Center Main Bearing Cap

[WayneT]

(FYI, I am working under the car.) I removed the center main bearing cap due to fact it has bad Babbitt. I am going to replace the bad cap with a good cap with good Babbitt. The old cap had 4 shims on each side totaling .014 shim thickness on each side. I am seeking an answer from someone that is knowledgeable on A main bearing cap replacement. (from under the car). My question is, how much total shims thickness should I start with when I install the replacement bearing cap? Other advice welcome!! Thanks!

[BNCHIEF]

Well the first thing to know is has your crank been ground, if that babbitt is bad why would the top be good what caused it to go bad. Not trying to be a pain but it sounds like you have issues that need deeper inspection.

[CarlG]

The top babbitt does not get the pounding that the cap gets. Most of the time, replacing the cap is all that it takes. That's not to say that the top doesn't ever need new babbitt, it's just not all the time.

[Mitch]

An excellent technical thread that may help you out along the way

https://www.vintagefordforum.com/forum/model-a/technical-reference/52374-adjusting-babbit-crankshaft-main-and-rod-bearings

[DaWizard]

Wayne, since the babbits are poured separately, it is possible that the upper babbit is good and the cap bad.

If I was starting the process of replacing the shims, I would start with whatever you want or have on hand and the piece of tinfoil to get a feeling for clearance.

The main thing is get a feel for the friction on the crank. REMOVE THE SPARK PLUGS! I would start with the cap off, move the crank to get the feel then use about .020 thickness shims and replace the cap with the tin foil.

Try the crank again removing .002 each time and trying the crank between removal of the shims.

When the crank becomes tighter you are close enough that removing the tin foil and replacing the cap with what shims were there should set it.

So, go in the house, tear off a piece of mama's aluminum foil, cut a 1" wide piece about 4" long, fold in half lengthwise and trim to fit the bearing cup. Just be sure it isn't the "heavy duty" foil as that is thicker, but since I don't have any, I can't tell you how much thicker.

Should look like this only on the center main cap...

Tin Foil.jpg

[tbirdtbird]

Wayne the above advice is all good. The article Mitch referenced you to is a super write up by one of our members, CM2.
1. If the cap is being adjusted motor in the car, I prefer to use the aluminum foil method, rather than plastigage.
2. We will assume your other babbitts are good, and that the thrust surface of the rear babbitt is not chipped out or cracked.
3. BTW what caused you to inspect the center main? Routine maintenance?
4. Last I knew standard Al foil was .001 thick and heavy duty was .002 thick. To be safe purchase or borrow a dial indicator, a very handy inexpensive measuring tool, so that you can measure the foil yourself, to be sure. Try this, or similar:
https://www.amazon.com/Vernier-Calip...r+caliper+dial
I have deliberately not shown the calipers with the digital readout, they can be very funky and don't seem to hold up well. Be sure to zero out the caliper each time you use it
5. If .002 binds the crank, and .001 does not, then you have the exact proper clearance. I would start with more shims than you think you need so you do not damage anything. Remember, you need the full torque spec on the bolt (70 ft pounds) to properly determine the clearance. It is OK if you have one less shim on one side than the other, but start with an equal number. Be sure all the plugs are out, and you will try to turn the crank with the crank handle, NOT the starter
6. To me, the unknown here is what is your crank diameter and what diameter was the cap intended for? This could get dicey, but if you are careful, you may be able to make this work. If the cap babbitt is too thick, you can get used babbitt scrapers on eBay and pare it down some, again go slowly
7. I would tend to believe that the upper babbitt in the block is OK, since all the force is downward on the cap. Most of the time the top is fine
8. Up until the early fifties, you could take your caps to the parts counter at a Ford dealership, and they would sell you a freshly babbitted cap, all you had to do was tell them what diameter the crank was. Sure wish we could do just that today!!!
9. You will need an 8 pt 9/16" socket for the bolt, since it has a square head
10. It might not be a bad idea to check the clearance of the rear and front mains as well, once the center is fixed. The center tends to wear first, then the rear, and the front hardly much at all.
This is because of the whipping action of the crank due to the verrry heavy 64# flywheel
11. You are gonna have more questions, just ask

[CM2]

Understanding how the babbit bearing is created precludes the replacement of a bearing half..the upper and the lower are poured,and cut at as unit with a line boring tool,how can a bearing half,even one cut to match the crankshaft diameter,match the 'personality' of the upper half you cant see? one thing is certain,any failure in the lower half transmits to the upper half,the shedded babbit. even from a crack, embeds on the upper half of the bearing.Although its a 'farmer fix' to get half a bearings sized at the turned size of the crank,without inspecting the upper renders what most 'farmers fixes' are... literally half assed...

[tbirdtbird]

possibly... have done it several times when we could still get caps from Bill Barlow, always with good results

[CM2]

Not doubting you at all,just a different view on the same subject.

[WayneT]

Thanks to all for the wealth of information, I appreciate it. To answer the question on why I am into the engine to start with is because at the Citrus Parade in Orlando my son was driving this A and it knocked and then died as we were waiting to pull out into the parade.. (I was driving my other A and drove the parade). We bought it home on a trailer and I started my investigation. There was no compression on all 4 cylinders so I pulled the head and inspected all 4 Cylinders, pistons tops etc. I then turned the eng over with the crank and the valves went up and down and the dist shaft turned. That threw me off a bit BUT I then pulled off the timing gear cover and found a bad timing gear. I replaced it and the front crank gear that drives the timing gear along with the oil slinger, 2 piece pulley and ratchet nut. Also 3 valves that were chipped on the edges. I then decided that I should pull the pan and clean out the "mung" and inspect the bottom engine area. This is when I could see the Babbitt sliding down the front edge of the center main. I will now install the center bearing cap utilizing your input trying tinfoil. I also purchased a fully restored original head and a new type head gasket. Thanks again for ALL of the input, very nice information by very knowledgeable people!!
Wayne T.

You might want to find out why you had "no compression on all 4 cylinders" before you go much further.

Also the so-called new type head gasket is not your friend.

[Mitch]

Magnificent 7,
He probably did not have any compression in all 4 cyl's because of the bad timing gear.

Mitch,
He said he "turned the eng over with the crank and the valves went up and down and the dist shaft turned."
That tells me that there is no way that he has no compression in all four, unless somehow a valve was stuck open on every cylinder, which also a lot different problem than just bad Babbitt. Might have a bad gear, but that is not the cause of no compression when it still turns. Just sayin'

[tbirdtbird]

OK, good, as far as the head gasket, suggest to avoid the Felpro one with the silicone around the water holes, they have a very bad rep for failing early and often.
Strongly suggest the Best brand gaskets.
If original head, by the sounds of it, then the Felpro without the silicone will work nicely. The Felpros do NOT fit the HC heads well at all

keep us posted.
would love to know how you got the crank gear off with the engine in the block, that has eluded me. There is no room to get a puller behind the gear
Dave

[Mitch]

Agree with Dave & Magnificent 7 about the silicone impregnated gaskets. Some folks like them but i have been bitten in the rectum by them. The BEST brand gasket as mentioned has been treating me well.

FYI, FelPro did not make any silicone crap head gaskets.

The gaskets with the silicone bead are just a cheap repro part, not a professional made gasket from FelPro.

The silicone bead gaskets were made in both Model A and Model B format, but not by FelPro.

Also, FelPro made copper clad asbestos head gaskets in Model A format, and made asbestos like Ford for Model B.
They also made tin plated steel clad asbestos gaskets in Model A format.

[WayneT]

Dave, Had a gear puller that fit behind the gear, had to apply heat to the gear. Who has Best Brand Head gaskets?
Wayne

[DaWizard]

Wayne, Egge.com sells Best gaskets.

[Mitch]

You can also go right onto BEST's website

[Mitch]

Thanks to all for the wealth of information, I appreciate it. To answer the question on why I am into the engine to start with is because at the Citrus Parade in Orlando my son was driving this A and it knocked and then died as we were waiting to pull out into the parade.. (I was driving my other A and drove the parade). We bought it home on a trailer and I started my investigation. There was no compression on all 4 cylinders so I pulled the head and inspected all 4 Cylinders, pistons tops etc. I then turned the eng over with the crank and the valves went up and down and the dist shaft turned. That threw me off a bit BUT I then pulled off the timing gear cover and found a bad timing gear. I replaced it and the front crank gear that drives the timing gear along with the oil slinger, 2 piece pulley and ratchet nut. Also 3 valves that were chipped on the edges. I then decided that I should pull the pan and clean out the "mung" and inspect the bottom engine area. This is when I could see the Babbitt sliding down the front edge of the center main. I will now install the center bearing cap utilizing your input trying tinfoil. I also purchased a fully restored original head and a new type head gasket. Thanks again for ALL of the input, very nice information by very knowledgeable people!!
Wayne T.

Things can sure snowball quickly on opening up an old engine. Isn't it amazing how well it ran even with having all these extra things you found.

[Mitch]

FYI, FelPro did not make any silicone crap head gaskets.

The gaskets with the silicone bead are just a cheap repro part, not a professional made gasket from FelPro.

The silicone bead gaskets were made in both Model A and Model B format, but not by FelPro.

Also, FelPro made copper clad asbestos head gaskets in Model A format, and made asbestos like Ford for Model B.
They also made tin plated steel clad asbestos gaskets in Model B format.

What company made those silicone beaded ones? I thought it was Felpro too...

'Shinola' Gasket company, or maybe it was the other one.

[tbirdtbird]

well whoever made it, suggest not to use it!

[Mitch]

I remember reading that AER was using those silicone deals at one point and switched because of to many issues.

[tbirdtbird]

everyone that tried it in our club had failure

[Dennis]

I tried one of the silicone and it was crap. I'm baffled why Snyder's recommends them. AER uses Best brand graphite 473G. I have one on mine, 120psi compression on all 4 cylinders and is dry all around.

Dennis commented
Today, 10:20 PM
I tried one of the silicone and it was crap. I'm baffled why Snyder's recommends them. AER uses Best brand graphite 473G. I have one on mine, 120psi compression on all 4 cylinders and is dry all around.

I believe you meant a Best 573G, not 473G.
BTW, those are Model B head gaskets, not Model A, and they have the added steam holes FYI.

Everyone has their lucky gasket numbers, and I have mine as well.

Some people study other peoples experiences and failures, and other people prefer to learn first hand by making their own personal experiences and failures.
...and I do both and am just dumb lucky!

[tbirdtbird]

am pretty sure Brattons and Snyder carry the Best gaskets, but they don't show the name with the part number, you have to call to ask.
If you have a stock 4.2 head, you will be fine with the Felpro, the area around the valves will be OK.
The problem with the Felpro and the HC heads is it does NOT fit around the valves properly

Victor, McCord, FelPro, Fitzgerald, Best, and other professional gasket companies are proud enough to put their names and numbers on all their products.
If a gasket is unmarked, that is your first clue to run, don't walk!
There have been quite a few low quality spurious reproduction head gaskets made over the years.
I will not buy or use any unmarked head gasket.
I also predicted failure on the snake oil silicone gasket the first time I ever held one in my hands!

[DaWizard]

I have also found that with the Felpro they don't offer the "sized to fit" gaskets anymore, only the .125 ovre gasket and if you have a smaller bore than .125 over you have a narrower web between 1&2 and 3&4 which is usually where the gaskets fail. I do know Best makes a gasket to fit your bore. Call Egge.com to get the Best gaskets.

[Mitch]

McCord & Fitzgerald gaskets? I don’t think i ever remember seeing either of those in my days

Also you have to be careful and observant when buying NORS gaskets because the big gasket companies sometimes supplied each other.

For example in the 1990s and beyond there were quite a few Victor/Reinz/Dana branded blister packed head gaskets which actually contain a Fel-Pro 7013 rather than a Victor 800. I have several of those still factory sealed.

In most cases you can read the Fel-Pro name inside the Victor packaging before you buy.

https://www.vintagefordforum.com/fil...iledataid=6189

As an example, here is a pic showing three different head gaskets in Victor packaging. The first is a Victor 800 C1, the Second is actually a Fel-Pro 7013 R1, also a good gasket. The third is a more recent Fel-Pro 7013 R3 which I don't like, which is made for max oversize bores.

Oh and by the way,
There is a 'trick' to spotting a Fel-Pro 7013 R1, R2, or R3 from the front or rear, in the transparent packaging, or from several feet away!

The gasket has a "tell" that is a dead giveaway as a F-P R1, R2, R3, but most people are not observant enough (or OCD enough like me) to have ever noticed.
Do you know what it is?
Bonus prize TBD for first person with correct response.

[WayneT]

Another Question--Having not used tinfoil I must ask, Does it make a difference if you use the "regular" (1 thousandth thick) folded in half with the shiney sides against the bearing and crank OR would it be OK to use the "heavy duty" (2 thousandth thick) with a shiney side and a dull side between the cap and the crank??

[tbirdtbird]

i'd avoid the .002 foil, since you are gonna need the .001 foil anyway. This is a go-nogo test. Just fold .001 foil in half to make the .002 foil.
Locked at .002, too tight. Turns at .001, just right. Then you are somewhere between .001 and .002 for clearance. Be sure to put a bit of motor oil on the foil, both sides. Do not actually turn the crank much, you are just testing to see if it is locked.

The strips I make are a bit narrower than shown above, I make my strips about 1/2" wide. The clearance you are looking to measure is at the very bottom of the crank, you are not trying to get up the sides at all.
The clearance spec is not .001 all the way around the full 360°, if you had that, you would actually be at .002" at the bottom, which is gonna be too much.

Shiney, dull, no matter what side is what

[Tom Wesenberg]

What Dave said is important, because if you run the foil up the sides, then you have just doubled the foil measurement.
You'd be taking up .002" on each side, for a total of .004".

[WayneT]

Thanks for the new input on the foil method of checking clearance, it answered my question completely!! AND also for the head gasket info, I really appreciate it! My "silicone" head gasket is from Brattons (part 8080) so I feel I am OK to use it.---- Wayne T.

My "silicone" head gasket is from Brattons (part 8080) so I feel I am OK to use it.

If your silicone gasket does not work out, let me know and I will fix you up with a quality NOS/NORS head gasket that will.

I suggest you take your silicone gasket and lay it on the head very carefully and note where the silicone bead travels and contacts the head around the water openings, especially at the "canoe" shaped opening in the head on the LH side between number 2 and 3 cylinders.

I think you will find that it does not follow the opening in the head, and has a significant designed-in water leak path to the head. You would not catch this just by looking at the gasket by itself.
Good luck!

[George Miller]

I never seen the the need for the foil I always adjust bearings until you get a heavy drag, then put in your.001 shims on both sides. Been working for me all my life.

[CM2]

Ford instructed the 'feel' method,also the use of a prussian blue style imprint compound for finding high spots.Tin foil method is handy when the engine is installed,when its hard to get a true feel.Doing a complete out of frame build you will end up using the 'feel' method in combination with plastigage or foil.Regardless of what the plastigage says,always rely on feel,the drag George talks about.Les Andrews recommends a torque wrench to feel drag,he even states a value,25 pounds..don't know if I agree with that,I believe it will leave folks with tight bearings.ALWAYS lean to the loose side of the feel,the crank should turn without a 'break' force to get it to turn..the same load it takes to start it to turn is what it should take to keep it turning.Remember Ford didn't run in new engines,he spun them with an electric motor to a prescribed load value then approved them for installation,Ford clearly felt a tight engine wouldnt last and it couldn't be measured running it in. Modern oils have modifiers which greatly help the engine builder,todays oils have a higher pressure and shear factor,perfect for gravity fed babbit systems..

[BNCHIEF]

I have not done an A buton model T prussian blue look for high spots ,scrape clean refit rods and mains if the engine is new you should not do anything, My engines were done by Kohke Babbitting years ago as well as balanced.

[George Miller]

If you put a new center main cap on you most likely will not have 100% contact. The center line of the crank will vary from one line bore job to the next. You need to put bluing or some thing on the cap then install with a little drag turn the crank take the cap off and see how much contact you have. Then you have to scrape the high spot and try again. it can be a long process. If you do not do this you will be adjusting that bearing again.

[BNCHIEF]

What you say is exactly how I was taught George.

[tbirdtbird]

bluing is good, you can use a magic marker, too

[BNCHIEF]

True Dave it works well.

[WayneT]

Thanks again for all the intelligent input. I will keep you all informed on my final outcome!! Wayne T.

[Dennis]

I bought my new head gasket and head from Bratton's, didn't know at the time the head was going to come in a Snyder's box. Still I used the silicone head gasket that they recommend and it started oozing coolant after about 200 miles. Retorqued numerous times and aluma seal still oozed out, never blew out. Ended up rebuilding engine and installed a Best graphite head gasket from AER. With 120psi compression and over 1,500 miles is dry as a bone. No weep or leaks anywhere.

[Mitch]

To clarify AER was using the silicone junk gaskets years ago, but had since switched

This is what i was told

Retorqued numerous times and aluma seal still oozed out, never blew out.

I am confused!
Where did the aluma seal come from?
You added it? Why?

ProTip:
Install a Best/Victor/McCord/Fitzgerald/Fel-Pro copper or steel clad 'asbestos' gasket, torque to about 55 three times and be done with it. Once and done!

Let all the adventurous people with too much time and money use all the miracle improved products, slick 50, STP, MMO, silicone head gaskets, mechanic in a can, etc.

[Dennis]

Have you ever watched Rich Falluca's engine rebuild video?

Water leaks and gasket blow-outs/burn outs are two completely different things.
Until you start mixing and matching causes, effects, and solutions.
Think about it.

[CM2]

Did you use new head studs on rebuild?

[Dennis]

Both times yes. Nothing to do with how it was assembled. If you don't think that silicone gasket is no good, go ahead and try one for yourself.