MF35 Locked up (z134)

[Cougsfan]

Something that struck me as a little odd from your pictures with the valve covers off is that it seems like all the valves are closed or very nearly closed. Perhaps it is just a distorted view in the photo, but shouldn't at least a few of the valves be open a bit more? Don't know how that would have anything to do with a siezed engine, but it seems a bit strange to me.

 

[rScotty]

Something that struck me as a little odd from your pictures with the valve covers off is that it seems like all the valves are closed or very nearly closed. Perhaps it is just a distorted view in the photo, but shouldn't at least a few of the valves be open a bit more? Don't know how that would have anything to do with a siezed engine, but it seems a bit strange to me.

That struck me too, and I forgot to mention it. Thanks for bringing it up.
rScotty

 

[shaeff]

I don't notice anything glaring, however it does seem that almost all of the rockers are nearly on the same plane. Tough to tell, I'll have to put a straight edge on it.

I did mention that all the rockers seem to be on the same plane- that's what I meant, it looks like they're all in the same position. I wonder if the cam snapped? Wouldn't be the first time I've heard of it happening on a z134.

I see that shim.... no idea at all. Not only do I not know what it is, I can't figure out where it would have come from. It has to be part of the rocker gear.. right?? And where is the rest of it?

I looked around online to see if I could find an exploded view or parts diagram for the motor and couldn't find one. If you know of a link, let me know. There does seem to be a parts dealer in Canada whose website seems promising.

What I was looking for was to see if a picture showed anything in the front cam drive/timing cover that could explain a sudden lockup.
If the timing is by gears and the rest of the shim got caught between two gears it is one of the few things that might explain what happened to yours so suddenly and without even running.
I keep coming back to the only clue you have - that it was running fine and then the starter moved it just a little and no more. Maybe it is something simple in the bellhousing/starter system.

The problem I have with anything in the head and bore locking things up is that I would think you ought to have been able to at least rock the engine a few degrees of rotation with your pry bar. Well we will know eventually.

My inspection scope isn't small enough to fit through a spark plug hole either or into the bell housijng - it's a 75 foot for 4" drain lines. Chinese. Quite surprisingly good quality and well made.
I see quite a few mechanic's endoscopes for under $50 on Amazon that are USB type made to plug into a laptop computer.
That is still on my Christmas list, but before I get one I'd have to have some sort of idea of what features to look for. I'm trying to slow down on buying tools just to satisfy a one-time curiosity bump (hopeless, I know) and I know nothing about mechanic's scopes.
rScotty

Looks like it came off that valve with the partial shim sticking out of it. The last pic I posted. If you see at both ends of the cam, there's also a spring, washer, and cotter pin. The cotter pin was broken on one side and partially broken on the other. No clue where those pieces went (maybe in the pan? Maybe in the timing gears?)

Exploded view, and pic attached:
Links don't work, attached pics at bottom.

I'll try my inspection camera in the bellhousing next. It's dark when I get home every day, only have weekends to play around with it. It was also down on power before I turned it off. Maybe one of the flyballs from the governor let go and jammed up somewhere...

Something that struck me as a little odd from your pictures with the valve covers off is that it seems like all the valves are closed or very nearly closed. Perhaps it is just a distorted view in the photo, but shouldn't at least a few of the valves be open a bit more? Don't know how that would have anything to do with a siezed engine, but it seems a bit strange to me.

Yep, I mentioned that in post #18 that I thought it was odd. This would fall in line with a broken camshaft.

That struck me too, and I forgot to mention it. Thanks for bringing it up.
rScotty

Yep!

I guess we'll see this weekend if I get some more time. Planning to pull the head.

 

[rScotty]

I did mention that all the rockers seem to be on the same plane- that's what I meant, it looks like they're all in the same position. I wonder if the cam snapped? Wouldn't be the first time I've heard of it happening on a z134.

Looks like it came off that valve with the partial shim sticking out of it. The last pic I posted. If you see at both ends of the cam, there's also a spring, washer, and cotter pin. The cotter pin was broken on one side and partially broken on the other. No clue where those pieces went (maybe in the pan? Maybe in the timing gears?)

Exploded view, and pic attached:
Links don't work, attached pics at bottom.

I guess we'll see this weekend if I get some more time. Planning to pull the head.

Thanks for the exploded views. They add to the fun. I was pretty sure we were looking at a Z134, but not positive.

Yes, you did mention that the rockers were all on the same plane - and I just forgot to comment on it. But that is absolutely fascinating. What in the world could cause that? Even if the camshaft broke in half at the center bushing....or spun or came loose from the timing gear it seems to me that some of the rockers would still be pushing valves open. Unless the lobes were worn clear flat.

I can think of several possible reasons for an engine to seize up tight.. - but other than crazy wear, I can't think of any reason for the cam not opening a single valve. Maybe it is, and we just are not seeing it.

On the cotter pins and shims on the end of the rocker shaft, I thought that you had removed those. If not, the chances increase in my mind that something got down into the timing chest and jammed the timing gears.

rScotty

 

[Jerry/MT]

I did mention that all the rockers seem to be on the same plane- that's what I meant, it looks like they're all in the same position. I wonder if the cam snapped? Wouldn't be the first time I've heard of it happening on a z134.

Looks like it came off that valve with the partial shim sticking out of it. The last pic I posted. If you see at both ends of the cam, there's also a spring, washer, and cotter pin. The cotter pin was broken on one side and partially broken on the other. No clue where those pieces went (maybe in the pan? Maybe in the timing gears?)

Exploded view, and pic attached:
Links don't work, attached pics at bottom.

I'll try my inspection camera in the bellhousing next. It's dark when I get home every day, only have weekends to play around with it. It was also down on power before I turned it off. Maybe one of the flyballs from the governor let go and jammed up somewhere...



Yep, I mentioned that in post #18 that I thought it was odd. This would fall in line with a broken camshaft.

Yep!

I guess we'll see this weekend if I get some more time. Planning to pull the head.

You might pull the timing cover and take a look. I still don't understand how at least some of the valves were not actuated. Is this an interference engine? I wonder if the timing gear failed and then the pistons hit the lowered valves and bent them and the push rods so they would just "hang there"? I can't believe that this would not be accompanied by a hell of a racket.

In the dim recesses of my memory, I seem to remember some of the Z series Continentals had a fiber timing gear. It has steel teeth bonded on a fiber center section.

This becomes "curiouser and curiouser"!

 

[shaeff]

Thanks for the exploded views. They add to the fun. I was pretty sure we were looking at a Z134, but not positive.

Yes, you did mention that the rockers were all on the same plane - and I just forgot to comment on it. But that is absolutely fascinating. What in the world could cause that? Even if the camshaft broke in half at the center bushing....or spun or came loose from the timing gear it seems to me that some of the rockers would still be pushing valves open. Unless the lobes were worn clear flat.

I can think of several possible reasons for an engine to seize up tight.. - but other than crazy wear, I can't think of any reason for the cam not opening a single valve. Maybe it is, and we just are not seeing it.

On the cotter pins and shims on the end of the rocker shaft, I thought that you had removed those. If not, the chances increase in my mind that something got down into the timing chest and jammed the timing gears.

rScotty

You bet! I started removing the head this past weekend, then got interrupted by a snow storm. This machine isn't high priority, so I'm not working out in the freezing cold AND snow. It's certainly possible that something dropped out and into the timing set, but I'd think I should still be able to spin it backwards. :dunno:

You might pull the timing cover and take a look. I still don't understand how at least some of the valves were not actuated. Is this an interference engine? I wonder if the timing gear failed and then the pistons hit the lowered valves and bent them and the push rods so they would just "hang there"? I can't believe that this would not be accompanied by a hell of a racket.

In the dim recesses of my memory, I seem to remember some of the Z series Continentals had a fiber timing gear. It has steel teeth bonded on a fiber center section.

This becomes "curiouser and curiouser"!

At this point, the head is nearly off, I'm just going to continue with that. This machine has a loader on it so it's very tight to work on. I may end up pulling the timing cover as well, but I'd like to pull the head first and see if anything is obvious in there.

The pushrods all look perfectly straight to me, I got them and the rocker assembly out and the head is fully unbolted. I just need to pull the carb linkage, governor, and exhaust pipe off and it's ready to lift out.

I'm not sure if this has a fiber center section or not, I've never had to dig into it this far. It'll be interesting to see no matter what comes of it.

 

[rScotty]

OK. Well then it isn't something really weird like the rods all suddenly bending or shrinking half an inch.... I doubted that too, but after enough mechanical mysteries we learn to check everything. Someday I'll write about the bug in the main jet.
So it stays curious.

Gotta say it sure is nice to sit here retired in my nice warm shop and get to follow an interesting problem like this one where none of the valves apperar to be opening. And on a nice old engine that ran fine right before quitting. ...

But even nicer is like I said... being warm while someone else does all the grunt work and the rest of us have the fun.
I'll try not to feel gullty. I've been there. It's about 18 degrees here today. Hope you have a place to warm up.

rScotty

 

[shaeff]

OK. Well then it isn't something really weird like the rods all suddenly bending or shrinking half an inch.... I doubted that too, but after enough mechanical mysteries we learn to check everything. Someday I'll write about the bug in the main jet.
So it stays curious.

Gotta say it sure is nice to sit here retired in my nice warm shop and get to follow an interesting problem like this one where none of the valves apperar to be opening. And on a nice old engine that ran fine right before quitting. ...

But even nicer is like I said... being warm while someone else does all the grunt work and the rest of us have the fun.
I'll try not to feel gullty. I've been there. It's about 18 degrees here today. Hope you have a place to warm up.

rScotty

Haha, I hear that! I love a good mystery, however I prefer it in a more climate controlled environment.

Once my house is paid off I'll build a shop. Projected to be 6yrs, hoping to have it paid by the time I'm 45. Until then, I'll brave the elements. Hoping to get the head pulled this coming weekend, but with a sick kiddo in the house, we're not getting much in the way of sleep. I'm coming down with whatever he's got, too, so that'll slow me down but it won't stop me. Weather, on the other hand will definitely stop me.

 

[Jerry/MT]

You bet! I started removing the head this past weekend, then got interrupted by a snow storm. This machine isn't high priority, so I'm not working out in the freezing cold AND snow. It's certainly possible that something dropped out and into the timing set, but I'd think I should still be able to spin it backwards. :dunno:

At this point, the head is nearly off, I'm just going to continue with that. This machine has a loader on it so it's very tight to work on. I may end up pulling the timing cover as well, but I'd like to pull the head first and see if anything is obvious in there.

The pushrods all look perfectly straight to me, I got them and the rocker assembly out and the head is fully unbolted. I just need to pull the carb linkage, governor, and exhaust pipe off and it's ready to lift out.

I'm not sure if this has a fiber center section or not, I've never had to dig into it this far. It'll be interesting to see no matter what comes of it.

we are all going to learn something out of your tear down. Anyway to remove the loader to make the job easier?

 

[ROUSTABOUT]

Engine sounded fine before shutting it down. No odd noises or anything. In fact, it was idling perfectly fine too.

When I went to crank it over a good 18hrs later, it sounded like it turned a tiny bit and stopped. Another forum I'm on (YT) one of the guys there suggested the same- spun bearing. I was hoping to avoid all that, but if it needs a rebuild, there's no better time than this winter to tear it down. The key is to get the motor in my basement and on an engine stand before the snow flies. I'm aware of the potential for the front to flop over without the axle wedged, but thanks for the reminder. If I end up having to pull it all apart, I'll be replacing the leaky rear main seal, checking the clutch for oil exposure from that leaky seal, tidying up everything that needs it.

Thanks for the tip on the PTO trick, that'll be helpful.

Side to side flop needs to be stopped by wedges. Need to take all weights off front bumper. Also check for a weight under engine front. I pulled one out of a MF that was 505#, but it was a bigger tractor than yours. You do not want it to flop over front ways either. Some tractors had an extra weight there so check for it.