Pushrod

mikeydpippin · Post by **mikeydpippin** » Fri Dec 10, 2010 12:00 am

Just refitted top end after G3 been stood up for many years and i notice the pushrod operating the rocker arm okay on the inlet side but the pushrod on the exhaust side has a large gap between the pushrod and the rocker arm and when pushrod adjusted to touch rocker arm the arm is not opening valve,slight tension on the kickstart and seems tight nothing moves. have i got a stuck valve, loosen the pushrod and engine spins fine.
Compared to my other G3 this rocker arm seems to be slightly closer to the top of the rocker box.
Any ideas?.

chasdev · Post by **chasdev** » Fri Dec 10, 2010 12:00 am

Sadly, it's almost certainly got a stuck valve.
Are you sure the rod is properly seated in the cam follower?Edited by - chasdev on 10 Dec 2010 12:59:29 AM

itma · Post by **itma** » Fri Dec 10, 2010 5:16 pm

agreed, can you get any movement on the rocker arm with a cranked ring spanner?

are the valve springs in the right way round they can foul otherwise.

I found a piston ring for you mikey, but I forgot to tell you.............................

thats what its like being a silly old ****

edited for bad spulling, time for a drink.Edited by - itma on 10 Dec 2010 5:17:47 PM

mikeydpippin · Post by **mikeydpippin** » Fri Dec 10, 2010 5:57 pm

Thanks Ken,managed to get ring from Cox and Turner eng.as i was working in the same town and saw their name mentioned on this site.
Rocker arm with ring spanner on moves about 5mm and is not springy,tother one i can feel the spring compression on.springs not been touched still in as original just removed top end to fit oil ring.
I have a reputable engineering company close by is this something i can free/replace or best to pass to the experts.Edited by - mikeydpippin on 10 Dec 2010 6:24:18 PM

SPRIDDLER · Post by **SPRIDDLER** » Fri Dec 10, 2010 8:48 pm

Mikey
Check to see if the rocker is binding on the zorst valve-lifter shaft, (which has a flat on the side facing the rocker arm).

itma · Post by **itma** » Fri Dec 10, 2010 9:55 pm

yes, you should not need outside help to sort this, take the rocker box off and check what's happening under there.

mikeydpippin · Post by **mikeydpippin** » Sat Dec 11, 2010 10:25 am

Removed rocker box with an overnight soak in penetrating oil and slight persuading the valve is now free and working okay i will refit later and see what happpens thanks for the advice.

paul knapp · Post by **paul knapp** » Sat Dec 11, 2010 10:47 am

It would be a good idea to lift the head and remove the valve so as to clean out what ever was jambing it in the guide.

chasdev · Post by **chasdev** » Sat Dec 11, 2010 11:22 am

Agreed, valve must be removed with stem and guide cleaned out.
Advise same treatment for both valves and guides.
Question, did you smell "varnish" from the fuel tank, fuel line or carb upon tear down?
If so, be informed that very old petrol turns to varnish and can freeze the valves in the guides when heated to operating temps.
It is most imperative that you clean the entire fuel system because the valves stems may become glued to the guides when the engine is brought up to temp.
I might add that here in the States, modern fuels have been altered to the extent that stale petrol can and will clog the smaller carb jets in just a few months where two or three decades ago it would not have done so, so be warned.Edited by - chasdev on 11 Dec 2010 11:23:39 AMEdited by - chasdev on 11 Dec 2010 11:24:37 AM

mikeydpippin · Post by **mikeydpippin** » Sat Dec 11, 2010 11:56 am

Excellent many thanks yes shed stinks of varnish/old leaded fuel, all cleaned and freshly fuelled,Will strip and clean valves and stems.