Minimum RPM?

Greetings fellow enthusiasts,

While cruising along in my 79 MGB, my mind does begin to wander. One question I've been meaning to ask all the gurus (or is it shamans?) is that when cruising at moderate speed - say like 25-45 mph- is there a recommended minimum RPM I should be looking for? The reason I'm asking because on my Triumph T160 MC, it is recommended to keep cruising RPM above 3k, something about keeping up the oil pressure,etc., etc.

I realize bikes aren't cars but I was curious as to what, if any, rules apply to MGs.

Thanks for any insight into this matter!

I'll take a crack at this...

For all practical purposes the oil pressure is going to remain sufficiently high no matter what revs are turned.

What may matter more, beyond the "perkiness" of the engine might be the issue of pounding the do-do out of the rods and more so the main bearings. The inertia if the flywheel and the controls that the harmonic damper supply will certainly help cancel out much of the hammering, but still, if the revs get too low and the engine is lugged the bearing are the first to suffer.

Specifically, a B enjoys the best of all worlds when run at a bit below the torque peak. That gives it some elbow room to hitch up its skirts and get on with business without falling on its knees first.

Depending on the load, hills or flat land, I would say that 2500 to 3000 revs would make the engine happy at cruise within normal speed limits and 3500 might be about right if you were feeling a bit more aggressive. What you want is to be able to put you foot into it without dropping too far off the torque scale. If that means dropping down a gear, doing so isn't a bad thing.

Jack

My MG driver's book says any speed that does not allow the engine to "labour." I think they like to crank-up the rpm's!

AS with any engine do not let it lug. 2500 to 3500 is the sweet spot in the RPM range.
I shift up at 3500 to 4000 RPM range. On long mountain grades I run at 4500 to 4700 RPM to prevent engine lugging.
Down shift at 2000 when slowing down.
Generally cruise at 2500 to 3500.

When slowing to a stop I use the brakes because they are easier to fix than the OD gearbox.
Most times when reducing speed quickly I use teh brakes for the above reason.

The transmission is a torque multiplier ,,so a certian speeds its better
to down-shift and stay close/in the torque band of that engine..
Easier on drive train and more responsive to demands..

My engine has always been happiest when running along at 2,500 rpms. The use of the overdrive and down shifting make this easy to accomplish. RAY

I'll cruise lower than that, sometimes as low as 1500-1700, more usually 2000 rpm. Realizing that going to WOT acceleration is apt to want a downshift

In 5th, 2000 is just about 45, a common speed limit out in the woods around here, and 2500 is about 55, the other common speed limit out in the country roads. So most of my cruising is in that range.

Thank you all for your feedback! As usual, I appreciate it very much.