Lightening and balancing the intermediate shaft.

[theman53]

I looked through are there any pictures I missed of the finished balanced shaft? I saw the before ones, just wondering.

[DieselKraut]

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[theman53]

SWEET!  :shock:  

[jtanguay]

very nice!!!

[subsonic]

Here you go, before and after shots:  Worth doing if it's out.  

[DieselKraut]

That looks sweet! I'm pulling my engine today and want to send off my IM shaft. Where did you have yours turned and balanced and how long did it take to get it back?

[gigaz2]

I am definitely getting that done to my SB project  :shock:

[subsonic]

Friend at a local machine shop did it for me.  Any decent shop should be able to do a good job.  Cost me one loaded cheese steak .

[gigaz2]

Cost me one loaded cheese steak .

lol

locally I believe its going to be more expensive than that, a lot of machine shops closed, and the ones still open demand a lot for puny jobs like these

[riddleyo]

I just installed my lightened and balanced intermediate shaft.
Here are the pics:




Overall impressions: I don't notice any difference in power. The intermediate shaft spins at half the engine speed anyway. But my old intermediate shaft was broken, and I had to take my new one to the machine shop anyway, so I had this done.
I'm glad I did it though, one less part to worry about. And any freed up weight, no matter how small, is welcome on my car (it is an N/A, it needs all the help it can get)

[subsonic]

Well, if you took off a pound or so of rotating mass, it is going to free up power.  It might be hard to tell, but trueing the shaft must help with vibrations.  In stock form it is ungodly out of balance.  Nice work.  I see you turned behind the gear as well.  Nice job.

[Mark(The Miser)UK]

Neat job, but was it worthwhile? Shavings amount to a couple of oz's at most. Moment of inertia at 2000 rpm at max? But less than 1500 generally. 1cm from axis?
Remember the offending lobe was only the bit in excess of the ring of meat all way round.
As Sir Walter Raleigh would say "Small potatoes"
Nice lathe sample though :lol:

[subsonic]

Worthwhile is subjective.  The part needed to be replaced, and he all ready had it at the machine shop.  Turning the shft is a very simpy job.  Cost should have been low.  There is no question that the part is improved.  Balance has been improved and weight reduced, both good things.  Is it the same as a flywheel turned down to 10 pounds? No.  
Does it help with engine performance / longevity?  Yes.
Would I pull the IM shaft just to turn it?  No way.  If I had it out during an engine rebuild, and had the opportunity to improve it at a low cost, would I?  I sure would.  Lots of small improvments add up to a better engine, cost goes up, but you still end up with a better product.

[53 willys]

Man I got my IM shaft just sitting here...I think I may throw it in the lathe today and turn  mine down.

so did they take the tapper completely out of the shaft??
this should be a real easy job...I will weight mine before and after too.

[VW Smokr]

Some more info:
"So do you take the taper out of the shaft?  What about the lobe that is on the shaft, near the gear end, that drives the vacume pump?  Do you take that off as well?"

Reply:
"I take the taper out of the intermediate shaft as well as the bump."


From doing a bit of reading, it appears that the IM shaft is pretty rough, and I suspect, not very balanced.  

 :idea:  I am going to put forth the hypothesis that the IM shaft being out of balance is one of the leading causes of the dreaded IM shaft bearing failure / flaking.
I would further suggest that balancing the shaft will reduce or eliminate many of these failures. :idea:

Interesting!!! Then how do you run the vacuum pump, once you've installed the new lightened/balanced/bumpless IM shaft?

J.R.