Tranny neutrals on hard left

[jeffcoslacker]

I've seen this on here before, I could probably search for it, but feeling lazy.

Not worried, just curious. This car has always done it.

Taking a real high-G left turn, and stomp down to downshift and really pull outta the corner, and it drops out completely instead of downshifting, making the engine RPM flare alarmingly.

What the hell does that on these ('97, 3.1)? It's pretty rare, happened maybe 3-4 times in the 118K I've put on it. Only when I drop down on it to the floor in a hard left. Right turn no effect.

I'm guessing I'm just G-forcing the fluid outta somewhere it needs to be, but with so little "slosh area" in these, and the correct level, I'm suprised it can happen.

[dwalmop]

Hmmm! I might have to go try to get mine to do this tonight. It sounds kinda fun - my tranny's never done that to me.

[jeffcoslacker]

Not fun - don't grenade the motor

[dwalmop]

yeah I know - but it's fun to go out and give it a workout sometimes!

[jeffcoslacker]

Originally Posted by dwalmop

yeah I know - but it's fun to go out and give it a workout sometimes!

Yesterday when it did it, I had my eye squarely on the tach, cuz I was wondering what kinda revs it hits when it double-downshifts on a good hard stomp. I was in an outside double left turn lane, coming onto a highway on ramp. When it let go, it bounced off the limiter a couple of times before I got my foot off the pedal, saw the needle jump over 6000

I hate hearing a motor free-rev. When I was about 18 or 19 I had a '68 Bel Air Custom with a 396, I had the carb off for a rebuild, and the thought struck me, "Can a motor run without a carb?"

So I splashed a little gas in the intake plenum, and hit the key. It instantly buried the tach, it may have hit nine or ten grand for all I know. I shut it off right away, it still took about 10 seconds to wind down. I'll never forget that sound. You know the hollow bellow of the secondaries opening on a four barrel carb? Multiply that by about 10x and you'd be close. I'm suprised it didn't suck the asbestos blanket off the underside of the hood.

Damn lifters clattered for days after that. Guess I was lucky they weren't buried in the walls and ceiling of the garage! An amazing amount of carbon came out of the exhaust onto the ground. Two big black circles stained the floor, a permanent monument to curious stupidity.

[jeffcoslacker]

A friend took me with him to a party at a machine shop (!) once. This guy owned it, and lived there. Talk about a guy amusement park. We watched him do things I've never seen before. He fired up a plasma cutter and cut a diff housing like butter.

He showed us rifles he'd made, we played with welders, and he had all kinds of performance stuff goin' on. He had a contract with McDonnell Douglas (now Boeing) to machine some very intricate stuff for aircraft, sweet deal, it paid the bills and left him with tons of time to play.

He started talking about his '68 Cutlass that he'd built. Bored and stroked ol' Rocket 350, he'd machined most of the parts himself, with an emphasis on low reciprocating weight (light rods, pistons, valves, etc) He claimed it could run, unloaded, at 7500 RPM all day.

OK, I had to throw the bullshit flag at this point. So we go out into the frigid night, and he starts it up. Amazingly crisp, cammy sounding motor. That crackle that only very high compression gives you. He let it warm up until the water temp was normal, snapping the throttle every now and then to keep it from loading up, and it would just bark, instantly returning to it's lumpy idle.

Then he put his foot down on it, and took it to just over 8000 RPM. The sound was deafening, like when a top fueler leaves the lights. He just sat there, casually finishing his beer while it screamed, never misfiring, for at least 30 seconds. Then he dropped the pedal, and it went back instantly to it's crackly off-cadence idle. The sound of it sceaming it's head off echoed around the valley in the cold air for many seconds after.

I knew then that this guy was a performance God, and not to doubt him again.

I still get chills when I think about that sound. It was awesome.

[dwalmop]

you gotta love the sound of an engine performed to run at 8000, AT 8000 rpm. Speaking of overrevving, my first car was a 79 cutlass, with a 4-barrell quadrajunk carb. I was at a stoplight when suddenly, the engine rocketed beyond points I never thought it could ever reach. After I shut the car down (it took seemingly about 10 seconds, also) and towed it away, the problem was a sticky accelerator pump. I have no clue what rpm it actually reached, because the car didn't have a tach. But I was amazed it survived, since that tired of chevy 305 had about 330,XXX miles on it at the time.

[jeffcoslacker]

Originally Posted by dwalmop

you gotta love the sound of an engine performed to run at 8000, AT 8000 rpm. Speaking of overrevving, my first car was a 79 cutlass, with a 4-barrell quadrajunk carb. I was at a stoplight when suddenly, the engine rocketed beyond points I never thought it could ever reach. After I shut the car down (it took seemingly about 10 seconds, also) and towed it away, the problem was a sticky accelerator pump. I have no clue what rpm it actually reached, because the car didn't have a tach. But I was amazed it survived, since that tired of chevy 305 had about 330,XXX miles on it at the time.

I had an old '75 Ford Country Squire wagon with a 460 4 bbl, I stomped it to pass a dump truck on the highway, and the throttle return springs broke.

Got stuck planted on the floor with the secondaries open, passed a state trooper going about 75 and accelerating hard. Showed him what happened, got a ticket for mech defect.

[tblake]

thats amazing, 8000rpms? from a GM 350? and I had no idea that a motor could run without a carb. Gas itself isnt flammable, its the fumes it puts off, or so I thought. I thought the job of the carb was to sort of ionize the fuel, sort of like todays injectors. Not to make you (jeff) sound like a liar, you know a hell of a lot more than I do, and I dont doubt it would happen, I just am curious about it now, and also would like to hear any more stories that you can throw my way. I love this forum. You guys are the best.

[jeffcoslacker]

You are right about that, blake. I will elaborate. The carb on the old cars was very simple, not having the tangled mass of vacuum lines and sensors they had near there final demise, you could yank one off in 30 seconds if you were familiar with it. Four nuts and the throttle linkage. Three, maybe four vacuum lines. Which is exactly what I did, having just got off work and going by the parts store to pick up a rebuild kit for the carb. It was summer, so the engine was still quite hot when I started working.

Ever pour gas on something hot by accident, and watch the cloud of vapor, praying to the god if ignition sources that nothing arcs near you?

When I dumped the fuel into the plenum, it did that, filling it with a dense fog of fuel vapor. That's what it was actually feeding on. If the engine had been stone cold, the result would probably not have been as spectacular, if it even started at all.

There is a guy in the country around here who has been in the paper before, claims he runs a 1974 Plymouth Fury with a 360ci V8 off heated gas vapor, and gets 60-70 mpg with it. In his system, no liquid gas ever enters the carb. It has an element that does exactly what I desrcibed above to the fuel, and the vapor is drawn in with the air charge.

He had to convert the heads to hardened valves and seats, since it is essentially a dry-charge intake now, like a port fuel injected motor, there is no quench effect from fuel being drawn over the intake valve face, so they run hotter. Same happens if you convert a motor for propane, hydrogen, etc. Atomized fuel droplets are a great cooler, and contact with the hot metal further conditions the intake charge, taking the fuel from droplet to vapor form, making it more combustible. But with nothing but vapor or gaseous (like propane) intake charge, the valves run hotter.

A lot of people doubt his claim, but I have reason to suspect he is onto something. There is probably some bugs in the delivery system, and it might not work well in all conditions. I would think proper mixture control would be hard to maintain over a wide variety of throttle positions/demands. But I hope he is able to make something useful from it.

Then, like the old stories, the oil companies will have him killed and bury his system in the desert.