Lotus Elan

72 Lotus Elan Oil Pressure

PostPost by: rodgerslotus » Tue May 10, 2005 1:52 pm

To All,

Now that I have stopped chasing the missing heater valve, a new question has arisen.

What is the correct oil pressure for a 72 Elan Big Valve engine. Please advise for cold and normal running condition.

Presently my oil guage reads 30 PSI at start and stays between 20 and 30 psi after reaching normal tempature, going from idle to 4K rpm.

I run Castrol 10w30.
The Elan has 21K miles it, it was stored in a garage for 27 years.

Please Advise.

Regards,
Ty Rodgers
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PostPost by: hat » Tue May 10, 2005 2:10 pm

I'm no expert but I would say that your reading is a touch low.

Mine runs at about 40 to 45 hot and 20 - 30 on tick over. My engine was rebuilt last year with standard oil pump.


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PostPost by: types26/36 » Tue May 10, 2005 3:25 pm

The Lotus Manual states: Normal pressure (hot) 35/40 psi
It does not state @ a given rpm but it is usually accepted to be @ 2500-3000 rpm
The the relieve valve in a standard pump opens 40 to 45 psi
No figures are quoted for idling as this is imaterial if the 35 to 40 is reached but can be from about 10psi upwards.
As its a +2 I think it has an electrical gauge? for verious reasons it could be under reading, I would suggest you have it checked out with a mechanical type gauge.
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PostPost by: john.p.clegg » Tue May 10, 2005 3:33 pm

Dear All
Colin designed these engines to use lots of flow rather than lots of pressure but unfortunately some people were concerned about the "low pressure reading on the oil guage" so he specified a 0 to 60 gauge instead of the 0 to 100 usual gauge.
Bearing that in mind,please try to ascertain firstly that you have a good stable 10 volts supply to your guages (voltage regulator/stabiliser) and if possible test your sender unit by replacing with a direct pressure gauge.
As far as i can see as long as you have some pressure all of the time you're doing fine?

John
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PostPost by: types26/36 » Tue May 10, 2005 3:42 pm

John,
Not being picky here but "Colin designed these engines" ?? we know about the head but I dont think Colin can be credited with the engine design and its lubrication system. :rolleyes:
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PostPost by: john.p.clegg » Tue May 10, 2005 4:16 pm

Okay.Okay he didn't design the engines or the head but using the same bottom end(approx) and lube system to feed extra camshafts etc must have taken some calculations??
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PostPost by: Foxie » Tue May 10, 2005 6:09 pm

The original recommended oil was 20/50. Even Castrol Magnatec 10/40 would be nearer the original spec.

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PostPost by: elans3 » Tue May 10, 2005 8:33 pm

I would concur with Sean, I've found in the past that the original oil viscosity 20/50 in these engines, always gives the optimum pressure. I've even seen erratic pressures given with duff filters
If you've got no rattles on start up from the crank, and the oil pressure comes up quickly, it's likely to be the gauge, or the fact you're using 10/30,
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PostPost by: jbrady2804 » Tue May 10, 2005 10:17 pm

My +2 has an electric gage which reads 35 psi compared to 40 psi indicated by a master mechanical gage. Also, this gage is powered at 12 volts rather than by the voltage stabilizer, this agrees with the +2 federal wiring diagram. After a recent engine rebuild I have 40 to 45 psi actual pressure above 2500 rpm with warm 10w40 oil.
I recommend that you install a mechanical gage in place of the suspect gage before moving on to more drastic measures.
jack 50/1915
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PostPost by: 1964 S1 » Wed May 11, 2005 4:17 am

Geez, I concur with everyone, especially the 20/50 (Castrol) recommendation. IF you drive in winter conditions, switch to lighter weight around mid October. Mine reads 38 psi at rpm, idle falls to 14. No problems for years and thousands of miles. Has anyone tried SLICK 50?
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PostPost by: poiuyt » Wed May 11, 2005 5:34 pm

I use 15W50 Mobil One and the guage shows about 50 - 55 pounds on start up and 45 or so when hot. The engine was rebuilt about 18 months ago and I believe it has a standard oil pump.

If you use the Mobil One you won't need any additives. My VW GTI VR6 is just shy of 190,000 miles and uses a quart in 2000+ miles. It has always run on Mobil One.


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PostPost by: Hamish Coutts » Wed May 11, 2005 7:57 pm

Folks,

+2 Big Valve running on Castrol GTX 15/40. 10k miles since rebuild. Standard oil pump casette filter.

Cold at 2,500 rpm - 55lbs/sq ins
Hot at 4,00 rpm - 40 - 45 lbs/sq ins
Hot tickover - 15 - 20lbs/sq ins

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Hamish.
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PostPost by: Hegg » Fri May 13, 2005 4:34 am

My readings are very similar to Hamish. I've got 10/30 in there, car sat for 25 years. This is the "small valve" engine.
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PostPost by: 72plus2 » Tue May 17, 2005 4:24 pm

Check out the voltage stabilizer in the facia wiring for problems. Do you have have several gagues, including oil pressure that read low due to a fauty stabilizer? If so, this could be the cause of the low reading.

Check out the classified section at this site for a home made replacement on offer from user "mrjxc09". I can recommend him as I bought one with no problems.
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PostPost by: twincamman » Sat May 28, 2005 10:26 pm

mine uses a capillary tube oil press gauge 0 to 120 lbs [ 180 degree sweep] so it always shows pressure ----the higher ones 180 lbs etc ] stop my heart as they register 0 at idle---and I don't want to see that :o ed
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