oils well that end well

[desertmonkey]

LOLNot a laughing matter folks I have a 260Z that slurps carb dampner oil I

add everday. I have tried ATF, Marvel

3in1 and motor oils. At times she will

idle smooth and steady and then she

will shudder and pop from the exhaust

Maybe I will pull the plugs and take a

look even though I just did that a day

or so ago. Are there supposed to be

O ring seals on the caps of these carbs

or just flush to the domes? They both

seem to respond to adjustments and

have power. Back to square one.

[beermanpete]

There is likley an o-ring on the caps, but that is not related to the oil going into the intake. There are no internal seals so if it is leaking oil intertnally it probably has worn parts.

[desertmonkey]

If the domes are screwed down tight and the pistons on the caps are snug in the well where would the oil go? I have a book on SU carbs so maybe if I get a kit to reuild them and do one at a time it may cure the oil issue. That could be the entire performance problem we have had all along cold or warm.

[Captain Obvious]

I have a 260Z that slurps carb dampner oil I add everday.

That's weird... There isn't supposed to be any way for the damper oil to drain out of the suction piston.

Does it go alll the way empty if you don't refill it? Or does it reach a point and level off and stop dropping?

[beermanpete]

If the domes are screwed down tight and the pistons on the caps are snug in the well where would the oil go? I have a book on SU carbs so maybe if I get a kit to reuild them and do one at a time it may cure the oil issue. That could be the entire performance problem we have had all along cold or warm.

The oil is going into the engine. What I meant in my previous reply is that if the carb is worn the oil will move into the venturi through the wider than intended clearences.

I think that the oil consumption is inherent to the desgin. The consumption rate increases due to carb wear. If you are adding oil daily you are either using the wrong oil or there is a problem with your carbs.

Try using 10W-40. Don't worry too much about how it might affect performance, just try it to see if it reduces the consumption rate. Thicker oil will stay around longer.

[30 Ounce]

Thicker oils won't flow around the plunger fast enough when the piston drops and gets pulled right out of the tube into the intake manifold through the vent holes at the bottom of the pistons. If you tried ATF and your still having that problem maybe your overfilling them. They only hold 3 teaspoons each. Maybe your plungers are clogged up.

[Captain Obvious]

I'm unclear how worn carb parts could increase the oil consumption. The damper oil is nowhere near the venturi and it seems that any worn parts should only make the situation better, not worse.

Thicker oils won't flow around the plunger fast enough when the piston drops and gets pulled right out of the tube into the intake manifold through the vent holes at the bottom of the pistons. If you tried ATF and your still having that problem maybe your overfilling them. Maybe your plungers are clogged up.

That's more like what I'm thinking... The only way (you should be able) to get oil out of the plunger tube would be to pull it up and out the top. Maybe the plunger check valve disk is in backwards or something?

desertmonkey, Did you ever disassemble the brass pieces off the stalk?

[desertmonkey]

Thanks I will take the domes off tomorrow on at a time and double check the mechanisms and clean all the surfaces and give them a thin film of silicone. Once I get them together I will static adjust them and add the oil to the dampners. I will work with the Unisync and get the flow checked. I will go with Marvel Mystery Oil.

[Bruce Palmer]

Okay, now this is getting way too silly.

First thing to do is take the aircleaner off and raise the piston. With the damper removed, look down inside the tube you just raised. The top of that tube is were the oil should fill (at the most). Once the puck goes in, it will displace it's volume of oil and that's where it'll remain for a long time. Filling to the threads well, you know what happens. Any oil above the top of that inner tube will just get sucked into the engine and burnt

[desertmonkey]

I will have to take the air filters off to use the Unisync so I will check the movement ofthe piston and watch the oil. I will let you know what happens

[Bruce Palmer]

You may even find a line scribed around the inside of the inner tube which approximates the "fill to" line.