Questions about adjusting bearing with engine in car.

[christian]

I have decided to check and adjust (if needed) the main and rod bearings with the engine still in the car. I have read much about the foil method, which sounds like it would work well for me. I've read about the procedure, but still unsure about the rotation of the crank, do you rotate it with the hand crank? Also, do you disconnect the rods so you can gauge the tightness without having the pistons still being dragged up and down?

 

[James Rogers]

When I adjust the bearings in a car, I leave the hand crank in the front while I work. Doing it this way allows me to reach out and tug on the hand crank to test the resistance of the bearing after adjustment. Don't disconnect anything but the bearing that you are working with.

 

[Ed in Maine]

This is a great question. Could you elaborate on the following:
1. You must take all the plugs out so the engine turns easily. Do you remove one shim per side of the bearing? Then retighten to spec.?
2. What do you look for when inspecting the bearing?
3. How do you know it is too tight and should place the shim back?
4. Any specific order, rods first, then mains?
5. Under the car, is there good access to all nuts?
6. I have never done this before, is there anything to look out for or avoid?

 

[KGBnut]

I've done this...only once. I didn't think it was a bad job at all, just messy and a little time consuming. The biggest challenge, in my opinion, was properly re-seating the oil pan and the multi-part gasket.

The one thing that I was not prepared for was the fact that all the bolts were square head. It made it very hard to get a torque wrench on them. Fortunately, Pop has all the old tools and found a square socket exactly the right size. I'm almost surprised that the usual Model A parts houses don't carry a set of square sockets. (After a lot of searching I now own a full set of 8-point sockets.)

Lastly, while you are doing the mains, this is a great opportunity to ensure that the oil drain tube from the rear main is good and clear.

I am not familiar with the foil method. Are you using the foil in place of Plastigauge, or as shims?

Ken

 

[christian]

I am not familiar with the foil method. Are you using the foil in place of Plastigauge, or as shims?

Ken

apparently the foil is used in place of plastigauge. when a piece of ordinary household foil is folded over onto itself (double thickness) apparently that is roughly the same as the required clearance. So the idea is you you place the doubled up foil between the cap and the crank, torque it. you then rotate the crank by hand, if it rotates with the foil in there then that means you have excess clearance. you take the cap back off, then remove a shim and put the foil and cap back on, if it wont rotate then you are good, remove cap and foil and you should have the proper clearance.

 

[CarlG]

...The one thing that I was not prepared for was the fact that all the bolts were square head. It made it very hard to get a torque wrench on them...

9/16 Eight Point socket is what is needed for the mains.

 

[jhowes]

Christian; Not quite, you have to continue with a single layer of foil to make sure that it turns over otherwise the clearance is to tgiht.

 

[Jon]

I've used the foil method a couple times and I wouldn't attempt this without having a good micrometer and know how to use it. You need to measure the thickness of the foil first and that will tell you if one thickness or doubled over is what you need to use. Also if removing and/or adding shims you need to know the thickness or it could take a long time by trial and error.

 

[Patrick L.]

I have only done this 3 times so I haven't run into all the problems one could probably run into. Its easier if you're able to hold the oil pump in the block. The vendors have a little plug with a screw installed to handle this. Make sure to clean the pan and oil pump screen. I check the oil pump clearance also and usually sand the endplate flat. You'll need to figure out how to get the rear main caps off/on, I welded a 12 point 3/4" socket to piece of flat stock. The hardest part of the job is removing those ^%@(@& cotters on the front and center mains.
Remove the sparklers and pan/oil pump.
Do one bearing at a time. Don't get the cap turned around. Look for previous punch marks. Put them back on the same way they came off.
I don't think it makes a difference which/where you start, but, I do the mains first.
When checking/adjusting a main, I jack the crank[ just a little tension].
Foil method. Foil should measure .001" thick. One thickness should allow the crank to turn, 2 thickness's [double] should not].
Plastigauge. I prefer this. Oil the cap so the plastic doesn't stick to it. Make sure to remove it when done.
I'm a shim sander. Most would say this is wrong, but, I find it a royal PITA to peel the shims. So I just sand them on the piece of glass. I think its easier and faster. I also make both shim stacks the same thickness. This apparently isn't necessary, but, I do it anyway.
I set all clearances to .0015" and make sure the crank turns easily when done with each one.
I think you'll find that the rods won't need too much. The center main will need the most attention. The rear may need a little too.
When tightening the retainers, I just tighten the rods to 30 #/ft and then tighten just enough to install the cotter. On the mains I tighten to 70 #/ft and then do the same. I doubt you need to use the cotters, or you could install locknuts or plain nuts with lock-tite.
Take a good look at the bearings to make sure they are still good shape.

 

[Keith True]

To turn the engine over I take the plugs out,and use a 1/2 drive socket on the crank ratchet.An extension long enough to clear the radiator shell,and a long ratchet that I leave hanging down.I can just reach over an push the ratchet handle,no making sure the crank is engaged in the teeth.Cranks always seem to be popping out and slipping for me.

 

[Mike V. Florida]

This is from the old Fordbarn,

Mike Flanagan has posted his description of interference fitting of the main bearings in the
Model A engine. Because of the weight of the flywheel and the flexibility of the Model A crank,
plastigauge my not be a reliable method of adjusting the bearing clearances.
Here's Mike:
How do you check the clearance on the bearings? It is not QED but can be done if you can lay on
your back and work with oil and grit and grime falling in your eyes.
First you gotta drop the pan, let it sit overnight to get all the oil that will fall out to do so. You are
still going to get oily. Pull the damn oil pump out and lay it aside. You can shine a flashlight up
in there to see which way the tang is oriented to reinstall and with it out there won't be so damn
much blood on it to clean off it.
Then I start with the center main. This one requires that the valve cover be taken off as the nut is
in side there. The other nut is between 2 and three outside on the other side. Remove the cap
being careful to keep the shims on the same side as they came from. Visually inspect the bearing
for cracks and places at both the front and back that look as if it has been compressing the babbitt
and pushing it forward or to the rear. Bad signs if so. To check the clearance, use a piece
of aluminum foil .002 thick. The heavy duty she buys to do heavy-duty things is .002 but the
regular like you cook a baked potato in is .001 so you fold it. You want a piece as long as the
cap and about 1/2 wide. Lay this in the cap and with the SHIMS BACK IN THERE put the cap
back on and tighten it up. Now you want to see if the motor will turn with the obstruction in
place. Stick a 6" punch in one of the balance holes in the crank throw so the pull will be
consistent each time you check. You are looking for lockup with the obstruction in there and
free without. The shims are increments of .002 or .003 depending on which the rebuild used.
The steel shims are generally in .002 and the brass in .003. Peel 1 increment from one side at a
time, one from one side and if that doesn't lock it up then do one from the other side. Yes it
tedious; just be glad you didn't by a space shuttle. Once you get this bearing to lockup then
remove the obstruction and replace it and tighten it up again and see if it will rotate. If it won't
turn with the 6" punch then put that dame shim back in and run it another 3k.
Do the rear next then the front. The rods adjust exactly the same way. When you finally get a
bearing adjusted like you want it put some pre-lube (engine assembly lube) on there before
putting it on there for the last time. Torque to whatever you has been using (75 minimum) and
go. The rod nuts torque to 40.
To put the pan on there install the oil pump using a 3/8 fine thread bolt in the plug hole in the
side of the block to retain the pump while you install the pan. Finger tight as the threads are
actually national pipe threads but the bolt will work in there. Get some 5/16 all thread and make
yourself some cheaters by cutting 4 pieces 4 or 5 inches long. Screw them into the pan rail and
let 'em hang down. Slip the pan over them and start a nut. Then it is a matter of tightening the
nuts incrementally in turn and thereby winching the pan up against the spring on the pump.
The gaskets and sealer is a matter of choice but my opinion is that the silicone belongs in the
bathroom. I use permatex red personally. When you put it all back together put some of the oil
down the dist hole so the valve galley is oiled. It should not have lost any oil but I like to make
sure.