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Long story short replaced the balancer. I was able to remove the old incorrect 6.75” diameter balancer by hand......it even wiggled a tick. As you can see it was off by 20 degrees!!
Installed a new 8” balancer, new seal and checked top dead center. TDC is dead on at ‘0’ on the tab. Next step is to check cyclinder leak down. With marks every 90 degrees it’ll be easy.....
Wow. That's a lot. There is no indication the outer ring was slipping. No difference in paint marks, rust marks or anything else. You just can't see it. Talk about messing up your timing.
I think if I ever do change out my hub to a better unit, I would take a chisel or a scribing tool and make a future reference mark across the inner hub and outer hub.
Then 100 years from now you can see if the outer ring moved.
Wow. That's a lot. There is no indication the outer ring was slipping. No difference in paint marks, rust marks or anything else. You just can't see it. Talk about messing up our timing.
I think if I ever do change out my hub to a better unit, I would take a chisel or a scribing tool and make a future reference mark across the inner hub and outer hub.
Then 100 years from now you can see if the ring moved.
Black marker line above 13 on the new balancer was my old tdc reference. Good idea about marking the new balancer...
2020 Corvette of the Year Finalist (performance mods)
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check your new seal before you install everything. I got my motor together with all new parts including the timing cover and the seal leaked 2 quarts in 100 miles. It was a god awful mess and I missed a free dyno day at the car show I went to. I also had a one piece pan gasket the was destroyed during the front seal replacement since the cover was out of whack and had to be removed.....so I have to pull everything...AGAIN... this winter and start fresh. Seams every new seal I put in that motor was out of spec.
I used a new 8" balancer as well but I cant fine the part number
check your new seal before you install everything. I got my motor together with all new parts including the timing cover and the seal leaked 2 quarts in 100 miles. It was a god awful mess and I missed a free dyno day at the car show I went to. I also had a one piece pan gasket the was destroyed during the front seal replacement since the cover was out of whack and had to be removed.....so I have to pull everything...AGAIN... this winter and start fresh. Seams every new seal I put in that motor was out of spec.
I used a new 8" balancer as well but I cant fine the part number
There is no way to check the run-out of the balancers inner hub, I suppose. But after changing brand new front seals, I would suspect the inner hub is out of specs. Maybe several thousandths two big and wearing the seal down prematurely? Or maybe the inner hub is several thousandths too small = leak. IDK
I thought there were different timing tabs, and so I looked it up online. Pre 69 were different than newer tabs, so it would make sense if you had a mismatch of balancer to timing tab that the marks would be off.
I run a Tavia adjustable tab and verified true piston TDC with the heads off...….No errors.
I thought there were different timing tabs, and so I looked it up online. Pre 69 were different than newer tabs, so it would make sense if you had a mismatch of balancer to timing tab that the marks would be off.
I run a Tavia adjustable tab and verified true piston TDC with the heads off...….No errors.
You are correct but there are 3 different timing tab positions. My car has the 2 o’clock position which is correct for my car. The old balancer was a 2 o’clock balancer as well as the new balancer.
TDC was previously checked with heads off and marked with black sharpie on the old balancer. New balancer is designed for 2 o’clock timing tabs and matched TDC at ‘0’ on the timing tab.
check your new seal before you install everything. I got my motor together with all new parts including the timing cover and the seal leaked 2 quarts in 100 miles. It was a god awful mess and I missed a free dyno day at the car show I went to. I also had a one piece pan gasket the was destroyed during the front seal replacement since the cover was out of whack and had to be removed.....so I have to pull everything...AGAIN... this winter and start fresh. Seams every new seal I put in that motor was out of spec.
I used a new 8" balancer as well but I cant fine the part number
I checked it over good. And it leaks. I guess the oil pan, water pump and timing cover's all coming off. Oh well.
Sometimes in the excitement of rebuilding an engine we forget the little things. Little things like adding a smidge of lube on the "outside" of the damper when installing.
That brand new timing cover seal is running dry for the first minute or so at break-in / start up until oil works its way up there.
Contact between dry rubber & dry iron together, spinning 2,000 RPMs is like . . . . . . . . insert your own sentence here.
You had an early balancer that requires an early timing cover........you fixed it.....but I do not believe the balancer was bad. Although changing the cover is a small PITA so a new balancer and tab is a solid upgrade.
And yes, some oil on the outside of the balancer hub is pretty critical for start-up......
Last time I had to do this job was on a 76'..........I pretty much cleaned and replaced everything with the oil pan off including the oil pump, shaft and pickup (which was pretty loose on the pump).......new one piece gasket, fasteners, Allstar 90010 timing cover, water pump, etc.......sounds like overkill but the pan leaked, the oil pump shaft had a plastic collar, the timing cover was grody along with the pan, and the pickup was surprisingly loose on the pump for which a new one was brazed on.......guy wanted to drive it everywhere so it was the right thing to do.......not sure of the condition of the rest of your car, but something to consider.
You had an early balancer that requires an early timing cover........you fixed it.....but I do not believe the balancer was bad. Although changing the cover is a small PITA so a new balancer and tab is a solid upgrade.
And yes, some oil on the outside of the balancer hub is pretty critical for start-up......
Last time I had to do this job was on a 76'..........I pretty much cleaned and replaced everything with the oil pan off including the oil pump, shaft and pickup (which was pretty loose on the pump).......new one piece gasket, fasteners, Allstar 90010 timing cover, water pump, etc.......sounds like overkill but the pan leaked, the oil pump shaft had a plastic collar, the timing cover was grody along with the pan, and the pickup was surprisingly loose on the pump for which a new one was brazed on.......guy wanted to drive it everywhere so it was the right thing to do.......not sure of the condition of the rest of your car, but something to consider.
Jebby
Thanks for the solid advice. I used Grey Ultra on the outside of the seal where it mates to the cover, oiled the damper and put a thin layer of grease on the rubber inner diameter of the seal. Last time I had the pan off, I set pick-up depth, had it tack welded to pump, installed metal sleeve, replaced rear main seal and used a one piece Felpro gasket. At least all that's out of the way. Should only take me an hour or so to get all apart.
This time around it'll be a new cover and possible a new timing chain depending on what I see. Hopefully the camshaft has ID markers on the end.
Thanks for the solid advice. I used Grey Ultra on the outside of the seal where it mates to the cover, oiled the damper and put a thin layer of grease on the rubber inner diameter of the seal. Last time I had the pan off, I set pick-up depth, had it tack welded to pump, installed metal sleeve, replaced rear main seal and used a one piece Felpro gasket. At least all that's out of the way. Should only take me an hour or so to get all apart.
This time around it'll be a new cover and possible a new timing chain depending on what I see. Hopefully the camshaft has ID markers on the end.
Sounds like you are in the zone! Should be a cake walk......and yeah, a new chain is cheap piece of mind too......the Cloyes 9-1100 is still a bargain in 2018 for a true roller chain.
The beauty of all this is that once you find true zero, you can set you a nice timing curve and total timing so it is spot on! Nothing like a well tuned 350.....they just continue to surprise!
Get this cover: https://www.summitracing.com/parts/aaf-all90010
Another true bargain in this world. Well made and it work with a cam button....(Try finding one that does....or one you wont have to modify for less than $125)
11-11-2018, 06:59 AM
Bad harmonic balancer
