Bush alignement in rocker arms

[chicken]

Hi guys

Just checking my oil flow over again !! and am finding that not all the rocker arms are feeding oil down the lifter rods, have i got my bushes in wrong ?
On looking at it again i think the groove in the bush should be uppermost so that the groove aligns with the outlet hole to the rocker screw and that of the hole in the top of the rocker arm (see attached picture of how they are now).
Guess i'll get something right eventually, shoudn't be in to much of a hurry.

 

[Dug]

The holes look as though you have them in the right spots to line up with the galleys ways in the rockers themselves. With the motion of the rockers they both line up at a brief time with the holes in the shaft to squirt oil to the right places.
I always felt the small semi groove belonged at the bottom of the rocker because the forces applied by the springs and valves keep the clearance that’s in the bushing mostly offset toward top. The bottom would be likely to have less clearance and therefore have a small “reservoir” or collection point as such to fill and give the oil a better chance of coating the bottom surface. To keep a film of lubrication there. It’s also the way all the old un-fettled with set have been orientated when pulled apart.
Dug

 

[Dave Russell]

There is an internal groove (slot) in the rocker arm bushing. This slot is supposed to be oriented (clocked) so that the groove connects the oil feed hole in the shaft ONLY to the bottom of the rocker & to the pushrod feed hole. It should NOT intersect the top rocker hole.

If the bushing has been incorrectly installed or has turned itself in the rocker arm, the oil feed slot will connect to the hole in the top of the rocker & oil will spurt out.

There have been cases where the top rocker holes have been purposely plugged to compensate for wrong or improperly installed bushings.
D

 

[Patrick67BJ8]

There is an internal groove (slot) in the rocker arm bushing. This slot is supposed to be oriented (clocked) so that the groove connects the oil feed hole in the shaft ONLY to the bottom of the rocker & to the pushrod feed hole. It should NOT intersect the top rocker hole.

If the bushing has been incorrectly installed or has turned itself in the rocker arm, the oil feed slot will connect to the hole in the top of the rocker & oil will spurt out.

There have been cases where the top rocker holes have been purposely plugged to compensate for wrong or improperly installed bushings.
D

Got a picture to show us Dave?
I've had engines where there was holes plugged.
Patrick

 

[Dave Russell]

This is the only pic I can find. Note that the correct bushing has a slot that extends only from a little past the bottom to just past the pushrod feed.

Some replacement bushings have a slot that extends way too far around the rocker & leaves the top hole uncovered. In this case the top rocker holes must be plugged. Definitely the wrong bushing.
D

 

[chicken]

Dave

As allways you come to the rescue, the rocker shown actually feeds ok but on some of the others the groove (slot) stops just short or the pushrod feed so i guess i'll have to re-bush them, i remember at the time wondering the correct way to fit them, allways a job when you only have a book to work from !!!
By the way my engine pressure is a bit over 20 now, having fitted the filter adapter correctly, will play with the pressure relief valve a bit to see if it comes up at all, then like you say get everything set and give it the big run up !!!!

Rob

 

[Dug]

Dave,
Thank you for that picture and explanation, it makes sense. I looked at it a bit differently but with out the any real proof.
Looking at later model rocker assembles (non big healey) and other makes of British engines of the same time period with and with out bushings installed in rockers it seems a little unclear of what the true intention was. Heck later car rockers arms left the holes out completely.
Some say it was that enough oil was splashed about without feeding them thru the holes in the rockers and some say it was due to a cost savings in manufacturing. But know I can see a reason and understand the need to orientate them in Big Healey assemblies.
Dug

 

[Dave Russell]

A couple more notes on the rocker arm assembly, just in case.

The threaded rocker shaft end plugs can extend so far inboard that they close off the oil feed to the end rocker arms. Check, & storten the plugs in needed.

The rocker oil feed banjo bolt threads into the aluminum rocker stand & extends into a drilled hole in the shaft. During the shaft assembly, it is important to align the rocker stand with the shaft hole & temporarily insert the banjo bolt. This holds this very critical alignment as the shaft is assembled & torqued down to the cylinder head. After the shaft is tightened down, remove the banjo bolt & install the rocker oil feed line.

If this critical alignment is not maintained, the banjo bolt will likely strip the threads in the aluminum stand as it tries unsuccessfully to realign the rocker shaft hole with the bolt.
D