INSERT ENGINE FROZE UP ! 31 Model A fordoor

[B0B]

Engine was rebuilt in California the seller said has inserts and crankshaft with balancing weights etc. it WAS hard to crank by hand we thought it needed to break in but ran good now yesterday while driving it it froze solid .

Taking things apart today rods are ok , pistons move up and down ok with caps off , cam ok Starter ok , nothing in the pan , all looks good , We now suspect since it has inserts that the rear main bearing has "SPUN" .

Anyone have anything like this happen ? any helpful ideas ?

We are now getting ready to "pull" the engine .

Thanks everyone ! B0B

[hardtimes]

Originally Posted by B0B

Engine was rebuilt in California the seller said has inserts and crankshaft with balancing weights etc. it WAS hard to crank by hand we thought it needed to break in but ran good now yesterday while driving it it froze solid .

Taking things apart today rods are ok , pistons move up and down ok with caps off , cam ok Starter ok , nothing in the pan , all looks good , We now suspect since it has inserts that the rear main bearing has "SPUN" .

Anyone have anything like this happen ? any helpful ideas ?

We are now getting ready to "pull" the engine .

Thanks everyone ! B0B

Hey Bob,
Sorry that you are having such problems with 'rebuilt' engine.
I almost bought the same type engine as you describe..'rebuilt in LA, Ca.
When I learned where is was 'rebuilt', I declined this great deal !
Do you know who was said to have done the work on your engine.
PM if you would like.

What I would do, if in you situation:
Now that you are digging into complete disassembly, I'd take all rods out and remove all main caps to look for obvious/visual problem. If no such obvious problem found, I'd start putting main caps on and tighten ONE at a time to recommended torque...then turn over crank after each cap is installed. Plastiguage each also as you go. If no seizing in this process, move on to doing likewise with each rod/cap. After every step, rotate engine few times. Somewhere in this process, the culprit will emerge.

Check piston to cylinder clearance and look for TOOO tight clearances and thereby cylinder scoring/damaged pistons/rings. JMO, good luck

[Towd56]

X2 on piston clearance. Especially on #4.

[George Miller]

Originally Posted by B0B

Engine was rebuilt in California the seller said has inserts and crankshaft with balancing weights etc. it WAS hard to crank by hand we thought it needed to break in but ran good now yesterday while driving it it froze solid .

Taking things apart today rods are ok , pistons move up and down ok with caps off , cam ok Starter ok , nothing in the pan , all looks good , We now suspect since it has inserts that the rear main bearing has "SPUN" .

Anyone have anything like this happen ? any helpful ideas ?

We are now getting ready to "pull" the engine .

Thanks everyone ! B0B

It most likely is the rear main has spun. The problem is the oil has to travel from the front of the bearing to the rear, with no real path. Some leave more clearance. This has happened to many more than just you.

[Dave in MN]

As George has stated, it is likely the rear main. If the engine builder will provide warranty service, take it to him first for repair work without opening it up....but read on if you can not get warranty service on it.

FWIW: I had an engine (my own high output touring build) lock up like this when I switched from Babbitt lined inserts to bearing grade aluminum lined inserts for the main bearings. The early aluminum lined insert rear main failure happened while I was running the engines on my dyno under full load and max. rpm.
I consulted with the bearing supplier (he suggests .00175" oil clearance) and my engine rebuilding associates and the consensus was to increase the oil clearance. I built up a test engine and ran test clearances. I found the rear main needs .002" oil clearance at a minimum for a stock output engine. I now set mine at .0022" on the standard builds and .0025" on high output engines. At these clearances, the rear main will not leak if all other clearances are correct and the drainage passage through the rear cap is no less than 3/8" and has the 3/8" drain tube installed. I have a Sunnen Precision hone set up with the proper mandrel and Sunnen stones to hone the aluminum surfaces of the insert. This specialized equipment allows me to adjust the bearing oil clearances in minute increments.
Photos of fixture to hold inserts while honing below:


If your engine builder will not provide service, When you get the engine on a stand and have the rod and main caps removed, lift out the crankshaft and post some pictures for us to evaluate. If the rear main inserts are aluminum and are frozen to the crankshaft, do not try to mechanically remove them without asking for further input. I will walk you through the procedure of removing them with a solution of muriatic acid. On my original high-output engine and my test engine that locked with aluminum lined inserts, there was no damage to the crankshaft journal when the inserts were removed using a muriatic acid solution. The acid softens the aluminum enough to release it from the crankshaft without damaging the crankshaft. Note: I actually locked up the test engine 3 times while searching for the required minimum clearance....better mine than a customer's.
The block housing bore showed no damage from the insert locking as in all cases, the engine was shut down as abnormal loading was noted and the crankshaft locked as the engine was brought down to an idle.
Please post some photos of the crankshaft when it is removed and the block and cap of the locked main. Hopefully, we can make this a minor issue for you.
Good Day!

www.fordmodelaengines.com

[Dodge]

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Hi Dave,
What about putting the rear main bearing in and checking it with a dial bore gauge.
Then have the crank ground with the clearance put in the crank?
Are the bearing shells close enough in tolerance to be repeatable on a bearing change?

[Dave in MN]

When you are adjusting down to a .0002" increment, the suggested housing bore tolerance range is more than this amount (2.5 times) and the varying crush on the insert changes the clearance more than this safe range. Add the crank grind range the bearing supplier suggests for the main journals and you are way beyond what I am comfortable with for a variance. So, no I find it is not. I clearance every crank I set if necessary by final honing the actual aluminum insert. It is the only way I can provide enough oil clearance without overshooting the upper limit and having a bit of a leak. JMO and what works for me. Others may have different methods that work for them.
My comments are in regard to aluminum lined inserts, not tri metal inserts.
Good Day!

[B0B]

Thanks guys your the best I knew you would know of this problem ... Sounds to me that the engine probably has aluminum type bearing surfaces on the inserts . It died just like Dave in MN said his test engine died . Just so you know the car belongs to my friend Roger and he called me because I have had model A's more years than I care to admit . My 29 A touring Has inserts too and these have caused no problems . So I spent the day over there working on Rogers engine . WE are both old guys and Roger is not able to work on the Model A as much as he would like due to Diabetes and its problems but he loves his Model A .

I will post updates but like I say it may be a few days .

B0B

[mike657894]

its not always what you think it is. i just bought a motorcycle the guy thought it had a bad crank. got it for cheap. turns out the fly wheel nut is loose and the fly wheel was creating the heavy knock with every engine rotation.

[oldredford]

2 different engines with the same problem. Rear main seizes after start. Both engines tore down and redone by the machine shop. Could not find out why. Then I was told to fill the valve chamber with oil prior to start. Pour oil down the distributor shaft hole with oil and a bit of MMO a day before starting. Since I started to do this pre oiling I had no more problems with rear main bearings seizing.

[1937pickup]

Assembly lube doesn't prevent this without the pre-oil.

[hardtimes]

Originally Posted by oldredford

2 different engines with the same problem. Rear main seizes after start. Both engines tore down and redone by the machine shop. Could not find out why. Then I was told to fill the valve chamber with oil prior to start. Pour oil down the distributor shaft hole with oil and a bit of MMO a day before starting. Since I started to do this pre oiling I had no more problems with rear main bearings seizing.

GOOD advice for any stored engine or which hasn't run in some time !
And, for newer / rebuilt engines upon initial run-in. Pressurize them prior to running , if you have the equipment needed.

[Dave in MN]

Originally Posted by Dodge

Hi Dave,
What about putting the rear main bearing in and checking it with a dial bore gauge.
Then have the crank ground with the clearance put in the crank?
Are the bearing shells close enough in tolerance to be repeatable on a bearing change?

Your suggestion will work. It requires extremely accurate measuring.
The bearing shells are pretty good as to limited variances.
Good Day!

[larrys40]

exactly why I still like babbitted mains!!!
I can do them myself and I know what they are.
Larry

[B0B]

Well we got the engine out today . Found the bearing closest to the flywheel seized right on the crankshaft . Managed to pop it off without damaging the crankshaft (We hope) . Lots of aluminum stuck on the crankshaft journal. Noticed the main bearing bolts were not tightened properly some were quite loose and some really tight . The timing gear nut was very loose . This engine has not been worked on since it was rebuilt in California it has so few miles on it . I will try to post pictures I have not done that before on the forum .I will send some pictures direct to you Dave I know how to do that ok ... B0B

[Gunmetal blue2]

Question did you have your engine line bored to make sure the block and crank were straight? It also looks like your rear bear was not getting enough oil. What was all the gasket sealer for. It looks like it was between the block and bearing cap.

[Dave in MN]

Those bearings look like tri-metal inserts. Babbitt, copper and then a steel shell.

Study the steel shell to see if you can identify a manufacturer.
You will need to measure the housing bore and the crankshaft journal diameter to determine the proper replacement insert.

Study your photos, you can see that the cap is not flat by the varying amount of sealant in the block under the footprint of the cap. The cap should be flattened before the machining of the block and cap for the insert.

[George Miller]

Originally Posted by B0B

Well we got the engine out today . Found the bearing closest to the flywheel seized right on the crankshaft . Managed to pop it off without damaging the crankshaft (We hope) . Lots of aluminum stuck on the crankshaft journal. Noticed the main bearing bolts were not tightened properly some were quite loose and some really tight . The timing gear nut was very loose . This engine has not been worked on since it was rebuilt in California it has so few miles on it . I will try to post pictures I have not done that before on the forum .I will send some pictures direct to you Dave I know how to do that ok ... B0B

I think you should take it to a Model A engine builder and have it checked over. It sounds like it has a lot of problems. You should also change those MG bearings or what ever they are to the newer one pice ones from A E R. They will work better than those.

[Phil Brown]

WAY to much silicone in an area where there shouldn't be any. All it takes is one little piece to of it to stop the oil flow.
Hope that you can save the crank, but she's really blue
Phil

[Flathead]

I hate blue silicone.