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Old 07-05-2020, 05:36 PM   #61
Synchro909
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Default Re: Insert bearings

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Originally Posted by Jack Shaft View Post
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.
There is no copper evident in the insert. What you say about a groove in the bottom compromising lubrication, I suspected. That is why I asked.
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Old 07-05-2020, 05:50 PM   #62
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Default Re: Insert bearings

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Synchro, Is it possible for that the timing was a it too far advanced for the load at times? It only takes a short run with took much advance to damage a bearing. Would you be able to share some photos of the insert shell? Thanks.
I'll ask my grandkids to help me get some pictures up.
Your question about timing might be on the money but not because I advanced it too far but because it developed the Model A 3/4 crossfire and it took me a while to find it. The symptoms were pinging at any time -- no relationship to load or advance or speed or octane of the fuel etc. Then, a few miles down the road I'd come to a hill and the car would fly up it with no sign of trouble - the very time you'd expect it to ping. The latter observation tells me that the timing was good. There is another complication here though. If there is a cross fire, number 3 fires at the same time as #4. The firing order is 1,2,4,3 which means that when #4 fires, #3 is at the beginning of its compression stroke and that would cause mayhem in there. When #3 fires, #4 is at the bottom of its power stroke which would be a bit of a non event. Clearly, it is the middle main bearing that would get the harder time of it, not the rear one. The middle main was fine but it is pressure fed at 25 psi. Was it protected by the pressurised oil feed even though it is much smaller than the rear (gravity fed) bearing?
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Old 07-05-2020, 10:54 PM   #63
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Default Re: Insert bearings

Maybe we are using the wrong material for bearings. My Dad told me that his buddy had to get from Omaha, Ne. to Lincoln, Ne. one night and 2 rod bearngs went out along the way.
They fixed it with 2 pieces of a leather belt and made it with time to spare. The engine was junk though.
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Old 07-06-2020, 02:57 AM   #64
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Default Re: Insert bearings

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Maybe we are using the wrong material for bearings. My Dad told me that his buddy had to get from Omaha, Ne. to Lincoln, Ne. one night and 2 rod bearngs went out along the way.
They fixed it with 2 pieces of a leather belt and made it with time to spare. The engine was junk though.
These are the inserts being sold by the vendors. I agree trimetal would be better but they wouldn't make as much profit
I'd rather keep the leather belt holding my strides up!
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Old 07-06-2020, 05:40 AM   #65
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Default Re: Insert bearings

I take it these are AER bearings sold by the vendors? I haven't heard of any AER engines having problems with their bearings. What is being done differently there?
http://www.fordgarage.com/pages/AERbearinginserts.htm
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Old 07-06-2020, 06:26 AM   #66
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I take it these are AER bearings sold by the vendors? I haven't heard of any AER engines having problems with their bearings. What is being done differently there?
http://www.fordgarage.com/pages/AERbearinginserts.htm
Those are the bearings and I can't see anything done differently in my engine but the front and middle bearings don't last either. A piece breaks out of them from the end of the oil slot to the edge of the bearing on the bottom insert. That hasn't been fatal but I got to the rear one just in time to avoid a more expensive exercise.I'm being serious when I ask "Is it possible to go back to babbit bearings now that the block has been machined for inserts?" I would be happy enough to stick with the bronze thrust faces but these inserts haven't been what I had hoped.
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Old 07-06-2020, 08:02 AM   #67
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Default Re: Insert bearings

Standard insert bearings are of laminated construction, the babbit is applied to a base metal,usually copper or steel.With copper sometimes the copper is applied to steel,then the babbit is applied to copper.It appears the thin layer of babbit on your bearings is delaminating.

Leather belt? the story I was told was the tongue of a shoe,They also ran them on penny a quart 'drain' oil,Oil saved from regular customers cars service.
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Old 07-06-2020, 03:37 PM   #68
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Default Re: Insert bearings

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Maybe we are using the wrong material for bearings. My Dad told me that his buddy had to get from Omaha, Ne. to Lincoln, Ne. one night and 2 rod bearngs went out along the way.
They fixed it with 2 pieces of a leather belt and made it with time to spare. The engine was junk though.
Hi Pete. A couple years ago I had my A up at Lowe’s and this older employee saw my car and Proceeded to tell me his leather belt story. Unfortunately, the leather doesn’t last for too many miles,- - - but the stories do!
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Old 07-06-2020, 04:09 PM   #69
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Default Re: Insert bearings

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Standard insert bearings are of laminated construction, the babbit is applied to a base metal,usually copper or steel.With copper sometimes the copper is applied to steel,then the babbit is applied to copper.It appears the thin layer of babbit on your bearings is delaminating.

Leather belt? the story I was told was the tongue of a shoe,They also ran them on penny a quart 'drain' oil,Oil saved from regular customers cars service.
AER inserts are described as bimetal, steel backing with aluminium silicon bearing surface. No babbitt in them. This information is from various sources including a long description from Vince Falter quoted by Updraught above in this topic.
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Old 07-06-2020, 04:53 PM   #70
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Aluminum alloy bearing? they can delaminate as well. Torsional vibration on well supported and correctly applied poured bearings should be tolerated better than on laminated shell bearings.Torsional vibration (and improper timing) act like a hammer on a bearing,a two or three piece laminated shell 'snapped' into a bearing cap might have just enough instability to be susceptible..if we are theorizing..
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Old 07-06-2020, 05:07 PM   #71
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Default Re: Insert bearings

Arnold.
Arnold, those bearings were just going into lockdown.
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Old 07-06-2020, 08:59 PM   #72
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Wow good thread, good info here
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Old 07-06-2020, 09:25 PM   #73
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Default Re: Insert bearings

Don’t you mean lock up?

I hesitated using King brand bearings because matl is aluminum
Finally had to use them, no problems at all
Just ensure clearances and lube

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Old 07-07-2020, 08:28 AM   #74
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Synchro909,
I have used AER bearing shells for the past 12 years in over 180 engines. Since I started using them I can only recall 4 engines that had the experience of the bearing material breaking loose from the steel shell like you describe. It was determined in all cases, the problem was too much advance while running under a high load or speed. One gent had his timing north of 40 degrees advance, the others were well over 30 degrees with higher than standard compression heads. In three of the cases, the repair was to polish the mains, replace the inserts and set the timing correctly. The fourth crank needed to be turned to the next size smaller.

In all cases, the engine also had insert bearings in the rods. The rod bearings showed excessive pressure marking on the inserts so they were also replaced as a precaution. The engine with the damaged crankshaft showed little bits of bearing material deposited on the rod bearings. Apparently, the oil carried some of the pulverized center main bearing material into the rods.

During this same period of 12 years while taking engines in for rebuilding, I have seen well over 75 percent of the engines with Babbitt bearings broken up and delaminating. That’s not to say that there is a problem with Babbitt bearings though as it would be normal the engines brought to my shop have bearing problems. The high percentage of failure exhibiting bearing fracture is typical of Babbitt because the clearances increase to the point where the oil film cannot support the loads and the crankshaft journal comes into contact with the bearing material causing it to fracture.

I specialize in installing insert bearings in engines. I do not pour Babbitt bearings. If someone wants Babbitt bearings, I refer them to another shop. If there was a shop pouring Babbitt correctly, close to me, I would be using Babbitt if the customer desired. I think either Babbitt or insert bearings will work well in our Model A or B engines if installed and fitted correctly. The debate continues as to which material is more suitable, I don't see the end to the debate anytime soon. I think of greater importance than the choice of Babbitt or insert is the precision of the installation. For those readers considering Babbitt or insert bearings: Choose a shop that is the best at what they use and one that stands behind their work. Keep in mind, oil clearance is critical for either type of bearing. Too much clearance and the oil film will be lost at high loads. Too little and the bearings run hot and are in danger of seizing if inserts.

Synchro, leading up to this failure, you know there was a “cross-fire” problem between cylinders 3 & 4 because you heard the pinging. Now that you are familiar with the cross-fire problem, you would be very quick to recognize it should it happen again. You understand the importance of proper timing and know how to set it. Lastly, you know to retard your timing slightly when pulling the camper up a long hill. I believe your bearing failure occurred during the cross-fire event. I also believe you would have done damage to any bearing material during this event.

You have gotten almost 40k trouble free miles on a set of insert bearings and would likely still be running if it were not for the cross-fire event. If the engine were mine, I would polish the journals, replace the inserts, make sure you have about .002” oil clearance at the rear main and run it. With the additional bearing width at the rear main, it can handle and actually needs the additional clearance. The pressure oil you feed to the center main is a very good solution to keep this often abused bearing well oiled. Keep your timing in check and you will very likely greatly exceed your previous 40k. (I have 98k on my Phaeton insert bearings with pressure oil to the center main and filtered oil.)
Sorry for the length of the post...it is long but hopefully helpful!
Good luck with your project and Good Day!

Last edited by Dave in MN; 07-08-2020 at 07:40 AM.
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Old 07-08-2020, 06:36 PM   #75
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Dave,
Your comments in the last 2 paragraphs are 100% correct. I would recognise a cross fire very quickly now and as you say, I understand how to adjust the timing. Until your comment where you mentioned the timing, I hadn't connected the crossfire with the failure (that was 4 years ago and I haven't done many miles in that car since). I have been told by many that the middle main bearing is no weak point in these engines. Experience said it was so I fed it anyway.
I am about to complete the reassembly of the engine today but we are back in lockdown so I won't be able to give it a good drive for a while. If I get another 40K miles out of it, I would be happy. I realise I ask a lot of the engine when I'm towing. Our longest day so far was 700 miles before we collapsed into slumber. I fully expect that my engine would be still going fine for many miles yet if it weren't for the demands I make of it.
Again, thanks for your input here.
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Old 07-08-2020, 06:37 PM   #76
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Dave,
Your comments in the last 2 paragraphs are 100% correct. I would recognise a cross fire very quickly now and as you say, I understand how to adjust the timing. Until your comment where you mentioned the timing, I hadn't connected the crossfire with the failure (that was 4 years ago and I haven't done many miles in that car since). I have been told by many that the middle main bearing is no weak point in these engines. Experience said it was so I fed it anyway.
I am about to complete the reassembly of the engine today but we are back in lockdown so I won't be able to give it a good drive for a while. If I get another 40K miles out of it, I would be happy. I realise I ask a lot of the engine when I'm towing. Our longest day so far was 700 miles before we collapsed into slumber. I fully expect that my engine would be still going fine for many miles yet if it weren't for the demands I make of it.
BTW, I use a full flow filter.
Again, thanks for your input here.
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Old 07-08-2020, 07:23 PM   #77
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Arnold , have a think about full pressure lube to all the mains.
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Old 07-08-2020, 11:07 PM   #78
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Ford made a number of improvements with B engine design to deal with the main bearing issues with the A.The most influential one was the mechanical advance distributor,taking engine timing from the operator does two things,it insures proper timing at all rpm ranges and eliminates the operator input...both beneficial in avoiding detonation,which works like a sledgehammer on bearings.
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Old 07-09-2020, 06:34 PM   #79
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Arnold , have a think about full pressure lube to all the mains.
Lawrie
I've seen a couple of descriptions on how to do that and they both look very complexicated (?!) I'm sure pressure would help and I will probably look into it at the next rebuild. You know how well this engine runs and longevity is about the only thing I'd like to improve. Pressure would do that and knowing what the crossfire symptoms are, I'm sure that won't compromise things again.
Which system for pressure is favoured by the members here. Plumbing in the valve chamber or in the crank case?
I think I prefer the latter so that oil can get to the top of the engine after going through the bearings and then get to the timing gears.
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