Parsons F Type. Oil level

[baffle]

Getting ready to go boating (!), and on changing gearbox oil realise that a Parsons F Type reverse gear in book should take 2.25 pints, but dip stick level is way lower than this. Before draining, the level was mid way between high and low on the stick, but there was only 0.5 pint in it, which seems worryingly low to me. My dip stick is stamped F Type, and I have a spare which is the same if not marked slightly lower. I would guess with oil up to the upper level on the stick there would be no more than 1 pint in the box. On neither gearbox or in the Parsons drawing is there a collar which would hold the dip stick up any higher than it goes.

So, oil capacity to the book, or to the mark, or between the two maybe?

Thanks!

[Ewart Hodgson]

I have a Parson's F type too, on the back of a Perkins P4. I never bothered too look up the capacity but just keep the oil between the two marks (not that it changes much anyway). I have been doing this since 1991 and all seems fine. I'm sorry that's not a proper engineers' answer, but it may at least calm your nerves that you do not have an immediate crisis!

[RLWP]

I have a Parson's F type too, on the back of a Perkins P4. I never bothered too look up the capacity but just keep the oil between the two marks (not that it changes much anyway). I have been doing this since 1991 and all seems fine. I'm sorry that's not a proper engineers' answer, but it may at least calm your nerves that you do not have an immediate crisis!

 

I'm an engineer - do what Mr Hodgson says

 

Richard

[Tony Dunkley]

 

I'm an engineer - do what Mr Hodgson says

 

Richard

 

I hope the OP looks at this topic again, and then ignores that piece of really bad advice.

He should first get some careful and accurate measurements taken to make sure that the dipstick in Ewart Hodgson's F type isn't shorter, or marked differently from the one he's using in his box.

I don't think I've ever known the exact oil capacity of an F type mainbox, but they've got a fairly bulky casing and from what I can remember about the last time I changed the oil in one, it was a lot more than a pint.

What I can remember for certain is that because the F type dipstick hole is at the front (engine flywheel end) of the box, Parsons supplied a selection of longer, or lower marked, dipsticks for use in installations where the engine and box were inclined down from the horizontal with the vessel in normal trim. Depending on the make of engine the box was mated with, and the hull form of the vessel it was installed in, this could be up to something in the region of 12 degrees, or more; hence the need for a selection of 'longer' dipsticks.

If the book says two and a quarter pints, then that's what he should put in, . . and then re-mark the dipstick.

Edited December 18, 2015 by Tony Dunkley

[David Mack]

Parsons supplied a selection of longer, or lower marked, dipsticks

So there is some truth in that old chestnut about buying a longer dipstick because the old one was too short to reach the oil?

[Tony Dunkley]

Getting ready to go boating (!), and on changing gearbox oil realise that a Parsons F Type reverse gear in book should take 2.25 pints, but dip stick level is way lower than this. Before draining, the level was mid way between high and low on the stick, but there was only 0.5 pint in it, which seems worryingly low to me. My dip stick is stamped F Type, and I have a spare which is the same if not marked slightly lower. I would guess with oil up to the upper level on the stick there would be no more than 1 pint in the box. On neither gearbox or in the Parsons drawing is there a collar which would hold the dip stick up any higher than it goes.

So, oil capacity to the book, or to the mark, or between the two maybe?

Thanks!

 

Under no circumstances heed the advice in posts # 2 & 3, . . . if you do, then you'll be running the box very short of oil. There is an explanation of why that would be, in post # 4.

[baffle]

Thanks for alerting to me to this Tony - what you point out makes very good sense. When I get round to it I will measure my dipstick(s) and if Ewart can do the same, we can have a little comparison.

Baffle

[Tony Dunkley]

Thanks for alerting to me to this Tony - what you point out makes very good sense. When I get round to it I will measure my dipstick(s) and if Ewart can do the same, we can have a little comparison.

Baffle

 

In suggesting a comparison with EH's dipstick, I was thinking more about the possibility that he may also have the wrong dipstick for his installation.

Your best course of action before using your own box again is to drain it, refill with the quantity specified by Parsons and then re-mark the stick accordingly.

[oldironsides]

Our 'F' gearbox dipstick is stamped 'Parson's F' so have always assumed it is correct!

[Tony Dunkley]

Our 'F' gearbox dipstick is stamped 'Parson's F' so have always assumed it is correct!

 

If it's the original stick supplied by Parsons when the box was new, then it would be correct for the installation it was supplied for. The majority of Parsons boxes were supplied for vessels with sterngear angled down rather than paralell with keel, or baseline, and horizontal as is the usual configuration in narrowboats.

There is further explanation back in post #4.

[baffle]

Hi people. For the record, my dipstick is 8 15/16" overall, and 7 1/4" from the end to shoulder of loop (ie what would descend into the gearbox. The marks are 1/2" and 1" from the end (low and high respectively. The advice to drain, refill and remark dipstick is sound - thanks for your help on this Tony. For the record my gearbox is serial 8803/3486, and came from the wooden boat Trees, last at Jannels, Burton.