flyingputz

I recently acquired a Smeding Performance 383 TBI shortblock, minus the damper. I was informed that it needs an 'external' balance damper (with the counterweight). Can anyone with a Smeding motor confirm this and give me a brand or part #? I believe these are available with different weights and don't want to cause any engine damage by installing the wrong part. I believe these have Scat cranks but a search on the numbers stamped on the crank turned up nothing! Thanks for any replies.

ibmtech

iTrader: (1)

I think this is something you are going to have to call them and ask Smeding for advise on to ensure you get the right setup for your engine.. It makes it so much easier when the engine is neutral balanced.

Damon

An externally balanced 383 will use the same balancer as an old factory 400. An application from the mid-late 70s, 400ci is what you're looking for (they were all 8" balancers, BTW.

You can also do some searching on the Summit website- there are many to choose from.

flyingputz

I emailed Smeding a couple times and got NO response. I then called them and the only info they gave was that its externally balanced, with the counterweighted damper. I guess they don't like to divulge too much info. Thanks for the replies guys.

grumpyvette

If your assembling a EXTERNALLY BALANCED 383 or 400 based engine,you'll need externally balanced flex-plate and damper components, obviously its best to have all components used balanced as a unit if possible

http://www.summitracing.com/parts/TFS-19001/

damper
http://static.summitracing.com/globa...structions.pdf
damper install instructions

there are 153 and 168 tooth flex plates (12.8" and 14.1")and flywheels
youll need to get one that matches and is also externally balanced
http://forum.grumpysperformance.com/...259&p=314#p314

http://forum.grumpysperformance.com/...p=13058#p13058

articwhiteZ

iTrader: (56)

i just happen to have A, sfi bal and sfi flexplate, from top name brand makers. for less then Half price!

flyingputz

It looks like I better give Smeding another call and pry some more info out of 'em. Better safe than sorry. Thanks for all the replies!

bwmcam

You never know until you consult the folks that built it. grumpyvette is right in general, however anything is possible.


When I bought my car the previous owner had a 383 stroker kit put in by a machine shop locally. He said it was internally balanced, every time I revved the engine from 2100-2800 rpms I would have engine vibration. So I tried replacing the harmonic balancer, it was a 6" non-weighted. I put a new 6" non-weighted on, didn't help my engine vibration. I left it that way for about 1 year only driving it once a month.

So I looked at the flexplate and found that it had a weight on it. I figured that he put the wrong one on, it should have not had a weight since it was supposed to be 'internally balanced'. I ordered a new one from summit 153-tooth No weight SFI approved. The flexplate arrived I took the tranny out, installed the new flexplate, then reinstalled the transmission, I started the engine and it shook WAY worse than before. I took the tranny back out and put the original flexplate on that had the weight.

The only thing that I hadn't tried was putting on an 8" harmonic balancer, but I didn't want to buy two balancers one weighted and one not. So I bought this one from Summit SCA-D-80003 it is a Scat balancer that comes with the External Weight that is removable (says comes with weight in the notes, I bought the wrong one the first time it did not have the weight).

When I received the balancer I installed it on the engine with the weight since I figured "a weighted flexplate needs a weighted Balancer"....right...NOPE not for mine. I started the engine up and the vibration was WAY worse again. So I had one last shot, I removed the weight from the 8" balancer and it was perfectly smooth.

So my setup has a Non-Weighted 8" balancer and a Weighted 153-tooth Flexplate. Nice huh...lol

BOTTLEDZ28

iTrader: (9)

I have an internally balanced or neutral balance 383 and I strongly recommend that you have all the rotating assembly parts sent out to be balanced. I put me engine together with all new parts and it shook like crazy on the dyno. I had to tear it all down again, replace all the bearing and then I had the crank pulley, balancer, crank, flywheel, and clutch all balanced on a special machine. The parts were then marked for proper reassembly and I can tell you now that my engine spins to 6500rpm without the slightest bit is vibration. It made the world of difference.

The verdict was that all my parts I had were balanced with the manufactures specs for that particular part. Well, a little off here dont mean much but a little here and a little there and little there turned out to be a big problem.

bwmcam

I appreciate your advice, but as I said before I don't have any engine vibration at any rpm. If I start to notice any problems I will let you guys know. I recall the previous owner had the engine balanced, I just think the machine shop used whatever they had and then balanced it.