Ger: The Morgo pump is a geroder type.
Sorry for the use of band width here, but the devil made me do it...
Phify: I am one of those old timers you are talking about. I have run one of the first "Real High Volume" Morgo rotary pumps, and several lower volume variants since. Until recently, I campaigned a Triumph 500 racer since our first one in 1959. I have used all sorts of oil pumps: iron and aluminum body, Morgo piston, Morgo rotary and four valve. Any one who runs one of these little 500s realizes it needs to run in excess of 9,000 rpm and you are always looking for an edge. My experience with these rotary pumps also includes using them in a short rod Triumph 750.
As far as improved valve/guide wear nothing ever changed from oil pump to oil pump. The only thing that ever made a difference is when I finally realized that the valve guides being sold, either cast iron or bronze, were not made from real valve guide material and the introduction of nitrited valve stems. This, only after I had the valve guides spectrum analyzed. Triumph had the same experience when they finally cured camshaft wear when they nitrited the camshafts.
Given the stock pump is in good working order, the spacing washers are assembled properly on the rocker shafts (most books, including Triumph workshop manual
, have them wrong) and the return line has the 7/32" restriction (not always included with custom oil tanks) you will get more than satisfactory performance from the plunger pump, even when used for racing. Triumph has a center feed crankshaft, and as such needs little, if any increase in oil flow or pressure. If you worked on these motors where imported oil feed seals were installed which often split or invert shortly after they are installed, and then ridden for many thousands of miles, you would understand. "Oh, the oil light always comes on when it idles." Triumph twins rarely tie-up a rod bearing unless the sludge tube is blocked.
My experience has also included the use of a 250 oil filter on the return side, since we discovered some horsepower and started using Nourish cranks (no provisions for sludge tube filter). I saw no improvement when a rotary was fitted.
Now heat is the limiting factor for how much you can get out of one of these little engines. Cylinder and head finning are at a minimum, and for the typical use of the day when AMA ran the bikes 200 miles, it was a problem. Triumph even fitted remote oil coolers to their little piston oil pump engines. Those little piston oil pumps served well, as the factory was getting a lot more horsepower from the 500 than most racer’s get today. And they were running the motor at race speeds for 200 miles, not 20. I would say that the average street rider would hardly approach the stress on a Triumph 500, and its piston pump, as the average racer today running 20 miles, let alone the 200 of yesteryear.
With current racing consisting of only a handful of laps it hasn't been such a problem (except when you use a full fairing). When running the Morgo rotary I saw no measurable difference in oil temperature over the same motor using a 4 valve pump – with, or without a filter installed.
There is talk above about diverting extra oil to the rocker box to cool the head. But let’s examine this. The hole that takes the oil from the overhead oil line into the rocker shaft is .054" in diameter. This feeds two more .054" holes in the shafts at the middle of the rocker arms themselves. So it would be true that your clear oil feed line would have visible flow of oil. But now the oil must make its way through the rocker arms, and the .0015" clearance the rockers have on the shafts. The increase in actual oil flow would be margin able.
So let’s say we enlarge the holes and drill a couple of holes in the rocker arms so that they spray some of this oil on the valve springs. This would divert some of the oil from the cavity created by the rocker shaft turning and divert the oil to the valve springs. For this to work, the pressure would have to be regulated, as pressure controls the pattern of the oil spray. Too much or too little and the oil will not spray properly and you will not get the desired effect. Some experimenting in hole size and pressure would be indicated.
This brings us to the question of how we are going to remove this volume of oil from the head. The four stock holes in the tappet guide blocks will be insufficient. You need to enlarge them or add some other path for the oil to return to the sump.
Yes, there is some potential in using the rotary pump. If I was preparing a bike to run 200 miles I would include one. I would also make provisions for the motor to handle the extra oil. One thing I did when I used the rotary was to divert the by-pass oil directly to the oil tank. This is something Triumph did in the 60’s.
But lets look at the Morgo’s instruction sheet. Actually one should look at the history of Morgo’s instruction sheets, but that’s another story. He learned a lot as people started to use them.
Priming the pump is an issue, and one should never assume that the pump is primed because you saw oil coming out of the oil bleed hole during installation. Air in the line or pump prevents this pump from working! The motor must be turned over with the plugs out and a preferably with an oil pressure gage attached, but removing the oil pressure switch can suffice.
On T140’s, you must tourniquet the oil feed line coming off the oil cavity plate when you drain the oil. The bottom of the oil cavity is below the pump and oil will drain out of the feed oil line requiring the pump to be re-primed. After changing the oil one should verify oil pressure before starting the engine.
To quote Morgo’s instruction sheet, “The golden rule with the MORGO SUPER PUMP is, if the oil is there and the pump is primed the pump will pump it.” Ah, yes primed…
One must have confidence in the crankshaft oil seal that is fitted to the timing cover. These seal come under a lot of stress during cold starts. It is made worse by the common belief that Triumph should be using 40 or 50 weight oil. The oil by-pass will be unable to divert enough of the cold oil to prevent excessive pressure build up behind the oil feed seal. This can be overcome, but Morgo has changed their instructions and do not include the part where you enlarge the oil passages the by-pass valve uses in the crankcase. If I was to fit a rotary I would be sure to include verifying that your engine cases have provisions to handle the extra oil by-passed by the by-pass valve. Not all Triumph cases are the same and some will not handle the extra oil!!!
As Beltdriveman mentioned, cold starts can be a problem. And I quote Morgo Section 13 of the instruction sheet, “It will also be noted that when the oil is cold, the oil level in the oil tank can reduce but will return to its normal level on warming up after only a few minutes running. The reason for this is, the new pump having a larger delivery than the old plunger type pumps, resulting in more thick oil being delivered back to the crankcase via the pressure relief valve. Because the oil is thick the crankshaft picks up and carries a higher proportion of waste oil than normal around itself and centrifugal deposits the oil on the crankcase inner surfaces. Also a great amount of oil is held in the timing cover, (and the primary cover ed.) until the oil warms up. As soon as the engine warms up only marginally, the oil drains to the bottom freely hence the oil level in the tank returning to normal. (The above can give the impression of wet sumping)”
Now you are ready to practice, start your motorcycle, fill your primary full of oil causing the clutch to slip ruining a new set of clutch plates and the extra oil wets sumps the motor and fouls your new B9ES plugs… I avoided this by directing the oil externally back to the oil tank.