340inabbody
Well-Known Member
Wonder if there is a visible cast line at the snout I could look for to determine if its cast or solid steel??
340 Static Compression Numbers and Test Procedure
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nm9stheham
Well-Known Member
That would be machined off. Now there might be a way to test the snout material and tell if it is cast iron or steel. I only know of how to do that on a grinder and tell from the sparks!
To really know about the whole balance situation, one would have to examine the 'guts'. See if rods are stock or modified or replacements, look at the crank type, see if there is heavy metal slugs in the counterweights, and so on.
The only other suggestion I have on externally visible balance clues is to remove the inspection cover a slowly rotate the crank 360* and carefully examine the flexplate and torque converter for weight. You have to read up and know what you are looking for... a TC can have small weights on it that are simply for neutral balancing, not for actual external weight. But it still would be a useful thing to do. Take pix.
If you have a manual trans, then the holes for external balance will be harder to spot.
Either way, it helps, but does not 100% tell you the whole story. It is conceivable to externally balance the rear half and internally balance the front half! (It seems like that type of situation showed up here in a thread 1-2 years ago....)
BTW do you think you are having engine balance issues? If so, what are the symptoms?
Or is this just about getting the damper marks all straightened up? I don't want to spin you off into left field on a wild goose chase! You have enough to do that IMHO ought to come first, like figuring out the cam specs and cam timing.
To really know about the whole balance situation, one would have to examine the 'guts'. See if rods are stock or modified or replacements, look at the crank type, see if there is heavy metal slugs in the counterweights, and so on.
The only other suggestion I have on externally visible balance clues is to remove the inspection cover a slowly rotate the crank 360* and carefully examine the flexplate and torque converter for weight. You have to read up and know what you are looking for... a TC can have small weights on it that are simply for neutral balancing, not for actual external weight. But it still would be a useful thing to do. Take pix.
If you have a manual trans, then the holes for external balance will be harder to spot.
Either way, it helps, but does not 100% tell you the whole story. It is conceivable to externally balance the rear half and internally balance the front half! (It seems like that type of situation showed up here in a thread 1-2 years ago....)
BTW do you think you are having engine balance issues? If so, what are the symptoms?
Or is this just about getting the damper marks all straightened up? I don't want to spin you off into left field on a wild goose chase! You have enough to do that IMHO ought to come first, like figuring out the cam specs and cam timing.
340inabbody
Well-Known Member
Not noticed any vibe.
nm9stheham
Well-Known Member
OK, then personally at this point I would go for one of the dampers with the screw on weights.
Like this, which also has a set of degree marks to make life easier for ignition timing:
http://professional-products.com/ha...7-25-318-340-360-chrysler-all-harmonic-damper
Once things are sorted out, you can opt for something better.
Like this, which also has a set of degree marks to make life easier for ignition timing:
http://professional-products.com/ha...7-25-318-340-360-chrysler-all-harmonic-damper
Once things are sorted out, you can opt for something better.
If you don't notice a vibration and the motor has been running this long already I would just leave the balancer on for now and remark it. If you don't want to get a piston stop to find exact TDC then try to find approximate TDC. Take all the sparkplugs out of the engine so it rotates easy. Look in the sparkplug hole and turn the motor with a wrench or socket until you can see the piston at TDC. Carefully rotate until you see the piston just start to move down the bore. Put a mark on the balancer that lines up with the zero mark on the tab. Next reverse rotation and do the same. Half way between these two marks is approximate TDC. Run the procedure again to see if your results repeat within a couple degrees. If it does you should have a good enough mark to time the engine with for now. This is not ideal but should get you closer than you are now. Set timing to about 35 degrees at around 4000 to 5000 Rpm. Add race fuel to the tank and see how it runs. Also mark the balancer with a straight line from inner to the outer hub so you can tell if the outer ring slips.
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yellow rose
Overnight Sensation
I have seen cranks that were 85 grams or more out that don't shake. The bearings look like crap when it comes apart, but they don't shake.
I wouldn't use shake as a method to determine if a damper is working.
A quick look at it will tell you if it's junk or not.
Look at the elastomer between the hub and outer ring. If it's not 100 pristine it's got issues. If you can see cracking and the elastomer squishing out or stuff like that, it is absolutely junk, whether it shakes or not.
That's why I always spend the extra money for a damper made without that elastomer in there. Chrysler did a ton of research on it and published it in the last engine book.
nm9stheham
Well-Known Member
Let's not confuse functions..... The elastomer and inertia ring in the damper is not for primary balance anyway; it is for torsional vibrations (i.e., very high rate twisting vibrations) inside the crank. The 'shake' question is related to primary crankshaft balance and whether the damper/balancer needs any external weight on it, or not.
But, if the damper mark is off 50 degrees like the OP sez, and not the 90 degrees + or - CCW like the older style damper, then something is quite wrong with the inertia ring position and the damper. So it ought to be changed out. And ditto for the cracks in the elastomer as said.
From imbalance reports here on this forum I can believe some pretty high bobweight mismatches (which I am sure is what YR is referring to) and not have it be felt. Does not mean it is good inside the motor. Just says we still don't know about the engine balance here.
But, if the damper mark is off 50 degrees like the OP sez, and not the 90 degrees + or - CCW like the older style damper, then something is quite wrong with the inertia ring position and the damper. So it ought to be changed out. And ditto for the cracks in the elastomer as said.
From imbalance reports here on this forum I can believe some pretty high bobweight mismatches (which I am sure is what YR is referring to) and not have it be felt. Does not mean it is good inside the motor. Just says we still don't know about the engine balance here.
340inabbody
Well-Known Member
Well one thing for sure its either a bad HB or the wrong one. My finger lines up with the mark and you can see it ain’t 6 degrees from the keyway. It’s way way off as I indicated from inspection on the engine.
The elastomer does not look bad and the mark not far off for a timing pointer on the driver side. So I am going to call it the wrong one.
Question looks like there are four drill and fill counter weights indicating is for an externally balanced application. Does that look that way to you?
The elastomer does not look bad and the mark not far off for a timing pointer on the driver side. So I am going to call it the wrong one.
Question looks like there are four drill and fill counter weights indicating is for an externally balanced application. Does that look that way to you?
nm9stheham
Well-Known Member
Yes, that's the right area for the old pre-70 damper.....
There are holes like that in almost all of them for balance of the whole assembly, to make the part itself neutral balanced. That looks like a standard neutral balance damper.
I'll be honest... that old? No way the elastomer is going to work like it should as a damper. The rubber absolutely will have hardened up with 50+ years of time and unknown years of use and exposure to engine heat.
There are holes like that in almost all of them for balance of the whole assembly, to make the part itself neutral balanced. That looks like a standard neutral balance damper.
I'll be honest... that old? No way the elastomer is going to work like it should as a damper. The rubber absolutely will have hardened up with 50+ years of time and unknown years of use and exposure to engine heat.
yellow rose
Overnight Sensation
I'll try and get this post correct.
Those holes are essentially to zero balance the damper. The next one may have two holes or no holes.
Again, I don't skimp on dampers. An elastomer damper starts to degrade from day one, and it also has a very narrow range to control harmonics. Change the bobweight, change the frequency the damper needs to deal with.
Chrysler has a pretty good write up on this in the engine book.
Those holes are essentially to zero balance the damper. The next one may have two holes or no holes.
Again, I don't skimp on dampers. An elastomer damper starts to degrade from day one, and it also has a very narrow range to control harmonics. Change the bobweight, change the frequency the damper needs to deal with.
Chrysler has a pretty good write up on this in the engine book.
340inabbody
Well-Known Member
Thanks! I thought all those mailable weights would make that Such an uneven distribution it would have to be for an externally balanced set up. So this leaves me with trying to determine if the crank is cast or steel. I don’t know anyway to tell without pulling the pan down and inspecting. Does the nose of both cast and steel look the same??
The HB I ordered from summit has a weight I can add for external balance or run internally without.
The damage to the Key wasn’t done by me. That would be another meat head...
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340inabbody
Well-Known Member
Understood, thank you YR going with an inexpensive unit for now that gives me the ability to trouble shoot the motor see my post above.
gzig5
Well-Known Member
The balancer is a casting. Castings aren’t uniform density throughout so they drill holes in the heavy side to get a nuetral balance. or in the case of a factory external balance, to tweak the offset weight
nm9stheham
Well-Known Member
You could pull off the timing cover and see the front edge of the front journal of the crank and see if it is cast or forged. Of course it does not answer the balance situation 100%.
It is a bit tricky to get loose from the pan (you may have to loosen the pan) but it can be done. Putting the cover back in place is a certain procedure.
The timing chain can be pulled off and that key replaced. That is not good....
Did you need a puller to remove the damper or did it just slide off the crank snout?
BTW, clean out the crud from the threads inside the snout. When the damper bolt get torqued down to that high torque (135 ft lbs), those threads see some real strain.
It is a bit tricky to get loose from the pan (you may have to loosen the pan) but it can be done. Putting the cover back in place is a certain procedure.
The timing chain can be pulled off and that key replaced. That is not good....
Did you need a puller to remove the damper or did it just slide off the crank snout?
BTW, clean out the crud from the threads inside the snout. When the damper bolt get torqued down to that high torque (135 ft lbs), those threads see some real strain.
340inabbody
Well-Known Member
HB was tight used my puller (handy tool use it a lot for many things). Saw that crud too and plan to clean out thanks. 135 lbs check. Will probably hold off on pulling the timing cover and assume the crank is cast original. I know the flexplate is for an internally balanced engine so I have to replace that as well....
Are you saying that the flywheel is internal balance and the balancer is internal balance?
340inabbody
Well-Known Member
No flywheel as this an automatic. But what I am trying to convey is that this is a 1973 vintage engine and I am guessing (I onow I could be wrong) that the crank is original and is cast ie externally balanced as that was stock for 72 and 73. I know there is a flexplate in there thats for an internally balanced motor. This will need to change if my hunch is correct.
Is there a weight on the torque converter?
340inabbody
Well-Known Member
I think not but I could be wrong. I am rationalizing this way. The motor is balanced by the harmonic balancer in the front of the crankshaft and by the flexplate in the rear of the crankshaft. So the torque converter should be neutrally balanced as the assembly is then in balance.
Honestly I don’t know why every engine is internally balanced? This would all be so much more uniform and help with compatibility. Not to mention less vibration comparatively.
nm9stheham
Well-Known Member
IIRC on the LA's, the rear external weight is on the TC. So you need to look. As with a neutral balance damper, a neutral balance TC will usually have a small weight somewhere for balance; the external balance weight for the TC is larger. Take pix.....
And, good on the damper needing to be pulled with a puller. Means the crank snout has not been messed up with a loose damper and damaged crank key.
These engines' cast iron crank is lighter than a forged steel crank, and is too light to be able to put in enough weight on the counterweights alone to internally balance it. So the external balance method had to be used.
And, good on the damper needing to be pulled with a puller. Means the crank snout has not been messed up with a loose damper and damaged crank key.
These engines' cast iron crank is lighter than a forged steel crank, and is too light to be able to put in enough weight on the counterweights alone to internally balance it. So the external balance method had to be used.
340inabbody
Well-Known Member
Thanks but are you sure the torque converter is what has counter weights and not the flexplate on LA’s? I understand that the flexplates are either externally balanced or neutral and the TC’s are always neutral.
yellow rose
Overnight Sensation
The converters have the weights.
That HB you pulled is for an internally balanced crank. That won't work with an externally balanced crank.
So, with no weights on the converter it's an internally balanced crank.
That can still be a cast crank, but if it is, someone spent way more money on a cast crank than I ever would.
nm9stheham
Well-Known Member
The weight went on the flexplate in the later Magnums ...... Early Magnums and LA's had the weights on the TC from the factory... as I understand it.
People will switch to an external balance flexplate (like the B&M types) and a neutral balance TC for convenience in getting a variety of TC's.
And yes.... we really don't know what is inside. YR, do you happen to have weight specs on those pistons in this engine? TRW L 2322, probably also the same pinston and number under SpeedPro. If so, I can double check against stock 340 piston weights.
People will switch to an external balance flexplate (like the B&M types) and a neutral balance TC for convenience in getting a variety of TC's.
And yes.... we really don't know what is inside. YR, do you happen to have weight specs on those pistons in this engine? TRW L 2322, probably also the same pinston and number under SpeedPro. If so, I can double check against stock 340 piston weights.
Magnum flex plate (rusty one) and B& M 360 external balance flex plate for zero balance converter.
340inabbody
Well-Known Member
The more I (we) dig at this the more unknowns we are finding guiding me closer to pulling this puppy.
The pistons are 0.30 from the bore scope readout. nmn9 what are you thinking regarding comparison of the TRW piston weight to the stock ones? I read on a other forum the weight is 735 for an 0.030 over TRW.
The pistons are 0.30 from the bore scope readout. nmn9 what are you thinking regarding comparison of the TRW piston weight to the stock ones? I read on a other forum the weight is 735 for an 0.030 over TRW.
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