TT5.9mag
Two atmospheres are better than one
No one is arguing against that.
Cam Phasing
- Thread starter Bodyperson
- Start date
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TT5.9mag
Two atmospheres are better than one
So if you take the key out, the thing the key kept in place is now going to no longer be kept in place right?
I think that's a fair statement.
TT5.9mag
Two atmospheres are better than one
Then it has to be carrying some load. Which has been my entire argument.
I think it carries just enough to keep things in place. How much more is anybody's guess. But I wouldn't run a balancer for example without a key. That would be stupid.
TT5.9mag
Two atmospheres are better than one
Well, (speaking directly about blower drives) we know one won’t carry the load of a roots blower. Because both the blower manufacturer and crank manufacturers make use of multiple keyways.
Newbomb Turk
Well-Known Member
It doesn’t carry ANY load or it will fail. You can leave the damn things out and nothing will happen.
It’s keyed for assembly line speed.
The reason you see blower hubs with an extra key is because the key has to do work. One key will fail. Two keys will fail but it will take more.
That’s why they have went to spline drives.
Using the key to take load is bad policy but sometimes it has to be done.
Edit: I should add that the blower loads the front of the crank much harder than NA does.
There is only room for so many bolts to increase clamp load.
TT5.9mag
Two atmospheres are better than one
That has been my point this entire time. Just because the engineering behind keys and keyways says they don’t carry load, doesn’t mean (aftermarket) manufacturers don’t use them for it. When you run out of area (for friction or bolt locations) you have to do other things. And they do. 20 years ago I had a vortec V1 S trim supercharger on a 347 in a mustang. I kept tearing up keys and bolts on the balancer over 20psi. Didn’t matter how tight they were I’d get 10-15 passes out of it and the key would be rounded off and bolts would be damn near worn through. My brother worked for Saleen at the time and I went to talk to Steve Saleen and his “engine guy”. Both of them said pull the crank out of it and have it broached for another key or replace the crank with one that already has two. I did and never hurt it again. I sold the car and 8 years later it was still together.
Yup.
I disagree with that about balancers on true high performance engines. The key must carry enough load to keep the balancer in place. Otherwise, it would slip on sudden hard acceleration.
Here are a couple of good examples. NON of the small journal small block Chevy engines had balancer bolts. They weren't even drilled from the factory. That INCLUDES ALL of the 283 HP engines and the 365HP and 375HP 327 engines AS WELL AS the DZ302. Most all slant six engines, although drilled for balancer bolts, had none. What was bearing the loads on all those examples?
TT5.9mag
Two atmospheres are better than one
As designed the friction between the press fit of the crank and balancer.
Have you ever removed or installed an early small block Chevy balancer? There's not much press fit. Just enough to need a balancer tool. Nothing like any of the Mopars, including the slant 6.
TT5.9mag
Two atmospheres are better than one
Earliest I’m familiar with is a stock 67 327 from a camaro. All the rest I’ve done have been late model stuff. But yea it’s a light press.
I'll put it this way. I had a mildly warmed up 300HP 327 in a 67 Chevelle. It kept throwing the balancer off. I finally took the radiator and all out of the front, made a jig to hold the drill centered and drilled the crank for a bolt. It didn't do dat chit anymore.
Funny how we have migrated to crank balance from cam phasing. Love it either way.
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