TR3/4 Oil pumps
Does anyone have a supplier, who can actually supply 'good/high'
pump, spindle & rotor assemblies? (504862)
I fitted a new assembly 1,500 miles ago, and the spindle journal,
the rotor, is severely scored and has worn down about 0.002" in
shaft material looks awfully soft to me as well which, obviously
Yet I have some original pump assemblies that don't have a mark
spindles? Anyone else come across this drama before me?
Thanks in advance
There was a rash of true stories out of England about 1993 where
suddenly lost all oil pressure. They all found that the lobe
piece that is
attached to the pump drive spindle was not pinned as on the original
were and as we see in the exploded view in the parts catalogs.
It was only
held on by some knurling that had been done on the shaft to save
The knurling failed and the drive spindle was still turning -
but not the
lobe part at the bottom. Hence no oil pressure.
In 1987, I had bought a new pump while in England and so about
1995, I took
off my oil pan to check. There was no pin. I bought a new pump
assurance from a major TR parts supplier in eastern US that it
had a pin.
When it came, it had no pin.
So I took things apart. The knurling was about 0.0015" deep
on both the
drive spindles. The shaft where it is supported by the bushing
about 0.002". The bushing was not worn so it went back in.
If you think
about it, you can't knurl a hardened steel shaft. So they use
and leave it soft. I checked the hardness and couldn't even get
on the Rockwell "C" scale. It was only on the "B" scale
that I got a
reading. So it was ordinary mild steel shafting.
Where to these chips from the wear go ????? I checked the babbitt
bearing shells and they were scored so I replaced them.
Next, I bought a 12" length of 1/2" diameter hardened
and centerless ground
steel bar stock from a bearing supply shop for about $10.00.
I checked it
for hardness and it was Rockwell 60-62 on the "C" scale.
I cut it to the
correct length with a grinder cut-off wheel, used a grinder wheel
thicker and ground in the off-set slot into the top end where
driven, ground through the hard outer shell on two opposite sides
I wanted to put a pin through, pushed the lobe part on and drilled
through both parts in one shot and pressed a new hardened pin
pieces. I peaned both ends of this pin with a center punch to
make sure it
And it's been fine for the last 8 years and over 50,000 miles
of high speed
highway touring. I have checked it again and there was no wear
hardened shaft that I used. And I still have 8" of this
hard shafting left
to make 2 more.
Or find a reliable supplier who makes and sells the oil pump
that has the
original design with the hardened shaft and the cross pin. With
wear on the
soft drive spindle, the lobes will also wear because things are
parallel. With this wear, the oil pressure will drop somewhat
It did on mine.
With the new hard shaft I put in, the oil pressure hasn't dropped
noticeable amount in 8 years.
Don Elliott, Original Owner, 1958 TR3A, Montreal, Canada
Because the manufacturers of the oil pump gears sets, (I believe
marketed in the US as "county" brand) found the inner
gears coming loose
from the shaft was a problem, they began to install a pin though
and the shaft about 6 or 8 years ago. We had one of those pins
work loose and
come out during engine operation and it consequently jammed the
immediately sheared the slotted upper end of the drive shaft.
stopped turning completely at this point. The engine kept on
it ran the bearings.
Previously, using original Triumph supplied pump rotors, two
times I experienced the slot ears shearing off when there was
no reason for them to
fail except normal stresses of operation. This always stops the pump from
turning. These shaft failures, I believe were cause by the shafts being too
hard and consequently somewhat brittle. They were, and the new repro parts
are also, machined with sharp corners to the drive slot in the top of the
shaft. These sharp corners are stress risers that will help induce the
beginning of cracks. We remachine the slots so that there is a full radius
in the bottom, then glass peen the inside of the slot to remove
As for the pin that is designed to keep the rotor from turning
on the shaft, We found that the pin on the original gear is
VERY hard to drive
out, while the pins in the new gears are very easy to drive out. So we now
remove all of the pins, tap the hole through the rotor and the shaft, and
then loctite in a 3/16 allen set screw as a new "pin". Being loctited
with maximum strength retaining compound and screwed into place, it is NOT
going to come out.
With gears modified in this manner, we have experienced no failures,
even in race engines turning over 7,000 rpm and pumping over 90 psi oil
Hose size for external oil coolers. This one is too small
for its own page and this is the closest asociation I currently
-10 oil hoses are the size to use. The longer the hoses the
diameter they need to be. For a TR-4, -10 is large enough for
applications. You do not want the hoses to be a restriction to
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