Valve Guide Removal Problem

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kjmc
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Joined: Mon Jan 27, 2020 8:13 am
Zip Code: 48105

Valve Guide Removal Problem

Postby kjmc » Thu Apr 09, 2020 12:18 pm

I got a Farmall Cub over the winter, and narrowed the problems down to stuck valves and a dead magneto. After pulling the head to get at the valves, I decided some of them were too loose in their guides, and others were too tight, so I went out and bought replacement valves and guides.

Yesterday I got 7 out of 8 of the valve guides out, but the very first valve guide wasn't having it. I'm using a 3/16 bar of steel to pull against, and had a 5/16" grade 8 fully threaded bolt. I stuck another piece of steel under the main bar to get the angle right.

For the 7 that came out, only one gave me a problem, and that bent my 3/16 bar a bit and damaged one of the grade 8 nuts. It finally gave up and came out. But that last one damaged both of my grade 8 bolts, bent my bar like a pretzel, and deformed three grade 8 nuts. Wow.

So, I hit it with PB Blaster yet again, and called it a day. But then on the way home I started wondering if that much force could be damaging my block. Is it possible to do damage by applying too much force to get a guide out? As it turns out, that is also the valve that was sticking the worst. I wonder if I'm not the first to find that guide is a problem. It's the one all the way at the front of the engine.

Then I also thought, heck, why not drill it out to get a bigger bolt into it? I tested one of the old ones at home, and there's no problem drilling out the shaft like that. It drills just fine with a cobalt bit. Anyone know of any problems with doing that?

I figure I'll leave it sitting in the penetrating oil for a few days, then try it again on a cold morning, with new 5/16 parts first, then drilling it out and using 3/8" parts if that doesn't do it.

CharlieK
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Re: Valve Guide Removal Problem

Postby CharlieK » Thu Apr 09, 2020 5:22 pm

get a bigger hardened bar
get er done; life is good

Frozenstate
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Re: Valve Guide Removal Problem

Postby Frozenstate » Thu Apr 09, 2020 6:31 pm

Can you knurl the guides and ream them instead of replacing?

Alan Riley
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Re: Valve Guide Removal Problem

Postby Alan Riley » Fri Apr 10, 2020 8:57 am

I didn't pull mine - I drove them out with a brass drift punch and a hammer.
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kjmc
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Re: Valve Guide Removal Problem

Postby kjmc » Fri Apr 10, 2020 1:08 pm

CharlieK - yep, I have a 1/4 thick alloy steel bar coming from McMaster to try. The bar I'm bending is 3/16" mild steel, so the new piece should be a lot stronger. I don't need to worry about the block then? I'm just kind of shocked by the deforming in those grade 8 nuts. It's impressive.

FrozenState - I'm past that at this point, with 7 of them out already. Kind of wish I'd read about that before I bought the parts and got started.

Alan - how in the world did you get enough clearance to use a punch and hammer? Did you drive them down? Doesn't seem like there's room there either, but at least that way you'd have a clear shot for the punch, coming at them from the top. I thought about trying to drive it down, but that seemed likely to get me stuck smacking into the lifter with no room to go farther. And the puller version seems to be what lots of people have done here.

So I think what I'll be trying next is grade 9 nuts, on a 5/16" grade 8 bolt, with the 1/4" steel bar, on a cold morning. I didn't even know there was a grade 9, but McMaster Carr had them. Any value to hitting it with a chisel from above first, to crack things loose a bit? No concerns about damaging the block? If that doesn't work, I'll drill it out to 3/8" and try 3/8" grade 8 nuts and bolts.

Thanks guys!

Alan Riley
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Re: Valve Guide Removal Problem

Postby Alan Riley » Fri Apr 10, 2020 2:52 pm

kjmc wrote:
Alan - how in the world did you get enough clearance to use a punch and hammer? Did you drive them down? Doesn't seem like there's room there either, but at least that way you'd have a clear shot for the punch, coming at them from the top. I thought about trying to drive it down, but that seemed likely to get me stuck smacking into the lifter with no room to go farther. And the puller version seems to be what lots of people have done here.



I did it with a bare block, no lifters or cam to worry about. I installed the new ones the same way, coming down through the top. I bought a reamer for the guides just in case it was needed but I didn't have to use it.
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Glen
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Re: Valve Guide Removal Problem

Postby Glen » Fri Apr 10, 2020 11:55 pm

Hi,
Here is info about the valve guides, if you need it.

The valve stems need the right clearance in the valve guides after the guides are installed in the engine.
It is good to read the engine section in the Cub service manual and see what IH said about the valves.

The valve stem clearance can get too small after driving the guides into the engine, the guides can shrink slightly. If the stem clearance is too small, a reamer is needed to make the holes bigger, like Alan Riley said above.
Someone on here had a Cub that he had the engine rebuilt, and it ran ok when it was cold, but when it warmed up, one valve would stick open, and the engine ran rough. The valve stem was too tight in the guide.
Below is a page from the Cub service manual showing the valve stem clearance.

http://www.farmallcub.info/manuals/gss- ... 001-07.jpg

Below is a page from the manual showing how the valves should fit in the valve seats.

http://www.farmallcub.info/manuals/gss- ... 001-24.jpg

The head torque sequence is in the manual too, on page 1-14.

Below is the Cub and LoBoy service manual, if you don't have it.

http://farmallcub.com/rudi_cub/www.clea ... index.html

Below is a post I wrote info on about replacing the head gasket. The info is at my first post on the page. :)

viewtopic.php?f=1&t=102173&p=807860

kjmc
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Zip Code: 48105

Re: Valve Guide Removal Problem

Postby kjmc » Sat Apr 25, 2020 8:29 pm

I got it out. I didn't see anything to say there's any damage - looked fine. I have the new guides in now. I think the most important part was using thicker bar stock. I ended up using both the 3/16" and the 1/4". CharlieK gets the nod on that part. I just drilled a hole in the 1/4 and put my puller bolt through both of them. I also used three grade 9 nuts - didn't know there were such things, but McMaster-Carr had them. Between the much thicker bar and the grade 9 nuts, it didn't put up much of a fight after that.

Then I had to get the oil pan off to get one of the valve retainers that got away from me. I got all the bolts off, and couldn't figure out how to get the pan off. It was blocked in the back by the flywheel and cover, and in front by the... Oh, hey, that's just the front toolbar. Maybe I should take that off... :oops: :roll:

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Glen
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Joined: Mon Mar 19, 2012 7:33 pm
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Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
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Location: Wa.

Re: Valve Guide Removal Problem

Postby Glen » Sat Apr 25, 2020 11:12 pm

Hi,
Besides the lower cover held on the clutch housing with the 4 bolts, that you would need to remove, there are 3 bolts holding the rear of the oil pan on the engine, like on the front of the oil pan.
The 3 rear bolts are hard to get at, they have said on here to use a socket with 1/4" drive, an extension, and a universal joint.

You might be able to find the valve retainer without removing the oil pan, using a magnet on a long flexible handle. They might sell them at auto parts stores.
You can put the magnet in through the oil drain plug hole, and the oil fill tube, move it around slowly every direction you can.

If you have to remove the oil pan, tighten the rear 3 bolts gently when putting it on, their threads are in the rear engine oil seal retainer, which is made of soft metal.

Below is a pic from TM Tractor of the oil pan showing the rear 3 bolt holes. :)
Attachments
Cub oil pan .jpg


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