Drag Racing Discussions > Front Engine Dragsters
Correct starting & shut off procedure of a blower motor
32bantam:
No one has mentioned preheating the oil on the first startup for the day.
Easier on the pump....gets everywhere quicker.
dreracecar:
Some of us don't need to because it doesn't get that cold and the engine diaper act's as a jacket, only a concern of running fresh 70wt
fuel749:
--- Quote from: Draw 3D on February 28, 2017, 07:53:38 PM ---
--- Quote from: rooman on February 28, 2017, 05:00:55 AM ---Draw3D,
all that coupemerc is suggesting is to get the oil through the motor before attempting to start it. We use exactly that procedure with Mark Vaught's 7.0 car. Roll the car out of the trailer and get it up on the jacks, pull the plugs and spin the motor until we see oil pressure. Put the warm up plugs in and fire the motor--with the galleries etc primed there is sufficient oil pressure by the time the engine lights off the squirt bottle and then begins running on the pump. We then switch to the race plugs and fire the same way on the line. Once the engine has been spun to get oil pressure the first time each day there is no need to spin it for more than a couple of seconds to get pressure and it takes that long to light anyway.
Roo
--- End quote ---
I think he is using a block mounted starter like I am and a block mounted starter turns the motor at a slow rpm and pushing 60 wt oil takes more than a couple of seconds to build up pressure.
I have a pretty good starter and it turns the motor over at between 250 to 300 rpm, that means my oil pump, which is internal in stock location, is turning at 125 to 150 rpm and if you spin for a couple of seconds, it will see 5 revolutions and on my system, it will not buildup to any usable pressure.
I don't start my motor until I see at least 25 psi oil pressure, I would much rather have a dead battery than a dead motor.
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We use a basic Summit brand block mounted starter but crank it with 24 volts...gets oil pressure quicker as well as get fuel moving from the pump. Most of these starter solenoids are rated at 36 volts, if yours isn't they're easy to come by. The actual starter motor itself is happier because it sees less load. If you're cranking with two batteries and they're not wired in series it's well worth a try.
As for oil pressure, I crank it with the plugs out in the morning before first fire up. After that I give it about a 3 count of cranking then fire it. Oil pressure comes up immediately.
nostalgic371:
--- Quote from: dreracecar on February 26, 2017, 04:18:07 PM ---Just before starting, should put a long ratchet in the top pulley a back the motor down to clear the cylinders just in case. Brings up another point, if you are using a block starter and not a blower starter, you should at least have the blower starter mount and drive dog installed. When the block starter fails, there is a chance to borrow the remote blower starter and fire the motor
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I'm sure its never a bad idea to back a hemi or any other motor down, but how effective is doing it on a wedge type combustion chamber? Would turning the engine with out spark plugs be an alternative?
rooman:
--- Quote from: nostalgic371 on March 05, 2017, 05:50:38 PM ---
--- Quote from: dreracecar on February 26, 2017, 04:18:07 PM ---Just before starting, should put a long ratchet in the top pulley a back the motor down to clear the cylinders just in case. Brings up another point, if you are using a block starter and not a blower starter, you should at least have the blower starter mount and drive dog installed. When the block starter fails, there is a chance to borrow the remote blower starter and fire the motor
--- End quote ---
I'm sure its never a bad idea to back a hemi or any other motor down, but how effective is doing it on a wedge type combustion chamber? Would turning the engine with out spark plugs be an alternative?
--- End quote ---
Exactly. On any engine where the exhaust valve is well above the bottom of the chamber (as opposed to a hemi where it is generally at the lowest point) spinning the engine with the plugs out is the best idea. This is especially critical on a fuel burning motor where any residual fuel may have a catastrophic effect.
Roo
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