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T

Tinster

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Engine stuttering problem-

I put a gan of that drygas stuff into my fuel tank.
Checked the carbs dip sticks as instructed-

ooops - one is low on oil.

I have 20w-50 engine oil
I have 80w-90 gear oil
I have hydraulic jack oil

Which of these oils is best to top off
the carbs?

thanks as always,

dale
 
TR6 uses auto trans fluid. Older cars used same oil as in engine. Diff fluid will never work (too thick). There is a SU fluid sold in some parts houses, but the auto trans fluid works.
 
:iagree:

I concur with Paul, use the engine oil.

Happy Motoring Dale

Dave
 
Dale I have this left over from when I had my GT6.

Pm me and I'll send it to ya!

DSC02332.jpg
 
I've found that 20W50 motor oil works best on the TR (triple 175 ZS setup) and automatic transmission oil is great for the Red 'Ropa (twin 175 ZSs). So take your pick. Another case for Mr. Trial and Dr. Error me thinks.

BTW Joe (the carb king) Curto recommends auto transmission fluid for ZSs.

Rob.
 
Larry: I have never heard of using ATF in a carb dashpot. I have always used what ever is in the crankcase. However, here is a excerptfrom the VTR site, suggesting that a change in dashpot oil viscosity to "tweek" carb response.

"<span style="text-decoration: underline">You can also modify your car's throttle response characteristics slightly by adjusting the viscosity of the oil in the dashpot damper. SU and ZS carbs are set up so that a thicker oil will resist the piston's attempt to rise in the dashpot for just long enough that the engine's increased load (when the throttle is opened) will pull more fuel across the bridge; this enriches the mixture and temporarily bumps power up to help the engine achieve higher speed more readily. For light damping, Marvel Mystery Oil is excellent, engine oil can be used for heavier damping.</span>"
 
kodanja said:
Dale I have this left over from when I had my GT6.

Pm me and I'll send it to ya!

DSC02332.jpg
Click to expand...

I always wondered if anyone actually bought that stuff. I think it comes out to $74.00 a quart. :shocked:

.
 
I have about half a bottle that has got to be at least 20 years old.


Dale is at sea level, so if he hasn't changed the needles, he would probably be fine going with marvel myster oil,atf, or engine oil. the marvel myster oil, being thinner viscosity will lift the pistons slightly sooner, giving more gas on takeoff(preferable at lower elevations) and the engine oil, and atf have very similar viscosities at a tropical climate(we are talking 20 weight primary oil right?) will take a wee tad longer for the piston to rise and the mixture will be leaner for just a skosh longer. Which at sea level should have no impetus on the selection of oil(s). course he could always experiment with different grade motorcycle fork oils to see which response he likes the best....

Sound like he's gotta replace an o-ring if the oil leaked out.
 
RonMacPherson said:
....will take a wee tad longer for the piston to rise and the mixture will be leaner for just a skosh longer.
Click to expand...
Pardon me, "guy", but isn't it just the opposite? At least according to the VTR statement?
 
RonMacPherson said:
the marvel myster oil, being thinner viscosity will lift the pistons slightly sooner, giving more gas on takeoff
Click to expand...
Sorry, Ron, but I disagree. Holding the pistons down is what enrichens the mixture, because of the increased air velocity through the venturi plus blocked (reduced) air flow. This is a much stronger effect than the needle movement. Thus thicker oil gives more enrichment when you first open the throttle.

Also, ATF is considerably thinner than straight 20 weight motor oil, at room temperature. They are roughly equivalent at 100C, but presumably your carbs never get that hot (the fuel would be boiling in the bowls). At 40C (which hopefully is closer to where your carbs run), ATF is somewhere between 0W and 5W motor oil (35-40 cSt @ 40C).<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Sound like he's gotta replace an o-ring if the oil leaked out. [/QUOTE]Yup, that I grees with !

Dale, the 20W50 is a reasonable place to start, IMO. If you want to, you can experiment from there to see what works best for you ... I liked straight 20 weight best in my TR3A with H6 carbs but the Stag with ZS carbs seems happier with ATF. On the TR, the heavier oil gave better throttle response, it had just a bit of lean bog with the ATF.

I used one of those $7 vacuum pumps from HF and an old Mason jar to build a "vacuum cleaner" for changing dashpot oil ... likely a MityVac with the brake bleeder attachment would work just as well.
 
Even "3-in-1" sewing machine oil is an option. MMO is fine, or whatever happens to go into th' crankcase.

Ron said:
Sound like he's gotta replace an o-ring if the oil leaked out.
Click to expand...

That's th' most likely scenerio. And th' architect gets to buy more proprietary tools and learn about another bit of English engineering in th' process. :laugh:
 
DrEntropy said:
And th' architect gets to buy more proprietary tools
Click to expand...
Yeah ... I used a pencil :laugh:
 
Not that it is all that important, but I found that my damper holds 3.5 ml of oil.
I drain mine by taking the "dome' off and removing the air valve and dumping the oil out. I have also attached aquarium air tubing to a 5cc syringe and drawn it out.
Not that I do that very often.
If you want to try putting Bards rear oil seal stop leak in the damper it may swell the O-ring enough to stop a leak. I'd say it was about as thick as 30w motor oil.
 
Just get a pair of Webbers and ya dont need any oil!!

Just kidding use what the experts use!!! :thumbsup:

a13.jpg
 
Hi Tinster,

As RonMac mentions; This stuff lasts almost a lifetime!

With all the "Blood, Sweat, Tears and $$$" you have in your car; Why play a guessing game now??

You can buy it from Moss or anyone of the suppliers and have a lifetime of using the proper fluid.

Regards,

Russ
 
Ha! You guys are awake!... And Randall came up with the explanation why. I was testing you, to see if anyone was paying attention, by giving only part of the physical interaction. We used to play with oils alot back in Riverside days, to see who could get off of turn 6 smoother. Same as putting heavier springs in the bikes..


Glad someone's watching.....
 
poolboy said:
RonMacPherson said:
....will take a wee tad longer for the piston to rise and the mixture will be leaner for just a skosh longer.
Click to expand...
Pardon me, "guy", but isn't it just the opposite? At least according to the VTR statement?
Click to expand...

Correct, it enriches the mixture, sounds totally illogical since moving the needle out increases the open area on the jet, but that is only 1/2 of the story.
When the throttle is opened quickly, the air velocity under the piston increases, and that causes an increase in suction on the jet pulling more gas into the mixture. Absolutely brilliant solution. Now adjusting the viscosity will affect how long it take for the enrichment to continue after hitting the throttle, so all of the above suggestions are quite valid. It just takes a bit of experimenting to find out what will work best.

Dale, don't rush off to take your carbs apart. Just put a few drops of oil in, DO NOT FILL THEM the oil will just spill out and make a mess. check them in a few weeks so you can get a feel for if the the oil level is really going down quickly or not.
 
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