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Balancer ? Spec, Clearance, Timing tab

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Old Aug 2, 2023 | 07:25 AM
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Default Balancer ? Spec, Clearance, Timing tab

Another Harmonic Balancer question..

car is a 1980 L48 4 speed.

Engine is a 1977 350 out of my Big 10 4x4 with 45k. Has 4 bolt mains, factory non emissions motor


Question 1 Spec:
The engine is in the c3 and has a front crank seal leak. Since i need to pull the harmonic balancer i was wondering if i could swap on one for a 1980c3 with out issue?

Question 2 Clearance:
the current balancer seems to come close to the power steering pump bracket. Did they have forged crank 350’s in pickups in 77? I have read these have the bigger balancer.

Question 3 timing tab:
i cannot see my 12 o clock timing tab because of the short water pump. If i swap to a c3 balancer the timing mark should be closer to 2:30 position. Would a bolt on tab work. I would rather not replace the timing cover at this time…. Would like to save that for a future cam swap.

Thanks for the information.

Last edited by The Grinch; Aug 2, 2023 at 08:08 AM.
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Old Aug 2, 2023 | 07:34 AM
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Throw the old balancers away and get a 7" either Summit, Pioneer or equivalent with a decent timing tab (I will not use anything but the billet pointer style now). You have two 40 year old balancers that have two different TDC positions.......so the mark is in a different spot on both. You could scribe a mark on it if you are seriously $$$$ changed......but $100 for a Summit balancer and a Moroso Timing pointer is money well spent (and the shipping is free @$100). I have installed at least 20 or so Moroso pointers and they are spot on or 1 degree off checked with a bridge......and the balancer has 0-50 timing marks on it......timing and curve is one of the most important aspects of engine setup and these two items make it easy button.
40 year old balancers will separate and spin.....not a question of if....when.

Jebby
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Old Aug 2, 2023 | 08:40 AM
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Thanks for the info jebby!

i would only replace the balancer with a NEW one i am not going to reuse old stuff that may have slipped or cracked.

with the summit balancer and moroso tab is there a set up process to ensure TDC? I have only use factory timing tabs or fluid dampers on diesel engines.
My thought with using a new balancer spec ed for an 80 C3 is that it would put my timing slot in a place where a stock timing tab would line up as the slot is diffrent in relation to the keyway depending on the location of the timing tab on the timing chain cover.

I am liking the aftermarket suggestion.



Last edited by The Grinch; Aug 2, 2023 at 09:03 AM.
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Old Aug 2, 2023 | 11:59 AM
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Originally Posted by The Grinch
Thanks for the info jebby!

i would only replace the balancer with a NEW one i am not going to reuse old stuff that may have slipped or cracked.

with the summit balancer and moroso tab is there a set up process to ensure TDC? I have only use factory timing tabs or fluid dampers on diesel engines.
My thought with using a new balancer spec ed for an 80 C3 is that it would put my timing slot in a place where a stock timing tab would line up as the slot is diffrent in relation to the keyway depending on the location of the timing tab on the timing chain cover.

I am liking the aftermarket suggestion.
You could use a piston stop to verify true TDC but I can tell you that using that balancer and pointer you will be spot on or 1 degree off just bolting it on.........
Now a stamped chrome pointer is going to be all over the place.....but a machined billet piece will be made on a CNC machine and the pointer installed and tightened down on a jig.....much more accurate.....and the Moroso piece is dead on. Piston stop is the right way but not everybody will or can use one so these parts are a no brainer and will get one very close.......one degree isn't going to change much but I have seen chrome ones out of the box as much as 8 degrees off.......

Jebby
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Old Jun 25, 2024 | 11:08 AM
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Sorry to dig this one back up but the C3 is now my daily and only car so i want to ensure my timing is spot on.

not seeing the 7 inch?

https://www.summitracing.com/parts/sum-161350?rrec=true

https://www.summitracing.com/parts/mor-60110


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Old Jun 25, 2024 | 03:30 PM
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I recently replaced one on a '59 pickup with a later 350 in it. I used a Summit one also....it's actually 6.75" I think.

I had noticed last year when I was working on some cooling issues and was setting the timing...the marks weren't close to where they should be. I used a piston stop through the spark plug hole and remarked it at that time.

The mark on the right is the one I made at that time....and it's aligned with the "zero" mark on the new balancer. The mark on the left "should" be back where the one on the right is!

JIM




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