Port Nozzel pressure

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Brad671, Jul 28, 2008.

  1. Slayer

    Slayer Member

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    Also, when you first leak your barrel valve, and then start the motor, you will have to adjust the idle (around 1800 for blown alky). When you do this it will change your barrel valve setting and you will have to either leak it again or adjust it while it's running to what you want (richer or leaner).
     
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  2. lucky2wd

    lucky2wd Member

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    Just checked my poppet and it's 9 to 10lbs. I did add to the top with 10 on each side in the rear and 5 in the next set forward. I think it helped some, I know that maybe a big jump but I need to see a change and it needed some fuel anyway... SoDak when it gets that cold I hibernate!!!
     
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  3. Mike Canter

    Mike Canter Top Dragster

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    Did you also check your idle return poppet? What is that set at?
     
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  4. lucky2wd

    lucky2wd Member

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    is the idle return the one coming off the return pill?? hard to read my gage down that far but I going to say 6 lbs. just ran the motor again and it still gets hot on the tail end of blower. should I put 2 more nozzles back there? it has 8 total now.
     
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    Last edited: Aug 5, 2008
  5. WJ Birmingham

    WJ Birmingham New Member

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    6 PSI is fine. According to SSI, the right rear of the blower is the hottest point.

    We run 10 nozzles up top, with the rear two being larger than the rest, and the right rear being larger than the left rear.

    If your blower has provisions for 4 in the case, run 4 there and 6 in the hat.
     
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  6. lucky2wd

    lucky2wd Member

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    it's a f rotor ssi, I could put 8 nozzles back there!!
     
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  7. WJ Birmingham

    WJ Birmingham New Member

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    Well, same here pretty much. 4 in the top, 4 in the sides. I went with 4 in the sides due to space.

    Why not call SSI and ask them for the F rotor what they recommend for the rear fuel spread percentages?
     
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  8. lucky2wd

    lucky2wd Member

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    I'm putting in the sides, the top went a little more back but only on that set so the fit is nicer on the sides.......I know I went by Belleville last week stayed at Fairfield sun, mon, tue, then rained out at Charleston tues night. I've always had poor luck there anyway
     
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  9. Randy G.

    Randy G. Top Alcohol

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    The whole purpose of leaking it is to have it right before you start it. Once you've set the butterflies and have checked the barrel valve leak, if you've maintained your records, you will not need to "adjust the idle." If you do, then you need to "adjust your records."

    Before checking the barrel valve with a leak down gauge you need to make sure the throttle is returned to the correct closed position. In your records you should have already decided what you want for a butterfly gap and you are verifying you have it set correctly in the closed (idle) position in the first place.

    If you are using an Enderle style injector you need to check all openings top and bottom to make sure the butterflies are postioned properly (centered) on the shafts and that the butterflies have equal clearance (gap) on the top and bottom. Make sure the throttle shaft doesn't bind and the butterflies are centered left to right as well. Don't forget to set both sides of the injector evenly (limit screws) and check and secure the jam nuts. Sometimes the butterfly shaft needs a tweek to make it right as it can get a slight twist in it over time. Press on the face of the butterflies at the bottom once you are happy with your settings. With a proper return spring attached, there should be no movement on either side of the injector. If there is, you have more adjusting to do.

    I suggest leaking it down in real world conditions by going through the fuel system (lines attached to port and hat nozzles).

    If you've had the barrel valve disassembled and you are new at it I would remove the main fuel line off the front of the barrel valve and remove the line straight through to the rear of the barrel valve (Enderle K-style) so you can see through the spool inside the barrel valve once it is completely installed on your injector. When the throttle is shut you'll only be able to see through a small slot on the spool. As you open the throttle you'll see the spool rotate away inside leaving an open passage for the fuel to flow straight through. It is possible to get a correct leak down on an incorrectly installed spool (rotated and leaked on the wrong side). Problem is, when you hit the throttle while it's running, you open up the air through the butterflies but you shut off the fuel. BOOM!

    During the leak down process, once your happy with the setting, flash the throttle to wide open a couple times to verify the leak down target number returns when the throttle goes back to the idle position.

    One thing to mention if you leak the barrel valve with the hat and injector nozzle lines installed. Make sure you back the motor down or spin it over with the spark plugs removed to get any residual fuel out of the cylinders that may have been blown through the lines before you start it. Otherwise you risk hydro-locking your motor, or worse.

    Also, leak down testers have personalities. My leak down tester may or may not show the same leak down numbers as yours. I spent a lot of money making two leak down testers. I bought good quality identical industrial gauges and regulators in making my own and they are still close to 1.5% off from each other in the 75% to 85% range. I use one and keep the other hidden and available in case of an emergency (with comparison notes in the box). Leak down is critical enough to me that I don't want to run all over the pits asking to borrow someone elses if I have a problem, then having to hope and pray that the borrowed set up is giving me the same numbers as mine did.

    Keep in mind when you are discussing your favorite leak down numbers with your pals, their gauge may read differently than yours. There are a lot of reasons gauges can and will differ. Just because Mike or someone else says a certain percentage, your gauge may not read those same exact numbers. For that reason, take good care of your leak down tester. Once you have landed on numbers you are happy with, keep good records.
     
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    Last edited: Aug 6, 2008
  10. eli

    eli Banned

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    Randy, when you made your tester did you put a flowed .040 jet in between the two gages? :D
     
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  11. Mike Canter

    Mike Canter Top Dragster

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    Eli is correct in that there should be a flow calibrated .040" jet between the two pressure gauge sections. One way to check the accuracy of your leakdown tester is to set the pressure in at a 100 psi with a flowed .080" jet at the other end. You should read at 80% leakdown. All this is an industrial standard on leakdown test sets.
     
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  12. LeWhite

    LeWhite BB/Alt

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    I put a 035 hole in the port check poppett to dribble cause I don't trust the pie opening to distribute hat fuel properly at idle. Right or Wrong?
     
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  13. Sandracer695

    Sandracer695 Member

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    Something else to remember make sure your air supply will maintain at least 110# of air pressure and not go below. I have seen some one use a compressor that turned on at 85# and shut off at 115# and while he was leak testing the air was going down. Needless to say his leak test was wrong.
     
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  14. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    leakdown

    one of our advertisers, Machine Design Service, makes a very nice leak down guage that measures airflow, not %. I can't give you the specifics, but I just got mine and it is a very trick piece. It is designed to avoid irregularities such as different air pressures, compressors, etc., to give you an accurate reading every time.

    check them out at www.machinedesignserviceinc.com
     
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  15. Wardworks

    Wardworks New Member

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    Fuel return routing

    I know this is a different subject but can someone explain why you would run a fuel line from the pump relief check on the barrel valve back to the top of the hat line distribution block rather than loop it to the pump or return the fuel to the tank?

    Thanks,

    Ron
     
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  16. Mike Canter

    Mike Canter Top Dragster

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    You use a pump saver return like that on a Rootes blower so the blower continues to be lubricated and cooled after you let up.
     
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  17. J-Drag

    J-Drag T/C

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    Check PM

    LeWhite,

    Check your private messages.

    John
     
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  18. blown375

    blown375 New Member

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    I have seen this done before and I thought it was a good idea... I was going plumb my car like that, to keep the blower cooled and lubricated ,until a friend told me that you can run the risk of hydraulicking the engine if you plumb it this way. Any thoughts?
     
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  19. Wardworks

    Wardworks New Member

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    That is what I was told; thanks for confirming... so if I had a lencodrive with a safety sprag and the motor drops to an idle when I let off the pedal at the far end I wouldn't need it and I would also take a big chance of hydraulic-ing the motor correct?
     
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  20. Mike Canter

    Mike Canter Top Dragster

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    As long as the motor is spinning you will not hydraulic it with the amount of fuel being returned to the blower. Remember when you let up and the barrel valve closes then that shuts off most of the fuel or at least down to idle flow and then as soon as the motor rpm comes down and the fuel pump pressure drops back down to where the pump sizer poppet is set then that also shuts off.
     
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