Lotus Seven - Lost Oil Pressure

[pethier]

On 8/9/2024 at 12:27 PM, Christopher smith said:

Carroll Smith's --- Nuts,bolts. fasteners and plumbing handbook.

Sidebar:  I have not been able to independently confirm the story that Mr. Smith wanted to call this book "Screw to Win" to continue the title-pattern of his previous books.  The story goes that the publisher refused...

[wdb]

"The Rotational Route to Victory Lane"?

[TEM]

Pump was removed and inspected.  Nothing out of sorts.  There is a little wear as expected but no big deep scratches, gouges, or broke pieces.  No debris and the gears rotate freely.  I did clean out the sandwich plate when this first occurred along with blowing out the oil cooler and all external lines.  Nothing was found.

I packed the pump with Vaseline and put it all back together again.  I filled all the hoses with oil in an attempt to eliminate as much air as possible.  Pulled the plugs and cranked 5-10 seconds but no oil pressure.  I squired some oil in the spark plug plug holes and cranked a few more seconds and saw the needle move to about 5psi.  Now that is was getting some oil pressure I decided to crank away.  After what seemed like a frightening amount of time on the starter, the oil pressure started to rise and topped out at just under 65psi.  I started the engine and all seems to be back to normal.

 

I'm still worried about these poor quality hoses so I plan to replace.  Does anyone have suggestions?  Just a better quality hose on my existing barbed fittings or Aeroquip style hoses?

[MV8]

I think you may have used a hose that was nicked. Hard to say when you didn't post any  pics or part numbers. I use standard universal push lock hose with standard barbs and clamps or push lock fittings for oil and fuel vent and replace the hot oil hose every few years when it starts getting stiff.

 

Since the lines and cooler are higher than the pan, I would expect a pressure delay to refill the system on a cold start. Oil level will be that much lower in the pan in normal operation if maintained to full mark cold.

[IamScotticus]

Suspecting that voltage fluctuations may be a cause of false readings,

Has anyone tried running the oil pressure circuit off the battery,  out of the loom?

[jbcollier]

It was a mighty convincing act what the trail of oil and dripping engine compartment.

 

Fill it with oil, start it, and see where it leaks.

[TEM]

I have been driving it locally with no problem but fear another prolonged drive.  Checked all of my local parts stores and none had appropriate hose.  I have a speed shop nearby that I will check tomorrow.  Does anyone know the fitting size needed to convert the hose from barb to Aeroquip style thread on?  I'm leaning towards Startlite hose.  Without taking the fittings off I don't know if the sandwich plate uses AN, NPT or something else.  And I really don't want to break the lines just to find out but will if no one knows.

[TEM]

By the way, The pump pressure relief valve was installed correctly.  it just doesn't look like the picture in the parts manual.

[7Westfield]

the adapter plates I've used have all been NPT--but check it anyway

what thread is on the cooler   BSP?

[pethier]

On 8/12/2024 at 1:16 AM, pethier said:

Sidebar:  I have not been able to independently confirm the story that Mr. Smith wanted to call this book "Screw to Win" to continue the title-pattern of his previous books.  The story goes that the publisher refused...

Just for laughs, I checked the Caroll Smith page on Wikipedia this morning.  It reports that Mr. Smith himself insisted the story was true and gave out stickers to cover the title on the book with his first choice.

 

Caroll's website is still up, and there is a lot of interesting stuff there.

https://www.carrollsmith.com/https://www.carrollsmith.com/

 

"As of 1/1/2023, we are now handling all orders through our Amazon Account."

 

[SENC]

For what it's worth, I don't care for the braid covered hoses.  Though they certainly provide external abrasion resistance, you can't see and monitor the condition of the hose itself - and I'm not confident the inner hose is any better quality than the cheap stuff.  I've stuck with high quality hose and barbs.

[MV8]

I have all Smith's books except for the pocket laminated book. Good stuff...

 

You can check if the threads are npt or bspt with a known same size fitting, point them in opposite directions and try to see the light between the meshed threads. Hoping they are npt. Can't tell just screwing them in, only if they leak.

[Udo Guido]

On 8/18/2024 at 12:06 PM, TEM said:

By the way, The pump pressure relief valve was installed correctly.  it just doesn't look like the picture in the parts manual.

Well?

 I guess the Travel of the Plunger should be verified.

If for some reason the Plunger dosn’t bottom out properly,and or sticks/stalls along it’s travel, that may cause A Drop in Oil PSI.

 

GOOD Luck!!!

[anduril3019]

On 8/9/2024 at 7:44 AM, TEM said:

When I pulled the oil pump the pressure relief valve plunger was facing the engine.  This appears opposite from the parts manual.  Certainly makes it a lot easier to install.  I can't imagine holding that retainer disc in place while applying pressure and installing the bolts.

 

Not sure if anyone has mentioned this yet. If you are referring to item 4 in the illustration, that should either be a press fit, or be staked in place. If it's loose, and you are trying to keep it in place while installing the pump, I could imagine it getting out of place and preventing the pump from seating properly.