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MG MGB Technical - Can't Find It in the Archives!

A while back there was a thread wherin the discussion evolved into the subject of high flow oil pumps. Somebody (Daniel Wong?, Leland?) spoke of the actual type of oil pump (by name) that's in the BMC B Series engine. I spent two and a half hours last night trying to find it in the Archives, without success. Does anybody out there remember what the title of the thread was?
Steve S.

Are you thinking of the Wayne Martin Power Pump.
http://www.peter-burgess.com/page32.html
joe robertson

Joe-
No, the thread was further back than that one.
Steve S.

Hi Steve,
Can't blame that one on me ;-)
To bad the thread titles can't be changed to identify the subject.
Leland Bradley

Leland-
Maybe it was Daniel Wong who was describing the type of oil pump in the thread.
Steve S.

Hmmm...funny, I don't remember knowing any
aftermarket high flow oil pumps for the MGB.

The stock pump flow enough oil volume to handle
almost any situation the "B" engine will likely
encounter (short of abusively over-reving). With
minor mods, the stock pump was used during the
MGB's SCCA heydays (Huffaker, Group 44, etc.)
as well as in the factory cars that ran at LeMans
and Sebring.

The Special Tuning Manual mentions machining
an extra feed port (or passage) in the bottom end
cover of the stock pump to improve flow a bit.
Today's replacement pumps already incorporate
a portion of the mods, but do not include the extra
feed port. Some parts companies offer stock
pumps fully modified (with the extra feed port)
according to the S/T Manual specs.

The "fly in the ointment" here is that when the
engine is shut off - that extra feed port then
becomes a drainage passage - and oil that
is inside the pump body flows back into the pan.
At each cold startup, it'll take an extra second or
two for oil pressure to build up. This is not a big
deal on a racer engine that'll get disassembled
several times during a season - but on a street
driven car, it can all add up to shorten the life of
the engine bearings.

Now, having said all that, I must admit that I've
done this mod to my own engines (a daily driver)
without much noticable detriment. I must point out
that I machined the extra passage at about 3/4 of
the depth of the spec given by the Special Tuning
Manual. Maybe the smaller port crossection helps
slow the drainback effect ...then, maybe it doesn't.
What I do know, is that - after every oil change - it
does take quite a bit longer to build up oil pressure
(about 20-30 seconds or more) - perhaps because
draining the oil pan exposes the oil pickup, and
this helps siphon the oil out of the pump through
the extra port). Because of this, I make it a point to
spin my engine (no sparkplugs installed) until I get
oil pressure on the dash guage, after performing
every oil change.

Another oil system mod the Special Tuning Manual
mentions...is the use of packing spacers behind
the oil relief valve, or the use of an uprated spring.
This'll bump the oil pressure up to about 70-75 lbs
(with good engine bearings). This is all located on
the port side of the block, near the bellhousing.
If you plan to do this while the engine is still in the
car...good luck. As the spring is rather stout, and
the threads on the cap must be lined up precisely
- it can be a real sweat trying to re-install the
retaining cap in those tight quarters! I've done this,
too, myself. Much cursing involved. Make sure any
children are away from earshot while doing this.
Daniel Wong

This thread was discussed between 17/09/2003 and 18/09/2003

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.