Chevy Nova Forum banner

1 - 20 of 30 Posts

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #1
My best-ever N/A pass was a few weeks ago with a 12.48 @ 106.11 mph with a 1.70 60ft.

The setup for that weekend was: Caltracs in bottom hole with 1/2 turn preload, 14# in the tires, left on the converter @ 3K. shift @ 6K, and open headers.

Yesterday (weather nearly identical), I put the exhaust back on the car (which weighs 30#) and I ran 16# in the tires, Caltracs in bottom hole with no preload (1/4" gap). Everything else was identical (carb settings, timing, etc).

It ran 12.51 @ 106.67 mph with a 1.717 60ft. What's interesting to me is that I have more MPH with a slower 60ft. It could be that the motor likes the full exhaust (more mph), but the additional 30# slowed me down .03...

Also glanced down at the gauges going through the traps on the last pass yesterday and saw the oil pressure gauge sitting on the peg at 0 :eek: It's an electric gauge, so I'm hoping it's something pertaining to that. The oil pressure was fine on the previous passes.
 

·
Registered
Joined
·
1,879 Posts
Did you hook good on the 12.51 run? Maybe you have a 1.66-1.68 60' in there with that faster MPH.:)
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #3
Repointer said:
Did you hook good on the 12.51 run? Maybe you have a 1.66-1.68 60' in there with that faster MPH.:)
If I spun, I couldn't tell. Next week, I'm gonna try bringing the motor WAY up on the converter and see how she likes that!
 

·
Moderator
Joined
·
3,863 Posts
I bet you pumped all your oil into the top end and uncovered the pickup.
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #5
72VenturaII said:
I bet you pumped all your oil into the top end and uncovered the pickup.
The gauge is getting 12v to it and has a good ground. I wonder if the sending unit can go bad?
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #7
teddisnoke said:
You did not say if the oil pressure came back to normal after the run ? CAr's running pretyy well though, huh?
The needle is setting on the peg below 0. It's not making any new noises!
 

·
Moderator
Joined
·
3,863 Posts
A new piece of information. Gauge still pegged at 0. Your first post implied that it was at the big end where it occurred. I would think that you could rule out the guage or sending unit with a multimeter with the car off and running and comparing at the sending unit and the guage. You are sure there is oil in the car aren't you?:eek: ;)
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #9
72VenturaII said:
A new piece of information. Gauge still pegged at 0. Your first post implied that it was at the big end where it occurred. I would think that you could rule out the guage or sending unit with a multimeter with the car off and running and comparing at the sending unit and the guage. You are sure there is oil in the car aren't you?:eek: ;)
Yeah, there's still oil in the motor. The gauge may have been at 0 earlier, I just happened to glance down going through the traps. How do I test the sending unit?
 

·
Registered
Joined
·
232 Posts
If it reads "Zero" try another unit, no testing needed. Most important Dave, is ya need a oil pressure safty wired thru your coil with a bypass switch for start up. Then ya don't have to worry so much. Mine shuts the motor down if oil drops to 7psi, it might save ya some parts=money!!!!
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #11
63SSNOS said:
If it reads "Zero" try another unit, no testing needed. Most important Dave, is ya need a oil pressure safty wired thru your coil with a bypass switch for start up. Then ya don't have to worry so much. Mine shuts the motor down if oil drops to 7psi, it might save ya some parts=money!!!!
Good point and good tip! :)
 

·
Registered
Joined
·
362 Posts
Hey Dave, sounds like if you run uncapped again, you will be about .1-.15 faster.. As far as oil pressue. My car holds 60 cold, 35 hot, when I go through thr traps at 7000 its at 60. Then the instant I let off the gas the pressure always plumits (usually down to about 20-30 for a second or 2). I have been told its cause by the oil being swished out of the rear sump when the car stops acelerating. But if you pressure does not come back right away or remains at 0, I would think you may have dropped the pickup off the pump. That is a somewhat common occurance.
 

·
Registered
Joined
·
132 Posts
If the pick up fell off, that could explain the higher MPH with mufflers on your last run. Oil pumps are easier to turn without oil running through them.:eek:

I hope you find out the problem.
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #14 (Edited)
MelloYello said:
If the pick up fell off, that could explain the higher MPH with mufflers on your last run. Oil pumps are easier to turn without oil running through them.:eek:

I hope you find out the problem.
The pass with the best MPH was my second run, not the last pass. If I pull the distributor out, remove a valve cover, run my priming tool (maybe for 15 seconds or so) and see oil continuously coming up through the push rods, I would think that would mean the pickup is still in place, right?!?!
 

·
Premium Member
Joined
·
1,562 Posts
Dave,
That wont tell you if the Pickup is still attached.If you have it Full of oil the Pump will be under the oil Level Setting still.You would have to have a poor return system to hold all the oil in the top of the engine spinning with a drill.
Joe
 

·
Premium Member
Joined
·
1,562 Posts
Maybe you could put just a couple inches of oil in the pan and see if it picks up.Did you Tack Weld the Pickup tp the Pump during assembly?
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #17
Joe said:
Maybe you could put just a couple inches of oil in the pan and see if it picks up.Did you Tack Weld the Pickup tp the Pump during assembly?
I didn't assemble the shortblock that's in the car. However, the pickup is welded to the pump. It will be easier to try a different gauge or sending unit first.
 

·
Premium Member
Joined
·
8,405 Posts
You may have a bad ground but I don't recommend not using an electrical oil gauge on a drag car.
I'd run an Autometer mechanical pressure gauge with direct -3 or -4 braided line.
 

·
Premium Member
Joined
·
13,245 Posts
Discussion Starter #19
Paul Wright said:
You may have a bad ground but I don't recommend not using an electrical oil gauge on a drag car.
I'd run an Autometer mechanical pressure gauge with direct -3 or -4 braided line.
That's what I'm literally looking at as we speak. The gauge's backlight is working, so the ground must be OK.
 
1 - 20 of 30 Posts
Top