Offcenter Rod bearing wear pattern

[turbodave231]

Take a look at the pictures of my rod bearings. I had the engine out and I figure I might as well look at the bearings.

The engine probably has 25 passes on since new. All 6 bearings had the same pattern to the bearings. No grooves, no real damage. But you can see the load has been on the outside of the bearing shells. Is this normal for an offcenter motor?

Engine specs: Carrillo 6.5 offcenter rods, Clevite 77 V series wide rod brgs .0019 to .002 clearance. Great oil pressure, no problems, just looking to be sure......opinions?

rod bearings

 

[BAGN]

I've seen that before. I had a fresh "109" Motor (off-center)wipe a cam lobe so I pulled the motor to clean & check everything. My bearings looked the same way with only 2000 "easy" miles it. I had the machine shop Re-Resize them just to make sure. I never checked them after that, But never had a problem.

 

[slamming 6]

Dave that is not normal wear they are shot check the finsh on the crank.clearence related

 

[turbodave231]

The crank is fresh from Moldex and the surface looks and measures perfect. The clearances are all set exactly at .0019 or .0020 (measured with dial bore gages.

I looks as if the bearing is riding on the fillet of the rod journal.

Dave

 

[oldtimer]

Originally posted by turbodave231
The crank is fresh from Moldex and the surface looks and measures perfect. The clearances are all set exactly at .0019 or .0020 (measured with dial bore gages.

I looks as if the bearing is riding on the fillet of the rod journal.

Dave

Dave,

just out of curiosity, were the clearances measured at the outsides of the bearing shells as well as the centres. Was wondering if for some strange reason the shells were cupped.

George

 

[QuickWrench]

How did the thrust bearing look, and how much movement does it have? Any possibility that the crank is rocking back and forth several thousandths?

Is there a groove at all in the bearings from the wear pattern, or is the pattern just on the surface? Any possibility that the rod end resizing was done slightly angled?

 

[turbodave231]

The markings on the bearings are definitely not grooves. They are more like polished than anything else. I didn't expect to see this type of wear on the outside of the bearing shell.

I did measure the bearings at the 12, 2, and 4 O'clock positions at three different depths.

I have heard about offcenter stage engines being harder on rod bearings and I wonder if this is what was meant?

I'm gonna reassemble and watch them closely. I haven't found ANY bearing material in the filter or pan to indicate a wear issue.

DR

 

[Louie L.]

Originally posted by turbodave231
s.

I have heard about offcenter stage engines being harder on rod bearings and I wonder if this is what was meant?

Dave,
The typical wear would be on the offset side of the rod. I seen the worn bearings off a 0016 block and they do not look like your bearings.

 

[slamming 6]

The center of the bearings look like they wore the coating clean off.could be a bad batch of bearings clevite might be able to tell you more.Good Luck.AL

 

[BEATBY6]

[url]http://www.thirskauto.net/EngineBearings.html[/URL]


http://www.circletrack.com/techarticles/1590/
http://www.federal-mogul.com/cda/content/front/0,2194,2442_2875_6752,00.html http://www.bobistheoilguy.com/bearingwear/bearingwearanalysis.htm

This should keep you busy for awhile.http://www.thirskauto.net/BearingPics.html

 

[turbodave231]

Great links, Thanks.

I'm gonna pull the motor down and remeasure everything. If I don't find anything specific, I'll replace the rod bearings with Vandervells and watch them carefully.

Dave

 

[GARY HARVEY]

bearings ?

Just as a point of interest?

What is your side clearance?

Is the Pin/Small end clearance in question (a bit loose)?

Seems the rod bearing is trusting in a lateral motion (as in: very slight excessive pin/rod movement or wobble). Something is causing a very slight big end thrusting... back and forth, hence the polished bearing edge surface.

Rarely have I seen this sort of thing. My impression would be that most of your ware or polishing occures at startup and at lower rpm.

Is this happening to all of the rod bearing surfaces?

Don't let this get to you! It ain't that big a deal, especially if you know to keep an eye on the situation...

no end to the possibilities,
Gary

 

[GARY HARVEY]

PS

You could call Jerry Ehlert with Calico and get his impressions and order a set of his coated bearings.

wouldn't hurt,
Gary

 

[65vette396]

Re: PS

Originally posted by GARY HARVEY
You could call Jerry Ehlert with Calico and get his impressions and order a set of his coated bearings.

wouldn't hurt,
Gary

Jerry is a great guy to deal with. I have used calico coated bearings and Jerry for quite some time now. As a matter of fact I just ordered a fresh set of bearings for my 00153 from him yesterday. Drew

 

[turbodave231]

Gary,

Too late, I'm in complete teardown mode already. I'm re-checking everything. I can't measure any taper in the rod journal and I'm taking my rods to be rechecked.

All 6 rod bearings show the same wear pattern, so it has to be an issue shared between all 6 rods/journals.

I have .001 pin to rod clearance and .010 side clearance (from memory). Pin bushings and pins look good, no visible problems

It looks to me like the edges of the rod bearing are riding on the fillets of the journal. The Clevite guys call this condition"Fillet Ride".

The 1398V bearings don't have a chamfer on them to avoid contact. I'm gonna try a 1398H bearing which does have the chamfer. I will identify and solve the problem one way or another!

How much does Calico charge for coated bearings? I may consider the coated versions once I know I have the problem 100% solved.

 

[65vette396]

Originally posted by turbodave231
Gary,

Too late, I'm in complete teardown mode already. I'm re-checking everything. I can't measure any taper in the rod journal and I'm taking my rods to be rechecked.

All 6 rod bearings show the same wear pattern, so it has to be an issue shared between all 6 rods/journals.

I have .001 pin to rod clearance and .010 side clearance (from memory). Pin bushings and pins look good, no visible problems

It looks to me like the edges of the rod bearing are riding on the fillets of the journal. The Clevite guys call this condition"Fillet Ride".

The 1398V bearings don't have a chamfer on them to avoid contact. I'm gonna try a 1398H bearing which does have the chamfer. I will identify and solve the problem one way or another!

How much does Calico charge for coated bearings? I may consider the coated versions once I know I have the problem 100% solved.

Got the federal mogul mains V-series for $102 for the set coated and a set of clevite 1398 H rod set for $78. I think it's well worth the difference in price. Drew

 

[turbodave231]

$78 for a set of coated bearings is really quite reasonable. The uncoated version cost me $42 a set for the 1398H's.

I'll wait and see what happens with the next set of bearings before I get any coated parts. I'd like to coat the pistons and the bearings in the future.

Dave

 

[GARY HARVEY]

Not to sure.

I don't have a clue about their current charges.

You'll have to give Jerry a call or you can check their website.

Your Clevite rep is most likely on target. There is a fixture you can get from Clyde Vickers that modifies bearings so this/your problem goes away.

A pocket knife run around the edge is something I do to the surface face.
Very quick and easy then SCOTCH BRITE in a criss cross pattern with the lightest grade SB on coated bearings to knock off the rough surface of the coating. With a quality crank you WILL be using a moly base coating which has a typically rough finsh compaired to the industrial (DuPont) teflon (black) coating used on cast iron shafts.

With the SII I'm doing the only coated bearings I'm using are cam bearings.
With a mostly street motor that has a preoiler and the harder bearings, it's a toss-up with using coated bearings. Everthing else is coated but the crank throws (another waste of money IMO on a (mostly) street motor).

I think you have found the cause of your situation.

Gary

 

[S2V6RACER]

Originally posted by turbodave231
$78 for a set of coated bearings is really quite reasonable. The uncoated version cost me $42 a set for the 1398H's.

I'll wait and see what happens with the next set of bearings before I get any coated parts. I'd like to coat the pistons and the bearings in the future.

Dave

Stop in to Automotive Machine and have Jack and Al take care of your needs. These guys do good work and I can't say enough good about thier service.

P.S. Tell Jack I sent you if you go.

Ted