• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Dashpot Oil

Share this page

D

DesertSprite

Jedi Warrior
Offline
What should I use? I've heard some people say Marvel Mystery Oil or something similar. ??

Joel /ubbthreads/images/graemlins/patriot.gif
 
Using 3 in One oil here.
 
Joel, everything from Marvel, to ATF, or even 20W50 will work. The actual factory recommendatation was for essentially the same oil you are running in the engine. In the '65 I have that lives north of you, I run 20W50 in both the engine and the carbs, and it seems to work just fine. It's on the west side of the Sacramento valley, so sees the same climate as Salinas.
Oil that is too thin may allow the pistons to rise too quickly, creating a temporary lean condition on acceleration. If you get this, try different oil. I actually had one set of carbs that used different oil in each of the pair, to match piston movement rates.
Jeff
 
We have always tried to use the lightest oil that works on the dashpot looking at it as a dampner. Meaning keeping the intake pulses from affecting the carb piston..fluttering..If you try it without any oil you can see what I mean. Also, this is for a modified motor. Seems like the heavier the oil, the slower the throttle response. This is assuming the tuning (needles and springs) are correct for the motor. Headers, cam upgrades, head upgrades and Air filters will have an effect on the tuning of the SU's..

Just my 2 c....
 
Hmmm...didn't know there was that much to it. Right now my engine is just a stock 1275cc motor (as far as I know). I'm just slowly going through things as I get to them, however, my throttle response seems to be a bit weird lately. Kind of hesitates a little. So, I thought I'd replace the dashpot oil as it's a fairly straight forward task.

Right now I run 10W30 Castrol Syntec in the car. Should I use that for the dashpots? Can I find 3 in 1 oil at NAPA?

Joel
 
Joel, try the Syntec, and see what it does. It may require a bit of experimentation to find what works best for your carbs. On my stock 1275 that I run here, I'm using straight 20W, and have no hesitatation or stumble problems at all. The California car has a heavily modified 1098 in it, and new carburetors on it.
You can probably find 3 in One oil at any good hardware store, but the cheaper alternative would be ATF. Like I said, experiment, and find out what works best. You're only going to use a couple of ounces of each, until you settle on one product.
Jeff
 
ATF works fine. I've used everything from straight 30W to ATF, usually just topped up with whatever I put in the crankcase.
 
[ QUOTE ]
What should I use? I've heard some people say Marvel Mystery Oil or something similar. ??

[/ QUOTE ]

Run what's in the engine... at least that's what I've always heard (probably because you'll always have it available I suppose). I actually use 20W50 - Same as in the engine. I tried lighter weight stuff (motorcycle fork oil - don't recall the weight), and didn't like the results.
 
When I was at the Austin Healey Encounter in Princton NJ (in '02), this question came up at a tech seminar. It almost started a fistfight, there were so many different opinions!
 
Well, I'll try the syntec. Just seems to stumble a bit every now and then...dashpot oil seems to be the cheapest thing to start with...

Joel
 
Back
Top