Huntmaster Pushrods

[Graeme.crawley]

had a copper head gasket that was weeping a bit so replaced it with a composit. Then I blew that head gasket. I replaced it with another copper gasket and now the thing wont run. It fires once and stops. Removed one plug and got two chuffs. Went away then came back and put both plugs in and got maybe 6 chuffs on the cylinder that previously had no spark plug when I got 2 chuffs. Somewhere i read that it is possible to put the inlet push rod in the exhaust cam follower and the exhaust rod in the inlet follower but unsure what engine that was about - is that really possible on an A10 engine? I looked at the rods before completing the rocker box installation and the short ones seemed to match each other as did the long ones on the indide yet on one cylinder I had to remove the Valve cap to get tappet clearance that was not an issue with the original copper gasket!!!. This is the cylinder that did 2 chuffs but now is not firing. When first assembling and finding there was no tappet clearance in the right hand inlet I pulled it all down again thinking there must be somethng under the rod on the cam follower but I checked the cam follower for any debri with a torch and magnet and saw and got nothing. On re-assemly it was exactly the same. All valves are opeing and closing but that valve cap is now removed else it simply had negative clearance. The valves are stainless, I was hoping they had work hardend after 14 years with caps on! tomorrow I will remove the rocker cvers and try to work out if I have the correct valve sequence. Assmbling the rocker gear on this engine is a nightmare.

[Roger Gwynn]

You cannot really assemble the push rods incorrectly, other than them not seating in the cups on the rocker arms. When you mention valve caps, do you mean rocker cover or do you have valve caps fitted on the ends of the valves? These should not be needed with modern valves and were never fitted to FH or A10. Your problem must stem from the lack of clearance on the valve your are having trouble with. I am also concerned with the blowing of head gaskets, these engines are not prone to that problem, are the surfaces flat?

[Simon.Gardiner]

Graeme - Steve Carter put together a good guide to fitting Huntmaster rocker boxes, on the Forum. It's been copied to a 'HowTo' in the online library of the main web site:
https://www.arielownersmcc.com/members_ ... rBoxes.pdf
I'd echo Roger's comments except for the one about head gaskets - in my experience (current Huntmaster and many years with an A10 'back in the day') head gasket problems aren't unusual, although that might be partly related to it being a complete PITA to get at the head bolts and do proper re-torquing...

(And moved to 'Four Stroke', topics are straying into the wrong places far too much )

SG