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Old 02-02-2017, 10:53 PM   #41
modelAtony
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Default Re: Insert bearings

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Modelatony . yes pet holds the record at 97.1 also ohv record at 116 mph , takes around 190 hp to push a stock body too that speed , Look forward too seeing run at speed week this year , we hope to have our ,( Cyrils ), 30 cpe to run too. We should get together & chew the fat , Derek in a hot NZ
Always wanted to ask you questions about the flats but didn't want to bug you about it. I really like seeing your post. Have fun modelAtony tony white Lafayette, LA
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Old 02-03-2017, 09:10 AM   #42
Dave in MN
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Default Re: Insert bearings

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Originally Posted by George Miller View Post
One problem is it is a long ways for the oil to get to the back of the bearing with out pressure oiling. The way I fix the problem is a oil groove in the upper bearing.
George, I tried the same thing by extending the oil "wells" along the seams of the two insert halves. I extended the well (both sides) to within .25" of the back end of the bearing. I put the engine back on the dyno and had the same failure on the first heavy pull. Granted, placing a groove at the top may be better than both sides but I did not try your method. At this point, it is not something I am going to try as I have found a solution that works for me....more clearance.
It was at this point, I invested in a Sunnen precision honing machine and increased the clearances.
No problems since.

FYI: This experimental engine had a Burlington crank, Lion Speed head III delivering north of 80 hp at 3000 rpm. So the temps and pressures were beyond normal Model A. A wisp of smoke was coming from the bellhousing as I finished the first pull and when I cut the throttle, the rear main locked up. (Strike Two!) The rear journal cleaned up, using muriatic acid, with no damage.

Last edited by Dave in MN; 02-03-2017 at 03:27 PM.
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Old 02-03-2017, 11:49 AM   #43
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Default Re: Insert bearings

You need to start the groove at the top front of insert at the pass side of the oil well, and end it at the driver side oil well at the rear of the insert. Then the oil will be forced under the bottom insert with hyd wedge. The oil getting into the bearing at the front is the wrong place. the oil should be interring at the center of the bearing.
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Old 02-03-2017, 12:49 PM   #44
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Have you guys talked to the manufacturer about doing this process to future bearings?
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Old 02-03-2017, 02:46 PM   #45
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Default Re: Insert bearings

On the oil well on the right side, at the seam of the block and cap, does the bottom edge (cap edge) have a nice radius to allow the oil to get rolled into the clearance?
A sharp edge would be more likely to scrape away the oil.
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Old 02-06-2017, 09:12 AM   #46
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Here are some photos of the fixture I built to hone the aluminum lined insert bearing shells.

The fixture is bored .00015" below the maximum block housing bore specified by the bearing manufacturer. Note there are a split dowels, like I use on all the mains, to hold position between cap and block incorporated into the fixture.

The insert shown is either the center or front main insert. The rear main insert fills the entire fixture end to end. Note the radial oil delivery groove in the insert.
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Last edited by Dave in MN; 02-07-2017 at 10:51 AM.
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Old 02-06-2017, 03:06 PM   #47
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Default Re: Insert bearings

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Here are some photos of the fixture I built to hone the aluminum lined insert bearing shells.
Hey Dave,
Very nice ingenious setup !
Inserts look to be ONE piece. Who supplies these one piece ?
Do you ever use TWO piece bearings per main ?
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Old 02-06-2017, 04:57 PM   #48
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Default Re: Insert bearings

See post #46: These inserts, designed specifically for the Model A, are supplied by Antique Engine Rebuilding (AER), Skokie, IL. They have worked very well for me.

If you look close, you will see the Plastigage marking on one half of the shell. The initial clearance was between .0015" and .00175" before honing. Between .002" and .0022" when honed to proper clearance.

hardtimes: I used two piece (two wide set with a radial oil ring between them) Clevite & Fed Mog bearings on about 16 engines but have not done so for the last 5 years. The supply for these bearings was getting difficult to find readily. They were constantly being backordered when I would order multiple sets. The two piece inserts worked good also. They were tri-laminated. Babbitt over copper on steel. I have two piece Fed Mog inserts in my Phaeton and have had no issues after 90,000 miles.
Good Day!

Last edited by Dave in MN; 02-07-2017 at 08:54 AM.
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Old 02-06-2017, 06:40 PM   #49
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Default Re: Insert bearings

It seems like there are different opinions about inserts. It looks like the quality varies between shops. I just want to mention that I have inserts by AER in Skokee. Very satisfied after 11,000 happy miles
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Old 02-06-2017, 10:42 PM   #50
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Default Re: Insert bearings

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Originally Posted by Dave in MN View Post
See post #46: These inserts designed specifically for the Model A are supplied by Antique Engine Rebuilding (AER), Skokie, IL.
They have worked very well for me.

If you look close, you will see the Plastigage marking on one half of the shell. The initial clearance was between .0015" and .00175" before honing. Between .002" and .0022" when honed to proper clearance.

hardtimes: I used two piece (two wide set with a radial oil ring between them) Clevite & Fed Mog bearings on about 16 engines but have not done so for the last 5 years. The supply for these bearings was getting difficult to find readily. They were constantly being backordered when I would order multiple sets. The two piece inserts worked good also. They were tri-laminated. Babbitt over copper on steel. I have two piece Fed Mog inserts in my Phaeton and have had no issues after 90,000 miles.
Good Day!
Hey Dave,
Thanks much for your helpful response !
I have a full set of main bearing shells for the B engine that I'm planning. Two sets per main. That is why I asked your input. You apparently are a successful A/B engine builder and post helpful pictures of your work ! There will have to be TWO tangs for each half, rather than the one tang on a one piece shell set. Next time, I'll check out AER shells for purchase.

One other question. I have a real nice set of B rods and have been told that inserts are available, if the rods are cut 2.140 (I think?). Do you know of anyone who does this work on original B rods ?
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Old 02-06-2017, 11:10 PM   #51
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Default Re: Insert bearings

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Originally Posted by hardtimes View Post
Hey Dave,
Thanks much for your helpful response !
I have a full set of main bearing shells for the B engine that I'm planning. Two sets per main. That is why I asked your input. You apparently are a successful A/B engine builder and post helpful pictures of your work ! There will have to be TWO tangs for each half, rather than the one tang on a one piece shell set. Next time, I'll check out AER shells for purchase.

One other question. I have a real nice set of B rods and have been told that inserts are available, if the rods are cut 2.140 (I think?). Do you know of anyone who does this work on original B rods ?
Ron Kelly would likely do this type of work. In the past, he machined original "A" rods for inserts. "B" is the same work...just different sizing.
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Old 07-04-2020, 01:32 AM   #52
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Default Re: Insert bearings

I know this is an old thread but I take back anything favourable I said in it earlier. I have just set about relacing the inserts throughout my engine. The big ends were good but the mains are a mess. The lower insert on both the front and middle main bearings had a piece of babbit missing from the slot for the oil to enter to the edge (about 3/8"). This is not the first time this has happened to me but the big disaster was the rear main. The babbit was wiped all around the bearing due to lack of oil. These inserts are incredibly poorly designed. There is waaaay too far for the oil to travel to get to the whole length of the bearing as George Miller said early on. I intend cutting a spiral groove in the top insert and maybe the bottom too to get oil to the back of the bearing. Comments on that would be appreciated.
Why on earth did the makers not do what has been done for many decades with babbit bearings and cut an oil groove in them??? Sheer incompetence, in my book.
This thread is old enough now that maybe someone has made this modification and done a lot of miles on it. How did it go?
In an effort to make sure the bearing is able to get enough oil, I tried blowing air from the lower end with one side of the gap where the insert would have been blocked with the old insert and looking for something at the top. I didn't find much at all. Is anybody able to describe to me where the top end of the oil hole to the rear main bearing is located - perhaps in relation to the cam follower bosses. I can't get to my spare bloch at the moment.
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Last edited by Synchro909; 07-04-2020 at 05:11 AM.
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Old 07-04-2020, 07:46 AM   #53
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Default Re: Insert bearings

When conversions were in their infancy on the Model-A/B blocks, and when we were using multiple bearings within the main bearing web, machinists would use an end mill and create a way for the oil to feed the hole in each of the bearing shells. When Rich created the one-piece bearing, this eliminated this op.

My personal take is that the 'art' of casting bearings has improved greatly to the point where the longevity of casting bearings exceeds what is available for the inserted bearings. The availability of top-quality "Babbitt", the knowledge of how to pour, peen, and burnish properly, -and the use of good quality line-boring machines (such as Tobin-Arp or Berco) that are rigid and use a hydraulic feed have been the game changer. For these reasons, we are seeing owners with failed bearings converting back to cast bearings. I liken insert conversions to electronic ignition conversions, powder painting, and hydraulic brakes where each had their day where they were considered necessary, yet all have seemingly failed the test of time and now deemed not superior or necessary.

On your own engine, two things that would scare me as an engine rebuilder. If the soft metal has failed on your bearings due to lack of oil, I would want to inspect/mic the crank journals carefully as I would expect to see a surface finish deterioration and wear that would cause the journal pin to be out-of-round. Also, when you 'carve' a groove for the oil to transfer, you will likely disturb the bond of the soft metal which could cause flaking and you will likely cause the soft metal on both sides of the groove to rise above the surrounding areas potentially causing scoring on the crankshaft.

One other thing to keep in mind is ensure you do not allow an insert bearing to roll or spin in the cap or in the block as this will distort the cap or block generally requiring both to be line-bored again.
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Old 07-04-2020, 08:52 AM   #54
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Technology has greatly aided the poured bearing process. Infrared temperature guns has taken the 'art' out of tinning and babbit pour temperatures.

The hydrodynamic principle requires adequate oil feed on the un loaded side of the bearing gravity or pressure. Insert bearings perform best when pressurized,it helps keep them clean and cool and will reduce the incident of failure with an A engine.Vendors love insert bearings,its straight forward work,line bore the block,snap in the bearings,ship the job.The risks are way less than the pouring process risk..and when they do fail its well out of warranty..win-win from a business perspective.What amuses me is how they sell inserts by propagating myths about poured bearings..they wont handle compression,they don't last,you name it.No bearing tolerates the torsional vibration inherent in a model a engine,Ford Engineering identified the issue in development..throwing in inserts and a counterbalanced crankshaft doesn't exempt you from that hard and fast rule.
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Old 07-04-2020, 05:05 PM   #55
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"One other thing to keep in mind is ensure you do not allow an insert bearing to roll or spin in the cap or in the block as this will distort the cap or block generally requiring both to be line-bored again."

Very true.
Most people do NOT realize that the tang on a bearing shell is there ONLY to locate the shell on assembly. It does NOT keep the shell from spinning. The crush holds the shell in place.
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Old 07-04-2020, 06:47 PM   #56
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The reason I asked about this is the concern in my mind about the bearing surface of the insert cracking or flaking near the groove. I don't think it would be a problem on the top insert but what of doing it on the bottom too? Comments sought, please.
I see no point reinstalling the current setup - it will only happen again. The inserts didn't spin in the block. I understand about the tabs. The bearing material was almost gone in places so I got in there just in time to prevent the inserts welding themselves tot he crankshaft journal. The pournal looks worse than it is. I can just feel slight ridges on it so I think I'll go again with it.
I do my best thinking while I'm asleep and I have awoken this morning with an even stronger leaning towards putting a groove in the top insert and reinstalling.
I PMed George Miller (who made comments above) but he hasn't replied yet. I'm not even sure he still posts here.
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Old 07-04-2020, 08:43 PM   #57
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Synchro,
I made a series of tests on an engine I was building for myself on my dyno some years back related to the required oil clearance for the insert bearings I use. I found I needed to increase the oil clearance for the rear main to between .002" to .0022". Any tighter and I could experience a failure (lock up) when the engine was heavily loaded. The manufacturer suggests .00175" and that will work for the front and center bearings, I prefer a bit more between .00175 to .002".
I tried increasing the oil groove at the parting line of the inserts approaching .25" from the rear of the bearing but it also failed. The only thing that worked was more oil clearance.
Hope you solve your issue.
Good Day!

Last edited by Dave in MN; 07-07-2020 at 06:02 AM.
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Old 07-04-2020, 09:58 PM   #58
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Default Re: Insert bearings

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Synchro,
I made a series of tests on an engine I was building for myself on my dyno some years back related to the required oil clearance for the insert bearings I use. I found I needed to increase the oil clearance for the rear main to between .002" to .0022". Any tighter and I could experience a failure (lock up) when the engine was heavily loaded. The manufacturer suggests .00175" and that will work for the front and center bearings, I prefer .002".
I tried increasing the oil groove at the parting line of the inserts approaching .25" from the rear of the bearing but it also failed. The only thing that worked was more oil clearance.
Hope you solve your issue.
Good Day!
Thanks, Dave. This motor has done about 40,000 miles, mostly while working hard towing a camper that weighs about the same as the car at 50mph all day long. The journals are slightly worn so I hope that will give a little more clearance for now.
I'm only mildly surprised that widening the gap between the inserts didn't work. I think a spiral groove would work much better because the rotation of the crank shaft would help the oil along it
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Old 07-05-2020, 09:53 AM   #59
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Spiral grooving and increasing clearance can have a negative effect on the oils ability to support the crankshaft.Modern oils have better load carrying properties,so opening the clearance to .002 works but resist the desire to do more.Any grooving on the bottom of the bearing (center of the cap) reduces the cushion effect in the area of the groove.Given what your experiencing Id say is a failure of the babbit adhering to the copper of the insert,not a lubrication issue.
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Old 07-05-2020, 11:38 AM   #60
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Synchro, Is it possible that the timing was a bit too far advanced for the load at times? It only takes a short run with too much advance to damage a bearing. Would you be able to share some photos of the insert shell? Thanks.

Last edited by Dave in MN; 07-05-2020 at 08:09 PM.
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