As part of my engine rebuild I have been recommended to take the oil pump .020” oversize. On the assumption this is a good idea for a road going splash fed sports engine without oil filter, this poses two questions:
Do I leave the jets the same size or enlarge them to get more flow through onto the crank? (I would have thought the latter, as there seems little point in just increasing system pressure for the hell of it)
and
Assuming that just shoving a wire through the jets is an unreliable way of proving where the oil will in fact end up I'd like to observe the flow through the jets after installing the crank but before fitting the rods and block. What cunning arrangements have people come up with to achieve this demonstration? e.g. is it better to find some way to drive the pump, or to stick a tank up high and allow gravity to provide the supply?
I stand the cleaned crankcase with oil pump installed in a clean tray with some clean paraffin in it and drive the oil pump with a socket (mounted in my electric drill) on the oil pump drive gear nut. Oh and the front camshaft bearing is positioned to blank off the oil hole. All of the crankcase plugs are loose and removed one at a time to flush any dirt out and it's surprising how much dirt appears in the bottom of the tray from a crankcase I had cleaned. I usually change the paraffin for a second go. Wellington boots are optional extra PPC.
All the pumps on my cars are over bored, Colin, and none have other than standard diameter jets. On the one occasion I did have jets that were other than standard diameter I ran No.4 Big End (Malcolm was there and will confirm)!!
I use a length of silver steel rod/wire to aim the jets into the crank troughs. Ordinary soft iron wire is not stiff enough.
(18-12-2018, 12:00 PM)Dave Mann Wrote: I stand the cleaned crankcase with oil pump installed in a clean tray with some clean paraffin in it and drive the oil pump with a socket (mounted in my electric drill) on the oil pump drive gear nut. Oh and the front camshaft bearing is positioned to blank off the oil hole. All of the crankcase plugs are loose and removed one at a time to flush any dirt out and it's surprising how much dirt appears in the bottom of the tray from a crankcase I had cleaned. I usually change the paraffin for a second go. Wellington boots are optional extra PPC.
In all seriousness, anyone who saw me hobbling about with a stick a couple of years ago at Beaulieu may be shocked to learn it was the result of getting my left sock splashed with paraffin. I was 'busy' at the time so ignored it for an hour or two. My foot inflated like a ruddy melon. Have been dunking stuff in paraffin since time began so don't know if I got some 'bad' stuff or perhaps have become sensitised after all these years.
This sounds like a good approach to me (I don't use splash feed!) but it makes me wonder all the more about how the heck the big ends get lubricated at all on a cold morning start (in which condition oil ain't nearly so runny as paraffin).
Another thing to consider when uprating oil pumps is the rating of your pressure relief valve spring - easily forgotten component!
Joined: Aug 2017 Posts: 381 Threads: 16
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8 Location: Port Elizabeth, Sunny South Africa
Car type: '26 Chummy, '28 Top Hat, '33 Type "65", single seaters
We fitted a second set of oil jets to the new supercharged engine we built, I sized them to match standard jets. We did the pump-paraffin-through-the-system trick by utilising an auxiliary pump which is driven via my big battery drill, one end of the pipe into a bucket of paraffin, the other end stuck onto the oil pump pick-up (it pumped past the vanes). Spin the drill and adjust each jet to have the maximum accuracy as well as duration into the crank pocket - the latter by bending the jets towards the crank axis as per the Mike Forrest double oil jet conversion published in the 750 Bulletins way back when.
If you are using a Phoenix crank it's important to note the the pockets on either side are not exactly in line, so you need to test both sides of the crank. In our case I had opened up the quite small Phoenix crank pockets quite a bit as well as radiussed the oil feed hole into the crank as much as I could to facilitate better flow. I then adjusted the jets to provide even streams of fluid into each pocket.
Paraffin goes everywhere, so we did it outside over a large sheet of plastic with a large catch drum under the motor.
Some pictures of the double oiler mod - with 4 oil jets now fed by a 20% bored out pump we are still getting 2.5lbs at pace. You don't need much pressure to provide a steady stream of oil through those little jets and upping jet pressure to a hefty PSI won't actually get any more oil into the crank, there is a finite amount that can be crammed into that little pocket, the rest will just splash feed everything including the center cam bearing. I'd stick my neck out and say that the splash at a 20% overbore with only 2 jets would be more than the motor needed for oil cooling, never mind lubrication.
I thought paraffin made your skin smooth and soft Chris? From your tale of woe it's clearly not something to be messed around with. I think rigging something up at the bottom of the garden and approaching with wellies and gloves is the way to go. Good tip about the silver steel Steve, and being able to stick with standard jets gives me one fewer jobs.
I think I may have been fortunate to have bought a John Barlow crank. The troughs on either side of the web do overlap and seem pretty capacious.
I put insulation tape over the camshaft thread, take off the gear on the crankshaft, put a bit of diesel fuel in the sump, and wind the camshaft slowly anticlockwise using a battery drill, having sat the whole thing in an old washing up bowl or similar.
You can get enough revs by hand, it doesn't have to be messy. The other hand turns the crank so you can see just where the jets are pointing.
I fitted a Phoenix and had to do as Grieg did, open out the pockets to make sure oil squirted into them evenly on both sides of the crank.The actual holes don't line up evenly.
I have an up-rated pump and standard jets. I also reduced the size of the hole in the cam bushes and will be running an oil filter. I spun the pump with a drill to test it (using diesel). Later on I tested it again just using a funnel on a hose that I could fill with diesel then lift up to start the flow and lower to stop it. You need to get the side to side aim right and that provided enough flow to do that easily.
I bent the jets with a steel rod with a hole drilled into the end that slide over the jet smoothly. I was worried that trying to bend it with a rod down the inside of the jet would distort the ends of it.
I see I left an essential bit out, when testing the oil jet delivery I have a plate cut with two slots in it representing the crankshaft troughs which goes in the crankcase so I can check the direction of the jet delivery.
(18-12-2018, 12:00 PM)Dave Mann Wrote: I stand the cleaned crankcase with oil pump installed in a clean tray with some clean paraffin in it and drive the oil pump with a socket (mounted in my electric drill) on the oil pump drive gear nut. Oh and the front camshaft bearing is positioned to blank off the oil hole. All of the crankcase plugs are loose and removed one at a time to flush any dirt out and it's surprising how much dirt appears in the bottom of the tray from a crankcase I had cleaned. I usually change the paraffin for a second go. Wellington boots are optional extra PPC.
In all seriousness, anyone who saw me hobbling about with a stick a couple of years ago at Beaulieu may be shocked to learn it was the result of getting my left sock splashed with paraffin. I was 'busy' at the time so ignored it for an hour or two. My foot inflated like a ruddy melon. Have been dunking stuff in paraffin since time began so don't know if I got some 'bad' stuff or perhaps have become sensitised after all these years.
This sounds like a good approach to me (I don't use splash feed!) but it makes me wonder all the more about how the heck the big ends get lubricated at all on a cold morning start (in which condition oil ain't nearly so runny as paraffin).
Another thing to consider when uprating oil pumps is the rating of your pressure relief valve spring - easily forgotten component!
One of the old timers taught me to turn the engine over by hand for a count of 12 (6 turns) as the first operation when starting up a cold engine on a cold day. Presumably this was to circulate some oil - hopefully it would get as far as the big ends?
