Interesting! I learnt years ago from an old school mechanic who specialised in Brit cars, namely Jags and Rovers that the best SU carb oil was ATF (automatic transmission fluid) as not only did it do duty as dashpot lubricant but it also acted as an excellent upper cylinder head lubricant.
Hi David, you'll know that there is very little oil in the dashpot at the end of the day. So mixing what is effectively a very light oil is no problem. As it will eventually be replaced by the ATF quite quickly with routine maintenance. A lot of people forget to check their dashpots oil level.
Add oil by drops? Utter nonsense. The little tube inside the piston holds a couple teaspoons. Do you need to top up? Remove the piston and push back down. If you're getting resistance about 1/4 inch before the threads engage, you're good. Forget about trying to "listen" for a slurping noise. 3 in 1, ATF, 20-50W, whatever. Too thin, you'll run lean. Too thick, you'll run rich. No single answer for everyone.
Thanks for the tips. Just got my Dad's '53 XK120 and trying to learn what I need to do.
I couldn't stop laughing watching this. Last time I pulled that thing out it didn't make me randy, so I guess I need to add some oil. Good tip!
Interesting! I learnt years ago from an old school mechanic who specialised in Brit cars, namely Jags and Rovers that the best SU carb oil was ATF (automatic transmission fluid) as not only did it do duty as dashpot lubricant but it also acted as an excellent upper cylinder head lubricant.
Very good
Can you mix oils in the dashpot or if you want to change to a different oil do you need to somehow drain all off first?
Hi David, you'll know that there is very little oil in the dashpot at the end of the day. So mixing what is effectively a very light oil is no problem. As it will eventually be replaced by the ATF quite quickly with routine maintenance. A lot of people forget to check their dashpots oil level.
Nut job :) I use ATF in my heap. I've also used 20w compressor oil in the summer as it can get a bit too thin in the heat.
very good ! also looking inside the carb , the thin tube at the bottom where the piston lives , needs to be full up to about 1/4 inch below its top .
It does the job well
Always wondered where the added oil eventually disappears to? Why does it ever need re-filling?
ATF and wait until there is some resistance, then the job is done.
And there's more.
Add oil by drops? Utter nonsense. The little tube inside the piston holds a couple teaspoons. Do you need to top up? Remove the piston and push back down. If you're getting resistance about 1/4 inch before the threads engage, you're good. Forget about trying to "listen" for a slurping noise. 3 in 1, ATF, 20-50W, whatever. Too thin, you'll run lean. Too thick, you'll run rich. No single answer for everyone.
Put Tizer in mine