Power pully woes..

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bighammer

bighammer

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Well, I wasn't expecting this little problem... I'm swapping out the 318 for a 360. One of the differences that needs to be addressed is that the power pully does not bolt up to the damper. The holes are 'indexed' or something like that.

I took the pulley off of the 318 cuz I need a double groove, otherwise I would have used the pulley that came on the 360, but it is only a single groove pulley.

The problem lies in the bolt holes... They don't line up. I can get 5 out of the six holes to line up, but there's always at least one hole that's half way covered up. I'm thinking this may have to do with balancing? The 318 is internally balanced, 360 externally... Would the damper have anything to do with the balance? BTW, this is an LA 360, not a magnum.

My options are: drill out / ovalized the one hole in the pully to make it work; take the damper off of the 318 and put it on the 360; or find a correct pulley with double grooves for the 360.

I haven't seen this come up before, any thoughts on which way to proceed?

Much thanks

Mark
 
Drill or "oval" it out and you'll be fine, I did this on my 74 :glasses7:
 
Ok, Il bite. The balance is in the balancer. The pulleys are zero balanced. I "ovalled" mine out.
Oh, sorry. Your comment was probably in response to swapping balancers. in that case " No! Dont do it!
But if you hadda done it, it wouldnt have taken very long and you would have realized the mistake. Besides its way, way, easier to just file that hole a bit.
 
So the damper is the same thing as a balancer? I don't know this stuff!

I thought the balancing was done internally on a 318. That damper / balancer thingy is external on the engine. The external balance on a 360 is done by means of the torque converter, or in some cases the flex plate!

What am I missin here? :banghead:
 
Common term for damper could be balancer, but it's a damper no matter what you call it. (Vibration damper is it's name)
Problem is, it's not designed to "dampen" a 360.
It's designed to "dampen" vibrations of a 318. (different balance)(vibration damper)
 
i thought a damper was something they made you wear when you got old
 
The internally balanced engines, such as the 318s and the early 340s have the "dampeners" with the symmetrical pulley mtg holes.The " dampener" for the cast crank 340 has the one offset hole,and the big" balancing" slug on it so you wont likely interchange it.It should trigger a red-flag in your assemblers brain. On the 360 which was always a cast crank and externally balanced, they continued the offset hole.As to the "balancing" slug on the front "dampener", Im pretty sure mine doesnt have one. I thought I had seen some truck ones with offset slugs. IDK. And yes the "balancing" slug was moved to the convertor and showed up as welded on weights, and in the flywheel as huge drillings.
-So upon reflection, my previous comment in post #5, may have been/probably was in error. Sorry, again.

Edit; Went out and checked; sure enough my 360 has the ugly :dampener on it.
 
I'd oval it out. I've done that before and it works fine. 2 minutes with a die grinder and your done.

As mentioned you never want to put a 318 damper on a 360 unless the 360 has been internally balanced. If you look close at a 318 damper you'll see it's perfectly round with no notching or added weights. Now look at a 360 balancer and you'll see it either has an add on weight or has some of the metal notched out (looks like they did it with a router). That's half of what balances the 360. The other half that externally balances it is the weight added on the converter
 
The pulley bolt pattern has nothing to do with balancing. Use the proper vibration damper/harmonic balancer and make the one hole oval shaped so you can get all the bolts in and you will be fine.

Some pulleys used a symmetrical bolt pattern, some had an offset pattern.
 
bighammer said:
So the damper is the same thing as a balancer? I don't know this stuff!

I thought the balancing was done internally on a 318. That damper / balancer thingy is external on the engine. The external balance on a 360 is done by means of the torque converter, or in some cases the flex plate!

What am I missin here? :banghead:
Click to expand...

TC weights AND balancer / dampener weights affect balance. 360 has weighted BOTH TC and balancer.
 
Both weighted is what I thought. I just didnt remember seeing it on the front of my "dampener".That motor hasnt been apart since 94.Thats a long time for this old guy to remember stuff. But yeah the offset balance is on my 360. So does that mean I get to unsorry the previous sorry?
 
AJ/FormS said:
The internally balanced engines, such as the 318s and the early 340s have the "dampeners" with the symmetrical pulley mtg holes.The " dampener" for the cast crank 340 has the one offset hole,and the big" balancing" slug on it so you wont likely interchange it.It should trigger a red-flag in your assemblers brain. On the 360 which was always a cast crank and externally balanced, they continued the offset hole.As to the "balancing" slug on the front "dampener", Im pretty sure mine doesnt have one. I thought I had seen some truck ones with offset slugs. IDK. And yes the "balancing" slug was moved to the convertor and showed up as welded on weights, and in the flywheel as huge drillings.
-So upon reflection, my previous comment in post #5, may have been/probably was in error. Sorry, again.

Edit; Went out and checked; sure enough my 360 has the ugly :dampener on it.
Click to expand...

There were actually 2 completely different looking 360 LA balancers. The early one (through 75 I believe) had the big offset slug. 76 and later didn't have the slug. Instead they cut a groove of material out of the front outer ring about 1/2 way around it.
 
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