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MG Midget and Sprite Technical - Too much oil - problem?

Hi,

I need some advice from you...

Few days ago I changed the oil as usually during this time of the year. I use mineral oil supplied by friend of mine from NL running oil distribution business. It is 20W50 spec. It comes in "almost 1 litre" bottles (one qt = 0.946 l). This time I used 4 qts and it turned to be a little bit too much, now I see oil level something like 3/4 cm over the Max mark.

But, I do not have any seal on the dipstick, like this one, part 81:

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=76624#top

I guess with the seal in the place oil level would be almost at Max mark, as the seal would make dipstick not to go that deep.

Am I right? Or should I take some oil out to be on the safe side? Can a bit too much oil be a problem?

Thanks!
Stepan Marek

It certainly can be in extreme cases. And 3 -4 cm above max seems like a lot.

In the extreme the crank will hit the oil in the sump. Akin to doing a belly flop into a swimming pool it will give the crank a good whack and can damage it.

Apologies for scare mongering. I'm sure someone will advise more specifically soon!

Malcolm

P.S. Hang on... do you mean 3-4 cm (3 to 4) or 3/4 (3 quarters)?
Malcolm Le Chevalier

3 quarters of 1 cm, Malcolm.
Stepan Marek

If the crank is whipping up the oil, you'll see blue smoke from the exhaust as the oil/air emulsion on the bores overcomes the rings.

As you say, the seal on the dip-stick will raise it slightly.

If you're concerned, you could always drain a little.

I used to run my ASeries with a little more oil than spec for track-days and speed events... helps prevent dips in pressure due to surge on fast corners and hard braking (sticky tyres!), and also the odd drop that escapes due to long periods of WOT giving little crankcase vacuum.

A
Anthony Cutler

Anthony,
thanks. No blue smoke, oil pressure also normal (65 psi under the load, 45 on tickover, both when warm).

But, am I right, if I think that going directly at Max mark level without the seal is in fact going lower?

I use this Ivor Searle engine for 4 years, another 4 years before I've been driving original engine and no seal on the dipstick in both cases...

Is it normal, do you have it also without it?


Stepan

Stepan Marek

Air/oil emulsion is not good for lubrication! Suck it out to the high mark.
Art Pearse

Stephan,
if you put it all in then 4 x 0.946l = 3.784 litres

the dry fill including filter according to my Driver's Handbook is 3.7l

as it's very unlikely you got all the old oil out then chances are yes you have overfilled but possibly not enough to worry about depending on your dipstick level and the dipstick being the correct one for the engine - there is a thread on dipstick length

the seal if you had it, and many don't, would lift the dipstick so the max level mark would sit slightly higher up in the engine, so you've overfilled by slightly less

I bought a dipstick seal and what I got was a rubber washer of poor fit I swapped it for a small blanking grommet which I put a hole in as it was a better fit

when refilling I only usually fill to about half way on the dipstick then allow plenty of time for the oil to drop by topping up in stages slowly the next day

you could syphon some out through the dipstick or depending on your sump plug washer risk dropping some out from there

my dipstick from under the flange (without seal) to MAX mark is 197 mm and to MIN mark is 218 mm (give or take a fraction of a millimetre)
Nigel Atkins

Stepan,
apologises for mistyping your name in last post
Nigel Atkins

Nigel,

thanks. I wanted to confirm my idea, that oil seal would move the dipstick slightly up. Few years ago I also bought the seal (from Moss UK) - poor fit, few days after it got lost, hopefully not into the engine...

By the way, I've spoken to one local petrolhead with many years of hill racing experience and building engines and he said, that in case of significant overfill the crank shouldn't be damaged by hitting the oil, but can possibly whip up the oil and make oil pump suck the air.

Anyway, I'll take out some of the oil to put the things right.

Cheers,
Stepan
Stepan Marek

Stepan,
as the difference between max and min marks on the dipstick are say 20 mm if your engine is overfilled by 30-40 mm (but without seal) then that is quite a bit extra so would be a good idea to reduce it

I find engines find their own happy oil level and that might be a bit below the max mark, once you've found this happy level you'll be able to better judge your consumption and/or leakage (if you have much of either)

Lawrence worked out how much oil it takes to get from the min to max mark but I can't remember, it's in a fairly recent thread in the Archives
Nigel Atkins

I can't remember if that was worked out or not Nigel. I remember posting the measurements on the dip stic (pictures), but did that get translated into quantities of oil?

Can you remember if it was in the general or tech section?
Lawrence Slater

On my car, '69 1275, it takes 2 pints, as near as makes no difference, to get from "MIN" to "MAX"
Ray Rowsell

an imperial quart then

Lawrence,
I can't remember but putting dipstick into the Archives search might just get you to my posts
Nigel Atkins

I've given up trying to search the archives "intelligently". It's too hit and miss. I get more success just guessing, and that's not much success at all.
Lawrence Slater

Stepan,
I've not found L's oil quanity thread but I have found this that might be of use to you -

(thanks to Keith (KTM Moore) for following initial measurements)

for future reference

1275 Spridget dipstick

Note:-

. the dipstick should have a washer and this washer obviously sits between the dipstick flange and the dipstick tube

. the dipstick tube sits 1 and Ό” (32 mm) out of the engine block

. millimetre measurements are rounded to whole figure



Length of dipstick – (from the underside of flange without washer) to:-

. ‘MAX’ line is 7 and 7/8” – (200 mm)

. ‘MIN’ line is 8 and 11/16” – (221 mm)

. end is 9 and 9/16" – (243 mm)



Distance from the bottom end of the dipstick to:-

. ‘MIN’ line is 7/8" – (22 mm)

. ‘MAX’ line is 1 and 11/16" – (43 mm)
Nigel Atkins

This thread was discussed between 29/05/2012 and 31/05/2012

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