There was a rash of true stories out of England about 1993 where TR drivers
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 pumps
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 pinning it.
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 with the
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 was worn
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 soft shafting
and leave it soft. I checked the hardness and couldn't even get a reading
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 on the
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 that was
thicker and ground in the off-set slot into the top end where it gets
driven, ground through the hard outer shell on two opposite sides just where
I wanted to put a pin through, pushed the lobe part on and drilled a hole
through both parts in one shot and pressed a new hardened pin through both
pieces. I peaned both ends of this pin with a center punch to make sure it
wouldn't move.
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 on the
hardened shaft that I used. And I still have 8" of this hard shafting left
to make 2 more.
Don Elliott, Original Owner, 1958 TR3A, Montreal, Canada
----- Original Message -----
From: "Peter Vucinic" <vucinic@b140.aone.net.au>
To: "FOT" <fot@autox.team.net>
Sent: Wednesday, September 03, 2003 3:26 AM
Subject: TR4 Oil Pump Rotors
> Does anyone have a supplier, who can actually supply 'good/high' quality
oil
> pump, spindle & rotor assemblies? (504862)
> I fitted a new assembly 1,500 miles ago, and the spindle journal, closest
to
> the rotor, is severely scored and has worn down about 0.002" in diameter!
The
> shaft material looks awfully soft to me as well which, obviously wouldn't
> help!
> Yet I have some original pump assemblies that don't have a mark on the
> spindles? Anyone else come across this drama before me?
>
> Thanks in advance
>
> Kind Regards
> Peter Vucinic
> WORKS-4
> TR-4
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