Refitting cylinder head

G Day Chaps,

This weekend should see the re fitting of the cylinder head to my 850 MKIII. I've fitted 2 new exhaust valves and lapped them in. All is clean and ready to go with new valve stem seals and gaskets, including an eyeletted head gasket from RGM. I even have a special spanner to tighten that tricky rear cylinder head nut.

While I have the manual, I have not done this job before so any advice on what to look out for would be gratefully received from all you veterans out there

I mainly ask because I found it a wee bit of a struggle getting the head off some weeks ago- definitley a two person job with the engine still in the frame, juggling pushrods and finding enough clearence to actually pull the head free.

I s'pose what I am asking is does the manual provide a sufficiently clear procedure for fitting, locating pushrods, tightening down, etc, to get it right? Experience shows the manual can be frustratingly, well, BASIC! :?

Many thanks Gentlemen!

There are several ways to get the push rods in and the head on. I'm sure some will chime in, there was a thread about it not long ago if you care to look. However you do it, I did it just like the workshop manual says, make sure when you tighten down the head bolts, that the push rods are seated in the rocker sockets. Go slow and even turn over the engine, inspect, go slow, inspect. You can hold the rocker arms up with rubber bands while fitting the head. I put the push rods in the head and hold them with rubber bands also, cutting the bands off later.

Good luck.

Dave
69S

Thanks Dave, that's just the sort of sage advice I was after I must admit I have yet to read up on it or search for previous threads, but what you say about elastic bands does make a great deal of sense, and I think the manual does mention that. Did you have any difficulty locating the pushrods with the cam followers (lifters?).

BTY Dave, I been reading the Phoenix thread with great interest and I enjoy your thoughts and impressions as much as the details of progress with the 69S. The start up video was especially good and a source of great enthusiasm to get mine going again.

Oh, for the tyranny of distance- I owe you an Urquell

Many thanks

Mick Hemmings says in his DVD that the push rods will fall right in, they did for me. But I have heard of some people that they didn't. As soon as you get the head in position, drop the rods in and it will be pretty apparent if they go in, but you have to feel them, you can't see. If they don't something will break. Make sure your lash adjusters are all the way out to start too.

Dave
69S

Make yourself this tool:

Take 2 pieces of 1" X 2" plastic cut from a milk jug or similar. Bend them in half so they make a folded plastic "spring". Punch a hole in them and tie a piece of twine between them. Stuff the pushrods into the head and use your new tool to hold them in place (stuff the springs up the pushrod tunnels) while you position the head. Then yank the springs out by the string and let the pushrods fall into the motor.

Saves untold grief.

maylar said:

Make yourself this tool:

Take 2 pieces of 1" X 2" plastic cut from a milk jug or similar. Bend them in half so they make a folded plastic "spring". Punch a hole in them and tie a piece of twine between them. Stuff the pushrods into the head and use your new tool to hold them in place (stuff the springs up the pushrod tunnels) while you position the head. Then yank the springs out by the string and let the pushrods fall into the motor.

Saves untold grief.

Click to expand...

Very nice idea, I'll be trying that next time.


Once the head is over the barrels the elastic band trick across the rocker arms is great for keeping the pushrods located as the head is torqued down, there's some pictures on this site somewhere if you search.

Are my pushrods properly located?

G Day Chaps,

Many thanks to all who replied. Much trepidation this weekend but I think I 've got the head on ok now. I abandoned the elastic band method becuase holding the rocker arms up means the pushrod ends are sitting down, thus reducing the clearence! Anchoring the elastic bands to the headsteady Allen bolts also means these bolts foul the frame around the headsteady/frame mounting point- don't see how this could ever work!

Anyways, I just followed the manual and the pushrods seem to drop into the cam followers ok. I bit of wiggling got the pushrods located in the rocker arm cups no worries. In fact it all went too easily that I'm worried I've not got it right. So I made a video so you can all tell me! The ratchety, metalic sound is the k/start ratchet. Film was made after I'd torqued down all the head bolts. That rear cylinder head nut is an utter git!

Let me know what you think !

By Jove, I think you've got it. Yes with the bands and the push rods, I guess I didn't tell you that you have to stuff them way up past the arms in the head and then let them fall in. Anyhow, spot on. That's what it sounds like. Working a bit late are we?

Dave
69S

Aye Dave, Aye! That's a huge relief to hear someone else thinks it's ok.

Aye, working late and still got the cricket highlights to watch! I'm getting married in 3 weeks and I'm determined to get the Norton going in time, so that I enter married life with a functioning motorbike, not some 'thing' in the garage that doesn't go.

Thanks for all your help. It was great to have dad's assistance, even if it was in 1962 when he last refitted the head to his Dominator!