Cranking Pressure?

[art leong]

I just checked my cranking pressure with a compression gauge. And was shocked by the number (close to 300 pounds). The motor starts up fine without bucking. And seems to make good power, picked up 3+ mph over last years motor.
This years motor has 14.5 to 1 compression and 30 more degrees duration in the cam, than last years 12 to 1 motor.
Should I be worried about the high number?

[Chris "drooze" Wertman]

Originally Posted by art leong

I just checked my cranking pressure with a compression gauge. And was shocked by the number (close to 300 pounds). The motor starts up fine without bucking. And seems to make good power, picked up 3+ mph over last years motor.
This years motor has 14.5 to 1 compression and 30 more degrees duration in the cam, than last years 12 to 1 motor.
Should I be worried about the high number?

Holy smokes Art, last time I had that Crank Pressure was on a flat track bike that broke my foot when I was screwing around and wanted to start it "one last time" before I went to dinner (not wearing my boot).

I really dono. were at 220-218 on ours at about 12.5:1 so.....If that helps any.

[art leong]

I wonder if my hydraulic lifters are collapsing a bit decreasing cam lift and duration, when I test the motor. I almost can't believe the numbers. The motor starts to easy and runs well.
What does cranking pressure effect?

[Chris "drooze" Wertman]

Originally Posted by art leong

The motor starts to easy and runs well.

And runs records

Maybe this will help, I dont know if the calc is in Pipemax, I dont have it on this computer

http://www.not2fast.com/turbo/compre...pressure.shtml

http://www.chevyhiperformance.com/te...ion/index.html

[art leong]

Originally Posted by drooze

And runs records

Maybe this will help, I dont know if the calc is in Pipemax, I dont have it on this computer

http://www.not2fast.com/turbo/compre...pressure.shtml

http://www.chevyhiperformance.com/te...ion/index.html

Thanks Chris I saw those sites. Right now I'm wondering if there is something going on with my lifters. It just doesn't make sense that I could have such high compression numbers and stil have the car run the way it does.
The gauge is a brand new gauge so I'm going to borrow one and see if it is the same.

[Chris "drooze" Wertman]

Originally Posted by art leong

Thanks Chris I saw those sites. Right now I'm wondering if there is something going on with my lifters. It just doesn't make sense that I could have such high compression numbers and stil have the car run the way it does.
The gauge is a brand new gauge so I'm going to borrow one and see if it is the same.

What with your bore stroke and duration did it come to on the calc if you dont mind me asking ?

[Billy Nees]

Hi Art, cranking pressure CAN be affected by your lifters not pumping up. I would say that 300 psi is too much but then I was taught to try and keep cranking pressure "more than 160 and less than 210" and I could have been taught wrong. When I was running really high compression Bracket stuff (15 to1) I was only winding up with about 210 but I was using pretty big cams.
If anybody has any other opinions I'd like to hear from them.

[art leong]

Originally Posted by Billy Nees

Hi Art, cranking pressure CAN be affected by your lifters not pumping up. I would say that 300 psi is too much but then I was taught to try and keep cranking pressure "more than 160 and less than 210" and I could have been taught wrong. When I was running really high compression Bracket stuff (15 to1) I was only winding up with about 210 but I was using pretty big cams.
If anybody has any other opinions I'd like to hear from them.

Billy I tried retarding the intake cam 6 degrees (dropped the cranking pressure to 270)
It slowed the car up. Put the cam back and I got the power back.
I had to change the timing offset. when i retarded the cam.
Then I had a brain fart and forgot which program I had in there (there are 13 different fuel curves). It took me 5 runs to figure it out, wasting a test and tune day.

[Billy Nees]

Art, did you check it with a plugged lifter yet?

[art leong]

Originally Posted by Billy Nees

Art, did you check it with a plugged lifter yet?

No I have just come to the bare fact that it it's running right don't mess with it If you do You will find something wrong.
The motor is making great power I still am close to getting in trouble with me shifting 1500 short. Even I am wondering "where the turbo is hiding"LOL
I seem to have worried myself silly (something I'm real good at) for a couple of weeks for nothing.
It's like the movie Dr Strangelove, or How I learned to stop worrying and love the Bomb.