FrontEngineDragsters.Org Forum
Technical => Spud Miller's Cave => Topic started by: Pat Johnson on July 31, 2017, 10:45:34 AM
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Hey Spud, I have some concerns about the nozzle set up that you helped me with last year, I am having too change my oil every other pass, too much alcohol in the oil, we put in 29 nozzles, all I do is seem to flood the plugs and oil with an excessive amount of fuel, need some direction for this issue, please help.thank's Pat, need too order what ever we need today, Please call me so we can handle this problem, thank's.
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Lean out the barrel valve
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We set our barrel valve with a cycl leakdown meter, @ 18%, on my raised runner iron SBC, no problems with milkly oil. We have also found with non raised runner 23° SBC heads might be even leaner.
Leaner BV helps build heat in an alky burning motor, I like getting my water filled SBC to get to at least 180° as we stage, and it gets up to 200-220° at the turn off. Alky burns better when the engine is hot.
Jon
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Agreed on the BV %. I tend to end up around 16-18 on injected sbcs. Rarely milks the oil. Warmups are the oil killers. Once it's at operating temp, the oil should stay clean.
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When warming up, trim back on the fuel shut-off till the RPMs start to go up and keep it there till the temp is where you want it, no milking-faster temp rise-less fuel consumed-does not hurt a a xxxx thing by idleing lean. Switch back to full pump, check to see it comes off idle clean, shut valve off to kill motor--- wait for call to the lanes.
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Ya, we warm-up the same, Don Enrquez , does the same and more when he comes back from burn-out, Bob McKray pulls the fuel shut off a bit until it's popping & banging to get the temp he looking for.
When we ran our non-raised runner 23° SBC , Bud, the driver, would pull the fuel shut-off part back while backing up, but you have to know where and how much to pull it back otherwise you can kill the motor. Just try it out while you are warming up the engine in the pits. One of our JF buddies from OK would put a cut MC fuel line over the choke cable type wire so he would safe, and then when backed up, take the hose off.
Yes engine temp is a big deal, I know some 7.60 braket racers that will very their engine temp to get real close to 7.60. If they ran 7.55, then they leave the line with a cooler temp on the next qualifier.
Have FUN,
Jon
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1. Lean out the barrel valve, most of the fuel wasted is idle and low RPM. Lean it down more with fuel shut off to warm it up. Pull the handle enough that RPM goes up to around 2400 RPM and toggle off and on the water pump until water temp is up where you want it.
At the end of the day your oil may still be a little milky no problem. Before you put it in the trailer pull fuel shut off and get water temperature up well over 200* and the water will evaporate right out of there and oil will clear right up. If you do not have a vacuum pump then pull breathers off to let moisture out.
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As has been stated already, fuel in the oil is mostly from a rich idle. Adjust the barrel valve hex link...making the link shorter is leaner, longer is richer.
The 29 nozzles you were setup with were suited to your engine size and RPM range and were flow matched within 1% of each other for you...critical for good performance on a naturally aspirated system. Please see the nozzle report supplied with your system. The small nozzles you purchased last week were NOT flow matched...they were the regular nozzle jets right out of the bin at Enderle. They can and do vary a bunch right out of the box.
When we set up a naturally aspirated methanol system on the bench, we use 7% of the engine size for a leak-down percentage to get started. As long as the main check valve (the check valve that the main pill blasts through) is set to 1-3 PSI, then that will make the motor start and idle and be a touch rich...ON PURPOSE. It must be fine tuned from there by the customer for idle temperature (350-450F) and good throttle response. We set you up with a 3 PSI idle check valve and 30% leak down for your 420" motor. It was intended to be a few percent rich. You MUST adjust it from there! If your idle check valve is set to a higher pressure, the leak-down percentage required will be MUCH lower. Set to a lower pressure, the required leak-down will be higher.
If you change nozzles, it will completely change the main pill required as well as the high-speed check valve pressure.
Spud