Rod Bearing Champher

[Chief]

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

[rustbucket79]

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.

[Dave Koehler]

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

If all else fails, I can machine them if you need.
Later
Dave Koehler
www.koehlerinjection.com

[bill jones]

-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.

[TORQUE INC]

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


TI

[Chief]

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....

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

[Dave Koehler]

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.

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.

Dave Koehler
www.koehlerinjection.com

[bill jones]

-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.
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-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

[Chief]

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