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Re: 1947 12hp

Posted: Thu Dec 02, 2021 4:23 pm
by digcot65
With the problem I`m having removing the head I was wondering if this deqa may help .If the two plates were secured on the thre studs shown,the centre ones being stud s 16 and 17 ,then if the nuts on these two bolts were turned ,to lift the plate up does anyone think it may release the head as there isnt really anything holding it in place ,other then some head adhesive that may have been used,many years ago,Im no artist,before anyone comments Len

Re: 1947 12hp

Posted: Fri Dec 03, 2021 12:50 am
by GOY189
Have you tried with all studs released, and plugs in, spinning the engine on the starter? that may break the seal.

Mike

Re: 1947 12hp

Posted: Fri Dec 03, 2021 6:36 am
by TonyG
Mike,

Just thinking about your suggestion; given that rockers etc all removed so valves all closed,would the pistons create any pressure within the combustion chambers? Just a thought!

Len, your idea of using metal plates and the studs may work but the risk of stripping threads is to be considered, particularly those in the block. Not something I'd want to do.

As Luli said, with just one stud in place at the front corner, sideways pressure applied at one or both rear corners, in turn, should loosen the head. Use a stout piece of timber against the side of the head, long enough to get beyond the bonnet opening, and hit very hard a number of times! Also apply heat with blowlamp around joint and alternate hitting from side to side. If you do this while also giving pressure from below then surely it must give way. Regardless of what has been used to stick it together, the head gasket is only two thin bits of copper with asbestos type material sandwiched between.

Good luck. Definately one of those aweful challenges that we hope are few and far between!

Tony

Re: 1947 12hp

Posted: Fri Dec 03, 2021 8:03 am
by digcot65
Thanks for the suggestion I have never had this before.Ive restored over 30 classic cars ,over the years as a hobby and every one,where the head has had all of the studs removed have just lifted off . Regarding the one short stud on the front corner ,I have fitted two nuts on it and really tried some force to move the stud I dont want to over exert the force,in case the stud snaps I`ll try a long length of timber first after running a heat gun over the head Its a bit awkward as its a friends car,a few miles from where I live.So I cant just turn round and pick up any tool I need I would have thought it would take a fair bit of force,to dtrip the threads on the 3/8 th studs ,but best be safe Thanks again Len

Re: 1947 12hp

Posted: Fri Dec 03, 2021 9:47 am
by digcot65
Ive tried spinning the engine with the plugs in and still it doesnt move.Next is to try a long length of timer and a good clout Len

Re: 1947 12hp

Posted: Fri Dec 03, 2021 7:56 pm
by RobHomewood
Hi Luli at al
I can see this topic has moved on a way but my previous query about tightening for head bolts on a 6 Cylinder is still related I think
I have started trying to draw up a similar diagram to the one Luli posted for the 6-cylinder heads based on a spare head that I have. I have belated realised that there are maybe 6 different heads listed in the parts book for 39 to 47 and I dont know which my spare is. The numbers it has stamped on it ie '148F' & 'MC16700' dont relate to any of the parts numbers or anything else I can find. Does anyone know how to interpret these numbers or identify the head otherwise please?
NB I have checked on the '47 16 engine which is in the car and that has '241R?' & 'MC16700' and the other spare engine (the original '39 14 ) has'191RF' and '?8653??'. The latter casting is almost unreadable though.
Any guidance would be gratefully recieved. I have done quite a lot of the draiwng but dont want to put it out there until I am more confident what it shows
regards Rob

Re: 1947 12hp

Posted: Sat Dec 04, 2021 2:32 pm
by digcot65
I`m going to try heat on the corner where the short stud refuses to come out at the same time hitting a length of wood on the rear of the head How hot dare I heat it I know cast iron can be funny material and not all that strong Len

Re: 1947 12hp

Posted: Sat Dec 04, 2021 7:17 pm
by luli
Rob,
As long as the bolts/stud pattern is the same - the year or p.n of the head does not matter.

Re: 1947 12hp

Posted: Mon Dec 06, 2021 6:41 am
by TonyG
Len,

I should think you need to heat all around the head where the gasket is, the aim being to loosen the sealer and get a bit of movement from the expansion. Too much heat in just one place may cause distortion, although unlikely as the cast iron will dissipate the heat well. Suggest you apply most hammer pressure to the rear near side of head so that subsequent movement is anti clockwise in relation to the seized stud.

Tony

Re: 1947 12hp

Posted: Mon Dec 06, 2021 8:07 am
by digcot65
Thanks for the useful information .This is what the club forums,are all about Len