Micro Welding of bearing shell to rod housing bore

Larry Hill · 08-22-2021, 01:57 PM

2.375 crank pin, 5W30 oil, close to .003 vertical bearing clearance, bore is round within .0002, stretch gage.

I'm not understanding how to check housing bore diameter with the bearing installed.

Thanks

Larry Hill · 08-22-2021, 02:45 PM

The welding on my 440 stocker engine is on the piston side of the rod. If the rod parting line would be 3 o’clock and 9 o’clock with 6 o’clock on the piston side. The most of the transfer of metal is between 3:30 and 4:30 on one side and between 8:30 and 7:30 on the other side, with very little if any at the 6:00 o’clock position. Rod and piston approx 1750 grams.

SSDiv6 · 08-22-2021, 03:09 PM

Quote:

Originally Posted by Larry Hill

2.375 crank pin, 5W30 oil, close to .003 vertical bearing clearance, bore is round within .0002, stretch gage.

I'm not understanding how to check housing bore diameter with the bearing installed.

Thanks

The bearing has a thickness specification that can help you determine the amount of crush you are getting after you torque the rod. How many use cycles do you have on the bolts and what type of bolt are you using?

Stan Weiss · 08-22-2021, 03:40 PM

OK, I have no personal experience with this problem. But have talked with someone who I believe had a similar problem. He modified his rod bearings to give a little more clearance in just that area and that seemed to fix his problem.

Stan

dragracerray · 08-22-2021, 05:10 PM

I have never had this problem. A long shot. Do you have your negative cable attached directly to the block? Ray

Larry Hill · 08-22-2021, 07:25 PM

Yes Ray the cable is connected to the block. I never considered an arcing or plating situation
Not sure on cycles on rods or bolts. Bolts are ARP 7/16 20NF 12 point. The big end of the rod stays rounder longer since we installed a clean neutral valve body in the trans. I use the brakes to stop the car without compression braking.

Adger Smith · 08-23-2021, 01:25 AM

Larry,
The design of the bearing is important. The size of the rod bore determines crush. You may need a bearing with more ellipse or a slightly thicker oil for the .003 clearance.
It is a long read, but Mahle has a good read on bearings.
All bearings are not created equal!
https://www.speedperf6rmanc3.com/con...20Bearings.pdf

Larry Hill · 08-23-2021, 09:59 AM

Thanks. I will read it

08-22-2021, 01:57 PM	#1
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,635 Likes: 1,929 Liked 10,693 Times in 2,227 Posts	Re: Micro Welding of bearing shell to rod housing bore 2.375 crank pin, 5W30 oil, close to .003 vertical bearing clearance, bore is round within .0002, stretch gage. I'm not understanding how to check housing bore diameter with the bearing installed. Thanks __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817

08-22-2021, 02:45 PM	#2
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,635 Likes: 1,929 Liked 10,693 Times in 2,227 Posts	Re: Micro Welding of bearing shell to rod housing bore The welding on my 440 stocker engine is on the piston side of the rod. If the rod parting line would be 3 o’clock and 9 o’clock with 6 o’clock on the piston side. The most of the transfer of metal is between 3:30 and 4:30 on one side and between 8:30 and 7:30 on the other side, with very little if any at the 6:00 o’clock position. Rod and piston approx 1750 grams. __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817

08-22-2021, 03:40 PM	#4
Stan Weiss Senior Member Join Date: Apr 2020 Location: Phila, PA Posts: 794 Likes: 0 Liked 733 Times in 384 Posts	Re: Micro Welding of bearing shell to rod housing bore OK, I have no personal experience with this problem. But have talked with someone who I believe had a similar problem. He modified his rod bearings to give a little more clearance in just that area and that seemed to fix his problem. Stan

08-22-2021, 05:10 PM	#5
dragracerray Member Join Date: May 2017 Location: Webster, New York Posts: 218 Likes: 472 Liked 208 Times in 89 Posts	Re: Micro Welding of bearing shell to rod housing bore I have never had this problem. A long shot. Do you have your negative cable attached directly to the block? Ray __________________ Ray Bassett I/SA 1687, SS/DA 1687 "SuperPro is both", unknown

08-22-2021, 07:25 PM	#6
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,635 Likes: 1,929 Liked 10,693 Times in 2,227 Posts	Re: Micro Welding of bearing shell to rod housing bore Yes Ray the cable is connected to the block. I never considered an arcing or plating situation Not sure on cycles on rods or bolts. Bolts are ARP 7/16 20NF 12 point. The big end of the rod stays rounder longer since we installed a clean neutral valve body in the trans. I use the brakes to stop the car without compression braking. __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817 Last edited by Larry Hill; 08-22-2021 at 07:27 PM.

08-23-2021, 01:25 AM	#7
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Micro Welding of bearing shell to rod housing bore Larry, The design of the bearing is important. The size of the rod bore determines crush. You may need a bearing with more ellipse or a slightly thicker oil for the .003 clearance. It is a long read, but Mahle has a good read on bearings. All bearings are not created equal! https://www.speedperf6rmanc3.com/con...20Bearings.pdf __________________ Adger Smith (Former SS) Last edited by Adger Smith; 08-23-2021 at 01:30 AM. Reason: add

08-23-2021, 09:59 AM	#8
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,635 Likes: 1,929 Liked 10,693 Times in 2,227 Posts	Re: Micro Welding of bearing shell to rod housing bore Thanks. I will read it __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817

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