Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Dashpot Oil Vanished :)

Hi Guys

I checked the dashpot oil level in my HIF carb yesterday to find that the oil level was non existent.

The oil level was full to where it should be approx 6 weeks ago, is it normal for it to vanish so fast?

R Williams

No, check the bottom of the damper tube for splits or corrosion.
Chris at Octarine Services

Rylan, when we discussed this before, wasn't it mentioned that you have a short tube, because the carb is from a Harley?

It is normal to top up the oil. I can't see how you could have a fracture in the dashpot tube, but I suppose on an old carb, anything is possible.

How old is your Harley derived HIF carb?

The other thing that occurs to me is this. The tube is short - stubby. If the piston is rising far enough, it will cause the oil to expel over the top of the tube. You may have to live with this.
Lawrence Slater

Rod and I are satisfied converts to "90 weight gear oil" (see other threads, the oil isn't as thick as you might think) as it's what John Twist recommends and he seems to know a thing or two about MGs from years of experience working on them as a business

it wont repair splits and corrosion or the excess (or all of it if there's something wrong) being pushed out of holes but it will help with running/feel and *might* slow down its loss
Nigel Atkins

The car doesn't need converting to anything just top it up with the same as the PO used and stop being paranoid about everything.
Alan Anstead

there's a few threads and posts on dashpot oil level and much debate on 'the correct' level

if you still have a bit of suction force on the rod as you lift it to look inside then you don't need any more oil

it may be than you overfilled last time

it seems to me that it depends how often you check as to how much reserve oil you need over this

you don't need to convert to 90 weight gear oil but you might want to

just because the PO was a mate of yours/known to you/local club member yours doesn't make the car perfect and beyond any improvement

I might come back with another point if I can find it

Rylan's probably a little cautious because of his experience with his previous midget
Nigel Atkins

yes, that's it, when Rylan first got his car the sidelight/indicators units were fitted other way round and/or upside down, not anything to worry about and not effecting function but it does show a very minor lack of detail and that the car wasn't 100% perfect and without any room for improvement

I'm not having a go at the PO, Alan or Rylan just that with these cars things can usually be improved but it's a different matter if it's really need or wanted

Rod and I chose to convert to 90 weight gear oil and we found what we thought or considered were sufficient improvements to stay with it
Nigel Atkins

gday all my conclusion is that the 90W simply evaporates slower and it works, but the throttle reponse will change slightly, which is OK after you get used to it. cheers Rod
R W Bowers

I'd be very surprised if the oil was evaporating. It would take a very high temp', and even then there wouldn't be much evaporation. Oil doesn't evaporate in the amounts water is able to, even at relatively low temperatures.

So Rylan, have you checked for cracks in the tube?
Lawrence Slater

Checked the tube for cracks, there was none.

I just need to top up frequently I think.

I do agree with Alan though, I think I am paranoid :)
R Williams

Then you need to listen up. ----------- :)

Finished with my woman 'cause she couldn't help me with my mind

People think I'm insane because I am frowning all the time

Or live.

Lawrence Slater

And almost alive, not quite dead yet. lol
Lawrence Slater

Until you get to know who you can rely on here your paranoia will only be fed by the insomniacs and maniacs.
Alan Anstead

Being both of those things, I would just add that checking your dashpot oil every 6 weeks or so is hardly onerous! So what's the worry if it does need topping up.
Guy W

What time do you go to bed Alan? lol

I'm up all night, listening to Napoleon. He's got some great ideas, when he's not blabbering on about ruling the world and shagging Josephine :).
Lawrence Slater

This thread was discussed between 17/06/2013 and 19/06/2013

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.