The head is on!

So we are all set. The sun is shining, I have a day free (after cutting the grass and making the family dinner) and I have all the parts, plus a very nice text from Bruce Longman via Draganfly with explicit instructions. Max is in bed, so he will be happy for a bit:

A Chocolate Sprocker, feeling very 'Sunday Morningish'

I have some high temperature silicone gasket as recommended by Bruce. Loctite say this is suitable for operating temperatures up to 275 degrees C (sustained) with excursions to 300 C:

So as recommended by Bruce, we start by laying a band of sealant around the pushrod tunnels, on both sides of the gasket. Actually easier to lay one bead on the gasket, and one bead on the block, making sure you have the handed gaskets the right way around:

No picture, but next I placed all the head nuts in position between the cylinder block fins, under their holes, with the flanges upward. Next, manoeuvre the head under the frame tube and drop it into place over the studs, making sure the extended, rounded ends of the studs drop into the nuts. Add the sleeve nuts inside the rocker boxes, and the 5/16" CEI reduced hex nuts outside the rocker boxes. You hand screw these down finger tight.

And as Kees Knegt pointed out in a comment to an earlier post, this would have been easier without the rockers! You cannot fit the pushrods with the rockers in place either (they don't slide sideways far enough) so I may as well have left them off... although I do like to trial fit everything at least once.

Next, with your thinnest 5/16" CEI open spanner, engage all the nuts on the downward facing head studs and turn them as far as they will go without using and force. You will realise now that if you leave one undone, and tighten the others, you will crack a fin by virtue of the loose nut pushing downward onto the fin below.

Once you have all the nuts finger tight you will see the head finally come down onto the gaskets. continue going around all the nuts inside & outside the rocker boxes until they are all snugged down finger tight.

You will need a variety of spanners to achieve this. The reduced hex nuts in the middle of the head, under the inlet tract are particularly inaccessible.

So, when everything is snugged down, use Bruce's torque figures and sequence to tighten down the head.

Job done.

Two heads are better than one

Regular readers might remember that I was lucky enough to find a reconditioned head at Draganfly a year or so ago, and wrote about it here.

 

Here it is again, ready for the head studs to be transfered to it from the old head, so that it can be fitted this week:

 

 

 Good plan, flawed by the condition of the old studs:

 

Worn threads



Worn & distorted threads

A bent stud

 

So, back to Acme for more studs... and nuts... and money...

 

And guess what? It wasn't until I wrote this blog post that I noticed that my 'new' head has a chunk out of the bottom fin at the back...

More Goodies from Draganfly

This week, I have been mostly working... and shopping, getting ready for the top end rebuild. a few more parts from Drags and Acme, for the Square (and one, a secret one, for the Huntmaster). Otto head gaskets, rocker oil pipes, rocker oil pipe banjo bolt newly available from Acme, and the rocker cover locating pins lost during bead blasting.

And some more

And this, for the future - this is the strainer for the FH, recently available from Clay at Acme Stainless.

And a blast from the past:

The railway straight at Brooklands. Wonderful, magical place, right next to my office.