wet sumping
- Thread starter macca47
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1up3down said:
The valves sold by CNW and several others are the Al Miles valve.
It doesn't matter which spring loaded automatic anti-wet-sump valve you have. They all operate similar and have the same potential to cause problems.
I would like to add that at this is just speculation on my part. Once the engine is blown then there is little proof of what actually caused the failure. Jim
ashman said:
It appears thatit is a hit and miss as regards to the gear type pumps that are fitted to different type of machines, and not just motor cycles. When I was an a apprentice I worked on one of an old line of identical milling machines, all, except one required the coolant pump to be primed to make them work (The coolant tank was in the base) whenever the machine was turned off.
Whether this has to do with the accurately of assembly of the oil pump is hard to say.
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For what it is worth a Vintage Norton racer had completed a new build of a bike with an alloy oil tank a few years ago. The first time out after a proper break in and at least one or more practice session the engine dropped power and began to seize during a race.
The apparent cause was a restriction in the alloy oil tank feed spigot. If I recall correctly there was some sort of cut off saw flashing on the spigot on the inside of the tank that was only apparent if you removed the spigot from the tank. In early discussions he described it as an equivalent diameter reduction but when you do the math and see the reduction in cross sectional area it was dramatic. I seem to recall 1/6th the cross sectional area.
So under most conditions the flow through that orfice was adequate but under race conditions I suspect the oil was much closer to vapor point and the resultant drop in pressure due to the restriction tipped it over the edge.
Norton attempted to remedy the wet sumping but note that they placed the valve on the pressure side which is good practice.
I would not put an anti wet sump valve in the suction side unless I knew it had adequate flow capacity at idle and more important, at speed without a significant (friction) pressure loss.
The apparent cause was a restriction in the alloy oil tank feed spigot. If I recall correctly there was some sort of cut off saw flashing on the spigot on the inside of the tank that was only apparent if you removed the spigot from the tank. In early discussions he described it as an equivalent diameter reduction but when you do the math and see the reduction in cross sectional area it was dramatic. I seem to recall 1/6th the cross sectional area.
So under most conditions the flow through that orfice was adequate but under race conditions I suspect the oil was much closer to vapor point and the resultant drop in pressure due to the restriction tipped it over the edge.
Norton attempted to remedy the wet sumping but note that they placed the valve on the pressure side which is good practice.
I would not put an anti wet sump valve in the suction side unless I knew it had adequate flow capacity at idle and more important, at speed without a significant (friction) pressure loss.
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Bernhard said:
Correct me if I am wrong here but I recall the Velocettes (350 and 500) have roller bearing big ends which really do not need a pressure feed like a plain bearing rod journal requires. The roller bearings are very tolerant of interruptions in oil delivery.
You do make a good point here and now I wonder how most dry sump bikes handle this. What comes to mind is the HD V twin and a whole slew of others.
Dances with Shrapnel said:
The HD oil pump has a check valve in the pressure line which works apparently quite well. I've owned my Shovelhead about a year now and wet sumping simply was no issue.
I'm currently working on race car engine and have some stakes in the dry sump system of that thing as well (no, sorry, I can't get any more specific ATM). A few days ago we had a design group meeting with eight team members and the subject of wet sumping came up - the engine we used to do before didn't have this issue because it was filled with pre-conditioned oil immediateley before and drained after each event. I used the opportunity to mentioned what was common - and IMHO bad - practise on my beloved Nortons. The reactions were: 5x disbelieving looks followed by heartly laughs, 1x heartly laughs and commiserative nodding (the 1970 Bonnie owner on the team) and 1x "Okay guys, now that we know what we will definetly NOT do please back to the topic, time's running and we don't have time for such a nonsense" (team leader).
:mrgreen:
SCNR
Tim
Then, pray tell ,why did Velocette do this to their 350 and 500s then :?:[/quote]
Correct me if I am wrong here but I recall the Velocettes (350 and 500) have roller bearing big ends which really do not need a pressure feed like a plain bearing rod journal requires. The roller bearings are very tolerant of interruptions in oil delivery.
You do make a good point here and now I wonder how most dry sump bikes handle this. What comes to mind is the HD V twin and a whole slew of others.[/quote]
Technically, you are quite correct as regards to the needle roller big ends on Velos, however the oil pumps on these bikes are gear type, the same as on the Norton, and would, if fitted to a plain shell big end, produce a similar high oil pressure to a Norton, Triumph, BSA, e.t.c.
Correct me if I am wrong here but I recall the Velocettes (350 and 500) have roller bearing big ends which really do not need a pressure feed like a plain bearing rod journal requires. The roller bearings are very tolerant of interruptions in oil delivery.
You do make a good point here and now I wonder how most dry sump bikes handle this. What comes to mind is the HD V twin and a whole slew of others.[/quote]
Technically, you are quite correct as regards to the needle roller big ends on Velos, however the oil pumps on these bikes are gear type, the same as on the Norton, and would, if fitted to a plain shell big end, produce a similar high oil pressure to a Norton, Triumph, BSA, e.t.c.
Tintin said:
The Velocette method is as follows;
A large diameter about 1 inch ball bearing is fitted into a housing held in place by a weak spring that only just holds the seal when oil pump is not working.
The size of the ball bearing is carefully calculated to allow the maximum amount of oil to flow, say the oil pump can pump x amount of gallons per hour then it must be able to flow slightly more than this amount.
The oil pipes to the oil pump are crimped and are air tight or it will fail to retain the oil in the tank. Also before fitting, this feed pipe has to be primed (filled with oil from the top) or it will fail to work.
Those of you who have had one of these will already know that there is a felt oil filter fitted inside a tube in the Velos oil tank.
I suspect that Velo obtained outside help when they designed this method of preventing wet stumping and spent a lot of time, money and effort on perfecting it.
(Velos were good, but not that good)
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Bernhard said:
Gear or plunger does not matter. With roller element rod big end bearing engines like the Velocettes and HD V twins, there is likely a need to provide pressure to some components such as rocker shafts but I see it more as a metering system that assures X volume of oil per revolution at the rod journal, not a pressure delivery system to the rod journals.
With the HD FXB I have it does register some pressure, enough to trip a pressure light.
I have a hunch that if engines with roller end rod journals exhibit any significant pressure in the system it is due to a designed restriction so that select non roller element bearing surfaces may receive proper lubrication. The roller rod ends just need a steady supply.
In fact, for many roller bearings, as bearing speed applications increase you see the lubrication recommedations change to misting only; anything more gets inthe way and contributes to waste heat.
I digress. Yes even with a metering pump it should be able to actuate a non drain valve. The question is where do the various manufactureres place the valve.
I remeber one foray into a BSA 650 twin and seem to recall a little ball valve beneath the motor under the dry sump screen cover. Anybody know about how the BSA twins handled this?
you OBVIOUSLY have a limited knowledge of hydraulics and an oil pump losing prime. you KEEP pushing how ONE manufacturer did this BODGE.
is this a joke or what!!!!!!!
you have been giving evidence that there has been engines lost and theory on this garbage from VERY knowledgeable people but you still don't get that it is not a good piece of engineering.
Bernhard said:
is this a joke or what!!!!!!!
Bernhard said:
you have been giving evidence that there has been engines lost and theory on this garbage from VERY knowledgeable people but you still don't get that it is not a good piece of engineering.
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