Britbike forum Forums British Motorcycle specific Brands Triumph bulletin board Rocker shafts - uncertainty!

Guys
I have a bit of a bits T120 , around 1970 age. I've got the head off just now , grinding valves and doing pushrod seals etc. Ive ran it for a bout a year and a half with no issues , but I've noticed black oil residue inside the rocker boxes , and i also noticed the rockers have solid washers fitted and no tracery washers fitted. there is a slight end float in the rockers , and also the rockers are the later notched type.
I fitted the rocker feed pipe to the banjo connections and pumped the feed pipe with an oil can , i was overcoming the plunger in the oil can trying to get oil to flow out between the rocker shafts and the rockers!
Looking at the various posts on various forums i've noted all the changes over the years, but i kind of got lost in the bit where the rockers were notched and shim was put against the rocker , i understand the oil will come out at the notch and probably drip off the washer or rocker arm, but should i have rocker shafts with a helical groove to let the oil pass between shaft and rocker easier ??
sorry if this has been covered multiple times, I'm just trying to make sure its right i may do Moto giro with this bike in the summer!
cheers
greg

Hi Mr. Greg,

I'm building a '70 T120, and asked the same questions.
Here is the long version of the reply that I have saved into a build folder.
It's all the info you will need on this topic.

"Rocker washers:
I made this change as well......from what I recall on a thread I had here last year, John H. recommended placing the thackery washers on the outside of the assembly (next to the rocker box wall). AIUI, when Triumph made the change from the drilled arms to the machined ones, this assembly order was changed but the drawings were not updated.

All the pressure increase available will not overcome the fact that on 1969 and later 650 rocker shafts there is no way for the oil to be distributed to the push rod or valve tip! Then in 1973, when they finally cut a spiral the length of the shaft did the oil have a path out of the center of the rocker, but the wrong placement of the spring washer insured that the valve tips continued to get little, if any lubrication.

So,how have you got the shims and thackeray washers installed?
Drilled rocker arms have the thackeray up against the arm,and the thrust washer against the rocker box casting.
Undrilled rocker arms should have the thrust washer against the arm,and the thackeray against the rocker box.
This is often done wrong,and was for many years.It affects lubrication of the rockers,valve-tips etc.
Here is the short version: Mr. Healey
"So if you want more oil to flow through the rockers, either lengthen the oil galley on the rocker shaft or get a set of T140 rocker shafts (or cut a groove in you old shaft) and reverse the thrust washer and thackery. If you choose to use your old rocker arms you will have to grind a chamfer in the end faces of the rocker and cut a small path to direct the oil toward the valve and push rod.

There, I think this reads better...
John

And here is the thread... http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=455760&page=1


In order for the tapered spindle to seat properly with this change, you need to replace the 3/8" (70-1330) thrust washers with the 1/2" (70-1575).


Oil Return ByPass:
It might be interesting to note that the stock little Triumph plunger pump will deliver by-pass pressure at far less than 2 thousand rpm. Especially when the motor is cold.

As a matter of course when installing a fresh motor, and rollers are not available, we remove the spark plugs, put the bike in high gear, and turn the motor over by hand using the rear wheel. We do this with a pressure guage attached to the oil galley in the front of the motor. It takes a couple minutes of turning, but it is easy to get the pressure guage up to 70 pounds. This insures full oil pressure to the rod bearings at start-up. To make the job easier we pre-fill all of the oil lines as we offer them to the bike.

It is common practice in the auto engine rebuild business to pressure pre-lube the motor before start-up. This ensures the cam and rod bearings have oil pressure before the motor turns over. The practice of starting the motor and waiting for oil presure to build almost guarantees some rod bearing damage even before you start using the motor.

The oil pressure by-pass holes in a typical Triumph, there are two, will more than handle the volume produced by a stock Triumph pump. The by-pass oil is diverted through two small holes. One into the timing gear cavity and the other into the crankcase it self. I have not know, or heard, of these holes becoming blocked in a Triumph motor.

When you fit a high volume pump, like the Morgo rotary, you HAVE TO increase the size of the by-pass holes to handle the inceased volume or risk inverting the oil seal on the end of the crankshaft. For all, but the very brave who will try to open up the hole leading to the crankcase without taking the motor apart, it means total engine dismantling.

The catch for the performance minded is: you are now introducing more oil into the crankcase and there is volumes written about oil and flywheels. To avoid this, you will see that a lot of Triumphs at the track with an additional oil line running from underneath the oil by-pass valve back to the oil tank. The two by-pass holes are welded up, a .015" hole drilled through the weld into the timing cover to spray lubricate the timing gears, and the oil diverted back to the oil tank.

Diverting the oil away from the crankcase is not a new idea in the Triumph world! If you look at many of the very early twin crankcases you will see a boss in the crankcase casting just below the by-pass valve. To convert a modern Triumph crankcase a boss would have to be welded on.

You can also modify the body of the by-pass valve. Grind a groove in the body so that when the by-pass valve is fully open it exposes the groove. This runs the oil by the side of the valve into the cavity that holds the spring. The oil by-pass body acorn cover can be modified to hold an oil line giving the by-passed oil a path back to the oil tank.

Jack Wilson, Big D Cycle, claimed that on the dyno they would consistantly see an additional 1 hp when the oil was diverted away from the crankcase directly back to the oil tank. Who knows, you would probably see more if the bike was fitted with a rotary pump.
John"

Lots of good info there...

...all we know about what Mr J. Healy says about the rocker shaft; however, I still never saw a later Triumph with this change...
Also I dismantled 2 78s and 2 79s; all had the shaft and washers like the manual not like Mr Healy says, so I still wonder when they decided to make the change, in the 80s?!
Plus, I always heard that something like those spring washer against to Aluminum is a candidate to wear away the aluminum

I completely agree with you.
I believe there should be a thin (0.010"-0.020") shim between the housing, and the Thackery washer.

This mainly comes down to common sense. You need the oil to have escape routes in specific places.

The areas where the shaft is in a bushing, the tops of the pushrods, and in a place to feed the tappet end of the valve.

I have considered turning down the boss ends of a new set of rocker shafts, and installing a welded, side drilled thrust type washer in place of the thackery/plain washers, and a positive pressure feed direct off the oil pump.
While some will argue that these engines have lasted 50 years as is, I argue that they can still be improved.

Someone here stated that they were curious as to what these engines could have become if they continued to develop them.
I like that train of thought.

...I thought about shims but I did not found shims with that internal diameter, I did not found shims for the crankshaft too.

Just a quick note---for racing it is common practice to leave out the Thackeray washer and put in an aluminum spacer of a thickness just to give a running clearance.
This eliminates the friction between the Thackeray washer and the rocker box etc.
The Thackeray washer is after all just a cheap way of positioning the rockers on the rocker shafts.
HTH

Common enough practice, but did it do any good?

Thanks guys
my bike looks as though someone has done the spacer modification as described by trident man. Today i'll trip out the rocker shafts and see if i can improve the oil path along the shaft, the clearance between shaft and rocker is maybe just a bit close for squeezing oil through , but with 4 rockers connected to one oil can i thought i'd manage to see oil somewhere!
cheers
greg

TT--less friction = more power to the back wheel.
I would agree--not a lot--but in racing every little bit counts.

And yet we NEVER see any pictures of these "worn" rocker boxes or tales of bits of aluminum in the sump? And what about all the T150's/T160's that were assembled properly? Do they have worn rocker boxes too?

With everything coated in oil, the rocker arms and thrust washers are going to be moving freely. The thackery washer, under tension, would remain stationary between the thrust washers and rockerboxes.

Not trying to be a PIA here, I just think the fear of catastrophe from this is way over-rated.

Steve

I think the washers could break in a racing engine..Shimmed in place might be better to control the rockers from walking back and forth if Triumph rockers do that sort of thing...I think my LSR Triumph still has the spring washers..Or not, can't remember what I did... But it goes fast...

They are more spacers than washers--they effectively replace the Thackeray washers so are quite thick.
Not much chance of breakage--and they have been used in dozens of Triumph racing engines to my knowledge with no failures of the spacer at all.
Not suggesting that the reduction in friction is large but as you know when preparing a racing engine you do all the little bits like this---they all add up.

I should have been more clear...I meant the spring/thackery washer could break.

hi Tridentman
With the spacers fitted as i have and the newer rockers with the notches , should i then have the later rocker shafts with the helical groove to allow oil along to flow along the shaft. I'm hoping so cos I've just cut a groove along both shafts to let a bit more oil along!!
Ive just kept it a real shallow groove and spiralled it as best i can with the dremel!
we'll see how it goes now!
I did notice on strip down the exhaust rocker was discoloured and looked like it had been threatening to pick up or seize, although during use i never heard and squeaks from top end , also I've just done the valves and didn't notice any undue wear on the top of the valves or any sign of burning /pitting on seats. so hopefully the shaft damage was historical and someone else drama!
wait till you see i'll be looking for valve seals next as it'll be reeking like an old fergie tractor !!!!
cheers
greg

Since my name was mentioned I thought I would review the history of the notched rocker arms.

The notched (non-drilled) rocker arms came out of a project at Umberslade Hall for the Triumph and BSA triples. It redirected some of the flow of oil away from the push rod cup and put more oil on the valve and the valve tip.

Beside the new notched (non-drilled) rocker arms the change include a rocker shaft with a deep groove extending the length of the shaft and repositioning of the flat and Thackeray (double coil spring) washers. These parts, including the repositioning of the rocker Thackeray and flat washer was used on all BSA and Triumph triples. The repositioning of the washers, with the flat washer against the rocker arm, is the key to redirecting the oil through the rocker arm notch and to the valve area. As is the shaft long groove which allows oil to flow to the end of the rocker arms. Other wise if the spring washer is left against the rocker arm the oil just dribbles out the end of the rocker arm.

Now,if there was going to be a problem with the Thackeray against the inside of the rocker box you would have heard about it by now. All BSA & Triumph triples have this set-up.

How Meriden ended up with the new rocker design is unknown to me, but it was in a period where BSA was doing more buying for the group in an effort to get some economies of scale. But non-drilled notched rocker arms showed up at Meriden in 1969.

See TriCor Service Bulletin No. 25 April 1969 650 and 500 models:
There was a mid-year change in the rocker arms - after DU79965 and 500 # H63307, the hole drilled in the rocker arm to supply oil to the ball was omitted in favor of a notch at each end of the rocker arm. Flat washers must be used against the side of the rocker arm on the later design!

And yes, the new rocker arms became standard on the 650 and 500. But in what was a huge disconnect between engineering and production neither the grooved shaft or the relocation of the washers never found their way to the assembly line. Both of which are essential for oil to flow through the top-end.

Has any one of you put clear oil line on the rocker arm feed for a late 1969-1972 650 and watched the oil sit gurgling in the pipe seeming not to be going any where?

Well in 1973 the light bulb must have gone off in the long tunnel between engineering and assembly and they finally grooved the rocker shaft. Oil began flowing again. Did they change the Thackeray - well, no.

To make the system work as designed, you need to finish the job and put the flat washer against the side of the rocker.

If you don't the rocker will get enough oil to keep it from seizing to the shaft, but there will be no flow to adequately lubricate the valve adjuster or push rod cup.


And the solid spacers work OK, but if they are not set-up properly it tends to increase the noise level as the rocker arm slides from side to side. Never seen one break-up!

Guys
Thanks for all the info ,
John
Ive machined a groove to let oil flow and I've assembled the the rockers with washer next to the rockers and spacer next to the casing.
As for a clear pipe i didn't try it but i did try fitting the rocker lube pipe to both the rocker covers whilst on the bench, i then fitted an oil can to the feed pipe and pumped , pressure built up whilst pumping but the ends of the rockers barely got wet with oil before i grooved the shaft.
I did the oil can experiment now I've grooved the shaft and things are much better.
cheers
greg

Greg--I cannot improve on Johns description of the situation.
Certainly using the grooved spindles with the spacers is A OK.
Just make sure that the spacers and rockers are all assembled in their original positions.
When machining the spacers they are made to fit ---that is they are not identical in terms of thickness.
When you have the rocker box assembled make sure that the rockers can easily rotate with little or no end movement.
HTH

Oh I can read the Unity catalogue! Has anyone measured the difference in effort required to move the rocker?

Some common mods make a difference to speed and some just don't. We've all seen drilled timing pinions.

Buying shims in bulk and packing them in go-faster kits = profit.

i've got some off-the-shelf rocker spacers made by . . . whoever that company was (from indiana?) that used to make the really nice high performance tubular pushrods for triumphs, but doesn't, anymore. not kibblewhite.

. . . alloy-tech. illinois.

http://www.ebay.com/itm/1104-Alloy-Tech-Triumph-500-Twin-Rocker-Spacers-New-Set-of-4-/231420126206

anyway, i have them in my street bike, and another set on hand for a race motor. they installed with no tightness and almost no axial play, which is an issue because if they're loose they're no better than misplaced thackery washers for directing oil.

the thackery washers cause enough friction in the stock set up to make the rockers noticeably stiff to work back and forth by hand, no matter where you install them. with the hardened spacers installed instead the rockers are floppy loose. the machine revs quite freely, with no additional clatter but i can't say that i have noticed a difference at the rpms i run it at (under 7000). no dyno info to compare.

i've read that one must carefully check and correct the location of the lash adjuster centerline over the valve tip when installing these things, but mine were fine.

TT--just a bit of machining and a bit less friction.
What is not to like?

The time and money that could have been usefully spent.

"The time and money that could have been usefully spent."
Value judgments made by the individual IMHO.
If the individual wants to replace the Thackeray washers by spacers then---it is up to him.

Like paying the internet bill so we can all take the time to discuss such things.

Ohh! I know... Beer, and pizza!!! I always have money/time for beer, and pizza.
Way better than fixing some clunky old bike.

Thackeray washers make assy. of the top end much easier. Spacers allow the rocker arms to flop around and loose contact with pushrods on assembly, not a big deal but annoying none the less. I never could tell any difference in noise or power on my street Triumphs with the spacers and after reading in the TIOC about Gary Nixon's track bike using the Thackerays, well good enough for me and easier to assemble the boxes to the head to boot.

Each to their own.
Spacers are not compulsory!