An Oil Change. How hard can it be!

[oldelanman]

Now can anyone give me the approximate dimensions of the correct size sump for a Sprint or late S4.

The well of the sump is approx 220mm square and the overall depth from the flange is around 170mm.
With the top of the dip stick tube 4.1" above the sump flange the FULL mark on the dip stick is 65mm above the bottom of the pan and the oil level corresponds with the top of the baffle (you can also see the "tide mark" on the attached pic).

[MickG]

Thanks very much Roger. It's obviously taken a bit of time to do what you have done, much appreciated.
Further to my last post I have measured the amount of oil drained during the change including filter and it comes in at just over 3 litres or 6 pints (near enough)
Allowing for residue left in the engine and a few spills I would think that 6 ? Pints is about all I need to top up to the full mark on the dipstick.
I will go and measure the dimensions of the sump later today and compare them to yours.

Thanks again

Mick G

[oldelanman]

As further confirmation I have just measured the volume of my sump and it takes exactly 3 litres up to the FULL mark on the dipstick. That's with the sump sitting level on the floor, in the car it slopes backwards slightly I think so it will take a bit more as the dipstick is at the front.

[john.p.clegg]

Not altering the direction of the thread but expanding it a little,can anyone give some figures re. the crank/con-rods swing into the sump?

Thanks
John

[oldelanman]

Hi John,

You caught me with my sump down

Not sure how accurate you want this but measuring from block face to flat end of conrod with piston at BDC I get 75mm on #2 and 73mm on #3. I don't think the rod bolt drops any lower as the crank rotates but can't be sure (can't turn the engine over at the moment). Let me know if you need more.

[MickG]

Thanks very much Roger. You have certainly gone above and beyond the call.
If memory serves me correctly (which at my age will be a first) was when I rebuilt my engine I checked the dipstick depth exactly as you have. I also found that 4 litres of water would go far beyond the full mark and questioned this with QED. I cannot remember their reply but I think it went along the lines of referring to the tube length depth that I found to be correct.
I have taken some measurements and found them to match yours.
The upshot of all this is that appears that I have been worrying unnecessarily about the amount of oil that should be in the sump and should go by the dipstick. Something that AHM said about 10 posts ago.

Thanks to all those kind souls who have gone to great lengths to provide me with answers.

Regards Mick G

[john.p.clegg]

And thanks to Roger,now I can work out the maximum level of oil without it being in the way of reciprocating parts...

Thanks

John

EDIT:-

Just done a quick calc. and it looks like Lotus got it right in the first instance.....

John

[ken ob]

Perhaps I am misunderstanding some of the replies on this topic but I thought the most important factor was ensuring that there is enough oil to properly lubricate and cool the engine ?
If I am correct on that point surely it is vital to accurately put the Lotus recommended amount of oil into the engine - whether that is 6 3/4 pints for earlier or 7 1/2 pints for later cars.
Having done this, if the dipstick reading is ''incorrect'' it is surely the dipstick, dipstick tube or sump pan that is somehow causing the misreading ?
This seems logical to me , or am I a dumb a??.

Ken

[oldelanman]

Perhaps I am misunderstanding some of the replies on this topic but I thought the most important factor was ensuring that there is enough oil to properly lubricate and cool the engine ?

No question about that, the issue is how much oil is enough.

My view is that providing you have the correct dipstick and sump and the dipstick tube is inserted to the correct depth in the front cover it does indicate the correct level of oil in the engine. That being the case the capacity figures given in the workshop manual must be wrong. How likely is it that an incorrectly marked dipstick would have been used throughout production of the twin cam engine without being noticed? Much more likely that someone made an error in compiling the workshop manual I would think.

Of course you need to make your own decision and do what you think is right but I will continue to use the dipstick FULL mark as my guide and ignore the workshop manual figures.

[ken ob]

Thanks Roger, I understand what you mean.

However unless you have owned a car from new how can you be certain that the dipstick , dipstick tube or even the sump pan have not been changed or altered at some time by a less than brilliant home mechanic to something that might give a different reading on the dipstick.
For example if the dipstick tube has been removed during an engine rebuild has it been positioned too far into the block or not pushed in enough ? ( I know some of the replies on here give the correct measurement )
As you say it is up to an owner to decide for themselves but I am sticking to my own full mark having measured exactly 6 3/4 pints into my S2.

Ken

[ken ob]

Hello again Roger, Having just re read your last post properly I see you have mentioned my points.

The only other thing I would say is how likely is it that all handbooks and workshop manuals would have a printing or typing error for 50 years without some so and so noticing ?

Ken

[MickG]

Hi Guys,
Just an update. Having taken and checked all the measurements given I am sure my set up is the same as most. I have filled the sump to the full mark on the dipstick and left it at that.
As stated previously I have used Castrol GTX which is now part synthetic and I am not impressed. The oil pressure is lower than prior to the change and the one leak I have (rear oil seal) in now slightly worse.
I have found that a 20/50w oil is available for classic cars from Halfords and Comma I'm sure a few others produce the same.
What oil do you use/recommend given that the twink was designed in a time when mineral oils were the norm and not the exception?
Regards Mick G

[AHM]

Hi Mick,

The original w/s manual reccomends 20w/30, the later one gives 20w/50. Oil technology has come a long way since - You wont go far wrong with an oil designed for classics.

As you probably know the second number is viscosity at 100oC - so a bigger number will leak less. And is likely to produce a higher pressure.

[oldelanman]

Castrol still do a classic 20W50 ............http://www.castrol.com/liveassets/bp_in ... y_2013.pdf

[rgh0]

Any modern full synthetic oil in the engine and gearbox is vastly superior to the traditional mineral oils. The original design intent does not matter in this regard. If the fundamental viscosity parameters for film lubrication and start up lubrication parameters for contact lubrication are the same or superior then a synthetic will perform better which they are and they are also better over a wider temperature range and longer from a shear stability perspective ( if not from a contaminant pick up perspective so don't extend your oil change interval unless you know the contaminate loading in your engine, and do you do oil condition tests to find that out?)

I just pulled the cam cover of my daughters corolla that is 17 years old and only done 50 thousand km's ( driven by my aunt only to church on Sundays literally over that time before being handed down to my daughter). It has been running on mineral oil over that time and the fouling inside the engine is an order of magnitude worse than on my Landcruiser that has done 300 thousand km's on synthetic oil over the 14 years of its whole life. The wear on the cam and buckets is also an order of magnitude worse. If I looked at the bearings and piston and bore
wear I would see the same story. My Landcruiser looks near new after 300 thousand km the Corolla is starting to see noticeable degradation after 50 thousand km. I know a lot of other variables are at play but type of oil is a major factor.

Oil pressure is not a total measure of lubricant performance, though it is relevant in some circumstances such as hot idle pressure.
Perceived leakage rates is not a measure of lubricant performance, and it prefer it to work and leak a little more or less versus it not working to lubricate my engine well.

But in the end these things are my personal preference and its your engine and gearbox and your car so its your choice. But any lubrication engineer worth his title will tell you the same.

I apologise for being so direct and potentially critical of what others write on this topic but myths around oils and lubrication and myths around good versus bad for Ford blocks are something that get me frustrated as they never seem to die on the internet.

cheers
Rohan