Cylinder head nut removal on 1989 FJ1200

[FJMAX]

Hi,

I need to change the cylinder head gasket on my 1989 FJ1200 but removing the cylinder head is a little bit difficult.

One of the 12 nuts can't be removed. I feel that the screw is rusty and it seems that it twists.

Any Idea how to remove it without breaking it ?

Can I use an impact wrench ? Or may I heat the nut ?

Thanks.

[Old Rider]

Since nobody has came with a suggestion yet i can try to help. First try to heat the nut with a torch flame if that does not help you  can try to puncture the rounded head and get some
wd-40 down in there and let it sit for a day so the rust losen up.I used a chisel and hammered it off like in the picks below    try to be careful so the treads on the stud dont get
damaged good luck

[FJMAX]

Thanks for the answer.

Did you do this ? It seems to be a difficult job. The cylinder head must be carefully protected.

I think it is a good solution and I will try this because this afternoon I have tried heating the nut but with no succes.

[Old Rider]

Thanks for the answer.

Did you do this ? It seems to be a difficult job. The cylinder head must be carefully protected.

I think it is a good solution and I will try this because this afternoon I have tried heating the nut but with no succes.

yes you must be careful so you dont damage the gasket surface if the valvecover is off.One more thing is...if i remember right you can also unscrew the hole stud but not sure if the
treads that sit  on the stud in the case end  can pass the hole in the cyl head that must the experts Robert Randy or Pat confirm. Anyway if you are interested you can read
about when my engine got overhauled in this tread : https://fjowners.com/index.php?topic=18143.0

[Pat Conlon]

If the frozen nut is turning, that means that the whole stud is turning, coming loose from the threads at the bottom cylinder case.
Can you get it out? I don't know.
With the engine in the frame, do you have the vertical clearance above the stud to be able to pull the nut and stud up and out of the head....or do you have to remove the engine to get the clearance?
Yes, as far as I know, the lower case threads on the cylinder stud will pass through the head.

I will defer to the engine building experts, Chris, Mike, Robert and Randy.

[chiz]

Keep bending or cutting stud as she is withdrawn?

[fj1289]

If the frozen nut is turning, that means that the whole stud is turning, coming loose from the threads at the bottom cylinder case.
Can you get it out? I don't know.
With the engine in the frame, do you have the vertical clearance above the stud to be able to pull the nut and stud up and out of the head....or do you have to remove the engine to get the clearance?
Yes, as far as I know, the lower case threads on the cylinder stud will pass through the head.

I will defer to the engine building experts, Chris, Mike, Robert and Randy.

I don't know - pretty sure I've only had that issue with the engine out of the frame... it's been a while, but pretty sure I had issues getting the stud out due to the amount of crap that was embedded around the stud.

[RPM - Robert]

The stud is small enough to come out of the hole.

In the frame is another question entirely.

[Pat Conlon]

I wonder if one of these would fit?



https://www.menards.com/main/hardware/fasteners-connectors/fastener-accessories/tool-shop-reg-nut-splitter-2-piece/2445294/p-1444428079784-c-19360.htm

[FJMAX]

 

It was difficult but I successfully removed the nut !!!

First, I made a hole on the top of the nut and filled with WD40.
2 days later, it was still not possible to remove the nut, this solution did not work.


So I used this tool :





And after 3 hours !!! the nut was removed.



As I was expecting, the second one came with the stud. There is no rust on the lower thread, so I think the crankcase is OK.

With the engine in the frame, do you have the vertical clearance above the stud to be able to pull the nut and stud up and out of the head....or do you have to remove the engine to get the clearance?

Yes, the vertical clearance is OK for all the 12 studs.

I wonder if one of these would fit?

Even with the engine out of the frame, there is no space to use this tool.



The best solution is to weaken the nut and then remove it with care !

Thanks a lot guys !!!!!

[Pat Conlon]

Thanks for the follow up and kudos for the perseverance. I'm glad it worked out although I shudder at the thought of bending over the motor for 3 hours grinding away at that nut with my Dremel....my back muscle spasms just thinking about it....

Cheers.  Pat

[Old Rider]

Good work and smart idea to grind a grove with a dremeltool