Colt Case Ingersoll Garden Tractors

I've got a 446 I bought back in October. Always wanted one of the high wheel tractors and finally got one. Unfortunately, I was either taken for a ride or the guy I bought it from had no idea what he was talking about. Long story short, it turned out the engine (Onan B43M) was only running on one piston as the other had thrown its rod. I pulled the engine and replaced both rods and pistons with used ones I bought online. Got it all back together and now the engine will turn all day long but will not fire. There appears to be an issue getting fuel but it will not fire even when gas or starter fluid is put directly into the carb. Plugs are sparking. I checked the heads and found what I (as a novice) would consider a lot of slop in the pistons. Got a compression tester and found that each cyllinder is registering zero. My question would be where to go now... I figure my options are to keep banging my head with this Onan in the hopes that I get it running before time to start mowing, repower it with a Vanguard and kit, or just junk the whole machine and buy something new. Any help would be appreciated.

Vivala446

page 18, https://manuals.ccigt.com/More/Onan-BSe ... Manual.pdf

If there is no compression then you have a valve issue. Are they opening and closing? It there carbon lodged in them causing them to stick or not close properly? If they are opening and closing completely then is the valve timing correct.

Those are questions to start with.

Spike188

I checked the valves when I had the heads off. Everything looked good to me. Seated properly and opening and closing good.

I'm no certified mechanic but I feel that the rings are not sealing things up good enough. But I'll admit that I could be 100 percent wrong on that

BTW, I appreciate the quick response.

Sometimes putting a table spoon of oil in the cylinder will bring the compression up enough to start. I have a 446 that had near zero compression and was able to bring it back to life using that method. The best compression test registered after that was 75 psi. It does need an overhaul but at least hydraulic and drive train were able to be tested.

Spike

I'll give that a try.

I'm assuming that if none of those things work the last option would be pulling the engine again and re-ringing it.

@Vivala446 Did it start and run on one cylinder?

Spike

Zero compression would mean there are actual holes by the rings. I suspect the engine timing is way off. If the valves don't close when they should it's impossible to build any pressure in the cylinder.

You should be able to assess this even just with the heads off, turning the engine and paying attention to the valves and piston.

My guess is that valve timing is off, but it did run on one cylinder when you got it. But if you did not touch any of that part, it should be the same.
Another guess is that you put pistons in this engine, and say they seem sloppy. So maybe the engine is bored out 0.030 and you put standard pistons in.

Noel

Good point Noel! The pistons must be stamped with their size, std for standard, 010 or 020 or 030.

Did you take any pictures of any of the pistons, old and new old?

Vivala446 wrote: ↑Mon Jan 24, 2022 3:23 pm I've got a 446 I bought back in October. Always wanted one of the high wheel tractors and finally got one. Unfortunately, I was either taken for a ride or the guy I bought it from had no idea what he was talking about. Long story short, it turned out the engine (Onan B43M) was only running on one piston as the other had thrown its rod. I pulled the engine and replaced both rods and pistons with used ones I bought online. Got it all back together and now the engine will turn all day long but will not fire. There appears to be an issue getting fuel but it will not fire even when gas or starter fluid is put directly into the carb. Plugs are sparking. I checked the heads and found what I (as a novice) would consider a lot of slop in the pistons. Got a compression tester and found that each cyllinder is registering zero. My question would be where to go now... I figure my options are to keep banging my head with this Onan in the hopes that I get it running before time to start mowing, repower it with a Vanguard and kit, or just junk the whole machine and buy something new. Any help would be appreciated.

Welcome aboard
Did you have the cam or crank out of the engine ?
Did you adjust the valve clearance ? No valve clearance, can cause no compression.
What rings did you use the ones that came out of each cylinder or the one on the used pistons ?
Who"s gaskets did you use .
Was there anything stamped on the top of the old pistons and the new used pistons ?
What shape was the crank in ?
Did the pistons come all the way out to the end of the block when at top dead centre ? A lot of the onans have the same diameter pistons in the same block , but have different stroke and that changes the rod length . The wrong rod , too short would cause no compression.

Bear with us we will help you figure it out .

Dave

Wow… I’m overwhelmed and grateful for all the knowledge here. Let me see… I didn’t check the size of the pistons but the rods had the same numbers stamped on them as the old ones so i assumed (perhaps wrongly) that everything else was the same too. I didn’t touch the valves or pull the crank. Just took off the heads and oil pan and changed the pistons and rods. When the pistons are extend level with the head.

Wow, I’m overwhelmed and grateful for all the knowledge here! Let’s see… the new (used but new to me) rods had the same number stamped in them as the old ones so I assumed everything else was the same too. I didn’t mess with the valves or crank. Just pulled the heads and oil pan and replaced the pistons and rods. It ran on one cylinder before. Now, nothing.

If it ran on one cylinder before the rod replacement, that hints that there was good compression on #2 cylinder.

Looking back at your first post for clues, where did you get the rings from that you used on the replacement pistons. You changed both pistons, did they come with rings?

Being a scavenger myself, and a onetime car jockey, I know salvaged piston can work. A dealer brought us a 305 GMC that had overheated and scored one cylinder. We did and in-frame bore using a hone with diesel as cutting fluid. A 0.030 oversize used piston was purchased and we hone the cylinder until the scoring disappeared and the piston fit. We even reused the salvage yard rings. That pickup engine outlasted the gentleman that bought it from the dealer.

You must have some mechanical knowledge or you would have attempt this. Since we don't know your mechanical background or what tools or experience you have, I will not make any assumptions.

Spike

I bought the replacement pistons off eBay. They came complete with the rods and rings already assembled.

As far as my mechanical knowledge, I’m self taught over the last 20 years or so. If something needs done I study up on it until I feel
comfortable enough to do it, then plan the job so it goes as smooth as possible. Doesn’t always work out, but I find when things are successful you end up knowing your machine better than anyone else.

in my opinion you must determine if the pistons you got from ebay are the same size as the pistons you pulled out. I think I can save you some work. Those you pulled out must be stamped; if they say STD, you're lucky in a way, because no way you could fit an oversize piston to replace an standard size piston, if the bore was not worn out like crazy. If the stamp on the pistons you pulled out says 020 or 030, or even 010, it's possible that the pistons you got from ebay are STD. I would still expect some compression to show, not zero. Zero psi compression is at the opposite spectrum of Dave's 140 psi compression. Don't shoot @DavidBarkey

Unfortunately, I already tossed the old ones. I don’t recall anything being stamped into them and I know there isn’t on the eBay ones

Vivala446 wrote: ↑Mon Jan 24, 2022 11:05 pm Unfortunately, I already tossed the old ones. I don’t recall anything being stamped into them and I know there isn’t on the eBay ones

It's a bit of a tough situation you're in, because you probably don't have the tools to measure the parts you have.

Usually ebay sellers do mention the size of the pistons. Have another look at the listing.

I'm still thinking there's gotta be something simple that has been overlooked though. Maybe one of the other guys see it, as I tend to over complicate myself thinking about things.

There will be a lot of ??? signs about it all unless you can go by the book. Are the heads flat, were the head gaskets new, all the head bolts torqued to spec and in the right order, and so on.

I doubt you get zero compression from orienting the rings wrong on the piston, but if you haven't paid attention to the ring gaps when you reassembled the engine, most likely that's also wrong.

At the very least you'll need a 3-4" micrometer and telescoping gauges to measure what you got there. The rods you got might not be a good fit for the original crankshaft. I totally understand you taking a risk, and when it works, you're flying. But it didn't, so I think you need to be careful now and go by the book, there's no need to throw the baby with the bath water. To measure the crankshaft you'll need a smaller micrometer, and I don't know which, as I don't have the Onan manual handy. Probably 1-2".

me here.

Let me add this. Onan engines are not the cheapest to rebuild, but they'll last many years again, once rebuilt. In general, the tools to rebuild an engine are not cheap. Might be better to have a shop do it, if you don't think you'll do it again and again.

Also, in my opinion, don't give up. I got my first Case tractor because I did not have patience and I wanted one, it was not the best but it was good to begin with. In the next 3 years a lot of really good deals on Case tractors came up and I got some of them.

We'll help you as far as you want to go with this engine. If you were closer it'd be much easier too!

@Vivala446 After all I have read I feel one of two things is going on . Either the rings are stuck in the grooves / wrong piston size.
Or the head gasket is on wrong .
How to tell where the compression is going is to do a leak down test .
Take both head tins off , remove both spark plugs, remove breathe assembly and air hose to fan shroud , look down large hole in shroud with flash light , rotate crank shaft to top dead centre marked on flywheel (fan) , pull dip stick out ,open choke and throttle, using compressed air and blower with rubber tip, blow air in each spark plug hole and take note of where the air comes out . Rotate 1 turn and repeat .
The cylinder that is on compression will leak air out of the fault and the other will leak out what ever valve is open .
Example
- ring problem will come out dipstick tube.
- head gasket will come out where head and block meet .most likely the top
- valve problem will come out carb or exh on both sides on test 1 and test 2 .

note engine can be turned over by engaging the clutch and turning the pto pulley
Good luck and let us know what you find .

Dave

I think that some times when a piston has no marking it means it’s standard. Again I’m guessing.
When I rebuilt my TEA20 Ferguson tractor engine, I bought used sleeves and pistons from a fella in Ontario, who deals in old tractor parts. I also got new piston rings, gaskets and bearings too. I had to reuse one ring off the old pistons to fit in the bottom oil ring groove of the new used pistons. The new rings would not fit this lower ring groove. These engines had an oil ring at the very bottom of the piston below the wrist pin.
Any way, the old 51 Ferguson works great. Engine was done about four years ago.


Noel

I think probably the situation is that I bit off more than I can chew and now I need to consider the financial aspect of things. What’s going to be A.) cheapest, and B.) quickest to get the machine running so I can take care of my property

Your options are roughly either re-power the tractor, or fix this engine. If you can find a good 10-14HP Kohler from another Case you'd get at least an engine that you can use the attachments you have because the engine comes with the right shaft for the PTO.

To fix the engine you have, without some tools, is next to impossible. As I said, you need to find out the state of the engine, dimension of the cylinder bore, dimension of the pistons you got, and what shape the rings are in. I think everyone around here agrees that a proper rebuild of the Onan B43M is rather expensive, compared to a Kohler for instance. This is the reason I myself got only a Case 446 and several Case tractors with the Kohler 14HP.

From what you've said so far it seems that the most likely scenario is that the pistons you got now are undersized for the cylinder bore you have. A rough measurement without taking the engine out would be to take one head off, bring the piston all the way up, and see what a feeler gauge says for clearance between piston and cylinder. If it's way big you'll know for sure these are not the right pistons.

I'm a little late coming to the party Vivala446. From what I just read you replaced the pistons from some you purchased from Ebay. You also said you read up on how to do things before you jump into doing it. So, my question to you is did you check the ring gaps on the rings in the cylinders before installing them?
If everything is the same as before you replaced the pistons there is a leakage somewhere in the cylinders and a leak down test would confirm where, as one of the members suggested.

Keep the Peace
Harry

@Vivala446 Please don't step on your bottom lip and walk away. You have been peppered with a lot of information in the preceding post.

Of all the advice given @DavidBarkey is my choice of where to start. You have had the engine a part so doing an in-frame test should be clean and easy. Here is Dave's advice in a step by step form.

1) Take both head tins off
2) Remove both spark plugs
3) Remove breathe assembly and air hose to fan shroud
4) Look down large hole in shroud with flash light , rotate crank shaft to top dead center marked on flywheel (fan) ,
5) Pull dip stick out
6) Open choke and throttle,
a) Using compressed air and blower with rubber tip to seal around the plug hole, blow air into a spark plug hole and take note of where the
air comes out on that cylinder.
- ring problem, air will come out dipstick tube.
- head gasket, air will come out where head and block meet .most likely the top
- valve problem, air will come out carb or exhaust or both
b) Rotate flywheel 1 turn, apply air pressure to the second cylinder and repeat step (a)

The cylinder that is on compression stroke will leak air out of the fault and if not on compression stroke it will leak out which ever valve is open .

Note: Engine can be turned over by engaging the clutch and turning the pto pulley

If anyone has any more steps to add please chime in.

Spike.

I had a stroke of good luck last night… I found that I had set one of the old pistons and rods that I took out of the engine— the one that was in good shape out beside my garage. It had STD stamped in it. I’m going to verify probably this weekend, but I feel just by looking that the replacement pistons I bought are in fact a little smaller. If that’s the case that could be the issue.

http://www.enginemastersinc.com/onanreb ... mation.htm

Onan twins only come in 2 bores sizes Small block 16-20 hp and BIG blocks 24-25 hp . The stroke changes the hp. If the pistons coming out are std. over sized could not go in the hole . at this point I feel since it ran on one cylinder prior and the pistons came flush with the block . The valve system not touched . We are down to 2 things . The head gaskets on backwards (almost did it my self once) . Or the rings in the "new pistons" are stuck in the grooves .

Leak down test will tell all

Dave

Dave, did you forget the BF-MS?

16HP twin Onan BF-MS bore is 3-1/8
16HP twin Onan B43M bore is 3-1/4



The good news is that you found the old piston. All hope is not lost!

Upon review of my receipt for the “new pistons”, they were for a BF-MS. My engine is a B43M

Ah ha, now we’re getting somewhere. You’ll get it fixed now. Get the right pistons and your in business.

Noel

Mystery solved! Hey, it could be worse, right?

Now at least you can make some more informed decisions. You know your bore is STD, and that you need B43 pistons. Wish you had joined us sooner before you did all the work and got the BF-MS. Oh well, as my wife says often, sometimes you win and sometimes you learn.

I would never have figured it out if it wasn’t for everyone that responded here

here's one of my favourite songs ever




https://www.youtube.com/watch?v=zf5mu_JBM9w

Wow, you could almost hear the collective sound of gears turning to figure this out.
Now let's get this 446 back to work.

Eugen wrote: ↑Wed Jan 26, 2022 1:35 pm Dave, did you forget the BF-MS?

16HP twin Onan BF-MS bore is 3-1/8
16HP twin Onan B43M bore is 3-1/4



The good news is that you found the old piston. All hope is not lost!

Doh , Ya , the nice thing about BF-MS is it is the same small block and I am told can be bored to standard B43M

Dave

Well, I spoke too soon. When I got home I pulled one of the heads and the “new” pistons are stamped STD as well. Even if the one on the other side was a different size at least one cylinder should fire I’d think. Could it be the rings are wore out?

Vivala446 wrote: ↑Wed Jan 26, 2022 6:25 pm Well, I spoke too soon. When I got home I pulled one of the heads and the “new” pistons are stamped STD as well. Even if the one on the other side was a different size at least one cylinder should fire I’d think. Could it be the rings are wore out?

I thought you put two BF-MS pistons in.

I was basing that on the receipt I had. When I took the head off I saw the STD stamped in it but it was very faint

That was based on the receipt I had. When I pulled the head off I saw the STD stamped very faintly. The one that I know is STD didn’t have as much slop in it as the other side. And the surface was kind of rough. And I noticed some oil that looked like it had been squeezed up the cylinder to the top in the course of turning the engine. Could it be the rings are just wore completely out? Or could it be that there are size variations within the STD?

I am greatly confused now. So you bought two BF-MS pistons. Did you put them both in or only one?

Lol. Yeah, I have weaved a twisted tale.

When bought the tractor it was running on one cylinder— the passenger side. The drivers side did was in pieces. I bought what we’re described as BF-MS pistons to replace them. I replaced both pistons and rods with the supposed BF-MS ones. I didn’t mess with anything on the engine other than the pistons and rods— didn’t mess with the valves, etc. Once I got it all back together the starter will turn the engine all day long but it will not fire. Plugs are sparking. Valves work, etc.

As I said the piston that replaced the original damaged one has a lot of slop in it.

That’s where I’m at now.

So both pistons were replaced ? Right or wrong ?

Noel

Good. The BF-MS pistons are both 1/8 smaller than the original B43!

That's a big gap!

You have to pull them out and get the right size.

That’s correct. Both were replaced.

I held the old piston up to the one currently in the cylinder and it looked to be the same size. No local auto parts store has calipers on a loaner program.

Am I to understand both BF-MS and B43M have their own individual STD sizes?

Vivala446 wrote: ↑Wed Jan 26, 2022 8:02 pm That’s correct. Both were replaced.

I held the old piston up to the one currently in the cylinder and it looked to be the same size. No local auto parts store has calipers on a loaner program.

Am I to understand both BF-MS and B43M have their own individual STD sizes?

Yes, they are both standard for that particular engine as it was built. So the standard in MS is an eighth inch smaller.

Ok. I’m going to really show my ignorance here (but I learned long ago a truly smart man admits when he doesn’t know something) it’s still possible that I just have the wrong size pistons for the cylinder?

Don't worry, we have many beginners here, including me! We all learn.


Yes, 100% you got the wrong size pistons. The pistons you got are from a different type of Onan engine. The pistons you got from eBay are 1/8 of an inch smaller diameter than the pistons that are the correct size for your engine.

You have the B43M engine model. The pistons you got are from the BF-MS engine model.

As the engine gets older, the bore of the cylinder gets worn out. All engine start with STD size pistons, and the diameter of the cylinder bore for STD pistons for your engine is 3.25 inches. The manual states that the maximum clearance between the piston and the cylinder wall is 0.0053 inches. Compare this, 0.0053 inches to 0.125 inches (1/8) which is what you have now, probably even bigger because of wear.

So, no doubt, you pull those pistons out, they are the wrong size.

Alright. Thank you all so much. I can’t thank everyone enough!

This is a standard piston that is beyond end of life. Notice it is smaller than the bore to the point of exposing the top ring. This is the same engine with a .020 oversized piston after the cylinder was bored to match the piston Here is an example of how to check ring gap.

Spike

I went out to the garage and measured the pistons as best I could with a tape measure (for lack of anything else) and the ones I ordered to appear to be a hair smaller than the original one

Would it be best to get brand new rings to use on the correct pistons?

Vivala446 wrote: ↑Thu Jan 27, 2022 12:44 pm Would it be best to get brand new rings to use on the correct pistons?

I think you should get the motor tore down and see if you can find a way to measure the cylinders for wear. That way if they are too far out you can look at having it bored and then get oversized pistons and rings.

I have to look into that