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dashpot oil
- Thread starter jackag91
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Light weight motor oil, 3-in-1 oil, ATF, etc., etc. They all work and have their admirers!
MGTF1250Dave
Jedi Knight
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I use motor oil, either 20W-50 or SAE30.
G
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I like the little blue flat plastic bottle of 3in1 that is 20wt motor oil. Very convenient to use and store in the trunk (oops, boot).
martx-5
Yoda
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It all depends on how badly worn you carbs are...
20 wt....Factory Original...Probably works great on brand new carbs, but there aren't a lot of those around these days!
ATF....Works very well...Thin enough to be responsive, but thick enough to smooth out off-idle performance. Requires that carbs be in good tune, and that throttle shaft bushings not be too badly worn out.
20/50....Moderate Driving /Worn Carbs...Thicker than either of ATF or 20 wt. Overall performance is similar, but responsiveness suffers. Makes the vehicle run better at low RPM. Thick enough to counteract leaking throttle shaft bushings and poor tune.
This info comes from www.teglerizer.com/sucarbs/index.html
20 wt....Factory Original...Probably works great on brand new carbs, but there aren't a lot of those around these days!
ATF....Works very well...Thin enough to be responsive, but thick enough to smooth out off-idle performance. Requires that carbs be in good tune, and that throttle shaft bushings not be too badly worn out.
20/50....Moderate Driving /Worn Carbs...Thicker than either of ATF or 20 wt. Overall performance is similar, but responsiveness suffers. Makes the vehicle run better at low RPM. Thick enough to counteract leaking throttle shaft bushings and poor tune.
This info comes from www.teglerizer.com/sucarbs/index.html
toysrrus
Yoda
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Hi There jackag91;
Moss Motors offers "Dashpot Oil" specifically designed for SU`s and Strombergs; The Correct blend for Top Performance:
I`ve been using it "Forever" and "Never" had a Problem:
Their P/N is 220-225 / Cost = $9.60 for bottle of 125ml: That`ll last you a Really Long Time unless you have a Leak somewhere:
I would`nt mess around with different grade oils: Do It right the First Time:
Regards, Russ
Moss Motors offers "Dashpot Oil" specifically designed for SU`s and Strombergs; The Correct blend for Top Performance:
I`ve been using it "Forever" and "Never" had a Problem:
Their P/N is 220-225 / Cost = $9.60 for bottle of 125ml: That`ll last you a Really Long Time unless you have a Leak somewhere:
I would`nt mess around with different grade oils: Do It right the First Time:
Regards, Russ
vettedog72
Jedi Knight
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I use ATF and had no problems.
Jack, I've used all of the above mentioned with success. The guideline from Paul Tegler's site is a good one.
The SU/ZS oil sold by Mo$$ is nothing more exotic than straight 20W oil. 20W hydraulic oil works beautifully, and is a whole bunch cheaper than 73 bucks a quart. Although for that price, you get the zoomie little squeeze bottle, (which I fill with my own oil :G).
Right now I'm running 20W50 in the SUs, and 20W in the ZS carbs.
Jeff
The SU/ZS oil sold by Mo$$ is nothing more exotic than straight 20W oil. 20W hydraulic oil works beautifully, and is a whole bunch cheaper than 73 bucks a quart. Although for that price, you get the zoomie little squeeze bottle, (which I fill with my own oil :G).
Right now I'm running 20W50 in the SUs, and 20W in the ZS carbs.
Jeff
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PSST!: BACON FAT!!! Th' SEEKRET ingredient! /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif
I've put about every kind of oil imaginable in there at one time or another. Fork oil works FINE, whatever is going in the crankcase at the time is FINE. Even Mineral oil works well in a pinch. To pay the equivalent of $70+ bucks a quart for something ya can drizz out'a the four quarts of Castrol after they're dumped inna crankcase seems a bit on the, um... the SILLY side. That's SOME snake oil! And a durned fine job o' marketing, too.
I've put about every kind of oil imaginable in there at one time or another. Fork oil works FINE, whatever is going in the crankcase at the time is FINE. Even Mineral oil works well in a pinch. To pay the equivalent of $70+ bucks a quart for something ya can drizz out'a the four quarts of Castrol after they're dumped inna crankcase seems a bit on the, um... the SILLY side. That's SOME snake oil! And a durned fine job o' marketing, too.
vettedog72
Jedi Knight
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MMO works very well. I ran out and used ATF. I think the cleaning action of either is very good for the carb and engine.
TR3driver
Great Pumpkin - R.I.P
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FWIW, the viscosity of the dashpot oil, in effect controls the "accelerator pump" effect, ie how much richer the mixture goes when you first open the throttle.
I did some experiments with different viscosities many years ago on my TR3A with H6 carbs; and found that straight 20 weight oil worked the best for me. ATF, etc. were a bit too thin : the engine didn't stumble but did have a bit of a lean bog. And straight 40 weight was too thick for my taste : smal movements of the throttle would produce bursts of power that quickly faded.
At the time, straight 20 weight was easy to find, but it's a bit harder these days; so I just use 20W50 (same as the crankcase). It works fine too.
Haven't done a similar study with ZS carbs yet, but 20W50 seems to work fine in the Stag.
Two other comments that most of you know but maybe some don't :
1) The owner's manual for the TR3 tells you to fill the dashpots every 6000 miles. The level they give is high enough that the oil will leak down the piston and lubricate the outer sliding surface. But this area doesn't need a lot of oil, so if you notice the level is down just a few hundred miles later, there's no need to top it off. The oil cannot leak out below the level necessary for proper carb operation (on a SU carb).
2) However, the ZS carbs do have a seal that can allow the oil to leak out below the required level. It's a simple O-ring, but the books don't tell how to replace it. If your oil level goes down low enough that you cannot feel the resistance as you put the cap in place, then you need to replace that O-ring.
I did some experiments with different viscosities many years ago on my TR3A with H6 carbs; and found that straight 20 weight oil worked the best for me. ATF, etc. were a bit too thin : the engine didn't stumble but did have a bit of a lean bog. And straight 40 weight was too thick for my taste : smal movements of the throttle would produce bursts of power that quickly faded.
At the time, straight 20 weight was easy to find, but it's a bit harder these days; so I just use 20W50 (same as the crankcase). It works fine too.
Haven't done a similar study with ZS carbs yet, but 20W50 seems to work fine in the Stag.
Two other comments that most of you know but maybe some don't :
1) The owner's manual for the TR3 tells you to fill the dashpots every 6000 miles. The level they give is high enough that the oil will leak down the piston and lubricate the outer sliding surface. But this area doesn't need a lot of oil, so if you notice the level is down just a few hundred miles later, there's no need to top it off. The oil cannot leak out below the level necessary for proper carb operation (on a SU carb).
2) However, the ZS carbs do have a seal that can allow the oil to leak out below the required level. It's a simple O-ring, but the books don't tell how to replace it. If your oil level goes down low enough that you cannot feel the resistance as you put the cap in place, then you need to replace that O-ring.