car is a 70 swinger...but has the wrong crank....the crank is from a later mopar....serial number for 72 up 340....so its cast. womp womp. it'll work, I just need to make the harmonic balancer and torque converter match.

I just wanted to get everyone to confirm with my thought that it is the wrong torque converter for a cast crank.

flexplate would be a good option, but this will be a good chance to get a better stall on a correct torque converter....and to take the tranny out to stop all the stupid leaks, not that i'm looking forward to that without a lift and in a packed garage. yippee!
 
if it's a cast crank, then it's externally balanced. the balancer in the front will have a visible offset weight, or you can verify by the part number

View attachment balancers.JPG

then, if it's externally balanced, at the back of the engine either the torque converter or flex plate will be counter-weighted (not both)

you can use a B&M external balance flex plate, then a neutral balance torque converter. (easier to find replacements. best out there is made by dynamic converters in my opinion)

the stock externally balanced engines had a neutral flex plate but the torque converter had weights attached. it's harder to find performance torque converters with weights. you can buy a kit to retrofit. but in the end you are better off going with a B&M sfi approved offset flexplate and the neutral converter.

if it's manual shift you need a flywheel that is drilled for the offset weight.

to be honest, you should verify (I know it's a pain in the ***). you should drop the oil pan and determine if you have a forged or cast crank. then you will know. at that point make sure you have the right balancer to match your crank. then get the right combo out back for your flex plate/torque converter.

don't just assume by looking at your current converter or the year stamped on the outside of the block that you know what is inside your engine...

if you have a forged crank the harmonic balancer will be symmetrical, the flex plate will be neutral balanced and the torque converter is neutral balanced.
 
That depends on which engine he has. You cannot make the blanket statement cast crank external balance and forged internal. Every single 318 from about 69 up uses a cast crank, but they were ALL internally balanced. Also, some of the 440 six pack motors had forged cranks and were externally balanced, so your theory is incorrect. If he has a 340, then you are right, but he has not said which engine he has.
 
If this is an LA you can likely buy a weighted flex plate such as from BM to run a neutral converter with an externally balanced crank

Rusty is correct, and not only that it's not simply "internal" or "external" as if there are "two." The Magnums are also externally balanced but they are weighted differently than a 360 LA, example.
 
sorry I should have been more specific.

70 340 block

I know the crank is cast. it is a 72/73 crank. serial number 3462387

the HB that was on the car was not weighted.....the new one will be.

the torque converter is not weighted, so it needs to be replaced with a weighted one for a cast crank.

I cannot see the flex plate...is that behind the torque converter? on my 55 Packard the flex plate is visible and has the starter ring gear on it. this car has the start ring gear attached to the torque converter so i'm a bit thrown off as to where the flexplate is.

if I have to drop the trans anyways, I might as well get a better torque converter...2500 stall or there abouts, and make sure it is weighted and be done.

the whole reason to figure this out is that the car has a serious droaning roaring vibration....druuummmmm....druummmmmm.....drummmmmmm..drummmmmm at a certain RPM/speed. pretty sure its because the HB/crank/TC are not all matched correctly. I don't want it vibrating anymore.

I suppose I could put the new weighted HB on the car and then drive it to see if the vibration stops. if so...good I don't need a TC. if it still vibrates...then the TC is wrong and i'll drop the trans at that point
 

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moparlover said:
if it's a cast crank, then it's externally balanced. the balancer in the front will have a visible offset weight, or you can verify by the part number

View attachment 1714691197

to be honest, you should verify (I know it's a pain in the ***). you should drop the oil pan and determine if you have a forged or cast crank. then you will know.
Click to expand...


He should be able to verify that pretty easily as the oil pan is off and I can see the oil pump in the picture....
 
from what I can tell the flexplate is the kinda star shaped piece right infront of the TC. the thing the TC bolts too. if that is it....then i'm pretty sure that is neutral too....there are no weights on it either.


edit...that is the flexplate.....looks like this is similar to what I have....and its internal balance application. so it wont work. http://www.hawkinsspeedshop.com/mop...rnal-engine-balance-2-piece-rear-main-se.html

the way I see it I can use the original flexplate and buy a new B&M externally balanced TC (if they have one)....or buy a B&M external balanced flexplate. i'm sure the flex plate is the cheapest option to solve my issue.
 
crankshaft 3462387 is '72&'73 340 cast crank.

so you need the offset harmonic balancer as you already said. has to be for a 340. I'm 99.999% sure the 360's had a different balancer.

find a 340 one, test it out & cross your fingers :D

if the vibration remains -----------

on the back side, for flex plate / torque converter...

I'd get the offset weight flex plate (B&M) for externally balance engines, and then you get an unweighted torque converter (neutrally balanced). it's much easier to find a torque converter, you get many more options. since the B&M flex plate has a cutout for your weight offset, then you just buy a converter without weights, made for an internally balanced 340.

your alternative to doing that is to use what they did at the factory... just use your current flex plate and get a weighted torque converter. that will work but will just limit your choices. they also sell weight kits that you can spot weld onto a neutral balanced torque converter to make it work.
 
Unless you just want to replace the converter, you don't have to. Like Del said, you can get a flexplate that will work on your externally balanced engine WITH the neutral balance converter.
 
that is what my dad and I just talked about. we are going to get a B&M weighted flexplate and use the TC that is in there now. its been working fine all this time.

since we will have to drop the trans...we will put a new seal kit in....damn trans drips like a turd and that drives me nuts too.

the HB is a professional products version from jegs. it has weights that you bolt to it for different motors. it comes with a weight for a 340. this is a good deal because if I ever do put a forged crank in it one day to make it 70 correct...i'll just take the weight off and use the same balancer as neutral. pretty slick. and along those lines...i'll just have to put back in my original flexplate...an bam...I got the forged crank setup.

hopefully no long term damage was done over the time span that this thing has had the wrong TC/HB setup. probably not...as the car has only been driven about 3k miles in the last 10-5 years.

I don't see a specific external balance flexplate for a 340 on B&M website....just for a 360. I'll call them as it may be the same one for both motors.
 
thanks I saw that one on b&m website, but it just said standard, so I wasn't sure if it was external balance or not. which was why I was going to call.

every other website says external balance.

I appreciate the link and everyone's time and attention to this subject!

great group here!
 
thanks, i think i'll stick to my plan. i have no desire or room in the garge to pull the motor and once i do that.....well...you cant just stop at the crank now can we.....$$$
 
Mad Dart said:
Hmmm, Is that the older version? I have not seen one like that yet. Different brand?
Click to expand...

I believe the weighted are older versions, the ones with "half moon" cutouts are newer. Some were sold with same part number.
 
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