Rocker arm assembly removal

[Tinster]

A non-mechanic's struggle. I have no oil from rocker arms No.1 and No. 12 I want to remove the entire assembly and clean it up. I am thinking there is sludge inside.

Q. If I set my engine at cylinder No.1 near TDC, with the dizzy points for plug one open- Can I just pull off the
rocker arm assembly (using my standards "parts board" so I know where everything came from), clean up the components
and put them back where they came from without going thru the process of "Static Timing" and adjusting the valves from scratch?

The car is running really well and I don't want to mess it up
trying to clean rocker arms No.1 and No. 12.

I ran the engine for about 20 minutes with valve cover off and even at 3000 rpms, rocker arms No.1 and No. 12 were dry. I stuck a piece of wire into the weep holes and still dry. A small bit of oil skim is on the rotating push rods of 1 and 12.

When I first purchased the car, no oil was weeping from any of the rocker arms. With a wire, I got all but two unclogged.

All thoughts and suggestions appreciated.

thank you,

dale (Tinster)

 

[TR3driver]

Dale, it doesn't matter which way the engine is turned when you take the rocker shaft off; it won't affect the valve or ignition timing. And, at least in theory, it won't alter the valve clearances either.

But when you remove the shaft, loosen the nuts gradually (like 1/4 turn for each nut, then another 1/4 for each nut, etc.) until all the valve springs are released. That keeps the spring pressure from putting the shaft in a bind and potentially bending or breaking it. Do the same when you put it back on.

Be sure to clean out the inside of the shaft, and the passage through the rocker pedestal while you are at it. You could even poke a piece of wire into the hole into the cylinder head, in case there is any sludge in there.

 

[tdskip]

Just use Berryman's or similar for cleaning the shaft Randall?

 

[Brosky]

Dale,

Once you get the rocker assembly off, this picture shows the oil galley hole that you will see on the rear of the head. That is where the oil comes up through the rocker shaft from inside the block. It must be clean and open or your cleaning work will be wasted on the stands and shaft.

 

[startech47]

Make sure you replace the rocker arms and push rods in the same places they are currently at. The wear patterns are currently matched.

 

[TR3driver]

Nothing wrong with the Berryman's; if you've got a vat big enough to get the shaft into. But I don't, so I just use whatever is handy, usually a combination of "jet spray" carb cleaner and rags, plus a rod to push a solvent soaked rag through the shaft (much like cleaning a gun).

And as startech47 notes, it's essential to put the parts back in the same places. Otherwise, at the very least, you need to readjust the valve lash.

 

[Tinster]

Thanks all for the help.
I'm the guy who always uses a parts board, remember?
And takes a gazillion photos.

Thanks all,

dale(Tinster)

 

[Brosky]

Dale,

Here is one more view for you.

 

[Tinster]

Thanks for the photo, Paul.

I can understand why No.1 could get starved for oil.
But No. 12, directly over the oil supply? Puzzling.

thanks all,

dale(tinster)

 

[Brosky]

You really won't know until you get the stands and shaft off and see what is really blocked. Probably a few spots are clogged. Obviously, something is not right, but you'll find it.

 

[Tinster]

Well, it appears the monsoons have quit today and sun is out.
I'll start a parts board and the process of taking the assembly apart for inspection and cleaning.

thanks,

dale(Tinster)

 

[tdskip]

Good luck with it Dale. Should we be expecting a write up on this once you are finished?

 

[Tinster]

Good luck with it Dale. Should we be expecting a write up on this once you are finished?

<span style="color: #990000">Yupper! I'm about 1/3 finished my "How To" for diagnostics
and replacing crankshaft thrust bearings in a TR6. I've got
a few hundred miles on the new thrust bearings, so I guess
my work was correct. End float at .007"

Once that is completed and if I don't mess up doing the
rocker arm assembly, I'll do How To for it also.

Wish me luck!

dale(Tinster)</span>

 

[Brosky]

You can handle it easily. Just follow Randall's advice about removing the assembly slowly by releasing the shaft hold down nuts incrementally, rather than popping one nut off at a time off and you'll be fine.

Punch 12 holes (numbered)in a piece of cardboard and that will serve as your guide for the push rods. Just clean them one at a time so they don't get mixed up.

If you completely disassemble the shaft, do the same thing as you've done with your boards in the past and it will be fine.

Just make sure you block any areas that can allow something to fall down into the block when everything is off of the head. And don't forget the main oil feed hole at the rear. That must be clear or you'll never get oil into the rockers.

Good luck....

 

[Brosky]

Dale,

One other thing. You may find wear on the shaft or arms that is normal or it could be excessive. Now would be the time to replace whatever needs done, while you have it apart. If you have any questions, post pictures and we'll get back to you with advice.

TRF and others do offer a complete reconditioned shaft assembly in the event that yours is BADLY worn. But let's assume that you don't need one for now.

 

[angelfj1]

This may have been covered by others. While your at it, remove each push rod (ONE AT A TIME) and check to see that they are dead straight by rolling across a sheet of glass or something else that is known to be flat. Let us know what you find.

 

[TR3driver]

Punch 12 holes (numbered)in a piece of cardboard and that will serve as your guide for the push rods. Just clean them one at a time so they don't get mixed up.

IMO it would be safest to just leave the pushrods alone.

However, if you do remove them, be careful not to pull the lifters up out of their bores. Sometimes the oil and sludge pooled in the lifter can create just enough suction that the lifter will come up with the pushrod and fall over. If that happens, it can be a major PITA to get the lifter back into it's bore without removing the cylinder head.

The trick is to pull the pushrod up only 1/4" or so, and spin it in your fingers until the lifter drops off. But it takes a delicate touch to judge whether it's holding the lifter up or not.

Unlike some engines, the TRs do not run oil through the pushrods, so I'd just leave them alone unless/until you are planning to remove the head.

 

[tdskip]

Hey guys - rocker assembly newbie question here. Can you "simply" pull the rocker shaft and replace just the shaft? If so, what can benefits would that potentially bring?

 

[TR3driver]

Can you "simply" pull the rocker shaft and replace just the shaft? If so, what can benefits would that potentially bring?

Sure, can be done. Foolish IMO to just replace the shaft without reconditioning the rockers at the same time; after getting a price from Rocker Arm Specialists I just sent them the whole assembly for reconditioning. Of course shipping costs might make that impractical for Dale, but I would heartily recommend them for anyone in conUS.

The difference with the rebuilt rockers & shaft was not dramatic, but there was a definite reduction in valve train noise, and the engine idled smoother. Seemed like a little more power too, but hard to say for certain. Also easier to set the valve lash, and the lash was more repeatable (before, I'd get a different number every time I would check it).

RAS did have a web site, but it appears to be gone now. However, according to the discussion at
https://www.british-cars.org/mgtd-mgtf150...18455711709.htm they are still in business, just not on the web.

 

[Brosky]

When I did the first head shaving job about three years ago, I bought a reconditioned shaft assembly from TRF and this is what it looked like as a complete unit then.

And as far as the push rods go, I would tend to agree if they look clean enough, but I'm a clean freak and while it's apart, I would just clean them for GP.