stockhatch

iTrader: (12)

Ali, you can crankwalk with a push type clutch just as easily. I actually crankwalked a Ford 5.0 once with a heavy clutch and excessive dry cranking with no clutch switch bypass. When I showed my machinist, he said he has seen it in a few race engines with heavy clutches. He showed me how he modified bearings in domestic V8s to feed the thrust faces with more oil.

spoolxexo

iTrader: (4)

If being on an internet forum for a number of years means anything, it means nothing.

Let's quit the condescending remarks as well.

CW happens when the thrust bearing starts to move.

This can happen from shoddy assembly (USA DSMs), to incorrect torque values on the main caps, to machining the main bore, to oil galley starvation..

It seems only the 1st revision of these engines were the ones that had the fault, Toyota smartened up and made the correct revisions to the Thrust bearing and/or any other problem with the crank area.

This will mostly come up on older engines MKIII Supra/Mark II.

But most JZ guys are either doing Turbo N/A's, or getting their JZ from a mid-90's car so the problem happens less frequently with the newer design changes.

Heavy Clutches don't make Crank Walk they just speed it up!

P.S. Saying you've been a member of the supra community since 2000 is a really good way of saying you've been an A$$hole for a while! J/K ; )

Ali SC3

iTrader: (10)

well that seems to be settled now, do the clutch bypass if you have a heavy PP and/or unsprung disk, regardless of push or pull.

Where did the OP go?
I think we all need an update and progress pics of the 1.5jz

stockhatch

iTrader: (12)

Spool, that's not really accurate. The MKIV guys see CW just as much if not more than early 1JZs. Also, the thrust bearings in a JZ engine float, so your comment about the bearing starting to move doesn't make sense. The thrust bearings tend to move in a JZ because they are not attached to anything

blk&blu*j

iTrader: (1)

I guess I did something wrong by defending myself??????

NINJA EDIT.LMAO

Ali SC3

iTrader: (10)

I was talking about the push and pull thing being settled.
The most important thing is to know is that bypassing your start switch helps prevent your crank from walking away.
Its just so much nicer starting your car without having to push the pedal.
For example, my 85 toyota pickup doesn't have a clutch start switch on it. you put the key in and it starts.
IMO, thats the way its supposed to be.

stockhatch

iTrader: (12)

No doubt. If anything, I think they should have neutral detection switches in manual transmissions so that the car wont start unless its in neutral. That would be nice for the remote start guys too. It would suck to leave your car in gear and hit the remote start

99SC42

iTrader: (44)

I am so scare of crankwalk i don't even think about it anymore..

If you are on R154 and want 500hp no need for an act or RPS clutch the stock PP works great with nice disc.

I turned the boost down on mine and it's been working great , and i still push the clutch to start my car but i'll bypass it this weekend.

I am not sure how much power the stock W58 PP will hold , so those guys may not have alot options.

6 speed stock PP will hold 600 whp with HPF disc.

Ali SC3

iTrader: (10)

That really would be a nice feature. the answer is really simple though, don't leave your car in gear unless you are actually on a hill, and start the engine before putting the parking brake down.
for the rare occasions that I take it in to the mechanic, they always leave it in gear and if I forget, pretty much the parking brake will catch it and stall it out. gives you a good shock though!!

blk&blu*j

iTrader: (1)

+111^^^^^^^^^^^^^
But I would like to add that the HP is not what destroys trannys or clutches its the abrupt and sometimes violent Torque curves that are the deadly equalizers.

2jznosht

I read the thread title and thought this was a dsm thread...

1JZPWRD

iTrader: (59)

Bumped for a great read..

If I have done the starter bypass that Biggu demonstrated, do I still need to do the sensor mod behind the clutch pedal? Maybe a dumb question, but I wanted it to be very clear.

I have a lightened DM flywheel with a ACT Stage 4, six spring clutch. I have done the starter bypass, is this all I can do to POSSIBLY prevent this, besides leave it out of gear, and have the parking brake applied, and after I crank the car, pull down on the parking brake? Did miss anything?

Is it best to leave car in neutral and start the car W/O the clutch engaged???

spoolxexo

iTrader: (4)

Correct.

This way, you are not using pressure plate force, and in turn not moving the crank co-axially with zero oil pressure during start up.

The more lbs of force a pressure plate has, the more it will try to push the crank.

Pedal out, no force on crank/ thrust bearing, is less stressful during even a 0 psi oil pressure crank over comparatively.

Lots of racing sanctioning bodies require a neutral clutch switch however, so keep that in consideration.

1JZPWRD

iTrader: (59)

Thanks man for confirming this.

I keep seeing more and more of this issue it seems here lately. I just wanted to prevent all the measures that I could.

I did find this good right up on SF:

http://www.supraforums.com/forum/sho...-Documentation

Ali SC3

iTrader: (10)

If you were manual originally just take a paper clip and stick it in the clutch switch and tape it back up. then you can start your manual car even if its in gear. obviously you want to take it out of gear before you start it. remember there are 2 different clutch switches (one for start and one for cruise control) on 2 different places on the clutch pedal, you want the one closer to the firewall If I remember right.

If you were auto I guess you don't have those switches? you could probably wire up a switch somehow.

If you ever take it in somewhere where they are not smart enough to deal with something like that, temporarily remove paper clip.
the mechanics never seem to have a problem though they always push in the pedal when they start it so they pretty much never know its bypassed. Its when they leave it in gear and turn it off and I come around to starting it and I am used to not pushing in the pedal where it turns into a problem, but now I just remember to check if someone else has parked my car.