Why does the rocker on the h100 2.6l diesel panel van 1992 shaft keeps on breaking what must we look out for?

though the holes in the head where the cam shaft runs
oil pump feeds to these holes through the block ,head gasket and head
cam shaft bearing caps keep oil pressure and clearance when running

Hi Edward , sounds not right , lol . You have to remove the whole Rocker shaft with it rockers before you can remove or replace the rocker arm rod .

if it does not have hydraulic adjusters then .012" inlet hot and .014" exhaust hot. If it has hydraulic adjusters then the noise will be from worn rocker shafts and rocker bushes.

Try checking the transmission mount. A bad mount causes the transmission to move back and forth too much, causing unnecessary strain on the axle shaft. Also make the shaft is the right length. Too long or too short can also cause the shaft to break.

if its a 3.3l or a 3.8l and its making a little clicking noise when you rev it up then you probably have a broken rocker shaft tower in one of the heads remove valve covers and look. or plug wires on wrong plug [fire order problem] burnt intake valve [not likely]
is 3.0l or 4 cyl. then check distributor cap for moisture, then all of the above except the rocker towers

the gas tranny should work. gm was pretty good about keeping the same bolt pattern.

Hello again,
Thanks for your response and further details, I have to say your unit it not one I'm too familiar with BUT all Engines are similar in many ways and I have done lots of Head rebuilds and gas conversions on Small & Big Blocks.Remember I'm across the Pond U.K.
O.K. Oil ways seem to be the problem here, I can't suggest much as I'm not looking at the Engine.
I can only summize.
I recently had a Cam seizure on a 4D51 Diesel Mitsubishi (Pajero/Montero) un-beknown to me the oil runs up the centre of the rocker shaft its is fed via the the Aluminium rocker shaft carriers. As this vehicle had suffered a Cam Belt break the Valves had ripped the whole Valve train off the top of the head, so clever Me Heli coiled the threads and on the last two had to use larger bolts.
I didn't realise I had blocked the flow of oil?????
So maybe your rocker shaft oil supply is blocked somewhere? possibly a shaft in back to front? or carrier cap on wrong base? I know we all make mistakes but sometimes it is really annoying when it is staring us in the Face and we just don't see it.
2 Heads?? eH!
Good Luck!
Please keep me updated, I'll do some more research and if not solved on this session please return with full description of engine and numbers etc.
Paul 'W'

could be the injector washers leaking or leak off pipes but you will have to remove the rocker cover trim for inspection

Rocker arm shaft to head torque is 19Ft-lbs

belts are usually directional so try 2 put it on in the rite direction otherwise will just disintergrate. and never retighten a belt esepecially if its hot