Putting bushings in ductile iron rockers?

Posted By: vern73

Putting bushings in ductile iron rockers? - 08/05/13 01:40 PM

Anyone ever done this or had it done? I have a set of 1.6 Cranes I hate to get rid of but they are galled some on the bottom. I am a machinist by trade but wouldn't know which bushings to order. Thanks

Posted By: lewtot184

Re: Putting bushings in ductile iron rockers? - 08/05/13 01:59 PM

i was thinking RAS or Drovak did the bushing thing. basically they put a .875 o.d.- .75 i.d. bronze bushing in the rocker and use a .750" shaft with some spacers to go between the shafts and shaft stands. being a machinist it wouldn't be difficult for you to fab your own set up. the only issue i see is choice of shaft material for strength and being compatible with the bronze.

Posted By: JohnRR

Re: Putting bushings in ductile iron rockers? - 08/05/13 02:29 PM

I think it's that Dvorak sells the kit that downsizes the ID, RAS bores out the rockers and installs a bushing that fits the stock shaft. RAS will also correct any geometry issues.

Posted By: Stanton

Re: Putting bushings in ductile iron rockers? - 08/05/13 02:30 PM

You hone the rocker to close to .936. You press in a .936 o.d. x .062 wall bushing and hone it to size. What you end up with is a bushing with about a .030 wall.

You don't use thin shafts ... for all that effort and expense you could buy the most expensive rockers on the market and still be ahead!!

Posted By: WO23Coronet

Re: Putting bushings in ductile iron rockers? - 08/05/13 05:07 PM

If you're going to bore the rockers out, what would you use as a reference to keep everything square? I have a set of Crane 1.5's that are galled and have been considering doing the same thing. I was thinking of using the adjuster nut hole to hold it in a jig, and then dialing in the bore and then clamping it? Does anyone know how Dvorak and RAS does it?

Posted By: lewtot184

Re: Putting bushings in ductile iron rockers? - 08/05/13 05:20 PM

i talked to Drovak about this several years ago and my impression was that his kit bushed the rocker and down sized the shaft.

Posted By: JohnRR

Re: Putting bushings in ductile iron rockers? - 08/05/13 06:04 PM

Quote:

i talked to Drovak about this several years ago and my impression was that his kit bushed the rocker and down sized the shaft.

That is what it does

Posted By: John_Kunkel

Re: Putting bushings in ductile iron rockers? - 08/05/13 07:00 PM

These guys bush the rocker arms and maintain the original shaft size.

http://www.rockerarms.com/pages/about.html

I've seen their work and it's first class.

Posted By: Stanton

Re: Putting bushings in ductile iron rockers? - 08/05/13 11:16 PM

Quote:

If you're going to bore the rockers out, what would you use as a reference to keep everything square?

"bore" is probably the wrong term to use. You would either ream them or hone them out. Either way, it would be self-centering on the current bore. If you want to get into optimizing the ratio ... well, good luck with that.

Posted By: dweller

Re: Putting bushings in ductile iron rockers? - 08/06/13 02:37 AM

Quote:

I think it's that Dvorak sells the kit that downsizes the ID, RAS bores out the rockers and installs a bushing that fits the stock shaft. RAS will also correct any geometry issues.

My RAS bushed rockers run undersized shafts...

Posted By: JohnRR

Re: Putting bushings in ductile iron rockers? - 08/06/13 04:52 AM

Quote:

Quote:

I think it's that Dvorak sells the kit that downsizes the ID, RAS bores out the rockers and installs a bushing that fits the stock shaft. RAS will also correct any geometry issues.

My RAS bushed rockers run undersized shafts...

When were yours done ? The set I have that I bought off a member back in June of 2011 have stock size shafts, they are cranes, I just looked at them.

Posted By: WO23Coronet

Re: Putting bushings in ductile iron rockers? - 08/06/13 03:06 PM

Quote:

Quote:

If you're going to bore the rockers out, what would you use as a reference to keep everything square?

"bore" is probably the wrong term to use. You would either ream them or hone them out. Either way, it would be self-centering on the current bore. If you want to get into optimizing the ratio ... well, good luck with that.

When I said bore I meant "material removal". Boring .030" using a boring head on a mill is easy. You could also use a reamer, but if your hole is off or crooked compared to the rest of the rocker a reamer won't fix that, it'll follow the existing hole, whereas a single point tool in a boring head won't, it will cut true. Good luck honing .060" out, hope you have alot of time to waste on your hands.

Posted By: vern73

Re: Putting bushings in ductile iron rockers? - 08/08/13 12:15 PM

I tried the rockerarms.com web site and it wouldn't come up. I would like to know where to get the bushings mentioned above .938 diameter and try it myself. What kind of material would they need to be? Or if anyone knows how to contact the rockerarms.com business let me know please.

Posted By: Dodgem

Re: Putting bushings in ductile iron rockers? - 08/08/13 01:43 PM

http://www.rockerarms.com/

probably get form any one of these
http://www.nationalbronze.com/?gclid=CIuKvLfw7bgCFahDMgodvgcARA

http://www.asbbearings.com/?gclid=COPV4NTw7bgCFc5FMgodUx8AlA

http://www.advancebronze.com/?gclid=CNS5tN3w7bgCFdBaMgodMkkArA

Posted By: Stanton

Re: Putting bushings in ductile iron rockers? - 08/08/13 02:48 PM

Quote:

Quote:

Quote:

If you're going to bore the rockers out, what would you use as a reference to keep everything square?

"bore" is probably the wrong term to use. You would either ream them or hone them out. Either way, it would be self-centering on the current bore. If you want to get into optimizing the ratio ... well, good luck with that.

When I said bore I meant "material removal". Boring .030" using a boring head on a mill is easy. You could also use a reamer, but if your hole is off or crooked compared to the rest of the rocker a reamer won't fix that, it'll follow the existing hole, whereas a single point tool in a boring head won't, it will cut true. Good luck honing .060" out, hope you have alot of time to waste on your hands.

I think building a jig and trying to correct geometry would be a much greater waste of time. In the end you'll just be older with a little more self-satisfaction but no performance gain. And you'd be surprised how fast a hone will cut those cast rockers !!!

Posted By: Locomotion

Re: Putting bushings in ductile iron rockers? - 08/08/13 05:04 PM

I got a set done by RAS, maybe about 10 years ago. The rockers are bushed down and run on smaller shafts. They did this to maintain the strength of the rockers. They tend to break with higher spring pressures when bored out for a bushing or the body under the tip is relieved for clearance. I think they are 273 rockers. I don't know how accurate of a job they did with the ratio. But I switched to Harland Sharp roller rockers because they became legal.

Posted By: BSB67

Re: Putting bushings in ductile iron rockers? - 08/09/13 12:50 AM

My RAS bushed rockers are on a smaller dia. shaft.

Posted By: BB65Barracuda

Re: Putting bushings in ductile iron rockers? - 08/09/13 11:31 AM

Talk with Cab Burge, I know he does this.
Im sending him a few of my old rockers so he can bush them for something he is presently working on.