Aluminium sump and the effect on oil capacity

[Bob Hughes]

Hi Guys

Last year I rebuilt the engine on my BJ7, part of the rebuild involved replacing the sump with a Dennis Welch aluminium sump.

When it came to putting the slippery stuff into the engine I noticed that the dip stick was showing oil up to the mark after only 8 imperial pints.

After phoning DW to enquire about this I was told that I would have to cut the bottom off the dip stick to clear the sump, and that was about it.

This is a nonsense as the dip stick clearly clears the bottom of the sump.

My local Healey chap said that if I was worried about it, just put in the other 4 as racing Healeys often had up to 18 pints in at the start of a race.

Ultimately I put the full charge of 12 Imp pints in, but wonder if this is really necessary, as in my mind the crankshaft could now be stirring the oil.

Have any of you guys who have these sumps noticed the phenomena and how much oil do you put in? Would putting in only 8 cause a problem?



Bob

 

[DerekJ]

Bob,I believe their aluminium sump is smaller capacity but I also got a muddled answer from them when I asked the question. I think it depends on who you get on the phone, that's not an excuse as they should all know the right answer. I think I ended up with about 5.5 litres in there, which is a litre less than 12 pints (I think).

 

[Bob Hughes]

Thanks Derek

I am using Penrite's finest so it is not cheap so using 8 pints will save a few pounds.

What are your thoughts of over running the crank with oil effecting tick over?



Bob

 

[John Turney]

I have the DW sump and spin-on filter. A change for me is 6 US quarts.

 

[busybrit]

As long as your dip stick doesn't touch the bottom of the oil pan, which would effectively raise the min/max level marks it shouldn't be a problem.

If it does touch, you would have to cut a bit off until it doesn't.

Then fill the beast up using the original marks on the dip stick.

FYI, I have a DW sump, "oil pan as you guys call it" on my 100-4, it takes more oil that the std sump.

 

[Stretch]

I don't think you should fill the sump any higher than the level a properly seated dip stick indicates because that would affect oil splashing. The splashing is part of the cam lubrication design and maybe some other things. It may affect oil foaming. I think all manufacturers caution against overfilling. Not sure of all the reasons.

 

[Bob Hughes]

Stretch, that splashing around also occurred to me, still have not got a really satisfactory answer - - yet



Bob

 

[CLEAH]

Bob, It seems to me that since the oil pickup and the dipstick are both mounted to the engine and not the sump, you want to make sure you only put in as much oil as the dipstick indicates. The dipstick is measuring oil relative to the bottom of the engine, not how much oil there is by volume. As long as there is oil at the mark, there is sufficient oil for the engine. Where you might have a problem is if you run the oil very very low, the original sump may be more forgiving of that situation since there is more oil sloshing around before it starves, but that would only be a factor in a completely un-maintained car.

I'm with Stretch: fill it to the mark, and don't overfill it.

 

[Bob Hughes]

Thanks CLEAH,

I will reduce it next oil change.



Bob