Sump oil leak

[joe7]

Tom D If you look closely at the 4 or 6 bolt oil pan OEM drain plug you will notice its a bit concave to accept the OEM crush washer which is not the same as the flat aluminum or copper crush washers. I used a stato seal with the OEM drain plug but it did weep a bit. So I filed the back side of the drain plug flat and using the stato seal no leaks. Regarding a magnetic drain plug, I purchased one from D Bean and with the stato seal no leaks. I think the drain plugs come in 2 styles 1) a small magnet that protrudes out from the plug and 2) one that has a magnet flush with the end of the plug. Also, check the pan area around the drain plug to be sure the aren't any gouges etc.

[Tom D]

Thanks Joe. I'll take a closer look at my current plug.

[512BB]

As promised, the reg no of the Colorado Sprint that I sold to Hendon Way Motors was WCS 764K. If anyone here knows or is the current owner, I have an invoice that they can add to the cars history.

I have over the last few days, carried out a poll of 3 Sprint owners re oil pressures. All confirm what I have previously written, in that, on start up at idle, their pressures are approx 50 psi when cold, dropping back to 20 ish when hot at idle and run at 40 ish hot when crusing, and I am entirely happy that this is quite normal with a standard oil pump. So we will prob have to agree to disagree on this one Rohan.

And thanks for the explanation on mineral versus synthetic oils. You may just have convinced me, but any changeover will have to wait until I have used up the 25 gallons of mineral oil that I have in stock. It should be noted that I have not experienced some of the drawbacks of mineral oil that you mention though, namely sludge, as the oil never gets that old, changed meticulously at 3k miles.

"As for using oil versus grease in trunnions I only discuss that now with lubrication engineers"

Good job I have just qualified then with Hons.

Leslie

[daverubberduck]

Closer examination of my oil pressure gauge showed that it is the capillary type. This is unusual for an early +2 (Jan 69), but the block in this car is a 1972 block, fitted some time before 1980. Probably fitted because of a front end collision, and I'm guessing that they kept the capillary sender and replaced the gauge.

I fitted an external pressure meter onto the engine as per Rohan's suggestion. Still reads quite high so gauge seems to have been right. Cold I'm seeing 60-70psi, I let the engine get hot this time, and when hot it was idling at about 20-25psi which seems right, but under revs going up to over 60psi which is still high. I am using Halford's classic 20w50 oil. Does anybody else use this (in the UK)? Is it OK to use? If the idle pressure is OK, then does that mean that the relief plunger must not be jammed or that there can't be a high pressure pump fitted? Or is 60+ acceptable?
Dave

[rgh0]

Dave
The pressure will increase with revs until the pump relief valve opens. At idle with hot oil the pressure will usually not reach the normal pump relief pressure of 40 PSI. With thicker oil or cold oil you may reach the 40 psi relief setting even at idle.

Once the relief valve opens then the oil pressure should hold around that pressure as the engine goes faster.

Typical high pressure modified pumps are set for 60 PSI and my guess is that's what your engine is fitted with judging by your description of its pressure behavior. For a normal or developed road engine there is normally no need for higher than the standard 40 psi in my opinion

60 PSI should not of itself be harmful and the joins and gaskets in the pressure containing passages if assembled well will handle that pressure. However if you have a marginal join the higher pressure may cause it to leak.

regards
Rohan

[mark030358]

Re Oil pressures.
I'm afraid Rohan is correct here, 40 to 45 psi when cold (depends on the "Chinese steel" relief valve spring tension) and around 20psi give or take a bit at idle when hot. At around 3000rpm when hot its usually around the 35 to 40 lbs mark, depends if you have thrashed it or not and the ambient temperatures. I have built three twincam engines, two Elans, S4 and Sprint and one Europa. All virtually the same given the accuracy or otherwise of the gauges. Too hign an oil pressure and you will blow those seals.

However, I guess if you have friends with engines that show 60psi then not all things are equal

thanks

[daverubberduck]

Hi Rohan
Many thanks, that is very instructive and all makes perfect sense. Since my engine is leaky then I will change the oil pump. I am hoping this can be done in situ. Has anyone changed the pump on a +2 with Lotus chassis? I am guessing that the webers will have to come off at the very least.
Dave

[daverubberduck]

And thanks to Mark also. 40psi hot and 20psi idle fits with my memory of a sprint I had many moons ago. I will change the pump and see if the oil leak improves.

[rgh0]

Dave
Once you take the filter off it is easy enough to get at the pump locating bolts from underneath. If you remove the end plate off the pump before you remove it then you can pull it back far enough to remove before it hits the standard Lotus chassis. If you find the steering column is in the way then disconnect at the joint and pull the column up.

A standard pump comes close to being removable with the end cover in place and it depends on the individual car if it its possible without removing the end cover. The hIgh volume pumps with the thicker end plate and longer rotor definitely need the cover removed in my experience. In some installations you may need to remove the RH engine mount and either jack up or lower the engine for the pump to clear the chassis flange but thats not normal. I need to do that on my Elan as the engine has been moved to the right a little to provide clearance for the exhaust on the left and I use the longer high volume pump.

cheers
Rohan

[daverubberduck]

Many thanks Rohan. I will give it a go.
Dave

[daverubberduck]

I just wanted to thank you Rohan for your help. I managed to replace the oil pump, needed to drop the engine a bit to remove the old one. Pressure is now normal. I then used your trick of applying epoxy putty to the area of the leak. Engine now no longer leaks. Hopefully this will last until next winter when I will remove the engine and fix it properly.
Dave