70 fastback correct oil level

macca49 · Dec 10, 2012

Hi Guys
i changed the oil today in the old 70 fastback and a few qusetions .
The oil dip stick is 3 and 1/2 " long
i put about 3 lts and its full !!, like really fulll, but only just showing on the dip stick .
so is this dip stick from a different model ?
cheers
macca

L.A.B. · Dec 10, 2012

macca49 said:
i put about 3 lts and its full !!, like really fulll, but only just showing on the dip stick .

I certainly wouldn't add any more oil.

macca49 said:
so is this dip stick from a different model ?

There appears to have been at least 3 different 'Commando' dipsticks, all with different level marks. :roll:

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DogT · Dec 10, 2012

Didn't the 70 FB have an oil level sight tube?

Dave
69S

Bob Z. · Dec 10, 2012

Here is an example of different dipsticks.

Left: 1973 750
Right: 1971? central oil tank

Edit: the shorter dipstick is 3-5/8" long. Note that the L mark on it corresponds with nearly the H mark on the longer.

L.A.B. · Dec 10, 2012

DogT said:
Didn't the 70 FB have an oil level sight tube?

I'm not sure if the Fastback oil tank still had the sight tube by 1970, possibly?

DogT · Dec 10, 2012

When I change my oil, it only takes 2 quarts. If the engine is completely dry, like a rebuild it will take 3. At least that's been my experience. Don't over fill it.

Dave
69S

macca49 · Dec 10, 2012

great thanks guys
and no sight glass on my tank , an old triumph i had had a mark about 2/3 up the oil tank saying min oil level so im guessing the same rough guide will do for the norton ?

L.A.B. · Dec 10, 2012

2.5 litres is probably enough. If it is overfilled then the excess oil is likely to be blown out of the tank breather.

Ron L · Dec 10, 2012

macca49 said:
great thanks guys
and no sight glass on my tank , an old triumph i had had a mark about 2/3 up the oil tank saying min oil level so im guessing the same rough guide will do for the norton ?

I assume then you have the fiberglass cover over the oil tank? The long-type tank without a cover ('68-'70) did not have a dipstick in the tank, only a sight tube at the front. Both the long and short dipsticks are not calibrated properly for this tank.

I would completely drain the tank and engine, refill with 3 qts (2.8 liters) and make a new mark with a chisel or punch on the backside of the dipstick. Then drain 1 qt (or better yet, 1/2 quart) and make a second mark. That way you will always know where your machine is full and low.

70 fastback correct oil level

macca49

L.A.B.

Moderator

DogT

Bob Z.

L.A.B.

Moderator

DogT

macca49

L.A.B.

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Ron L

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