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| Fuel leaking from vent | Rate Topic |
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| Posted: 08-14-2020 03:01 am |
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21st Post |
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redracer Member
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Here's a "free" version for Strombergs; https://www.triumphwedgeowners.org/uploads/3/0/4/2/3042952/_zenith_stromberg_factory_tuning_manual_-_complete.pdf Things I normally do: 1) block off both bypass valves by making a solid gasket 2)turn the 3/16" nut all the way in to make the temperature compensator nil/void/useless 3)steel ball in the 90 degree rubber elbow coming off the center of the intake manifold to void the vacuum retard capsule on the distributor and void the actuator(on the rear carb) for the bypass valves many other tricks but these are the major ones
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| Posted: 08-14-2020 02:01 pm |
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22nd Post |
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Jagwire64 Member
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Thanks for the Tips. These look like useful steps. Now i have to find the right size steel ball. Last edited on 08-14-2020 02:18 pm by Jagwire64 |
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| Posted: 08-14-2020 05:46 pm |
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23rd Post |
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Esprit2 Member
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I agree with Bruce's steps for defeating the vacuum powered emissions devices, but I go a step further. Instead of plugging the hoses with a ball bearing, I just remove the hoses. Go to an auto parts store, and they sell little rubber caps specifically for plugging/ capping vacuum spigots... little spigot condoms. They're cheap. One big one for the spigot on the intake manifold, and smaller ones for the distributor's vacuum capsule and the bypass valve. Functionally, the vac capsule & bypass valve don't have to be capped, but it's nice to keep any crud & corruption out of them. For the spigot on the intake manifold, secure it with a nylon cable tie. Vacuum would normally hold it on, but one backfire would be enough to blow it off, then you have a massive air leak. Add the cable tie for security. Bruce's 'plug the hoses' approach preserves the original look of the engine bay. Concours purists will appreciate that. To me, there's too much of a Rat's Nest on the 'stock' engine, and removing anything you can is an improvement. But that's a detail. Bruce's point to block/ defeat those vacuum lines is what is important. How you do that is a detail. He blocks. I remove. Both work. Regards, Tim Engel
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| Posted: 08-14-2020 05:49 pm |
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24th Post |
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Esprit2 Member
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The 'Enrichement Device' (aka, 'choke') requires two gaskets. One inside to rebuild it, and one between it and the carb body to mount it. Most Z-S carb rebuild kits only include one of the gaskets, and you must order the other one separately. Rebuilders who are not familiar with Z-S carbs often omit the one missing gasket, and that can lead to a fuel leak. Make certain you get both. Regards, Tim Engel
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| Posted: 08-14-2020 06:06 pm |
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25th Post |
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redracer Member
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Tim: most of the rebuild kits do include both the gaskets, but I only use the one(originally it only had this one) that mounts to the carb body. The additional 2nd gasket that they want to have between the 2 choke halves is thick enough to reduce the necessary spring pressure onto the inner half, which can allow a gas leak(I have had to actually carefully sand down the outer half to get a smooth/leak free surface). What I do instead is use a pin and put Permatex aviation gasket cement(#98) CAREFULLY where the gasket would have gone. I didn't plan on all this typing, but as lob=ng as I'm here, here are a couple of more tricks: 1)the 2 bolts from the fuel bowl that go into the flow venturi should have #2, #98, #3 Permatex on the thread ends as they are prone to getting some gas sucked up. 2)The lower choke machine screw should also hace the same(even use some teflon tape on the end) as it directly enters the fuel bowl AND WILL LEAK enough now--fingers getting tired
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| Posted: 08-14-2020 06:35 pm |
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26th Post |
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Jagwire64 Member
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In regard to emissions the PO also removed the charcoal canister. The 2 lines going to it are connected (line to the fuel tank then the two carbs. I have seen other people doing this. There would be no reason to go through the expense to put a charcoal canister back in would there? My wife has been complaining about the fuel smell in the garage since the car arrived. I think now it is probably due to the carb leaking, But originally thought it may have to do with fuel vapor which is usually trapped in the charcoal until purged. Without the black can is vapor being trapped in the line and leaking out the carb? Or is this something i don't need to worry about?
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| Posted: 08-14-2020 07:30 pm |
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27th Post |
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redracer Member
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Jag: you can leave out the fuel cannister but don't block the line or a possible vacuum could form. Many just run a short tube form the rear carb to the front carb brass vapro tubes
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| Posted: 08-14-2020 07:52 pm |
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28th Post |
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Jagwire64 Member
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Ok Thanks. I just discovered the anti siphon feature is missing from the fuel line. Will have to put one in. The tank stub has a small piece of hose with a bolt shoved in it. From my research if i plumb a T along the hose going to the carbs, with a check valve between the T and the stub at the pressure relief valve. I assume the check valve flow goes toward the tank and not the T to the carb?
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| Posted: 08-14-2020 09:17 pm |
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29th Post |
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Jagwire64 Member
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Ok, Gauge reads 4.5 to 5 pounds fuel pressure. Didn't have sufficient fittings to run the gauge in line so tested at the end before the carb. Not sure if 1-2 lbs over pressure is enough to get past the needle valve? Also sprayed some carb cleaner into the fuel inlet, though it may free up the valve. It had no effect. Looks like I need a new pump or regulator. Will probably just replace the pump as it looks pretty iffy to start. I should probably just rebuild the carbs to know everything is fine. we will see when the new pump is on. Last edited on 08-14-2020 10:41 pm by Jagwire64 |
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| Posted: 08-15-2020 02:41 pm |
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30th Post |
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redracer Member
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Jag: the original anti-siphon valve is about the size of a .22 bullket and gets stuffed into the end of the hose(only later gas tanks had the 3rd vent coming of the breather nec. You may still have it as there is no bulge in the fuel line to show it is there, so remove the bolt and check. a brass"T" in place of the original plastic/nylon one would be a good upgrade--just be sure to have it located at the TOP of the gas tank
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| Posted: 08-15-2020 03:34 pm |
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31st Post |
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Jagwire64 Member
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The little .22 bullet thing is long gone I think. Trying to figure out the proper hose routing for the tank is mind bending. The tank is a aluminum replacement, not sure who made it. Looking at the parts schematic on Martin Robey... There are three nipples on the pressure relief valve side. Top going through the floor venting to atmosphere. Nipple on rear going to the charcoal can in the engine. Nipple on the side toward front of car going to the brass T for anti siphon. Mine is setup (without the T anti siphon) like Theymightberacing.com shows in tank replacement pictorial. He has the two lower nipple backwards...front nipple going to the vapor can and the rear a 2 inch tube plugged with a bolt (to anti siphon) The fuel tank has the same connections as the schematic. I can only assume that is how my fuel tank should be setup. My guess is it doesn't matter which nipple the hoses use as they both go to the same place...the top of the tank under the pressure relief valve? At any rate, I will be changing the fuel pump so would like to sort the lines properly. I will set the lines as in the parts schematic..With a brass T for the anti siphon, and a generic fuel line check valve. However, I am still not sure which way the check valve should work? My understanding of the anti siphon circuit is to prevent fuel from flooding the carbs when parked on a seep hill nose down. So the flow of the valve should be running toward the tank? For the life of me I can't seem to figure out how it is supposed to work. Last edited on 08-15-2020 03:46 pm by Jagwire64 |
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| Posted: 08-15-2020 05:26 pm |
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32nd Post |
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redracer Member
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the aluminum tank was probably made by Antonio, who used to advertise on ebay: Antonio: (619)802-4795(played pro soccer in Mexico) Paypal account: FCOAntonioMorales@yahoo.com $400+ shipping As for the 3 tubes from the top: 1) the one from the pressure valve on the top center goes to the charcoal canister; when the tank gets "warm" and the pressure increases, the vapor goes to the charcoal which is then "sucked" into the 2 carbs(Top, in center; small brass tubes) 2) one line goes to the breather for the differential(usually in the top driver's side) 3) the last goes to the anti-siphon valve(MUST be as high up as possible When the fuel pump is running, the 3-4 lbs of pressure pushed a small ball back against a very light spring, thus preventing the fuel from going back into the tank. When the pump is off, the spring pushes the ball back allowing air to enter, thus negating the siphoning effect
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| Posted: 08-15-2020 05:53 pm |
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33rd Post |
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Jagwire64 Member
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Thank you redracer, your explanation makes allot of sense. Not sure if a generic fuel line check valve will do the same thing. I will try it.
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| Posted: 08-18-2020 08:15 am |
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34th Post |
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subwoofer Member
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They are not difficult to work on, but the butterfly spindle bores wear out. If the throttle axle has radial slop, find yourself another set of carbs, the air leaks will make you chase your own tail until dizzy. The concept is actually quite brilliant, needle profile maps mass air flow to air/fuel ratio, similar to early fuel injection systems. Later computerized injection systems added another dimension - engine speed - to the air/fuel ratio control. Not strictly necessary for performance but vital for emissions and economy. That being said, I am not a fan of the 907 Stromberg inlet manifold, being 540/180 degrees rather than 360/360 on the cylinders it is feeding. -- Joachim
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| Posted: 08-25-2020 09:46 pm |
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35th Post |
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Jagwire64 Member
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Got the fuel pump replaced and the anti siphon line set up. Have rebuilt the leaking carb. Seals looked relatively new, so on the plus side PO wasn't lying about the recent rebuild. However, the float height wasn't properly set. The needle valve couldn't close. Installed the Grose jets...I assume they only need to be installed with the red fiber washer that came with them and not an aluminium washer the standard valve uses? They didn't seem to fit right with the Al washer. Fixed the emissions things and new proper metering needles. The air valve now works as it should. Will be doing the other carb tomorrow...Hopefully I will be driving soon.
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| Posted: 08-25-2020 11:09 pm |
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36th Post |
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redracer Member
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the torque on the Grose jets will be JUST enough to start breaking into the fiber washer--no more. Adjusting the height to 11/16" is relatively easy by bending the tab with your fingers
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| Posted: 08-28-2020 06:44 pm |
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37th Post |
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Jagwire64 Member
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Put everything back together. Fuel still leaks out rear carb fuel bowl vent. Engine not running..key on run. Takes a minute or two for then fuel runs out the vent steady. New fuel pump was listed as 2.5-3 psi direct replacement...tested at 5 psi same as what I had originally. Would the pressure be less with the engine running? So I am back to where I started. The floats..floated. Jets replaced with Grose...I ordered a pressure regulator to bring it down to 2.7 psi. I hope that solves the problem. Did the car have some pressure regulator hidden in the fuel line somewhere originally? The PO replaced the tank and the rubber lines...if there is some regulate its gone now. I think I remember reading about some kind of thing the the line to regulate pressure? Last edited on 08-28-2020 09:54 pm by Jagwire64 |
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| Posted: 08-28-2020 11:42 pm |
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38th Post |
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redracer Member
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Jag: please call or SKYPE me ASAP. something VERY SIMPLE is not right. bruce/RedRacer 404-261-2552; SKYPE name: RockClimber52
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| Posted: 08-30-2020 04:16 pm |
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39th Post |
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Jagwire64 Member
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Fuel pressure regulator installed and set to 2.5 psi. Took longer...but still leaked. The saga continues.... Will take carbs down again this week and check needle valve torque and function on advice on redracer.
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| Posted: 09-01-2020 01:10 pm |
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40th Post |
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Jagwire64 Member
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Carb removed...much faster this time. Torqued the float bowl valve a wee bit...no more leak. Result...finally. Thanks all for your help. Will be back on the road very soon.
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