Harmonic balancer indexing...

[DennyB]

I'm replacing the stock 72 307 with a 74 350 in my 72 C20.
The 74 350 had a long water pump with the timing tab mounted to the timing cover near the middle behind the water pump. The 72 307 had a short pump so that is what I'm using to keep the ac, ps, etc pulley alignment correct.
Here is the problem...
I need to use the timing tab that mounts on the side of the timing cover.
I've tried original 350 the balancer.. no good. I tried the 307 balancer (which is much smaller) no good. I even pulled a balancer off a old crate motor here with the side tab....even worse.
The 74 had #1 on the distributer one behind the 307. I can change the clocking of the distributer to work but the balancer should be on 0 when at TDC
What am I missing?? Am I having a total brain fart? What balancer do I need?
Did these motors have different cranks/cams? I though they were all the same.

Thanks all.

Denny

[rage'nrat638]

the older engines had the smaller balancers.. my 69 had a 6 3/4 inch and i just replaced it with a 8" balancer. the 6 3/4 balancer use's the timimg tad spot welded to the cover..that i have seen... the 8" has the tab that uses the the cover bolts to hold it on.some are spot welded too..both will work fine. just need to know which timing tab you have...the 6 3/4' is very hard to find.

the dizzy don't have any thing to do with the balancer..both size balancers will show TDC. for getting on TDC to drop in your dizzy

[crazy longhorn]

Well ,as you already know , the balancer & the cover need to match! Or not.......set #1 piston TDC, & make your pointer fit what you have. lets forget about the big balancer , with the timing marks @ about 1 oclock.....it wont work with the short waterpump(you already know this tho!) The trouble with the stock stuff is that there was several ways to go, & thats why I suggest building your pointer to fit the balancer. best of luck.... L

[DennyB]

Thanks for the input guys.
The 8 inch balancer and pointer from the old crate engine has the bolt on pointer on the drivers side of the timing cover. I figured that would do the trick...NOT!
Besides the fact that none of the pullys would line up, at TDC the timing mark was 45 degrees off. Seems like I could put the timing light on #8. This makes no sence to me.
The smaller balancer from the 307 is only about 22.5 degrees off.
Did they make different cranks?
I would like to get this correct.

[WorkinLonghorn]

I notice you also have a Ford. Sometimes I forget that the cylinder numbering is different ford to GM and waste a bunch of time,not to mention confirming that I'm an idiot sometimes. You ARE using the driver side 1st from the radiator right???

[WorkinLonghorn]

The reason I ask is that if you are using Ford's #1 (same as GM #2) you will be exactly 45 degrees off.OOps,90 degrees,oh well.

[Billla]

TDC #1 is TDC regardless of the balancer size. Pick up an adjustable timing pointer (for the size balancer you want to use) and then index it to TDC. You do give up showing advance on the timing tab, but this is resolved with a) MSD timing tape applied to the balancer or b) (the right choice an adjustable advance timing light.

My gut tells me that we're missing something on finding TDC - sorry if I'm telling you stuff you already know but just wanted to be sure you know there are 2 TDCs - one on compression, one on exhaust - be SURE you're finding TDC COMPRESSION.

http://store.summitracing.com/egnsea...69&D=%2D106869

[DennyB]

Thanks guys.
I'm Using TDC on compression stroke and the correct firing order.
I may have to use timing tape.
It just gets in my craw that I've taken a balancer and pointer from a crate moter and its at tdc on #8. Like the crank has the key grove in a different place....goofy

Thanks again

[Billla]

My only caution here is that when things don't line up I get a little hinkey and look for another set of eyes to make sure I'm not missing anything

[DennyB]

Yea Bill, I got to doublecheck everything. This seems screwy to me.
Also gona have to pick up a dial indicator, I need one anyway.

Will keep ya posted..

[cooters]

the cranks are all the same but the balancers are machined with the keyway in different spots depending on some applications. Double check that the balancer is good, i have had the outer ring rotate as much as 40 degrees

[DennyB]

OK, got a dial indicator and found my first mistake..assuming the original balancer was true. Its what I based tdc with and its outer ring had rotated. Alls good now!
Thanks all for your help.