Head extraction tool

[Keith Clements]

See this being used by Leeds City College.
Perhaps someone in the area can get some drawings off them???
http://s1293.photobucket.com/user/leeds ... sort=3&o=3

[Tony Fearn]

Is this a known tool, or is it a 'thing-of-purpose' designed by the college itself? Does anyone know?

It looks a bit Heath Robinson, but rather useful.

Tony.

[PJGD]

OK, I have done a sketch [in two formats] of the tool that Leeds City College have made up.
The positioning of the holes in the plate are critical, but one can use another cylinder head as a jig for the head stud holes. The location of the rocker stud holes will have to be established by measurement. Those holes are simple clearance through holes, but the other holes are tapped. I have shown them as being tapped BSF thread, but any similar sized bolt thread will do, Imperial or metric. Likewise, I have shown the plate as being 9.5" X 5.5", but you may be able to get away with 9" X 5" if that is more convenient. The bolts that you use to jack the head off could be improved if the ends are counter drilled slightly so that they are concave, the better to engage the head stud ends. It will not normally be necessary to use a full complement of jacking bolts to extract a head, but the plate should have all the holes drilled and tapped since you don't know which studs may be missing.

Suggestions for improvement are welcome.

Philip

[Forumadmin]

Thanks Philip.
I have not worked out exactly how the extraction is performed. What is turned to produce the force to extract the head?
Does the plate rest on nuts on the block studs? When the cylinder stud nuts are turned, this pushes the plate against nuts on the rocker studs .
It just seems there is more involved in the LCS device.

[PJGD]

Keith, I thought that the LCC device was relatively simple. Having made up the plate, it is dropped down over the two rocker studs and then nuts are run down as far as the threads allow. The plate is now loose on those studs but trapped to the head nevertheless. Then long setscrews (or simply threaded rod) are inserted into the threaded holes in the plate until they bear against the tops of the head studs - hence the advantage of concave ends to these setscrews so they don't wander off the head studs and damage them. Then the setscrews are turned evenly to jack the head up off the block.

In the LCC case, they seem to have used threaded rod with two nuts locked together at the outer end for the socket wrench to engage. They also appear to have a loose nut under the plate as well, but the objective for that is unclear to me unless it was to stabilize the plate and keep it level.

Philip

[Tony Fearn]

Thanks Philip. All seems clear now.

In my 7 hp pre-war world I have used a simplified, and more robust plate, with only two holes, to remove the flywheel from the rear of the crankshaft. The flywheel itself has two threaded holes in it, and the holes in the 1/2" steel plate are drilled slightly larger to allow threaded rod to pass through them.

Tony.

[Forumadmin]

It must be a fine line between having a concave set screw that stays on and one that damages the stud thread. I guess one could leave the nut on the stud, loosened of course, until the seal has broken.