Morris Minor Owners Club

If you find a cylinder head nut that won't move, I would suggest applying a little heat from a blow tourch to expand the nut.
Better the breaking the stud in the engine block.
Of course this applies to any troublesome nut.

I’ve tried to reply to this before but my ISP came up as ‘blacklisted’. I’m expecting the site had been hacked.

Back at home, now, so trying again from my more usual ISP

I have often found that more than moderate heat is necessary to sort out stuck nuts.

Anyway, my reply to this post was that it was entirely blinkered and that there are several alternative options to just using a gas torch to heat the nut.

1) Use an oxy-gas torch as a ‘hot spanner and cut the nut.

2) Drill the nut adjacent to the stud threads to loosen its grip.

3) Use a nut splitter to effect removal.

4) Even a cold chisel and lump hammer could do the same as a nut splitter (but a bit too brutal, perhaps).

5) Use an angle grinder to carefully cut the nut is yet another option.

5) Use a release agent (not WD 40 !) - the most often first attempt by most?

The above would mostly destroy the nut, but I would likely change the nut anyway.

I think there may have been another option I wrote down previously, before my reply was lost initially - but this post is added to demonstrate that heating the nut is not the only option to the problem.

Indeed, if the nut has been over-stressed previously, further damage may still be inflicted on the stud threads.

Excessive heat may well soften the stud threads, and these may give the same problem the next time the nut is removed (red heat and steady cooling might well anneal a previously hardened/tempered nut/stud). Not applicable to many agricultural jobs with mild steel bolts, I might add.

Wow Oliver!

1 Oxy? who has that at home? also it may melt the nut and the stud.

2 drilling. good luck with that. Better get a good supply of drills in.

3 nut spitter. may be ok but will it fit?

4 cold chisel. So we are going to hammer the cast iron cylinder head along with the nut with a club hammer.

5 angle grinder. Going to get those silicon carbide (or what ever the cutting discs is) particles in the engine.

6 release agent probably won't work as the nuts are torqued down.

"Excessive heat may soften the threads. "oxy"?

Gentle blow lamp should be ok.

I do agree with the angle grinder.
I often use it to cut stuck nuts off.

On head nuts It would be a good idea to somehow cover the top of the head.

A bigger problem on the nuts under the rocker cover.

Impact wrench?

Often a combination of Plus Gas or similar release agent, some heat, and the impact wrench will get results. Otherwise, it is quite usual for the stub to unscrew from the block and come away with the nut still attached. At least it is then easy to work on the nut away from the engine, or just fit a new stud.

I think there's a difference between a seized cylinder head stud nut on an engine in regular use and an engine that has been sitting on the floor of the garage (or worse) for years. The engine in regular use is likely to be oily and any seizing shouldn't be that difficult to deal with. I would be reluctant to use great heat where there is a risk of an oil fire.......As Simon says, if the nut is seized it is likely the stud will come out with the nut attached. A Dremel tool with a cutting disc is a lot more precise and controllable for cutting off a nut and less likely to cause collateral damage although it can be a bit slow. Probably a safer tool for the home mechanic who is not under commercial time pressures.

Stephen

Induction heater very good but expensive circa £150+ if only occasionally used. Personally air powered impact gun usually overcomes most things with a help from hot air gun.