When using a balance plate with a 350 flexplate on a 383 (external balance) engine, does the balance plate go between the crank flange and flexplate, or between the flexplate and the torque converter? The reason I am asking is that when I put it between the crank and flexplate, the torque converter won't turn past the "bumps" on the flexplate, so I am unable to line it up with the bolt holes. However, if I try to put the plate on the outside of the flexplate, the torque converter mounting tabs hit the plate by one of the bolt holes, preventing the converter from bolting up. I have installed/pulled the engine 3 times today, trying different combinations. None work. There simply isn't enough slack space between flexplate and torque converter to make it work, when plate is between crank and flexplate, as the manufacturer states to do. My patience is about shot. Anybody out there have any experiance with this problem?

[This message has been edited by b-boy (edited 04-15-2001).]

Bboy,
Why dont you just buy the correct, 400 flywheel ???? They are only about $50 and they will be balanced correctly. The balance plate is just a rough balance fix and not very exact. It is supposed to go between the flex-plate and the crank. About the only time they might be worth messing with is on a Manual Transmission car, or Marine application where the flywheels are a lot more expensive.

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Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73

Bill,
Well, the engine has allready been balanced at the machine shop with the plate. So would a 400 flex plate still work, or would the engine need to be rebalanced? Also, I liked the idea of using the 350 flex plate so I didn't have to buy more than one ( I have a 327 that I swap in place of the 383 every now and then, like when I'm going through the engine rebuilding it). Also, since I drive my car alot, I thought if I ever tore up the flexplate ( hung starter, etc...) it would be far easier to find a standard flexplate vs. a 400 at any old out of the way garage/junkyard. After spending the day today like I did, I believe I made the wrong decision.

Are you sure you have the convertor pushed all the way into the trans? It sounds like it possibly isn't on all the way. Sometimes you have to push and turn on them a while before the splines line up on the pump and lets the convertor go in that last little bit.

Jody

b,
If the motor was balanced with the plate, then it is probably best that you stick with it. The thickness should not be causing a problem with the converter, I would have to agree with Jody that the converter is not all the way into the front pump drive of the trans. It can be a pain sometimes to get it to go in. I have had to stand a transmission up on end and spin the converter by hand a bunch to get them in the final "notch". When it is in properly, you should be able to pull it away from the mounting "humps" at least 1/8" or something is wrong. If you can not get it to turn freely, by all means..do NOT force it and bolt it up. You will instantly ruin the front pump in the trans when you start the motor.
Take a deep breath, and keep fooling with the converter to get it to go in all the way. The other possibility, if the converter is new, is that it was made incorrectly. Converters that are made for motors with mid mount plates are about 1/4" longer and will cause the problem you are having if you dont have a mid mount. If the converter is new, it can be very tight going onto the pump drive. You might have to take the trans out to get it to go in all the way....just part of the fun of high performance vehicles http://www.camaros.net/forum/smile.gif

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Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73

I have run this same engine/converter combo about 5 years now. Until this year I have used a stock OEM 400 flex plate with no problem. I had a starter hang up on it last year and strip the teeth of flexplate. Then I bought an SFI approved 400 flexplate. It is noticably thicker but I ran it last year with no problem (it had about 1/16, maybe a hair more clearance between flexplate and converter tab mounts). I pulled the engine last fall to rebuild and noticed that the external counter-weight on the flexplate had broken 1 of the four spot-welds holding it, and another one was partially loose. I wasn't impressed being this was a "good" SFI piece. So instead of spot-welding it back on, which we talked about at the machine shop, we chiseled it off and put a balance plate on the engine when balanced. So here I am. Torque converter is all the way in. There are 2 options we are going to try tomorrow. First is put the current flex plate and balance plate on the balancer and spin them. Then put another 400 flex-plate on and spin that, then compare numbers. If it's close. we'll use the new flex-plate. If not, then instead of tearing the engine apart to re-balance, we will probably mill about 1/8" off the converter mounting tabs in order to gain the proper clearance. How's that sound? What a FUN time. I've had worse. By the way, to confirm converter is on all the way, do any of you have depth measurements? Lay a straight edge across bottom tranny to engine bolt holes. This should disect the center of the converter centering hub. Then measure from straight edge to hub. Mine is 3/4". Also, from straight edge (still same position) spin converter and measure to mounting "tabs" on converter. Mine is 15/16". Is yours the same? I'm going to post this same question as a new thread, cause sometimes people don't read "older" postings, and I need a comparison before I head to the machine shop and have them perform steps as listed above. Thanks.

[This message has been edited by b-boy (edited 04-17-2001).]

<BLOCKQUOTE>quote:</font><HR>Originally posted by BillK:
Bboy,
Why dont you just buy the correct, 400 flywheel ???? They are only about $50 and they will be balanced correctly. The balance plate is just a rough balance fix and not very exact. It is supposed to go between the flex-plate and the crank. About the only time they might be worth messing with is on a Manual Transmission car, or Marine application where the flywheels are a lot more expensive.

<HR></BLOCKQUOTE>


BillK,

Does this do away with the need for an externally balanced flywheel??? I have a six speed that needs to use the matching LT1 flywheel. I currently have the six speed behind a one piece rear main 350. The LT1 flywheel works with this engine. If I wanted to go 383, could I then use a one piece rear main 3.75 externally balanced crank, 400 balancer, the LT1 flywheel and a balance plate?? Thanks




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Mark

1992 Firebird 355/Six Speed (Soon to be LT1)
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
"Speed KILLS, so drive a FORD and live forever!"
http://personal.lig.bellsouth.net/~racer383/

Member of the "unwanted" 3rd Gen group.