Javelin Oil Pump Strainer Assembly

[Forumadmin]

Good Morning,

I have recently received a photograph of the broken oil pickup pipe that was the cause of loss of engine oil pressure in Neil Hood’s Javelin, see photograph Oil Pickup-01. It appears to me that the pickup pipe is formed from copper pipe and the broken off end is, very likely, due to work-hardening caused by vibration.

The second photograph, 05-035a, shows the modified oil pump that was installed in Phil Squire’s Javelin engine. Note that in Phil’s engine there is also a copper oil pickup pipe, along with an added copper relief valve discharge pipe to ensure that relieved oil is discharged below normal oil level. In addition to those changes, the oil pump base plate is the early brass type, which I understand tended to droop so that the strainer came into contact with the sump surface and thus restrict oil flow into the pump. I have not yet seen a bent brass oil pump base plate and, therefore have not had much concern about the setup in Phil’s engine, mostly due to the low amount of intended use related to club activities.

Richard Homersham’s engine does have a Series III oil pickup assembly.

I do now have concerns about the use of copper pipe used for increasing the diameter of the original pipes smaller diameter. That means I am wondering if it is known how long (mileage) it took for the pickup pipe to break in Neil’s engine. Also, I do not know the pipe’s wall thickness in Phil’s engine. I do know that my local plumber says that common house copper water pipe does frequently fracture at bends over long periods of use – this has happened a few times here!

Another point, as I understand the situation, Jowett Cars Limited only used steel pipe in this application.

Are we on a course for concern here?

One consequence I do know is that, after my Jupiter losing all oil pressure for a number of seconds, the crankshaft journals and bearings survived the treatment. It also survived loss of oil pressure due to a rocker cover nut (RHS) falling off and oil plastering the side of the car during a dark early morning rush to a job interview 140 miles from home in 1963. Used a front bumper overrider nut for repair!

I hope that Neil Hood’s crankshaft and bearings have not suffered too much after the breaking of the pickup pipe.

Any comments or thoughts?

Regards,

Mike A.

[Forumadmin]

It is known that solders do cause hardening of copper and should not be used on copper wires subject to vibration.

It strikes me that that braising leaves a lot to be desired!

[PJGD]

I would agree that the copper pick-up tube failure was likely due to work hardening as a result of vibration. This pipe needs to be steel.

The pick-up strainer should have a turned down lip at the far end so that it ensures that the strainer is not restricted by the sump floor.

Back in circa 1973 late one dark winters evening, I was about 10 miles from home when the flex oil pipe ruptured and dumped the contents of the sump onto the roadway. I drove all the way home on a relatively light throttle, and the next day put on a spare oil hose and filled up with new oil and set off for my 30 mile drive to work. The engine was none the worse for the experience. The aluminium crankcase is good for carrying away the heat from the bearings.

[Mike Allfrey]

Hi Neil,

Thank you for your reply, also thanks are due to Andrew and Keith.

During my welding course at the Bristol Technical College, then, it has been upgraded to university status over the years, it was a lengthy night school course and included oxy-acetylene work including silver soldering and bronze welding. We were taught that ‘weld’ joints in copper to steel and cast iron could cause embrittlement at the copper adjacent to the bonding metal. The basics being that as the joint cools slowly, the copper plate/pipe is no longer annealed in the immediate join area. However, in the Jowett oil pickup arrangement, an annealed copper pipe would still have a limited life expectancy due to vibration and temperature changes while in use.

We were also told that soldered (lead/tin) electrical cable connections would not be affected by embrittlement provided the soldering iron temperature was kept in tight control. At that time, we were discussing the use of oxy-acetylene for soldering battery cables. That was in 1958 and the methodology has probably changed over the years.

Hydraulic tubing, where I worked we used many metres of ½-in. bore tube on combine harvesters and had a sophisticated tube bending apparatus for forming the bends that were required.

With regard to the oil pickup assembly in Phil’s engine, I have no knowledge of where it came from. At the start of the job, I naturally assumed that it came from New Zealand, mostly due to the built up banjo boss on the oil pump body. I also understand that the brass oil pump cover and relief valve housing should not be used. For some reason, against my thinking, I went along with that assembly. I have no qualms about the enlarged copper delivery pipe, due to never seeing fractures at the joints.

The question is what to do about the oil pickup assemblies for Neil Hood and Phil Squire? It would be good if we could find out where those copper pipes came from. I can, sort of, understand that Phil’s oil pump could have been equipped with a brass cover originally and this carried through. I have gone through the Service Bulletins that are in the Technical Notes Series and could not find a bulletin referring to the change from brass to cast iron for the oil pump cover. There is, however, mention of the change in the late Dr. Harry Brierley’s Javelin/Jupiter engine notes, but no mention of the reason for the change of material. I do remember reading in Jowetteer a long time ago, a report about the oil pressure relief valve spool wearing its bore due to actions of the relief valve spring causing spool chatter. Memory is hazy, but the fact that there was no Service Bulletin advising of the change is strange – maybe that was left to the spare parts person in a dealership?

Upon re-reading what I originally wrote, an error leapt out at me! At paragraph two, the word ‘anger’ should have been ‘and’. I think I am getting too old for all of this!

I will copy this and paste it into the Jowett Talk topic that Keith has provided. There could be valuable comment from Philip Dingle on this subject?

All the best,

Mike A.

[Mike Allfrey]

Please note that my reply above was addressed to Neil Moore in New Zealand as part of our E-mail discussion on this topic.

Towards the end of my reply, I suggested that Philip Dingle could provide information, that has happened - thanks Philip!

I am not too sure about the bending downwards of the lip of the strainer flange to hold the clearance for oil collection. Again, I think it was in a newsletter some time back where it was reported that such a bent lip had worn through the sump metal and thus drained the sump. I do not know if that oil pump had a brass cover that may have drooped and caused the rubbing action. Most sumps that I have seen here in Australia have been dented from underneath, which can compound the concern I have described.

Regards,

Mike A.

[Forumadmin]

Hi Mike, Mmmmmm, the body looks like one I have brazed and rebored for larger banjo, but to my knowledge I've never used copper pipe for the suction pipe . I purposely bought a few metres of suitable hydraulic tube for that purpose. Also don't remember ever using a brass base?!? May have done one, but wouldn't have sent it to Aussie. You're right copper tube for there is a non starter due to work hardening and unsupported weight. I normally use silver solder for all my joints tho have brazed the steel suct pipe due to gaps. Neil

[Forumadmin]

Dear Mike,

Thanks for the update on Neil's engine failure - I'd heard about it from John Walker.

Because that fracture at the inlet to the pump is above the oil level in the sump, the oil pressure would have dropped to zero. There is a possibility that it didn't drop suddenly to zero though, because it might have cracked progressively across the copper pipe thus letting air in on the suction side, but hopefully Neil shut the engine down immediately the gauge indicated that there was an issue. If Neil didn't shut the engine down until he heard it start rattling, it might have been too late to save the crank bearings.

Despite the 30 psi oil pressure that the engine ran after Neil added heaps more oil, I'm told that the bearings were rattling all the way home, and so unfortunately it appears that the bearings have been damaged.

Copper does indeed work harden, and brazing can make it brittle, so your suggestion to only use steel tube on the pick-up is very valid. Work hardening of copper is another reason why you should never use copper tube for brake lines, although many people do!

Incidentally, we too had an incidence of a copper water pipe fracturing due to work hardening at a joint, and also multiple issues with brass water pipe fittings in our solar HWS system fracturing due to zinc leaching out of the brass (dezincification). Have you read about the massive issue they have currently with thousands of homes built in WA, where modern polybutylene water pipes are bursting in only homes that use one particular brand of pipe? 7 homes per day are failing out of 30,000 homes fitted with the suspect material since 2017, and an estimated $700m to repair damaged houses and replace all the pipes!



Kind regards,

Andrew

[Forumadmin]

Hi Neil,



Thank you for your reply, also thanks are due to Andrew and Keith.



During my welding course at the Bristol Technical College, then, it has been upgraded to university status over the years, it was a lengthy night school course and included oxy-acetylene work including silver soldering and bronze welding. We were taught that ‘weld’ joints in copper to steel and cast iron could cause embrittlement at the copper adjacent to the bonding metal. The basics being that as the joint cools slowly, the copper plate/pipe is no longer annealed in the immediate join area. However, in the Jowett oil pickup arrangement, an annealed copper pipe would still have a limited life expectancy due to vibration and temperature changes while in use.



We were also told that soldered (lead/tin) electrical cable connections would not be affected by embrittlement provided the soldering iron temperature was kept in tight control. At that time, we were discussing the use of oxy-acetylene for soldering battery cables. That was in 1958 and the methodology has probably changed over the years.



Hydraulic tubing, where I worked we used many metres of ½-in. bore tube on combine harvesters and had a sophisticated tube bending apparatus for forming the bends that were required.



With regard to the oil pickup assembly in Phil’s engine, I have no knowledge of where it came from. At the start of the job, I naturally assumed that it came from New Zealand, mostly due to the built up banjo boss on the oil pump body. I also understand that the brass oil pump cover and relief valve housing should not be used. For some reason, against my thinking, I went along with that assembly. I have no qualms about the enlarged copper delivery pipe, due to never seeing fractures at the joints.



The question is what to do about the oil pickup assemblies for Neil Hood and Phil Squire? It would be good if we could find out where those copper pipes came from. I can, sort of, understand that Phil’s oil pump could have been equipped with a brass cover originally and this carried through. I have gone through the Service Bulletins that are in the Technical Notes Series and could not find a bulletin referring to the change from brass to cast iron for the oil pump cover. There is, however, mention of the change in the late Dr. Harry Brierley’s Javelin/Jupiter engine notes, but no mention of the reason for the change of material. I do remember reading in Jowetteer a long time ago, a report about the oil pressure relief valve spool wearing its bore due to actions of the relief valve spring causing spool chatter. Memory is hazy, but the fact that there was no Service Bulletin advising of the change is strange – maybe that was left to the spare parts person in a dealership?



Upon re-reading what I originally wrote, an error leapt out at me! At paragraph two, the word ‘anger’ should have been ‘and’. I think I am getting too old for all of this!



I will copy this and paste it into the Jowett Talk topic that Keith has provided. There could be valuable comment from Philip Dingle on this subject?



All the best,



Mike A.