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mikebutt 09-01-2012 07:51 PM

Harmonic balancer
Ive posted last week regarding multiple starter problems with starter being kicked out even after shimming and perfect starts prior w/ no answers in sight.
My QUESTION IS THIS ... can it be that my harmonic balancer is bad and kicking out the starter? The reason i say this is i recently heard harmonics at 50 mph and none in park.2)i've virtually had to reseal the whole front end of the motor and the top. 3) my belts started squeaking and loosened up and were previously tight. 4) the timing has been off and havent touched anything... and when i look at the flexplate while running on a lift it looks like its not dead straight and has slight wobble. If these are all happening can this make a perfectly new good shimmed starter kick out and not work? ANY HELP WOULD BE GREATLY APPRECIATED ....and after replacing hundreds of high end parts and seals etc,,FRANKLY THIS CHEVELLE HAS BROKE ME!!!!!

cdminter59 09-01-2012 11:58 PM

Harmonic balancer
I am going to ask this question in case you can find out. When the motor was rebuilt was the rotating assembly balanced? You will have to know if it is internally or externally balanced. You say Eagle pistons and crank. Eagle sells cranks and rods, if you buy a rotating assembly the pistons are made from someone else. Did he give you any paper work from a machine shop or where he bought the crank, rods, and pistons. To be on the safe side you can buy a ProForm Harmonic Balancer Part No. 66513 from Advance Auto for $80. As for the flexplate was it purchased for an externally balanced 400 cid? It should have a weight welded to it under the ring gear. This is if it is externally balanced. Also is it installed correct. The recessed side bolts to the crank.

DoubleVision 09-02-2012 05:03 AM

What engine do you have? Also keep in mind that the balancer can be cracked and this will cause the belts to go slack. The balancer not only has a bolt to retain it but it's also a press fit and this is vital important. If the balancer slides on loose it works against the bolt until it breaks it, then all kinds of problems occur. WHen this happened to my engine it sheared off a section of the crank and I had to replace it.
As mentioned on the Eagle parts, this hints at a 383 stroker, if it's internally balanced but has a external balancer on it, this is big time problems. If it's a externally balanced crank with a internal balancer this is also big time problems, same goes for the flywheel and flexplate.

mikebutt 09-02-2012 06:17 AM

the only documentation i have is a smudged piece of loose leaf paper with the mechanics writing on it. Ive been searching for the builder in Savannah for months. "Tommy Loggins"
This is what is says
400sbc rotating assy w / block
.030 kb hypertecic pistons
scat h-beam 5.7 rods
scat 4130 steel crank
speed pro moly rings
clevite h series bearings
8" balancer w new flexplate

I purchased a new b@m flxplate for a sbc 168t ext balanced 400. I had it installed the same way the old one came off. I dont have bad harmonics just slight at @ 50mph and with all the other issues w/ leaks and not being able to set the timing and loose belts i am assuming that there is dryrot in the balancer. Ive had to replace almost every single gasket on the car. It did sit for 3 years. I cant find a single person who can get a starter to last for more than 6 cranks or so. SO i did some googling which is apparently also dangerous and it kinda points to a bad harmonic balancer. It this is the case could it move the crank enough to kick out these high torque mini starters? Sorry for my ignorance ive only been in this a few months and altho i have learned a lot i cannot afford to learn the hard way.

DoubleVision 09-02-2012 08:14 AM

Check the distributor. The mechanical advance in any distributor must be checked on occasion, in time they get junk and crap on them which makes them stick. If the advance sticks open and you go to fire it off it could be in full advance which will cause it to kick back. pop the cap and grab the rotor, If it will move then see if you feel any sticky or rough spots. If you do then inspect it and find out why and where. In most cases if it's severe you'll have to remove the distributor and disassemble the unit. Before I use any HEI the first thing I do is strip it down then clean everything on the mechanical advance. Then I use fine grit sandpaper and polish everything that operates with the mechanical advance as I want it to operate smooth as glass.
If this proves to be the problem then fix it then move on to replacing the balancer and the problems should be over.

mikebutt 09-02-2012 08:21 PM

Turns out it wasnt the balancer....After trying three more starters it appears all good. Thanks for all the input.

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