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Ex-hardtopper
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^^ +1 and alot of it depends not only on the car's setup, but the drivers habits as well.
 

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1993 Car
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^^ +1 and alot of it depends not only on the car's setup, but the drivers habits as well.
Such as?

I've got an ACT PP with HPF disk. Is there really any connection between crank walk and single disk clutches, or just the usual internal BS that gets blown out of proportion?
 

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Ex-hardtopper
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Such as?

I've got an ACT PP with HPF disk. Is there really any connection between crank walk and single disk clutches, or just the usual internal BS that gets blown out of proportion?
such as not doing the clutch switch bypass and constantly pushing the clutch in on cold startups. Also, some people love to sit at stoplights with their clutch pedal in, which doesn't help since oil pressure while there, is relatively low in most cases. I had the HPF feramic clutch with ACT pp and mine crankwalked.... while I did not have the clutch bypass done, I did not do anything out of the ordinary that i believe would have contributed to my crankwalk. Here is a pic of my thrust bearing that got wedged between the crank and #4 main cap.



 

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1993 Car
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That is unfortunate.

I'm trying to learn more about what causes CW, as well as what prevents it effectively. I'm willing to buy a twin-disk, but before I spend $2500 I want to know that is actually the solution to the problem. I'm wondering if the switch bypass and an Accusump would solve the problem?
 

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That is unfortunate.

I'm trying to learn more about what causes CW, as well as what prevents it effectively. I'm willing to buy a twin-disk, but before I spend $2500 I want to know that is actually the solution to the problem. I'm wondering if the switch bypass and an Accusump would solve the problem?
Ck,

Years of posts on this subject can be summarized into the following guidelines:

1). Disengage neutral bypass switch first and foremost.

2). Absolutely purchase a twin or triple (have a carbonetics triple which is LOUD due to the open bell housing but is OEM like, RPS has worked out the kinks in their design and I've driven a Supra with an RPS triple and it feels even better than the carbonetics). The Supra was never designed for a single plate heavy clutch. Divide that force and inertia with multi plates and the pressure increase on the crank is negligible compared to OEM. Also with the clutch out, take the time to gauge the current health of your thrust washers by getting the car on a lift / jackstands and apply forward and rearward pressure on the flywheels with a micrometer on the front of the car on the crank bolt to detect any play. Don't listen to anyone who says if you can't "see it" move you're good. Toyota spec is 8-11 thousandths of an inch. A telltale sign the crank is out of spec, at least on mine (mine was over 50 thousandths of an inch) is scoring on the back of the plastic timing belt cover).

3). Driving habits like going to neutral with foot off the clutch at stoplights will ensure a good oil seat.

Good luck!
 

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1993 Car
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I appreciate the guidance! I JUST got off the phone with Dusty from MVP. I'm going to be picking up a twin or triple as soon as I am able to. I'd rather put up the $2600 now than the rebuild/downtime (+the twin) later.
 

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Racing is Life.
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So, now that my stomach is in a knot, I have an RPS Stage 3 6 puck disk with the blue pressure plate. It looks like reading from this thread that even if I use a switch to disable the clutch pedal switch that it'll still crank walk when I do high rpm shifts. This is crazy. Why would reputable sites sell things that actively damage our built motors? I gotta clear this up with some folks..... I'm pretty upset reading about this.
 

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Wow you just realized that?lol

I've lost 4+2jZ engines using act clutches.

All my cars were originally auto converted to manual so no need to push the clutch to start it up and I put it in neutral whenever I come to a stop sign or light..

I will drive my car on the stock Toyota pressure plate before I use Act, Spec Or rps single disc in my cars.
 

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Racing is Life.
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Yup, had no idea a simple clutch could do something like that. And apparently judging by your experience the switch doesn't do crap for it. Nor does not using the clutch sitting at idle. I bet I've already done the damage..... FML. Now I don't want to drive my car until I get a twin disk. So what's the irrefutable way to fix this? Which clutch? RPS CC? Clutchmasters 850? OS Giken twin or triple? TILTON? I also don't want my car to chatter and sound like an aluminum can full of ricks while I sit at a street light, and I need it to be able to hold the power I'm making.

Or is there something that can be bought to beef up these snap rings in the motor?
 

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I would take the twin or the triple disc rattle over the the quiet single disc that will destroy your $7k-$20k motor.

Seem like you have alot of money in your setup, I would get twin disc if I were you.
 

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Racing is Life.
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k, which one? That's the next dilemna. Every person I ask I get a different take on it. Kinda like, take a guess! Yes I have way too much into this lol
 

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OK. I would like to do a short summary for those of you who are asking how to tell for signs of crank walk.

Extremely small crank walk WILL NOT be noticeable.

Moderate crank walk can be found by:

1. Observing the Harmonic Balancer when the engine is idling. Have someone push in the clutch and observe any forward or back movement (thrust). Any movement forward or back is respective to the type of clutch on the car (push or pull type). If it's an automatic, you can put the car in drive, hold the brakes, and rev it to stall speed. If any visible thrust is present, the crank is walking. Do the same procedure with the engine off, transmission in neutral. This is why I say that minor crank walk will not be noticeable. Nobody can see .005" of thrust with their eyes.

2. Once the vehicle has warmed up, push the clutch in while idling. If the engine drops in RPM, begins to stumble, or sound like it's working harder, the crank is walking.

3. With the engine idling, lightly depress the clutch. Do not fully depress it. Just when it begins to engage, feel for any awkward vibration or pulsation. If you feel some, more than likely the crank is walking. This in some cases can be confused with a bad throwout bearing.

Heavy crank walk will produce:

1. Extreme load when clutch is depressed, resulting in severe drop in RPM or engine stall.
2. Major pedal pulsation while engaging clutch
3. Metallic oil
4. Very visible harmonic balancer thrust either forward or backwards. (again, push or pull type clutch)

It is worth noting that even moderate crank walk can result in catastrophic engine failure. At this point, the engine should be thoroughly inspected.

What is happening ECACTLY? Well, in short summary, the engine is wearing itself to death. Engine internals are not meant to experience much lateral thrust. A tiny bit (.005) is normal, however once the thrust washers wear to the limit, the connecting rods begin to "bind" by going up and down at an unintended angle. This causes wear to the face of the connecting rod and crank journal. The crank will also wear at the main journals. (see page one for pictures of the main cap worn entirely) Rod bearings will wear to one side or the other, with respect to the direction of the thrust. At this point, the engine has begun to wear catastrophically. Eventually the thrust washers will have worn so thin that they will fall right out of their positions on the face of the main and cap. Once this happens, the crank will walk forward and backward only to the limit of the angle the connecting rods can sustain before they either fail, or the engine stalls. When this happens, like it did in my case, absolutely NOTHING in the block is reusable. The walk was so bad, the timing reluctor (or timing pulley attached to the crank as most call it) was wearing into the face of the oil pump. Furthermore, if you look at page one, you can see a pile of bent thrust washers sitting in a pile. While making the last drive home before the engine failed, I actually heard one of the thrust washers fall out of its' slot and get thrown around in the engine by the crank. It was a very faint pinging that lasted for about 3 seconds. That explains why it twisted and contorted.

I hope this helps all of you. Bypass that clutch switch!!

Sincerely,
Ki11bert
My engine drops about 200 RPMs from 900 to about 700. I was told this was normal, but seems to me that I was lied to and my crank is starting to walk. What can I do (short of pulling out the engine) to check for crankwalk. Doesn't help that I JUST finished getting my brand new ACT HD PP with 6 puck in also.
 

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ELITECUSTOMBODY
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My engine drops about 200 RPMs from 900 to about 700. I was told this was normal, but seems to me that I was lied to and my crank is starting to walk. What can I do (short of pulling out the engine) to check for crankwalk. Doesn't help that I JUST finished getting my brand new ACT HD PP with 6 puck in also.
Have someone press the clutch while you're looking at the crank pulley. If movement is visible,drop lower oil pan , most likely thrust washers are worn down and halfway out.If you haven't had FMS leak yet , it's bound to happen any time.20k miles on brand new Toyota short block with stock clutch, 4k on ACT yellow PP,cranking car up ,sitting at the light with clutch pushed in killed my thrust washers ,took a chunk of piston on it's way out.
 

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Have someone press the clutch while you're looking at the crank pulley. If movement is visible,drop lower oil pan , most likely thrust washers are worn down and halfway out.If you haven't had FMS leak yet , it's bound to happen any time.20k miles on brand new Toyota short block with stock clutch, 4k on ACT yellow PP,cranking car up ,sitting at the light with clutch pushed in killed my thrust washers ,took a chunk of piston on it's way out.
Alright will do thanks for the info, do I have to replace more than the Front main seal and thrust washers also? I'm planning on just changing everything out just to be safe, but a short block is a bit much.

So I dug around threads for a few hours and here's what I came to. Front main seal, ACL thrust washers. Check crank for damage, and if you want to be safe replace rod and main bearings.

I've read somewhere of people using 2jz-ge bottom ends, can I do that too with my Aristo 2jz-gte?
 

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I lost 2 cranks due to crank walk with a super single disc clutch. I just spent the money on a tilton so I will see how this works out. This crankwalk issue for me is becoming very expensive and a royal pain in the ass!
 

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Just to bring an old thread up from the dead: has anyone come up with a better thrust washer design, material, install, or a way to notch the block, or some other method of preventing crank walk?

Fuck, I could just put an external plate with a bearing and a shaft that bolts to the chassis that will limit the crank motion toward the front of the car!
 

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I used the ACT Xtreme PP for a number of years with no crank walk issues. I believe that Jack's Transmissions has the real reason why this occurs.

http://www.jackstransmissions.com/pages/crank-walk

"On another note, people seem to think that heavy pressure plates cause crank walk too. I found that to be untrue. If your engine is going to walk, it will walk with a factory clutch. I have seen 7-bolts walk in factory OEM trim and even with automatics. Thrust pressure has nothing to do with it, it's a lubrication issue. If you have no oil reaching a bearing, it's toast."
 

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Last year I put a brand new built block in running an rps carbon carbon clutch. After about 2500 miles the crank started to walk. Lucky enough for me I got it back to the shop in time . No damage to the block. The machine shop who built it put some sort of retrofitted pin in so the crankshaft won't walk ever again. I'm not sure exactly what they did but if you call mike at e -shift performance he is the owner of the shop I use, he can tell you what the machine shop did. 7325539301 my name is mike btw and it's the 94 red tt auto to 6 spd swap. If I get in touch with him I will try to post the exact directions. Btw the compression is 150 across the board after this incident. No smoke and runs beautifully so it is possible to catch it in time
 

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I guess I get to join the club... ACT Extreme PP (r154) and a lightweight 1jz flywheel < 500 miles after install. Happened on a high rpm shift into 3rd.

I had ran a slightly lower clamping force Spec clutch before this setup for some time without issue.





Crankshaft thrust face has a slight grove from thrust washer spinning/spiting out.

#4 cap and block show slight damage to lip intended to hold the thurst bearing in place. Seems minor, but enough for the crank to become a paper weight and the block a coffee table (fml).
 
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