Ford 3910 engine internal issues

ford401 · Aug 22, 2021

Hello all, this new to me 3910 was struggling to turn over with a fully charged battery with charger on boost. It also wouldnt even attempt to fire on ether. So I figured something was going on internally. Decided to split the tractor and open it up. As soon as I took the pan off I found a bunch of bearing metal all chewed up. So far Ive only taken the main bearing caps off and found only 1 of them is all scuffed up and you can see the chunks that were holding the crank up from spinning.

My question is; and let me preface this by saying I understand its not the right way. But so far the crank shaft looks really good, no damage on the journals at all. If I take the motor the rest of the way down and clean all the shavings out of the block and everywhere else, could I save the thousands of dollars in machine work, and just throw new rod and main bearings in the motor and run it? Also what would cause the damage to the bearings that I have? Any advice is appreciated. Ive attached some pictures. As well as a video of how hard it was turning over.

Oh and does anyone know what these main bearings cross too? Ive googled these numbers and I cant seem to match them up? Thanks

ford401 · Aug 22, 2021

Forgot the pics

ford401 · Aug 22, 2021

(quoted from post at 18:45:58 08/22/21) Forgot the pics

ford401 · Aug 22, 2021

Bern · Aug 22, 2021

With the possible exception of the thrust surface, I don't see enough damage to the main bearings to make it hard to turn over. I'd be
pulling some rod caps off before you declare the crank to be OK.

Destroked 450 · Aug 22, 2021

As a general rule of thumb when a engines is run low on oil pressure or no oil pressure at all the first bearings to be damaged will be the rod bearings, they should be checked first.
As Bern said the thrust side of the main bearing doesn't look good but that isn't the cause of the hard cranking.
I notice the bearings are marked 0.030 meaning the engine has been apart before and the cranks main journals have been ground 0.030 undersize
It's very unusual for these cranks to need to be ground undersize unless they have been run without oil pressure, in my area oil pressure lose is usually cause by someone mowing tall grass and hitting a stump crushing the left side of the oil pan, which in turn breaks the oil pump off .
Also the radius on the sides off the journals looks pretty sharp, these cranks have a long radius to reduce stress in that area

This is what the radius should look like

This is the short radius a machine shop ground into my 4000SU's crank

I had not used that shop before and missed the improper radius while reassembling the engine in a unheated shed in February.
This was the end result

Found this when looking for a low oil pressure issue at hot idle

After disassembly

This post was edited by Destroked 450 on 08/22/2021 at 08:58 pm.

ford401 · Aug 23, 2021

(quoted from post at 19:28:27 08/22/21) With the possible exception of the thrust surface, I don't see enough damage to the main bearings to make it hard to turn over. I'd be
pulling some rod caps off before you declare the crank to be OK.

With the head off and the motor sitting on the deck on the ground. I took the one single main bearing cap off that I could see the bearing shavings stuck in, and as soon as that was off I was able to spin crank freely by hand at the pulley bolt. After that I popped the other 3 caps off and did not find any damage to those bearings. Ill take the rod bearings off today and see if I see anything else. Thanks bern

ford401 · Aug 23, 2021

Do you mean like this??

ford401 · Aug 23, 2021

I took the rest of it apart today. Here are the pics of the damage. It seems that there is really only any damage on the thrust bearing. The others look pretty good, minus some very small scratches (assuming they came from the metal shavings from the one that went bad). Its common for just the thrust bearing to go bad and no damage to others if it had low oil pressure?? Crank has some small imperfections but doesnt seem too bad, thoughts? If this is the worst of it, what are thoughts on replacing the bad bearing, cleaning and reinstalling it?

ford401 · Aug 23, 2021

Destroked 450 · Aug 23, 2021

It didnt break the oil pump off but it mashed the screen up pretty bad
Your going to need a new oil pump and oil pan
Which main cap did you take off that allowed the engine to turn freely

ford401 · Aug 23, 2021

That would be the second cap from the front of the tractor that I took off first and motor spun good by hand. Prior to taking that one off the motor would hardly budge with a socket and pipe. And really struggled with the starter to spin.

sotxbill · Aug 23, 2021

why is the back of the thrust bearing ate up?? improper clutch install? bad pilot bearing? something else going on?

Bern · Aug 23, 2021

If you maintain that the thrust bearing is the worst of the damage, that begs a question, did you recently replace the clutch or have the
tractor split for some reason before this last time? Thrust bearings usually don't go bad unless there is an unusual thrust load on the
crank.

ford401 · Aug 23, 2021

(quoted from post at 06:31:09 08/23/21)
why is the back of the thrust bearing ate up?? improper clutch install? bad pilot bearing? something else going on?

The clutch in it does look brand new, doesnt look like it has any wear on it whatsoever.

Destroked 450 · Aug 23, 2021

Second cap from the front would be the thrust bearing which is the one chewed up
There has to be a reason why the thrust is so badly damaged, what condition is the thrust face on the crankshaft

kenbob · Aug 23, 2021

Try this on for size: Do you think there is a chance the bearing cap on backwards? My brother and I were overhauling his 56 ford 223 in frame. When we put it back
together no amount of pressure with a breaker bar would turn it over--even with the head off. SO, we took the rod caps off. Being old, those numbers are hard to see so
when we put it together we noticed the first 3 all had the ford oval stamp on the same side of the bearings so we put them all in that way. It turns out 2 of the other 3
had the oval stamped on the other side. When we got them turned around the right way with rod and bearing numbers on the same side it turned right over. So, if a bearing
got put in wrong on an overhaul and if someone forced the issue, it seems it would chew up that maybe it would chew up a bearing when who ever was forcing it got it to
break free.

Destroked 450 · Aug 23, 2021

That a very good possibility
There's a notch in the block and main caps that the bearings tang fits in, when installing the caps those notches go on the same side as the ones in the block, the main caps also have what looks like a arrow cast into the top of the cap, it should point towards the front of the block
The way the cap is laying in the first photo is backwards

kenbob · Aug 23, 2021

My brother and I have 2 vehicles with the 223 engine. I guess we are close to experts on that one. In demand like dirigible mechanics.

ford401 · Aug 23, 2021

(quoted from post at 06:32:53 08/23/21) If you maintain that the thrust bearing is the worst of the damage, that begs a question, did you recently replace the clutch or have the
tractor split for some reason before this last time? Thrust bearings usually don't go bad unless there is an unusual thrust load on the
crank.

It looks like the clutch is brand new. Doesnt eVen look like there is a bit of wear on the discs. I really didnt pay any attention to it when I took it apart. How would that have caused the issue with the bearing?

root · Aug 24, 2021

Can't tell from the pic but is there any chance it hit hard enough to misalign the main cap? That might cause the the thrust surface to look like it does. I would put some assembly on the mains and reinstall the #2 main cap. I would be curious if it would turn over.

ford401 · Aug 24, 2021

(quoted from post at 06:45:41 08/23/21)
Second cap from the front would be the thrust bearing which is the one chewed up
There has to be a reason why the thrust is so badly damaged, what condition is the thrust face on the crankshaft

Just minor scratching from the bearing shavings.

ford401 · Aug 24, 2021

There is obviously damage to the oil sump, and pan. But I did not notice anything out of the ordinary with the caps. Bolts came off nice and easy, did not seem bent or misaligned. Caps came off like normal.

ford401 · Aug 24, 2021

Can anyone confirm that this is a 192 engine? I want to be sure before I order parts for it.

Destroked 450 · Aug 24, 2021

Stroke is the only difference between a 192 and 201
Bore is the only difference between a 175 and 192
The difference is enough you can measure it with a ruler

175 = 4.2 bore x 4.2 stroke
192 = 4.4 bore x 4.2 stroke
201 = 4.4 bore x 4.4 stroke

You need to know the year model as they made some changes it the engines around 86/87 and again in 90

ford401 · Aug 24, 2021

(quoted from post at 07:41:03 08/24/21)
Stroke is the only difference between a 192 and 201
Bore is the only difference between a 175 and 192
The difference is enough you can measure it with a ruler

175 = 4.2 bore x 4.2 stroke
192 = 4.4 bore x 4.2 stroke
201 = 4.4 bore x 4.4 stroke

You need to know the year model as they made some changes it the engines around 86/87 and again in 90

Thats a problem because I cant make out what this part number is on the block to decode the year or what it is.maybe someone might be able to tell me on here

Sean in PA · Aug 24, 2021

It looks like D5NN5015G, which a Google search claims should be a 201, but measure your bore and stroke to be sure.

ford401 · Aug 24, 2021

(quoted from post at 10:08:05 08/24/21) It looks like D5NN5015G, which a Google search claims should be a 201, but measure your bore and stroke to be sure.

Ill try to get that measured tomorrow. Any clue on the year?

Sean in PA · Aug 24, 2021

C630777 is the engine serial number, but they are not well documented anywhere. The C at the beginning means that it was made for the 3xxx series of tractors. The D5 at the beginning of the casting code means that the block casting was designed in 1975, but they used that casting design for a number of years, so there's no way of knowing for sure exactly when the engine was built. The code for the date that the block was actually cast is above the D5NN6015G casting number in your picture, but it doesn't appear legible in the picture. There should be another date code stamped into the block, off to the right of the engine serial number. See if you can find that.

Ford 3910 engine internal issues

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