Engine oil level

[Russlin]

Seasons Greetings to all.

My 1928 magneto engine is fitted with an alloy sump which is approximately 3/4" - 1" deeper than the original pressed metal sump at the point where the dipstick drops in. As the dipstick still 'bottoms out" in the deeper sump the Full mark now sits at a lower level than previously resulting in a false reading.

As the dipstick does not have a shoulder I have packed it up with washers to restore it approximately to the correct depth.

For accuracy I would prefer to measure the distance from the oil filler hole to the oil level when correctly filled but am unsure if this dimension is known or whether somebody is able to confirm.

Thank you, Russell.    

[Tony Press]

I thought the early dipsticks sat on the flange in the crankcase 

[AustinWood]

It does. The dipstick still shows the oil depth.
We have a similar sump in our 1929 coild engine so have estended the oil pickup on the pump by the difference in the depth of sump between the alloy sump and the original steel one.

[Reckless Rat]

On the earlier crankcases the dipstick was at the flywheel end of the crankcase. Later coil cars it was forward. The best way to check is to find another car the same engine as yours but with a tin sump, with the correct oil level and then measure the distance between the top of the crankcase hole to the oil. You can then replicate that on your own engine, irrespective of the depth of the sump. If you then drain the oil and refill you'll know how much it needs to regain the proper level. There have been instances of cars having the wrong dip stick inserted. Running with too much oil is likely to be counterproductive.

As an aside, the alloy sump on a "standard" engine is a waste of time. It makes engine removal difficult and with the extra oil it takes a lot longer for the engine to reach optimum operating temperature, particularly at this time of the year. If you can, If it was me, I'd swap it for a tin one and sell it.

[AustinWood]

I bought the alloy sump for our car after struggling to find a tin one that was sound. I got fed up with new pin holes appearing which I 'fixed' by drilling them out and inserting a 2BA screw and nut. Also they are difficult to seal having been overtightened and distorted over the years. I expect silicone gaskets have fixed that now.
The Alloy sump is very rigid and the crankcase isn't, so I think it helps in that department. We have the 'shallow' Allan Raeburn version rather than the deep 'Nippy' one. It doesn't hold a great deal more oil than the tin one. One day I may measure its capacity!
If the engine is being removed the sump will probably need to come off anyway.
I agree that the Seven engine is slow to warm up. This is remedied by fitting a thermostat. Our car is everyday transport all year round. In winter it would never warm up properly otherwise, even running with no fan belt.

[jpsmit]

Obvously not directly relevant to this particular thread (though related) and I do realize it is a different marque - though I think it is fair to say this falls in the parts interchangeabiliy list.



       

(not sure why it shows up twice)

[Colin Morgan]

Not having a magneto engine, I can't help directly.  But you have what you need to work it out accurately?  You can accurately measure the outside of the old sump at the correct point, and the new sump, and take the difference in height?  This will be close enough as there is not a lot of difference in the thickness of the metal?  Or am I missing something?

[Malcolm Parker]

I don't think you need to be paranoid about the oil level in a road going Austin 7.   For years I ran mine with too much oil in it due to using the wrong dip-stick.   All that happened was an oil leak that stopped when the level dropped to what it should be, following which very little oil was used.   I have also run with a very low oil level, such that the oil gauge was fluttering, and managed to limp home with probably no more than half a pint in the sump.
I don't worry too much about what grade of oil I use and don't hesitate to mix grades with different viscosities. As long as there is some oil in the engine you should be okay.  The engine in my much used RL saloon hasn't had the sump off in at least ten years and that in the Pytchley, which I built up in 1982 has never had the Nippy type sump off in over thirty years.  I generally change the oil every two years which is about 1000 to 1500 miles motoring.

[Colin Morgan]

I agree. I don't tend to fill up to the mark - no need to - just put a bit more in when it is looking low. However, it is good to know where the level was designed to be - say to within 1/4" - so as not to overfill.

[Russlin]

Thanks Tony Press, Austin Wood, Reckless Rat, J P Smit and Colin Morgan for your helpful replies.

I have extended the original dipstick by 3/4", the difference in height between the tin sump and the new cast one.

The longer dipstick is now at the correct height as it rests on the floor of the deeper sump and the "Full" mark is in the correct position.

Russell.