Making an oil pump for a Jawa DOHC engine

[Charkmandler]

I dont get it. Are you not contradicting yourself? In #16 you recognized the need for a voluminous oil flow for cooling, while here you claim a Gerotor oil pump (Morgo) delivers "way too much oil flow".

I suggest you do your homework and calculate the oil flow needed (get outside help if needed). Oil flow to the roller big end will be a tiny fraction (less than 10%) of the total oil flow. Pressure and volume flow division is reached by inserting nozzles in the respective oil lines.
Maybe Jawa (the works) can assist you? Good luck!

- Knut

Yes I do need to increase the oil flow for cooling but there are limits. Currently the pilgrim pump delivers less than 1/2 pint an hour which has no cooling effect. I am not able to calculate the flow I need as I'm not that knowledgeable but I can use a similar pump to my application i.e. the Norton pump. This will flow a great many times more oil than the pilgrim pump.
As noted in my initial post the oil in the oil tank does not heat up at all due to such a small flow with the pilgrim pump, however with my racing 350 the oil heats up so is taking heat from the engine.
The mainshaft quill size is limited so will only flow so much oil and I can't see it being able to handle the output from a modern pump.

 

[acotrel]

A few years ago there was somebody in Queensland supplying oil pumps for Jawa motors in road racing. If you know anyone who still races historic in Australia - Keith Campbell is the last person I know who bought one of those pumps. It is mainly about the return of oil from the dry sump - not oil pressure. When a Jawa motor is on speedway, it is usually buzzing along at about 8000 RPM. It does not take much oil to lubricate a roller bearing big end. I have wondered about oil pressure in a Commando with the plain type big ends. With Triumph engines the indicator button lets you know about the condition of the big end bearings. When you run race motors on petrol, you need to worry more about heat. Jawa speedway motors usually run on methanol. What class do you race in, and do they do fuel checks ?

 

[acotrel]

Yes I do need to increase the oil flow for cooling but there are limits. Currently the pilgrim pump delivers less than 1/2 pint an hour which has no cooling effect. I am not able to calculate the flow I need as I'm not that knowledgeable but I can use a similar pump to my application i.e. the Norton pump. This will flow a great many times more oil than the pilgrim pump.
As noted in my initial post the oil in the oil tank does not heat up at all due to such a small flow with the pilgrim pump, however with my racing 350 the oil heats up so is taking heat from the engine.
The mainshaft quill size is limited so will only flow so much oil and I can't see it being able to handle the output from a modern pump.

Fit an oil cooler.

 

[Charkmandler]

A few years ago there was somebody in Queensland supplying oil pumps for Jawa motors in road racing. If you know anyone who still races historic in Australia - Keith Campbell is the last person I know who bought one of those pumps. It is mainly about the return of oil from the dry sump - not oil pressure. When a Jawa motor is on speedway, it is usually buzzing along at about 8000 RPM. It does not take much oil to lubricate a roller bearing big end. I have wondered about oil pressure in a Commando with the plain type big ends. With Triumph engines the indicator button lets you know about the condition of the big end bearings. When you run race motors on petrol, you need to worry more about heat. Jawa speedway motors usually run on methanol. What class do you race in, and do they do fuel checks ?

Hill climbs and some track sessions at classic race meetings. The hill climbs are fine as they are no longer than a speedway race its the track session and possible future races. I'm not looking for pressure as it's a roller big end just get some flow round and that will keep it cool. Running on methanol so that helps with cooling.

 

[kommando]

Fit an oil cooler.

An oil cooler does not cool roller bearings, its not the oil that gets too hot its the bearing and you need oil flow to extract the heat from the bearing and to move it elsewhere. Stick to giving tips on the wrong frame geometry which are dangerous.

On the flow rates required Phil Irving has a table of oil flow rates in 'Motorcycle Engineering' which is a good reference point.

From Phil Irving's, Motorcycle Engineering: pg. 232-234

"So one can see that there are several possible sources of friction, and therefore some degree of lubrication is essential. Up to a certain point, this need not be very great. T.T.'s have been won with engines lubricated only by an occasional shots of oil from a hand-pump simply squirting oil into the crankcase and thence into the big-end (somewhat problematically) through a couple of holes, while even today the Speedway J.A.P., normally running much above 6,000 r/p.m., performs very well with a flow to the big end which is only a fraction of that normally provided on a road-racing machine. In the latter of course the copious flow provided assists greatly in internal cooling which is not of much importance on the speedway motor run exclusively on alcohol and only for short distances.

It is a well-established fact that if any caged ball or roller bearing fitted to a high-speed spindle is run full of oil, it will become very hot through the churning action set up in the lubricant. This has lead to the development of other systems, such as that in which a jet of compressed air is used to blow oil in the form of a mist into the bearing, so lubricating it and cooling it at the same time; there is little more than a film of oil present on any of the surfaces, and so no extraneous heating from churning.

On the other hand, if enough oil is poured through by a circulating system, heat is carried away with the stream and can be dissipated else-where, this being the normal state of affairs with an ordinary dry-sump engine. If the oil-supply is accidentally cut-off, the bearing is momentarily still full of oil, which rapidly heats up due to frictional heat plus churning heat. At around 300 degrees C. (depending on its composition) the oil will start to vaporize off, and at 450 degrees the rollers will commence to bond themselves to the aluminum cage, after which complete seizure follows immediately.

The inference is that there is a "pessimum" (opposite of "optimum") quantity of oil which is particularly conducive to seizure, and either more or less is required to permit continuous operation. This is only a theory, but it may help to explain the satisfactory life of the two-stroke bearing with very much less lubrication than the four-stroke."

 

[acotrel]

An oil cooler does not cool roller bearings, its not the oil that gets too hot its the bearing and you need oil flow to extract the heat from the bearing and to move it elsewhere. Stick to giving tips on the wrong frame geometry which are dangerous.

On the flow rates required Phil Irving has a table of oil flow rates in 'Motorcycle Engineering' which is a good reference point.

From Phil Irving's, Motorcycle Engineering: pg. 232-234

"So one can see that there are several possible sources of friction, and therefore some degree of lubrication is essential. Up to a certain point, this need not be very great. T.T.'s have been won with engines lubricated only by an occasional shots of oil from a hand-pump simply squirting oil into the crankcase and thence into the big-end (somewhat problematically) through a couple of holes, while even today the Speedway J.A.P., normally running much above 6,000 r/p.m., performs very well with a flow to the big end which is only a fraction of that normally provided on a road-racing machine. In the latter of course the copious flow provided assists greatly in internal cooling which is not of much importance on the speedway motor run exclusively on alcohol and only for short distances.

It is a well-established fact that if any caged ball or roller bearing fitted to a high-speed spindle is run full of oil, it will become very hot through the churning action set up in the lubricant. This has lead to the development of other systems, such as that in which a jet of compressed air is used to blow oil in the form of a mist into the bearing, so lubricating it and cooling it at the same time; there is little more than a film of oil present on any of the surfaces, and so no extraneous heating from churning.

On the other hand, if enough oil is poured through by a circulating system, heat is carried away with the stream and can be dissipated else-where, this being the normal state of affairs with an ordinary dry-sump engine. If the oil-supply is accidentally cut-off, the bearing is momentarily still full of oil, which rapidly heats up due to frictional heat plus churning heat. At around 300 degrees C. (depending on its composition) the oil will start to vaporize off, and at 450 degrees the rollers will commence to bond themselves to the aluminum cage, after which complete seizure follows immediately.

The inference is that there is a "pessimum" (opposite of "optimum") quantity of oil which is particularly conducive to seizure, and either more or less is required to permit continuous operation. This is only a theory, but it may help to explain the satisfactory life of the two-stroke bearing with very much less lubrication than the four-stroke."

The only Jawa engines which have the additional return pumps are usually in road racers. On dirt, dropping oil does not matter. If you road race using petrol, an oil cooling radiator can be fitted on the return line. But in Australian road racing, most Jawa engines are eligible to race in classes which permit the use of methanol fuel. My brother's two valve Jawa engine is 600cc, is in a speedway sidecar and does not have a return pump. When Keith Campbell was racing a featherbed with a pushrod Matchless motor, I suggested he should buy a Jawa motor and start where he had finished, He bought two motors from Neil Street - the first time he raced with a Jawa engine, he won a race, beating a Molnar Manx.

 

[Charkmandler]

The only Jawa engines which have the additional return pumps are usually in road racers. On dirt, dropping oil does not matter. If you road race using petrol, an oil cooling radiator can be fitted on the return line. But in Australian road racing, most Jawa engines are eligible to race in classes which permit the use of methanol fuel. My brother's two valve Jawa engine is 600cc, is in a speedway sidecar and does not have a return pump. When Keith Campbell was racing a featherbed with a pushrod Matchless motor, I suggested he should buy a Jawa motor and start where he had finished, He bought two motors from Neil Street - the first time he raced with a Jawa engine, he won a race, beating a Molnar Manx.

What oil pump did Keith Campbell use?

 

[Charkmandler]

The only Jawa engines which have the additional return pumps are usually in road racers. On dirt, dropping oil does not matter. If you road race using petrol, an oil cooling radiator can be fitted on the return line. But in Australian road racing, most Jawa engines are eligible to race in classes which permit the use of methanol fuel. My brother's two valve Jawa engine is 600cc, is in a speedway sidecar and does not have a return pump. When Keith Campbell was racing a featherbed with a pushrod Matchless motor, I suggested he should buy a Jawa motor and start where he had finished, He bought two motors from Neil Street - the first time he raced with a Jawa engine, he won a race, beating a Molnar Manx.

This is basically why I'm using the gears from a similar type of engine so that I don't over load the big end with oil.
It's interesting that engines such as Hondas XR400 and XBR500 use trochoid oil pumps that deliver far more than say a Norton single or I would guess a Norton twin. These bikes (XR400 etc) have roller big ends - does this suggest that there needs to be a very high oil flow past roller big ends before they start over heating, certainly more than a geared Norton pump.

 

[mdt-son]

These bikes (XR400 etc) have roller big ends - does this suggest that there needs to be a very high oil flow past roller big ends before they start over heating

No. If you had read my reply carefully, you would know how Honda manages oil flow and what the flow rate delivered by the Gerotor (=Trochoid) oil pump is used for.

- Knut

 

[kommando]

The small hole in the big end journal will limit the optimum flow, try to force too much flow through that hole and the churn it creates will heat the oil negating the benefit of the higher flow. So measure the hole size and match the flow to suit the hole. Problem is how do you calculate the optimum flow.

 

[acotrel]

What oil pump did Keith Campbell use?

The pump was one that was made by a guy either in northern NSW or Brisbane. I will ask my brother Doug, he might remember. The last time I talked to Keith was about 20 years ago. His father George visited Doug when he had bought the two motors from Neil Street. Neil use to swap between the UK and Australian summers. He was associated with the riders at Poole Speedway Club. They might know something

 

[Charkmandler]

The pump was one that was made by a guy either in northern NSW or Brisbane. I will ask my brother Doug, he might remember. The last time I talked to Keith was about 20 years ago. His father George visited Doug when he had bought the two motors from Neil Street. Neil use to swap between the UK and Australian summers. He was associated with the riders at Poole Speedway Club. They might know something

That would be really helpful, thanks

 

[mdt-son]

So measure the hole size and match the flow to suit the hole. Problem is how do you calculate the optimum flow.

Wrong approach. There is no "optimum" flow rate. Design is governed by the maximum required amount of lubrication, which happens at the revs @ maximum torque, or revs@ maximum hp (the latter is probably the governing flow rate for a racing bike).

There are some factors which makes it difficult to use the Jawa's factory settings for guidance:

• Faster rotations generate more friction and heat, requiring more oil to maintain a stable temperature and prevent excessive wear. An engine used for road racing run at higher revs and a longer distance than the typical speedway bike. They also run hotter due to the use of Avgas rather than Methanol.
• Bearings under significant load experience higher contact pressures, demanding more lubrication to maintain a protective film. A speedway engine is probably developed for running at maximum torque rather than maximum hp. Changing the operating condition will require more oil to the big end bearing.
• In environments with high operating temperatures, oil helps dissipate heat and prevent overheating. A road racing engine runs much hotter than a speedway engine, due to the fuel, the duration, and the load level. This will increase the flow requirement.

To bring this discussion back to Norton related content, it may be helpful to look at the crankshaft oil supply of a Norton Manx 30M or Matchless G50 (500cc all alloy engines).

- Knut

 

[Charkmandler]

Wrong approach. There is no "optimum" flow rate. Design is governed by the maximum required amount of lubrication, which happens at the revs @ maximum torque, or revs@ maximum hp (the latter is probably the governing flow rate for a racing bike).

There are some factors which makes it difficult to use the Jawa's factory settings for guidance:

• Faster rotations generate more friction and heat, requiring more oil to maintain a stable temperature and prevent excessive wear. An engine used for road racing run at higher revs and a longer distance than the typical speedway bike. They also run hotter due to the use of Avgas rather than Methanol.
• Bearings under significant load experience higher contact pressures, demanding more lubrication to maintain a protective film. A speedway engine is probably developed for running at maximum torque rather than maximum hp. Changing the operating condition will require more oil to the big end bearing.
• In environments with high operating temperatures, oil helps dissipate heat and prevent overheating. A road racing engine runs much hotter than a speedway engine, due to the fuel, the duration, and the load level. This will increase the flow requirement.

To bring this discussion back to Norton related content, it may be helpful to look at the crankshaft oil supply of a Norton Manx 30M or Matchless G50 (500cc all alloy engines).

- Knut

I'll be running on methanol so helping keep things a little cooler. Talking to the speedway guys they run at maximum revs. Modern engines are reving up to 13k.
I've not been able to find a Manx oil pump to look at the gear sizes - that was my first try. If anyone has a Manx or G50 pump and could let me know the gear sizes both diameter and width that would be helpful.