Rod Bearing Champher

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Chief

Rod Bearing Champher

Post by Chief » Sun Jan 14, 2007 8:05 pm

I was assembling an engine today and I noticed the rod bearing was riding up to the radius on the crank. The bearings do not have enough champher.
I have a lathe and can cut one but I need the fixture to hold the bearings.

Anyone have an idea where I can get a fixture?

Thanks
Dave

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Post by rustbucket79 » Sun Jan 14, 2007 8:34 pm

If you have an old rod you could cut the rest of the rod off, install the shells and use a set of brass jaw covers to eliminate damaging the bearings, or you could buy the narrowed bearings from FM if you have a common domestic engine.

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Post by Dave Koehler » Sun Jan 14, 2007 9:00 pm

Dave,
In your neigborhood. http://www.precisionmeasure.com/block8.htm

If all else fails, I can machine them if you need.
Later
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Post by bill jones » Sun Jan 14, 2007 9:07 pm

-you could use a piece of some sort of plastic or pvc pipe etc---chuck up a short piece and machine the OD leaving a step to align the bearings---the diameter to fit the bearings in their natural state--then use a simple radiator hose clamp to hold the bearing shells to the plastic.

-Takes about 5 minutes to make this if you have the something to make it out of.

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These guys also make bearing narrowing fixtures

Post by TORQUE INC » Mon Jan 15, 2007 2:25 am

R&R racing ask for Mike

http://www.rrconnectingrods.com/about.htm

Makes some damn fine billet steel and aluminum rods as well

http://www.rrconnectingrods.com/brackets.htm


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Chief

Post by Chief » Mon Jan 15, 2007 9:58 am

I must be getting old because attaching them on the outside of something didn't even enter my mind.... Thanks Bill.

Rustbucket, I knew FM has the bearing and I knew this crank has a large radius so this falls on me for not ordering the right bearings to start with all I can say is see the above first sentence... LOL

Dave, Thanks for the link and I will call them Tuesday and get a fixture on the way but meanwhile I think I will give Bills idea a shot. Beats sitting here in the ice with nothing to do. Except wait on UPS to find me.... :lol:

Thanks to all for the info and advice. That's why I like this site. Mostly I just read but I have never failed to get a workable solution when I have a question.

Dave

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Post by Ken0069 » Mon Jan 15, 2007 10:27 am

rustbucket79 wrote:If you have an old rod you could cut the rest of the rod off, install the shells and use a set of brass jaw covers to eliminate damaging the bearings, or you could buy the narrowed bearings from FM if you have a common domestic engine.
Is it a good idea to put a bearing in a rod, tighten it up to machine it then install it in another rod? Would this have any negative effect on the "crush" the bearing experiences when it's torqued in place? Seems to me this might be a problem if that rod end was smaller than the one it will end up in?

Yes/No? Am I all wet here or what?
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Post by Dave Koehler » Mon Jan 15, 2007 11:16 am

My procedure when using Bills time honored method.
1: install bearing in connecting rod and measure the ID.

2: chuck up some nylon round or some other plastic stock larger than your bearing OD. The larger OD is so that you leave a wall for the back edge of the bearing to seat against. This will line up both halves easily.

3: machine round stock .0005 to .001 larger than your measured ID. It doesn't take much to hold it since you are not doing serious hogging.

4: machine the width where the bearing clamps less than your bearing width so that the champher sticks out enough for you to machine it.

5: hose clamp it and go to work.

6: Oh, and pay close attention to which side of the bearing you want to machine. :oops: :roll:

A little history on the female clamp that is available.
As I recall, Barry Little at Specialty Automotive Engineering (SAE) was the originator of these, circa 1980. He quit making them so I made them for a while in the 90s, then Adrian at Precision started making them. I now see R&R does also.

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Post by bill jones » Mon Jan 15, 2007 12:23 pm

-just for sh-ts and grins I just made up a plastic piece like I described and touched up the chamfers on a set of used BBC bearings---just to get the dimensions I'd use.

-The bearing shells need to just slightly expand to snap onto a 2.285" diameter snout---which is sort of nice because you can just pop'm on there and they stay put while you install the hose clamp.

-I put the step back at .710" and that leaves you enough room to get your lathe tool in there and to be able to see all of the chamfered area.

-The OD of the fixture needs to be 2.375" as a minimum for the step.

-Took about 5 minutes to make the fixture and chamfer the one pair of shells.
--------------------------------------------------------------------------------------
-Years ago I took 3 sizes of Chevrolet rods-----cut the beams off with a bandsaw and ground'm sort of smooth----chucked each rod up in the lathe and machined the outside side edges of the rods round----to where I had enough an area to grip'm in my lathe jaws.

-Then I tack welded the head of the rod bolts to rods---removed the nuts & the rod caps and cut the bolt off to where I had about 7/16" of the rod bolt left to act as a dowel for the rod cap.

-Those have served me well for 30 years.
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-The only problem with the larger diameter of the plastic part is there is gap which means that if you wanted to do a hand scrape with a deburr tool you wouldn't be able to.
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-I have photos of both a modified BBC rod and this plastic part if anybody is interested.

-photos are available at http://ryanbrownracing.com/Bill_Jones_Page_20.html
Last edited by bill jones on Fri Feb 23, 2007 8:58 pm, edited 1 time in total.

Chief

Post by Chief » Mon Jan 15, 2007 9:03 pm

Just as an update for anyone interested.

I made a fixture out of plastic as Bill suggested. It worked like a charm and now I have my short block assembled.


Thanks

Dave

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