Blown06

iTrader: (32)

I've never done this, but have heard that unless the trans is modified to do so that it can destroy the trans.

I'm asking this question in relation to the 4l60 and 4l80 transmissions. I would like to do some plug reading on a few cars that I'm working on and was wondering if this was safe. Does idling to the turn off and shutting off as soon as I hit the return road change the fuel ring enough to make a difference? I would assume the timing mark wouldn't change much.

So, should I:

1. Shift the trans to N and kill the motor.
2. Leave trans in OD and kill the motor.
3. Just wait to kill the motor after I've turned off the track on to the return road.

tektrans

iTrader: (23)

This is straight off Rosslers website:
3 speed and overdrive transmissions: Caution never shift into neutral position at high speeds. This will cause internal components of the transmission to rotate 2 and ½ times faster than your finish line RPM. (Example, If your car’s finish line RPM is 7,500 RPM’S and the Transmission is shifted to neutral then the internal components will spin at 15,000 RPM’s THIS IS VERY DANGEROUS! The parts are spinning so fast, they can explode, turning your transmission into a shrapnel type bomb possibly causing bodily injury and death.

I just drive off the track back to the pits. Faster guys pull of to the return road and kill it there.

z28rob18

iTrader: (7)

this only apply to automatics or 6 speeds too?

JL ws-6

iTrader: (50)

I wouldn't shift ANY 4 speed into neutral at the end of the run, pull off the reaturn road, click the key off and do what you have to.

6 speed it doesn't matter you can throw that in neutral and turn the car off (no power brakes/steering) There's no drums and the like that will start spinning like mad that you need to worry about there.

Blown06

iTrader: (32)

Can I kill the motor the second I lift off the throttle, or could that cause possible trans damage from the pump not spinning?

Just trying to get a plan for the most accurate plug reading.

JL ws-6

iTrader: (50)

I've heard both ways on that, but I have been killing the motor at the top end of teh track for years and NEVER had a problem..... depends who you ask.

tektrans

iTrader: (23)

You cross the traps at 7000+rpms, you just worked your motor to the max, everything is hot, those piston rings are real hot too, you shut it down and those hot rings just sit it one spot instead of moving up and down in the cylinder dissipating heat as the motor comes down in rpm.
It's not like we are tearing these down after a pass like the pro's or anything, I just let the motor run and drive back to the pits. If you're hot at least take it to the return road under power and shut it down there. JMHO.

JL ws-6

iTrader: (50)

Only problem with that is if you're really trying to get an accurate read on a plug, you won't get it if you don't click it off.

Beleive me I understand what you're saying, but I think running a tune that's off will probably run the risk of damaging parts worse then shutting it off.

Once you get the tune right, shutting it off once you're on the return road and pulling a plug, just to make sure everything's the same is probably fine.

mrdragster1970

.

I click my engine also. Not the split second I cross the line, but shortly after.
As long as the engine winds down, it's still turning the trans pump,
and I don't worry about anything binding in the engine.
We read all 8 plugs every pass, and as mentioned,
you don't want a bunch of fuel washing out the readings.

You definitely don't want to shift after the lights.
It doesn't happen a lot, but it only takes once to ruin your day, and car.
I got into the habit of throwing it in neutral one season for some reason.
My trans guy knew immediately I had started doing it when he opened it that winter.
He called and bitched me out, so I stopped immediately.

Leave it in gear, and don't risk grenading shrapnel.

.

Blown06

iTrader: (32)

Thanks for the info guys