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Rocker arm oil flow

Posted: Thu Mar 11, 2021 12:24 pm
by FosterS
I'm on putting the head back on my 1098 engine after fitting a second hand block, I have cleaned all the oil ways out as I have gone on, now comes the head.
Does anyone know if there is an oil feed in the rocker arm from the rocker shaft to the tappet adjusting screw hole. There is a hole in the rocker arm bush as in the photo but nothing I have (carb jet cleaning set) will go in let alone through.
IMG_20210311_115704.jpg
IMG_20210311_115704.jpg (1.92 MiB) Viewed 877 times
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IMG_20210311_115649.jpg (1.61 MiB) Viewed 877 times

Re: Rocker arm oil flow

Posted: Thu Mar 11, 2021 1:15 pm
by philthehill
There is an oil feed passage from the rocker bush/rocker to the tappet adjusting screw.
The rocker drilling is plugged at its outer end if forged rocked are used. The pressed steel rocker is wrapped around the tappet adjusting screw and joined at the anvil end of the rocker. There is a formed oil passage between the two faces of the pressing/forming.
Does your tappet adjusting screw have a oil passage from the waisted section to the ball tip?
If it does not there is no need to worry about an oil passage.
The waisted tappet adjusting screws are prone to breakage and should be replaced with the later non waisted, non oil passage type.
Due to the breakage problem BMC replaced the tappet adjusting screw with a non waisted non oil passage type.
There is sufficient oil splashing about to maintain adequate lubrication of the rocker tip, the tappet adjuster screw to push rod and the cam follower.

Re: Rocker arm oil flow

Posted: Thu Mar 11, 2021 2:01 pm
by FosterS
Thanks Phil this is the tappet screw.

Re: Rocker arm oil flow

Posted: Thu Mar 11, 2021 2:16 pm
by philthehill
Thank you for posting the picture of the tappet adjusting screw.
As it is not waisted no oil is able to pass the screw so therefore you do not have to worry about a blocked oil passage - just fit and forget.
Phil

Re: Rocker arm oil flow

Posted: Thu Mar 11, 2021 2:19 pm
by FosterS
Cheers Phil puts my mind at rest thanks.

Re: Rocker arm oil flow

Posted: Fri Mar 12, 2021 12:28 pm
by jaekl
I once had two dry adjuster/push rod interfaces that squeaked. Tried and tried to open the oil passageway but determine it wasn't there as stated. Ended up just putting everything back together with oil applied. It's been fine for forty years.