Head Removal

[goxu1]

Shiny paint can hide a multitude of sins as I’ve found out

[Stanton]

No one likes to have a head bolt(or any bolt) break. But you can’t approach the task like it’s the end of the world if one does. You just have to do your due diligence in whatever method you use for removing stubborn bolts and if one or more breaks, just go on about the task of removing the broken ones. Just all part of the procedure. Good bits (and not overheating them) makes the job not so bad if you have to drill it out.

Agreed. I’ve had drill out several head bolts and although it’s not something I wanted to do, the task got done and I moved on. That engine runs great, by the way.

I’m sure whatever you have to do to get the job done, this will serve as a reminder to keep your head bolts the exact length the Parts Manual calls for and use thread sealant.

You’ll do fine…

[Stoffregen Motorsports]

Such a nice looking Cub in your picture by your username, hard to believe they are rusted in place that bad!

I have a book that I got 20-25 years ago, about how to restore your farm tractor. Some title like that. Opening the book and scouring the pages, there's not a lot of actual restoration going on. Mostly just cosmetic and hoses. Maybe the book should be titled "how to sand blast your farm tractor and paint it, but leave the mechanical things alone, because I don't want to get in there"

[Jim Becker]

If you want a pretty good book on tractor restoration, I suggest Spencer Yost's Antique Tractor Bible.
https://www.amazon.com/Antique-Tractor- ... 0760303355
There are other books that are very good on specific topics. But this is probably the most compehensive.

[goxu1]

Out of curiosity , how much of the threaded section goes into the block ?
The few bolts of mine that have snapped so have snapped at the start of the threads

[Glen]

Hi,
Below are pics at TM Tractor of new head bolts, it shows the amount of threads that the bolts have.

http://www.tmtractor.com/tm-tractor/gen ... ts_001.htm

One way to tell would be when you have the head off, put the unbroken bolts in the head and see how much is sticking out the bottom.

[SamsFarm]

Out of curiosity , how much of the threaded section goes into the block?

3 inches..........












Just kidding!

Seems like it was around 1 inch. But it has been a small handful of years since doing one!

[goxu1]

That's not funny

[SamsFarm]

I went to a auction probably more than 15 years ago on behalf of my brother while he was on vacation, while there I picked up a few things for my self, one of them is a Ridgid extractor set. https://www.ridgid.com/us/en/25-screw-extractor-set

Think I used one of the pipe extractors once since having it.

But for the 25 or 30 bucks I paid for it, sitting there it is cheap insurance.

My brother has the same set he bought long long before I bought this one, so I knew what it was and a idea how pricey they was back then! (I am sure I could have used his, but nice having your own!)

One of the things it has guides that fit into the holes that keeps you centered while drilling.

[goxu1]

I was in the shed tidying up today and decided to see how one of the broken bolts would drill
I clamped it in a vice and drilled away
Anyways , 15 minutes or so and 3 or 4 different drill sizes I stopped. The old bolt drilled pretty easy
Now , for the broken bolts in the block , the final drill size is 7.9mm
Question is what do the experts do next ?
Do you have to pick away the first couple of turns of bolt left in the thread so the tap starts in the right spot?

The old bolt I had a practice drill on

[SamsFarm]

Wow, that is a exceptionally well centered hole you drilled in there..... You sure you did not chuck that up in a lathe?

7.9mm down under = .311" up here!

Have removed tons of broken screws in my day, but broken due to stress or shear, not much for rusted in place and torqued off.

If using something that will keep you perfectly centered, the possibility exist to upsize the drill to the tap drill size and the heat created from drilling sometimes will be enough to break the old threads loose. Sometimes the drill will catch and with a right hand twist drill, drive the threads out the bottom. (Left hand twist drills unscrews them out the top) Thats for right hand threads.

Sometimes there is a sweet spot in drilling just a big enough hole that once the center material is removed, that the old threads contract a tiny bit, and a tapered screw extractor (Ezy Out) can remove them.

Be careful not to drill to big on the diameter if using a ezy out, the tapered design of the ezy out will want to expand the broken screw in the hole working against you.

The screw extractors like in the link above from Ridgid dont have the expanding nature like the ezy out does.

There is also a square tapered extractor made to be hammered into the hole you drilled into the broken screw.
Kinda works like the Ezy out, but does not expand the screw with torque like the Ezy out does.

Sometimes you will need to blast a torch through the hole you drilled to get the heat to help break the bond. If you heat them up, let them cool completely (and contract) before trying to remove.

Be careful trying to tap out the threads with a tap. Sometimes the tap will start some degrees off from the original threads lead in, and will remove a portion of the material of the block that you dont want to remove.

Some people have luck mig welding a nut onto the broken part. Surely I bet a tig weld might work also.

Dont know if any of this helps, but wish you luck!

[goxu1]

The battle goes on , but I was looking at old threads re head bolt torque in preparation for the big day..
45 ft/lbs seems to be the torque value which is mentioned most.
Some threads said that 45 ft/lbs exceeded the max for a 3/8 bolt and that grade 9 was needed.
I googled the subject and came up with about 4 pages that were similar.
44 ft/lb - dry
39 ft/lb - plated
33 ft/lb lubricated
The bolts I bought were from TM , which are plated.
So if I use these with anti seize , is the max torque now down to 33 ft/lbs ?

https://crafter.fastenal.com/static-ass ... r8_Gr9.pdf

[Stoffregen Motorsports]

Technically, yes.

But...

You can almost always exceed the torque values, and go with the high number. I worked on racing engines for years before anyone told me that rule, and I can count on one hand how many times I had a failure from overtorque.

[Glen]

Hi,
The Cub and LoBoy service manual says torque the head bolts to 45 ft lbs.

The head bolts should have non hardening sealer put on the threads as you put the bolts in.
The bolt holes in the block go into the engine water jacket.

They have said on here don't use anti seize, it doesn't seal the bolts, and coolant can leak up the bolt threads, and come out the gasket.

[getitrunning]

maybe try heating g with an acetylene plumbers torch or mapp gas or if your very careful with oxy-acetylene torch then use your impact gun.
ive gotten lots of rusted bolts loose with a plumbers torch