Cat 426 Inframe Overhaul Advice

Nige said:

Do you have a good photo of the Serial Number plate from your engine.?

Click to expand...

Here is pics of it.

Rocket Man said:

Here is pics of it.View attachment 245134 View attachment 245135

Click to expand...

Here is a better pic.

Rocket Man said:

Here is pics of it.

Click to expand...

The original engine for the machine S/N is listed as "128179" in the Cat system. That's the same engine as the one on the plate IMHO. So the engine appears to be original and will date from anywhere from 3-6 months before the build date of the loader (18th Dec 1986).

As I see it you have a few possible options from here on in:-

1. Use the Parts Manual SEBP1589 that @edgephoto shared with you and buy parts from a Cat dealer based on Cat Part Numbers. Don't ask the dealer to find a specific number for you, give it to him.
2. Continue down the route of trying to find Perkins parts based on the engine Serial Number.

Random comments from the photo regarding the interpretation of the engine Serial Number:-
1. I don't think the last letter is an "A". It looks almost like an upside-down "V" because the "crossbar" part of the "A" is missing completely. So I wouldn't put too much emphasis on the Year Code being "wrong" based on the YOM of your loader.
2. "LD" at the start of the number is the Code for a basic 4.236 engine. If it was a C4.236 it should be "LH" or if it was a T4.236 (full-blown turbo) then it would be "LJ".
3. The "U" in the middle signifies it is a UK-built engine. Correct if it was built for a Cat BHL. All the engines for the Cat BHL product line are still built in Peterborough to this day.

Nige said:

The original engine for the machine S/N is listed as "128179" in the Cat system. That's the same engine as the one on the plate IMHO. So the engine appears to be original and will date from anywhere from 3-6 months before the build date of the loader (18th Dec 1986).

As I see it you have a few possible options from here on in:-

1. Use the Parts Manual SEBP1589 that @edgephoto shared with you and buy parts from a Cat dealer based on Cat Part Numbers. Don't ask the dealer to find a specific number for you, give it to him.
2. Continue down the route of trying to find Perkins parts based on the engine Serial Number.

Random comments from the photo regarding the interpretation of the engine Serial Number:-
1. I don't think the last letter is an "A". It looks almost like an upside-down "V" because the "crossbar" part of the "A" is missing completely. So I wouldn't put too much emphasis on the Year Code being "wrong" based on the YOM of your loader.
2. "LD" at the start of the number is the Code for a basic 4.236 engine. If it was a C4.236 it should be "LH" or if it was a T4.236 (full-blown turbo) then it would be "LJ".
3. The "U" in the middle signifies it is a UK-built engine. Correct if it was built for a Cat BHL. All the engines for the Cat BHL product line are still built in Peterborough to this day.

View attachment 245138

Click to expand...

OK. I magnified that number on my screen and u r right, it is not an A, it is an N that was stamped at an angle and the other leg missed the nameplate area and is barely visible off plate. I was not able to see that detail until i spray painted the number this morning. That N signifies the year 1986, which is the right year.
Thanks to all of you here for all the input and parts numbers etc. I have been able to compile enough info to be able to buy the right aftermarket kit now. I have been buying all my parts from Cat so far and the prices are reasonable, hydraulic hoses , radiator hoses etc. but the engine hardware, not so much. One piston is $190+ and one set of rings $85+. One after market rebuild kit $600+. So not much contest there.
One other question comes to mind: how does the Cat BHL compare to the Perkins line? I wonder if any of the parts are the same or interchangeable? Just curious.

Rocket Man said:

One other question comes to mind: how does the Cat BHL compare to the Perkins line? I wonder if any of the parts are the same or interchangeable? Just curious.

Click to expand...

Perkins is/was purely an engine manufacturer, they never built complete machines. Cat selected Perkins to supply the engines for the original line of Cat backhoe loaders such as yours back in the 1980's. In 1998 Cat bought Perkins outright and the engines for the smaller Cat machine lines (BHL, SSL, MTL, etc) supplied from the former Perkins factory in the UK became known in the trade as "Perkapillars" - still built at the Perkins plant but with Cat logos on them.
AFAIK most if not all Perkins engines supplied to other OEMs apart from Caterpillar are still badged as Perkins today.

I don't plan on touching my engine unless something happens to it. It runs, does not smoke and sounds fine. If I do have to tear it down and replace parts I will measure the sleeves for taper and round. If in spec. I will measure the pistons. If they are in spec. I would hit the cylinder with a light hone and re-ring. Why replace the hard parts if they are still serviceable.

Although if the $600 kit includes all gaskets and seals as well as rings, pistons and sleeves it might be worth it. Providing the parts are of good quality.

You are very lucky by having a good engine. These things are really awesome and if taken care of will last for decades. We are looking at 35 year old machines and still running.
I can tell you these engines are tough!! After all that ether and bad treatment by the PO, the cylinders in mine really do not look that bad. At first they looked in good shape and were glazed over pretty bad. I then used a hone and found lots of vertical grooves in number 1. I could not see the grooves before the honing. That # one could have been honed out with minimal loss of the walls.
Number 2 was a total loss. The first few ups and downs revealed not only the vertical grooves but it was egg shaped as well. So bottom line is i have no choice but to replace them all. I installed my puller on #1 and it is stuck. It crushed my wooden space blocks and never moved. Today i will drag out the welder and go that route. They should come out easily.
Now the anticipatory fear is replacing them. On the old Ford tractors the walls were only 90mm and i would dry ice them, coat the cylinder walls with Loctite red and drop them in. Sometimes i had to finish off with a block of wood and hammer. But these Perkins liners are much thicker and may not be so easy.
Now, my question is, would you go back with the 3 ring piston or the 4 ring piston? There is a choice and either piston will work. I am getting my kit from an American firm and products made in USA. (So it is said). Kit that is recommended comes with the 3 ring pistons. But i can substitute to one which has the 4 ring pistons.

Do the farmers carry out artificial insemination of cattle around your way.?
If the answer is yes then you ought to be able to rent a container of liquid nitrogen which is the mutt's nuts when it comes to installing shrink-fit parts such as your cylinder liners. Just be careful - it's f'kin cold (-320F).

Nige said:

Do the farmers carry out artificial insemination of cattle around your way.?
If the answer is yes then you ought to be able to rent a container of liquid nitrogen which is the mutt's nuts when it comes to installing shrink-fit parts such as your cylinder liners. Just be careful - it's f'kin cold (-320F).

Click to expand...

Nige, good idea! I never thought of that, just the dry ice. I will double check on that. Don't know about the cows but there are lots of race horse farms here and they probably do the same thing. Also, they use that liquid nitrogen in the oil fields which are not far away.

An old trick is to steam-clean the cylinder block while the liners are chilling in the LN2. The combination of the expanded block with the shrunk liners means you have to be careful the liner doesn't fall straight through the hole when it is installed.....

Nige said:

An old trick is to steam-clean the cylinder block while the liners are chilling in the LN2. The combination of the expanded block with the shrunk liners means you have to be careful the liner doesn't fall straight through the hole when it is installed.....

Click to expand...

H Ha that would be funny, except it would be tough getting them back out. Luckily mine have the wide flanges at the top so they can't fall thru. I will pressure engine cause i don't have a steamer.

I just wanted to post an update on the engine rebuild on my Cat 426 Backhoe. I was waiting on my parts to come in and took forever to get them it seems. Complete rebuild kit including upper and lower gaskets, many of which won't be used because it is an "inframe" rebuild i am doing. Bought all the extra items i thought i would need and many i will not use. For example, i bought a new OIL PUMP, but won't use it BC you can not get the pump out without pulling the front crankshaft pulley and cover off. I checked the crank shaft rod areas and they were exactly what the manual said they should be at standard.
The good part of this is about the sleeves. Took lots of effort to get the sleeves out as they were really stuck in there. After i got them out and checked the part number on them i understood why, maybe. There are two sleeve types, one that is finished and ready to go and the other is the one that can be installed but requires machine finishing AFTER they are installed. Mine had the last one and apparently they maybe had a closer tolerance fit?
So i bought the one that was finished and ready to install. I used DRY ICE to cool the sleeves down before installation. ( I wanted to use liquid nitrogen which is plentiful here BUT no one had containers to go with it, No rentals either. You are required to furnish your own.) I used about 40 lbs of dry ice to completely cover the sleeves and let then stay in the crushed ice for 30 minutes per sleeve. Results were surprising, the first one just dropped in all way to the flange. The second one hung up at about 1/4 inch in and had to work it back out. I skipped that one to be the last as it was going to be trouble. The third one dropped in to about the last inch and had to pound it in rest of the way. The fourth one dropped in perfectly.
Now back to the trouble one #2. Left the sleeve in the dry ice for 30 minutes or so and took a deep breath and tried again and it just dropped in all the way to the bottom. Problem was, it has to be started PERFECTLY straight immediately Or it will hang up.
Here is a hint on buying dry ice. I went to the source of dry ice production thinking it would be cheaper. It cost me $250 per pound. I happened to be in that all encompassing big store (next day) that sells everything and guess what, they had dry ice for $1.25 per pound. So check your local grocery store for dry ice, it will be somewhere close to the customer Service area in a freezer that looks like an ice cream chest. Name on it is Penguin.

Hello all. I now have a big mystery on my hands and am turning to you all to maybe help me out.
These pics are of a piece of metal i found under my back hoe engine and i have no idea what it is. It is one piece and the pics are the front and back.

Recall that i have been doing an inframe engine overhaul and have completed all the tasks i set out to do. I have reinstalled the pan, head and most major components. I am taking my time and cleaning things up as i go. As i was installing a new alternator i dropped a small nut in the dirt and was using a magnet to find it when i latched onto the above "clip". It is about 2 1/8 inches outside diameter and 1 inch inside diameter. It kind of looks like a "thrust" spacer/washer but is way to small. Looks like it might be some kind of retainer? The raised slots on the outside tells me that it is designed to maybe fit into a recessed area?
Anyway it was laying directly under the rear part of the engine and as you can see it it not rusty and looks fresh out of a moving past area. Since it is fresh looking i can only assume it came from my engine?
Any help would be greatly appreciated.

It looks like 1/2 of a crankshaft thrust washer to me.

Tinkerer said:

It looks like 1/2 of a crankshaft thrust washer to me.

Click to expand...

Yes it does resemble one, except it is way to small. ID of the one in the pic is only 1 inch and OD of crank shaft is 2 1/2 inches. It is more likely to have been a shim for a cam shaft, but they don't come in half circles. All the ones i have ever seen are full circles and fit onto the cam shaft as it is installed, usually in the front behind the "sprocket".

OK, here are the pics again but more to actual scale as i have set them against a quarter to show the actual size.

This will give a more realistic view and maybe trigger some recognition. I am beginning to doubt that it came from my Perkins Engine and that deepens the mystery as to exactly what is the item and where did it come from? Driving me crazy. If it does belong in the engine and is an essential part i will have to tear the engine down again. I just can not imagine where it might fit in.

Rocket Man said:

I am beginning to doubt that it came from my Perkins Engine

Click to expand...

I'm beginning to agree. Looks nothing like a crank shaft thrust bearing from your engine. Looked right through the parts pictures... front structure, alternator, oil pump, starter, camshaft, fan hub, etc, found nothing that looks like that (unless I'm blind, which is possible).

Any witness marks or wear if you look really closely?

I agree that it certainly is too small to be crankshaft thrust washer. But it sure has the appearance of one.

Chrisso said:

I'm beginning to agree. Looks nothing like a crank shaft thrust bearing from your engine. Looked right through the parts pictures... front structure, alternator, oil pump, starter, camshaft, fan hub, etc, found nothing that looks like that (unless I'm blind, which is possible).

Any witness marks or wear if you look really closely?

Click to expand...

The only marks are the circular ones on it that indicate it indeed is a "shim" or "thrust" washer of some kind. I too looked at the parts manual for everything from engine to differential and there is not a pic of this item. I know it did come from this machine BC there ground it is sitting on was brought in from my "back 40" by this very machine and when it is sitting right where it quit running. I did pressure wash the entire machine right where it sits and maybe that piece was laying on the machine somewhere ? BUT, it WAS directly under the motor as if it had fallen straight down from the engine.
BTW, i went to alibaba and pulled up all pics of thrust washers and never found a likeness of this one. LOL
Anyway, i believe i have been convinced that it is NOT from the engine and it is safe to finish the re-assembly.
Thanks to all.

Well i completed the re-assembly and all went well. Bled the air out of the fuel system and it fired right up instantly. Runs like a top !! Thanks to all with all the great advice and support.