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Drilling new conrods
#11
Don’t agree. On a sprint or Hillclimb it’s difficult to get the oil hot enough to not have problems with splash fed. I know someone will say I’m wrong but believe me I’ve been doing this a long time and I’d use pressure fed, always.
Alan Fairless
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#12
The supercharged engine in our new build single seater is splash fed, there are 2 very good reasons for that, firstly the job lot of bits we bought included a new splash fed 1.5/16 crank & rods and secondly we chose to drive the MAG blower directly off the nose of the crank, so the drive screws in where the original starter dog screwed in.

We are running an over-bored oil pump with new vanes and springs, carefully fettled to be as smooth as possible, thus absorbing minimum power losses. The edges of all the entry & exit angles are all radiused & dressed smooth & the pressure relief valve was shimmed up. The pockets in the Phoenix were cleaned up and the holes opened up to be a bigger entry with a pronounced entry radius to facilitate oil flowing into the holes from the pockets. The crank, rods, flywheel & pressure plate were then balanced.

Lastly a Forrest double oil jet conversion was made & installed & by pumping paraffin through the oil pump via the pick-up we could adjust each of the 4 oil jets to spray the maximum amount for the maximum duration into the respective pockets. I simply capped 3 jets & focused on aiming one jet at a time. There's almost 80* of arc on each oil jet now, so top & bottom means the crank is getting a steady supply for 160*rotation per pair of crank pins. The original direct down single oil feed was an arc of about 15* and they seem to have lasted a goodly while.

I'm off the 10lbs gauge when cold and after several good runs it's holding 6lbs at 6000rpm at the top of the hill. 1 gallon pan sports pan so the oil probably hasn't got enough hot enough to get really thin, but even if it drops to 2 or 3lbs, that's plenty on 4 oil jets. The hill climbs here are 2kms each or 1.25 miles

The blower is on sealed bearings and I run a dollop of Castrol R in the gear case - so far so good.

Ciao
Greig
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#13
I posted on the Austin 7 facebook group yesterday having taken my bottom end apart and found that after 5000ish miles a couple of the shells had worn quite badly. The consensus was that shells aren't great with a splash fed engine. I have Hadley 1 5/16 rods drilled as shown.

That said I also have no oil pump which certainly doesn't help. I think I will fit one now to try and improve the bearing life.

A related question, I have seen discussion about reprofiling he pick ups on phoenix cranks, could somebody post a picture of this?
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#14
Pigsty engines are splash fed, and seriously fast, so it seems splash lube is adequate for them.
Again one of those situations where no one is particularly right or wrong.
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#15
(07-12-2020, 09:43 PM)tomcotez Wrote: That said I also have no oil pump which certainly doesn't help. I think I will fit one now to try and improve the bearing life.

hope an oil pump will improve things Smile


the splash vs pressure debate is warming up nicely - unlike the oil in my deep sump...
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#16
(07-12-2020, 11:31 PM)Dirk73 Wrote:
(07-12-2020, 09:43 PM)tomcotez Wrote: That said I also have no oil pump which certainly doesn't help. I think I will fit one now to try and improve the bearing life.

hope an oil pump will improve things Smile


the splash vs pressure debate is warming up nicely - unlike the oil in my deep sump...

Oops I meant filter!
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#17
Something over 60 years ago, Simplicity went up Prescott faster than most do today.
Splash Austin 1 5/16" crank, 2-jet, overbored oil pump. Of course, Austin cranks were a lot younger and more plentiful then!
The sump was the normal Austin tin variety, with a chunk cut out at the front to provide clearance for the steering track rod, so had less capacity than standard. At that time I think it ran on Shell X100 before my father became a Castrol convert.
Other specs? All internals polished and balanced, lightened flywheel and clutch plate.
Jack French cam (!), large radius lightened and shortened tappets, 1.25" inlet valves, ports blended. Nippy carburetter and inlet manifold, Brooklands exhaust. Unblown Ulster cylinder hesd with relief for valves. All meticulously assembled, probably the most important thing about it! Chummy 3-speed gearbox, changed into 2nd soon after start and stayed there.

Simplicity was very reliable, being driven to events, racing and driven home.

Thought you might be interested.
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#18
Presumably Austin had some firm basis for the rod drillings. It would be interesting to know just how function. Were the baffles to direct draining oil to the rods? When first introduced Austins would not have been providing for sustained revs beyond normal valve bounce (or near). The trench at the top is agin all theory, often ridged on the trailing side; whether due reduced film as per theory or dirt entry I dunno. On the upstroke considerable oil must enter at the drillings
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#19
(08-12-2020, 05:58 PM)Rogerfrench Wrote: Something over 60 years ago, Simplicity went up Prescott faster than most do today.
Splash Austin 1 5/16"  crank, 2-jet, overbored oil pump. Of course, Austin cranks were a lot younger and more plentiful then!

I remember reading the specs on Simplicity a long time ago in Allan Staniforth's book, quite impressive! there is something far more hands-on about the approach to tuning back then, maybe lost now with the improved components we have available to us.
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