Stuck 4A Cylinder Head

[rcreweread]

Hi sages - need some advice re a stuck head

 

Am stripping down a 4A engine to rebuild it - it has been dry stored for 35+ years and has seized during that time - no water has got near it, plugs were in but no carbs fitted so maybe some moisture got inside. I did fill the bores with diesel and left it for a fortnight before starting the strip down.

 

Anyway, try as I might, I can't shift the head- I've made up an angle iron frame attached to to the rocker pillar studs ( have removed rocker shaft so all valves should be shut) and the manifold studs, and hung the whole engine, supported on this frame, from a beam for a week - no movement to speak of.

 

Can't use the rope through the spark plug trick as the pistons won't move - so got an old spark plug, knocked out its inners and welded an airline connector to it, and stuck 125psi into each cylinder - tiniest of movement such that the pressure won't build up inside combustion chamber and a few bubbles of liquid/air coming out of cylinder head gasket joint- but still can't get any noticeable movement to shift head.

 

So changed tack and thought I would see if I could get crank out and pistons out from the bottom and then use large wooden drift to knock head up from underneath.

 

Undid all main bearings but crank with pistons wouldn't budge - fortunately crank orientation had seized in a position so I could just undo all connecting rods - disconnected them and removed crank - looks in excellent condition with standard journals ( one bit of good news!).

 

However couldn't budge conrods and pistons from within the block, so put big end cap on, rope through and onto hoist - lifted engine and stand off the ground, then stood on engine stand frame and jumped up and down and hey presto piston came up the liner and stopped - yes, didn't realise the pistons cannot come out through the bottom as fouling on the main bearing cap block casting - bu--er!

 

Back to square one - next used mapp gas blowlamp to heat studs up to red hot and then allowed to cool - used double nuts to try and remove studs- they wouldn't budge at all - tried hanging whole engine( attached to stand) from my head frame and then jumped up and down on stand frame - nothing

 

So guys, got any ideas where I go from here - am I likely to achieve anything by trying to drive a wedge between block and head, other than bu--ering either the head, block or both?

 

Also, trying to remove camshaft from block, I can move it outwards so that the first bearing journal is clear of the block, but then it won't come out any further - it's obviously catching on something but I can't see what, and I don't inadvertently want to cause any damage - I can see if it comes out a bit further, then you must carefully align the other journals to come through the next bearing carrier, but it hasn't come out far enough yet for that to be a problem - least of my problems, I'm sure, but as I'm on here, thought I might as well ask!

 

Any thoughts will be most welcome.

 

Cheers

Rich

 

 

 

 

 

 

 

 

 

 

 

[RogerH]

Hi Rich,

regarding the cam shaft - have you got all the ancillaries removed (fuel pump, dizzy etc)

When trying to remove cam is the engine upside down or right way up. If the latter then you need to move the tappets out of the way

 

Clearly the head is stuck on the studs. These can really gum up in the extreme.

If using the double nut method there may be a chance of simply snapping the studs.

 

Using a wedge between head and block may work and may cause a some damage but what choices have you got.

 

Roger

[RAHTR4]

Hi Rich,

 

I have never had to deal with a seized engine...!!!!

 

But I would put money on corrosion build up between the studs and the head as being the problem - as you say you are unable to remove even one stud.

 

Therefore you have to break the bond - you appear to have achieved a little upward movement, why not replace the nuts and re-torque the head, then remove the nuts and try to lift the head again to obtain some more upward movement.

 

You may well have to do this process a fair number of times.

 

Have you soaked each stud hole in Diesel for a period...?

 

I have encountered two engines with "stuck heads" and both turned out to be the same problem.

 

The two lowest / outer exhaust manifold studs were wound in so far that they locked into the side of the cylinder head studs.

 

After removing these two manifold studs each of the heads then came off, still with a quite a bit of cajoling as they were tight on the remaining head studs.

 

Regards, Richard

[boxofbits]

Hi Rich

 

To remove the cylinder head peneTRating oil and the double nut method is the best option. I think you have more chance of breaking the seal by twisting the studs a little than TRying to lift the head up.

 

A sharp tap on the top of the studs after applying Duck oil or even around the head itself with a copper hammer, may eventually help to break the rust seal. Patience and perseverance will hopefully pay off.

 

Regards

 

Kevin

[Lebro]

You should try removing a Stag head - even worse

 

Bob.

[RogerH]

..grab it by the antlers and ....twist.

 

Roger

[Alec Pringle]

Hi Rich,

 

plasticine cup round each stud and pour in some phosphoric acid, ie 'milkstone remover' at 50/50 dilution, which equates to 10% acid . . . . leave overnight to soak then flush with water and heat the studs with your blowlamp.

 

Then repeat with Plus Gas instead of acid.

 

Then start working your way round the side of the head with a hefty wooden mallet, bashing away all the way round, and round, and round - horizontal blows, not too hard.

 

Then take a hardwood wedge and try walloping it into the head-block joint at various points - you'll doubtless get through several wedges, a piece of old chair frame beech is a good source.

 

Fingers crossed !

 

Cheers

 

Alec

[AndyR100]

If you are getting desperate, Try 'tickling' the top of the studs with an SDS hammer in chisel-mode with a blunt tool of your choice - causes enough vibration to break the corrosion of stud to head. Obviously you'll need to go round all taking your time, but it often works.

...... Andy

[rcreweread]

Thanks guys for all your ideas - off to try and few now! The exhaust stud theory is interesting so I'll try removing them - but typically one has been broken off in the head, so another job to do!

 

Will keep you posted on progress - now off to try and find some platiscene- might have to make do with linseed putty and hope milkstone doesn't eat it!

 

Roger - I'm looking for a big deer to practice wrestling antlers - need to find a big forest first though!

 

cheers

 

Rich

[RogerH]

Hi Rich,

as mentioned previously the front and rear manifold studs can and do get graunched in and grip the head stud.

 

Roger

[ChrisR-4A]

Tip on removing studs, before applying torque to undo try to tighten up a bit more first. An impact wrench is useful for this. 2 seconds tighten then try and undo 2 sec and repeat. It's the impact vibration that often does the trick.

[peejay4A]

If all the above fails the pistons are scrap anyway so maybe you could smash them to bits with a cold chisel to get them out of the bores then try bashing the head upwards with a length of hardwood.

[Motorsport Mickey]

If you are getting desperate, Try 'tickling' the top of the studs with an SDS hammer in chisel-mode with a blunt tool of your choice - causes enough vibration to break the corrosion of stud to head. Obviously you'll need to go round all taking your time, but it often works.

...... Andy

+1 for this method. Often used on Stag engines which with the mix of alloy head on steel blocks rust like no other and glue themselves together. After the blunt chisel trick try retorquing the heads putting at least 110 lbft through the nuts to try and break the rust seal (if something shears so what) and then building the plasticine reservoirs around each stud and flooding with diesel again.

 

Mick Richards

[Dave Larnder]

Hi Rich,

as mentioned previously the front and rear manifold studs can and do get graunched in and grip the head stud.

 

Roger

Roger

That would only work on those studs opposite the exhaust studs, what about all the others?

When I did mine, the head would not come off either, so trying all those ideas I finally used 6 hard wood wedges around the joint working them in similar fashion to head stud torqueing a little at a time and opposite the previous one. It came off after a long time but trying the well and diesel method on the studs, over many days, after the head was off, I still could not get at least one stud out, so they are still there and holding the head down. Needless to say the head was sent for sin plomb conversion.

 

Dave

[RogerH]

Hi Dave,

it is only possible for the front and rear studs to touch the head studs. The other manifold studs do not align with head studs.

 

Roger

[JohnG]

Hi sages - need some advice re a stuck head

 

Am stripping down a 4A engine to rebuild it - it has been dry stored for 35+ years and has seized during that time - no water has got near it, plugs were in but no carbs fitted so maybe some moisture got inside. I did fill the bores with diesel and left it for a fortnight before starting the strip down.

 

Anyway, try as I might, I can't shift the head- I've made up an angle iron frame attached to to the rocker pillar studs ( have removed rocker shaft so all valves should be shut) and the manifold studs, and hung the whole engine, supported on this frame, from a beam for a week - no movement to speak of.

 

Can't use the rope through the spark plug trick as the pistons won't move - so got an old spark plug, knocked out its inners and welded an airline connector to it, and stuck 125psi into each cylinder - tiniest of movement such that the pressure won't build up inside combustion chamber and a few bubbles of liquid/air coming out of cylinder head gasket joint- but still can't get any noticeable movement to shift head.

 

So changed tack and thought I would see if I could get crank out and pistons out from the bottom and then use large wooden drift to knock head up from underneath.

 

Undid all main bearings but crank with pistons wouldn't budge - fortunately crank orientation had seized in a position so I could just undo all connecting rods - disconnected them and removed crank - looks in excellent condition with standard journals ( one bit of good news!).

 

However couldn't budge conrods and pistons from within the block, so put big end cap on, rope through and onto hoist - lifted engine and stand off the ground, then stood on engine stand frame and jumped up and down and hey presto piston came up the liner and stopped - yes, didn't realise the pistons cannot come out through the bottom as fouling on the main bearing cap block casting - bu--er!

 

Back to square one - next used mapp gas blowlamp to heat studs up to red hot and then allowed to cool - used double nuts to try and remove studs- they wouldn't budge at all - tried hanging whole engine( attached to stand) from my head frame and then jumped up and down on stand frame - nothing

 

So guys, got any ideas where I go from here - am I likely to achieve anything by trying to drive a wedge between block and head, other than bu--ering either the head, block or both?

 

Also, trying to remove camshaft from block, I can move it outwards so that the first bearing journal is clear of the block, but then it won't come out any further - it's obviously catching on something but I can't see what, and I don't inadvertently want to cause any damage - I can see if it comes out a bit further, then you must carefully align the other journals to come through the next bearing carrier, but it hasn't come out far enough yet for that to be a problem - least of my problems, I'm sure, but as I'm on here, thought I might as well ask!

 

Any thoughts will be most welcome.

 

Cheers

Rich

 

Rich

I trained on marine engines and have had to remove many a cylinder head rusted into place by seawater.

 

What we used, to persuade the head to move was a lead hammer.

(A steel tube with 4lbs of lead on the end, poured in the shape of a hammerhead)

 

You can hit the hell out of a cast iron head with this thing, without damaging it.

The lead takes all the damage

 

I have my lead hammer here in Chelmsford, if you would like to vent your frustration.

 

Note;

I will be in Tiptree from 14.30 to 16.00 today

PM me if you are interested and I will give you my phone number

I will stick the hammer in the car now, just in case.

Edited September 17, 2016 by wjgco

[rcreweread]

Hi everyone - thought I would give you an update - good news - it's off - head and block are now separate!!

 

Slow and patient approach paid off - plasticene well full of penetrating fluid, lots of tapping with my copper wire wheel mallet, on the block rather than head seemed to be more effective, together with using an SDS drill on rotorstop on the studs - I used a pointed chisel attachment on which I ground off the point and then put a nut 3/4 on the stud to act as a locator - in this way I managed to save all the studs at the expense of one nut.

 

From first seeing the tiniest gap between the two, it took another 3 hours before I got the gap up to approx 1/4 inch, and then progress speeded up.

 

Overall, the engine looks in remarkably good condition - as I said before, I'm hoping the crank won't need a regrind ( haven't measured journals yet) but all bearings are standard size, bores have no ridge, although one has some slight rust coloured discoloration - will clean up the bore before trying to extract the piston and after securing the liners in place. I may even be able to salvage the pistons and bores.

 

Camshaft doesn't appear to have any wear and most of the cam followers are completely unmarked - 3 have the very slightest marks which are rectangular shaped indentations, not dished, which makes me think those followers were not rotating - I think they are supposed to, aren't they?

 

Have stripped head and minimal wear on rocker shaft and rocker pads - can I carefully file the pads to leave then totally smooth or will that destroy the case hardening or should I leave as they are? You can just about feel a bit of ridge with a finger nail.

 

Valves appear sound with plenty of meat between seat and valve face but probably sensible to recut valves and seats - you can just feel a little sideways movement when valve is in guide (dry no oil) but no scuffing or picking up evident - this conveniently leads me onto another question - is it worth converting to unleaded at this juncture? There seems to be a growing band of opinion which says not, with plenty of evidence of decent mileages without issues on original seats - do you think future owners will want to see an unleaded conversion?

 

Will try and upload some pics when I get a chance.

 

Final question - what make of main and big end bearings should I go for, and where from please.

 

Cheers

 

Rich

[RogerH]

Hi Rich,

regarding the rockers. The depressed area is where the valve stem has pushed the hardened metal into the softer parent metal - it isn't wear as such.

Grind (you will not be able to file) the surface flat. Do NOT grind away any of the original depressed area.

You will need to do this in order to set a decent accurate gap.

 

Hardened seats - if the valves are not re-cut then why not leave them alone. If you need to re-cut the seats then inserts would be a good idea.

 

County bearings are good and a reasonable price.

 

Roger

[Ian Vincent]

Grind (you will not be able to file) the surface flat. Do NOT grind away any of the original depressed area.

You will need to do this in order to set a decent accurate gap.

 

Or use a tappet adjusting tool.

 

Rgds Ian

[Dave Larnder]

Hi Dave,

it is only possible for the front and rear studs to touch the head studs. The other manifold studs do not align with head studs.

 

Roger

Hi Roger

I think you missed my point. What about the other studs on the dizzy side?

 

Dave

[Lebro]

?

 

Bob.