carb oil

[H48HPE]

until recently i was of the oppinion that any oil would do in the carb dashpot, so depending what was at hand ive used different grades of engine oil, 3 in 1 oil, and for some mad reason ive even put redex in in the past but usualy thick engine oil. however since i caused an oil leak by using over thick oil in the engine, ive been doing everything by the book. a few weeks ago i got all the oil out of the dashpot and replaced it with duckhams 10w40. there has been a noticable increase in performance and im sure that its running on less too. it makes sence really because if the oil is too thick it will cause the mixture to be too rich for too long on accelleration.

I just thought id share that with you because I was pleasently suprised by what happened. from now on my advice on servicing will be to do it by the book.

andy

[MGTurbo]

As mentioned by me on another post on this BBS, dashpot oils are a black art and i've tried every single different type and done on the road testing and rolling road/Air/fuel ratio tests to determine which is best for my engine at least. IMO, the best all-rounder is the oil you've already mentioned, 10w 40 grade, in most cases. In my car, for quick pick up response and responsive feel throughout the rev range, ATF oil is the one. I've used it in the past and apart from an increased thirst for drinking oil thru the carb its the best for performance. Go heavier on oil and you'll lose response and gain nothing unless your engine is running really weak in the first place. Alot of throttle response gains can be made by adjusting the idle mixture screw.

Gareth

[topgear]

ive used redex too! will def check out the 10/40 stuff tho.

Smashin'

[e692wtt]

With reference to using Auto Transmission Oil in the carb dashpot, I said I would try it and report back, on the same thread Gareth mentions.

In my Monty 1.6, just topping up the 10w/40 that I normally use with ATF, performance is better and smoother but I am not yet sure if the dashpot leaks any more oil than before (into the carb). Have topped up again with ATF tonight, will report again. The engine needs a service (esp an air filter - been on 'too long'!) anyway, so perhaps I will see further improvements? Using 10w/40 rather than 20w/50 in the dashpot gave better performance anyway, so am impressed at the further improvements with ATF.

The other other Rich.

[e692wtt]

Well, the ATF isn't disappearing any quicker than the 10w/40 did, and performance is smoother and quicker still. Engine smoother on the motorway as well and the car hesitates less from initial revving when pulling away with the engine hot in hot weather (it *was* like a flatspot and had to be 'driven around' - no longer!). I know Agony Uncle refers to the S-series engine's 'slow getaway', and the ATF has lessened this.

The other other Rich.:eek:

[MGTurbo]

This confirms my findings. With a thicker oil you may get a *rich* flat spot which will seem like a lean flat spot unless you know what your looking for. Makes the engine very 'wooley' and fluffy. ATF oil seems to be the ideal oil.

Gareth

[e692wtt]

Gareth,

Thanks for the hint! Glad it confirms what you said, I'm very happy with the results too.

The other other Rich.
:eek:

[H48HPE]

what is this 'ATF' stuff that you talk about?

[Wonko_The_Sane]

Automatic Transmission Fluid..:)

The pink oil that goes into automatic gearboxes, and power steering pumps..:)