Micro Welding of bearing shell to rod housing bore

pmrphil · 08-22-2021, 09:32 AM

I don't know if it's correct or not, but I use a height gauge to measure each shell and to verify that the shells are square, which I've found some that are way off. I've had rods on the small end of spec as well as the big side both do it.

FED 387 · 08-22-2021, 11:20 AM

using too thin of an oil ?---oil is not "thick" enough and not enough "pressure on the bearing" to keep the proper spacing between bearing and crank

SSDiv6 · 08-22-2021, 12:35 PM

How much clearance are you running and what oil weight?

Race bearings usually have additional crush built in them. Are you using a torque wrench or a bolt stretch gauge values? Make sure the main bore is round and check the size without and with the bearing installed.

This is a method used to check crush.

pmrphil · 08-22-2021, 01:46 PM

I have seen the microwelding almost 3/4 the length of the bearing, and probably 3/4 of the width on the most severe ones.

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

08-22-2021, 09:32 AM	#1
pmrphil Member Join Date: Aug 2010 Location: CT Posts: 456 Likes: 1,795 Liked 346 Times in 150 Posts	Re: Micro Welding of bearing shell to rod housing bore I don't know if it's correct or not, but I use a height gauge to measure each shell and to verify that the shells are square, which I've found some that are way off. I've had rods on the small end of spec as well as the big side both do it. __________________ Phil Molski PMR Performance S/C 1623

08-22-2021, 11:20 AM	#2
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,416 Likes: 522 Liked 330 Times in 178 Posts	Re: Micro Welding of bearing shell to rod housing bore using too thin of an oil ?---oil is not "thick" enough and not enough "pressure on the bearing" to keep the proper spacing between bearing and crank

08-22-2021, 12:35 PM	#3
SSDiv6 VIP Member Join Date: Feb 2003 Location: Glendale, Arizona Posts: 3,041 Likes: 712 Liked 1,575 Times in 580 Posts	Re: Micro Welding of bearing shell to rod housing bore How much clearance are you running and what oil weight? Race bearings usually have additional crush built in them. Are you using a torque wrench or a bolt stretch gauge values? Make sure the main bore is round and check the size without and with the bearing installed. This is a method used to check crush.

08-22-2021, 01:46 PM	#4
pmrphil Member Join Date: Aug 2010 Location: CT Posts: 456 Likes: 1,795 Liked 346 Times in 150 Posts	Re: Micro Welding of bearing shell to rod housing bore I have seen the microwelding almost 3/4 the length of the bearing, and probably 3/4 of the width on the most severe ones. __________________ Phil Molski PMR Performance S/C 1623

08-22-2021, 01:57 PM	#5
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,629 Likes: 1,919 Liked 10,681 Times in 2,222 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	#6
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,629 Likes: 1,919 Liked 10,681 Times in 2,222 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	#8
Stan Weiss Senior Member Join Date: Apr 2020 Location: Phila, PA Posts: 793 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	#9
dragracerray Member Join Date: May 2017 Location: Webster, New York Posts: 217 Likes: 467 Liked 207 Times in 88 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