Engine swap, flywheel question

[towcat]

Most any balancer can be balanced for a turbo or the flexplates can also be turbo balanced. I have seen the specific turbo wheels and balancers but any can be balanced to work. Just saying..

you must have been inflicted with Al's disease or something close to it. From a guy who was just talking about the closest gram to this drivel, you should be ashamed of yourself.
read up guys......if you don't want to get thrown out of a engine machine shop on your ass, don't go in expecting them to balance individual parts without the WHOLE ROTATING ASSEMBLY it just plain won't happen at a shop with any reputation.
I have a E4DOA oem turbo flexplate and spacer. they are no different from a C6 as far as offset goes. how can I say this? it's very simple. the part number for the starters has been same from 83-94 (lester #17037) if the bendix engages at the same location for the 6.9 with c6 as do the oem turbo motor with the E4DOA, then the location must be the same!
simple

 

[icanfixall]

Al's disease... Now that funny as hell. I probably should have used a few more words Calvin. When my rotating parts got balanced they were originally the na version pistons. then I added turbo pistons that I personally balanced. Then all this rotating group of parts was sent to a balance shop for "fixing". Now being my second rebuild on the block because I melted the pistons from a lost freeze plug the balane guy had to add metal to the mid plain of the crank. He was shocked at how much knowing it had just been done 5200 miles before this. I'm not sure why this was so but it sure is a smooth running engine. Never was even after the first blance rebuilt engine this I know. BTW I did use 2 differant balance shops or at least I hope I did. The first shop wouldn't tell me who they used. Taking in just a balancer or a wheel and asking some guy to balance it for this or that is never going to be correct but it can get close. You just need ALL the parts to make it correct. Main bearings don't rotate but the rod bearings do so you need to include at least one set of rod bearings. Not all 8 of them. Once everything has been weighed then the bob weights can be made up and hung on the rod bearing journels of the crank. Then the wheel and balancer is hung on the crank and its spun up. Then the fun of adding weight to the ends or the mid plain or taking weight away from those places or a combo of all... I used to balance up to 100 ton steam turbine rotors down to 2 ozs. Thats a job too. Scared the hell out of me to see that much weight spinning at up to 500 rpm with nothing holding it in the roller bearings on the balance jigs but gravity...

 

[ifrythings]

Well I'm having zero luck trying to find a flexplate for an idit, I just called a local shop that does balancing and they said if I have a flywheel that is balanced for that engine(I do have a smf for it) and I bring in the flexplate for the non turbo, they can match balance it for me, going to cost around 150-200 bones though will this work just as good as factory does (as I know some will say balance the whole rotating assembly but its a running engine) I really have no other options unless someone has one kicking around that they wouldn't mind passing along?

Also just to put out there the part numbers I came across

F3TZ-6375-B 7.3NA with E4OD
F3TZ-6375-A 7.3turbo with E4OD
1816637C1 7.3turbo with E4OD (found this but no way of checking for accuracy)
E9TZ-6375-A 7.3NA with C6 (also seems to be the same part for 6.9 with c6)

Is the C6 torque converter too light so they use the heavy version of the flexplate, instead of the stamped flexplate that the E4OD uses, which probably has a heavy torque converter?

 

[OLDBULL8]

Reading this whole thread about the balance, I don't get it. A lousy flexplate that is balanced, isn't going to balance an engine that seems to be totally out of balance. Why can you put a turbo on a 6.9 or a 7.3 NA and virtually do nothing else to it and it don't try to shake off the engine mounts? The only thing I see, is the NA engine rods and pistons were changed to turbo rods and pistons. If the crank counterweights/throws were not rebalanced for the difference, I can see why you would have a shaky engine.

The way I see it.
IF your gonna use the E4OD trans, then you have to use the flexplate and spacer so the starter will engage. It has nothing to do with balancing the engine.

If your gonna use the C6 trans., then you should use the cast iron flywheel and fexplate, or just use the E4OD flexplate and spacer so the starter will engage.

The cast iron flywheel provides inertia for the 6.9, has nothing to do with balance of the engine.

 

[cpdenton]

I don't understand the difference either. The 6,9, 7.3 NA, and 7.3 idit all use the same crank. The only difference is the weight of the rods, wrist pins, and pistons, but they are all heavier(I assume) equally.

I know there are some cranks that are externally balanced. I guess our engine needs some external balancing, or the flywheel and balancer would not be weighted. But would it need to be that much different than the NA engine, since all the pistons and rods go up in size equally? I have an engine from a 92 and a turbo block from a 94. Both had the same flex plate installed. I did not run the 94 before I brought it home, so I'm not sure if it shook or not...

 

[OLDBULL8]

When the factory balances cranks. The machine is set up with a master crank with the proper BOB weights installed on it, all readouts are then set to Zero. The "rough" cranks are then spun and a pickup on each end of the floating table, the crank is then automatically rotated to the proper position and balanced, either by drilling the counterbalance and or crank throw, then spun for a check of balance. Very similar to an electronic tire balancer as a comparision.

 

[racer30]

The flex plate is balanced with weights welded to it at a specific distance from the crank center and then those weights have small amounts of weight removed from them to get the rotating weight at the rear of the crank within spec. The harmonic balancer has a larger weighted area with drill marks on the balancer to bring the nose of the crank into spec. Factory balancing spec is not as tight as a truly balanced assembly with all the parts weight matched to within .25 grams or less like race engine parts. The IDI Turbo Rods are over 100 Grams heaver than NA Rods...Turbo rist pins are 353 Grams NA rist pins are 245 Grams. The rotating mass was made heaver by the same amount on every cylinder or throw, YES.. But there are more forces involved than just the weight of the rods and pins...The extra weight of the pin and the larger small end of the rod is split between the rotating mass and the reciprocating mass. Engine balancing formula is 100% of The rotating mas and 50% of the reciprocating mass to determine if the counter weight on the crank is correct to bring the engine into balance. When you add weight to the rotating mass and the reciprocating mass I-E the Turbo engine internals. You need to add weight to the crank counter weights, Harmonic balancer and or the flex plate/flywheel. The engine manufacture determined it was cheeper to use a different balancer and flywheel/flex plate to bring the Turbo engine assembly into spec than to redesign the crank shaft... I lightened and weight matched the NA rods and pistons in my engine and like most performance engines the parts are made lighter so metal is removed from the crank counter weights to bring the assembly into balance. IMO Money spent on balancing the engine is never wasted...I'm sorry you are having trouble finding a IDIT flex plate assembly....I had one complete assembly that sold 2 years ago before Knowing how hard they are to find....Good luck...

 

[ifrythings]

Ok, sounds like we need a little more detail is needed.

The engine I'm having issues with is a 91 block and crank, that's were it ends, I have idit rods, pistons, exhaust valves gasket set (I believe you can only get the turbo gasket set now) and the turbo specific vibration dampener and I also got the top oil port drilled out to 1/4".

Now the problem I have is I tried the thin flexplate (from a junk 91 engine) that is used with the E4OD with my C6 and above mentioned engine. It shook fairly bad at idle (felt like you could feel every cylinder firing individually) Now I'm thinking this is due to the flexplate being improperly balanced for this engine, but being that this flexplate is also made just for the E4OD which I'm assuming has a way heavier torque converter vs the c6 that maybe that is also compounding my issues.

So my questions are this

1: If I get this flexplate balanced for this engine can I just fire the engine up without any trans hooked up and see if the vibration is gone or does it need the torque converter as part of the fly weight? (engine inertia)

2: If the torque converters are used as part of the fly weight, should I be getting this thin flexplate balance and try to use it with my c6 or should I get the heavy c6 flywheel rebalance for this engine?

3: How important is the weight of the flywheel to the operation of the engine? Can it cause damage to a balanced engine that doesn't have enough flywheel weight?

I know for future engine rebuilds, I'll be getting everything balanced.

 

[racer30]

You can run this engine without a trans because the starter mounts to the adaptor plate. The converter is Zero balanced so it has no effect on balance. Its mass is only load to the engine. If you had the engine disassembled you could have a NA flex plate modified with steel weights to balance the engine...Your only bet is to keep looking for a correct part.....Try this....Look for a complete Truck...maybe you can find one that has a engine still in it at a wrecking yard, or on craigs list, check in areas at the limit of what your willing to drive to....Don't tell the guy you only need the flex plate.... Get it for parts... then part it out and scrap anything not reusable. I found a lot of engines just by calling everybody selling or parting out Trucks. Good luck...

 

[stuborn nut]

what about just jetting an aftermarket flex plate for the 7.3idit? it would not be the quality of oem stuff, but it would work.

 

[ifrythings]

You can run this engine without a trans because the starter mounts to the adaptor plate. The converter is Zero balanced so it has no effect on balance. Its mass is only load to the engine. If you had the engine disassembled you could have a NA flex plate modified with steel weights to balance the engine...Your only bet is to keep looking for a correct part.....Try this....Look for a complete Truck...maybe you can find one that has a engine still in it at a wrecking yard, or on craigs list, check in areas at the limit of what your willing to drive to....Don't tell the guy you only need the flex plate.... Get it for parts... then part it out and scrap anything not reusable. I found a lot of engines just by calling everybody selling or parting out Trucks. Good luck...

The balancing shop I talked to said they could spin up the flywheel I have for the idit, find the weight offset and then they would spin up the flexplate I have and set it to the same amount of offset (I hope I worded that right)
This does sound like it should work and get it at least into factory range, I do understand the best way of doing it would be getting the whole thing balanced but its too late to do that.
I would defiantly by a parts truck and part it out if I had the cash to get it and somewhere to put it, but as it is it hard enough trying to find this engine to begin with never mind the insane price people want for a rust bucket up here.
I tried all the trans shops around town and none of them could find one, tried the jobbers but all they could get was powerstroke one or what we believe was the flex plate part of the heavy cast iron one, auto wreckers here don't have much of anything over 10 years old and only one of them has an idit but its standard and he wants an arm and a leg for it, Kijiji up here is like craiglist down there and not much pops up on there for theses old idi to begin with

what about just jetting an aftermarket flex plate for the 7.3idit? it would not be the quality of oem stuff, but it would work.

Trust me if I could get an aftermarket one, I would, I'm not a die hard has to be oem everything person