baconbomb

recently finished my 1j swap and went to drive it and noticed that when the clutch is pushed in the engine bogs down and eventually dies depending on how far the clutch gets pushed in. I was reading up on stuff and sounds like it could be crank walk.

I went out and looked at the harmonic balancer when someone stepped on the clutch and the harmonic blanacer had noticeable movement. Am I correct about whats going on. Is it crank walk?

If so what is the best way to go about fixing it. I was thinking about doing a 1.5j using me GE block. But what extra parts are needed for that. Ive read you have to get GTE pistons? Anyone know anything about this?

stockhatch

iTrader: (12)

Yep. Sounds like crankwalk. I think the 1.5JZ is a good idea. You may not have to get GTE pistons. Do some research, as I am not sure what the CR will be on GE pistons. I know Biggu is running GE pistons, but he also is running E85, so CR is not a big deal like it will be if you run 91/93 pump.

Biggu

iTrader: (12)

Correct but I also have a 2.5mm headgasket which lowers the compression quite a bit as well. most people that do a ge bottom end with 1jz head do a TT gasket which is 1.1 MM iirc and that puts it at 9:0:1 IIRC. Mine should be lower.

blk&blu*j

iTrader: (1)

You are correct the thrust bearings on the crank are probably in the oil pan and you have most likely scared the crank.

What clutch are you running and have you done the clutch start delete if not, would highly recommend.
the 1.5 J is a definite option and most just use a GTE HG ARP studs and pending on the bottom used 2J or 2J GTE will be the determination as to CR if your running E than don't worry about CR if not you may want to consider as stated above a GTE piston as they are 8.5CR.
GL.

xspsi6

iTrader: (31)

What clutch are you running? If you have a heavy pressure plate then this is most likely the cause also bypass the clutch start switch as there is no oil pressure when you have the clutch pushed in without the car running then add in a heave aftermarket clutch and that my friend is a recipe for crankwalk!

Ali SC3

iTrader: (10)

You do not have to change the pistons and you don't really want to. Its just alot of cost to reduce your power alot. I am not sure why I keep hearing this all the time but the best thing to do is just change the headgasket.
get a fresh ge block and keep it that way, dont start ripping into it.. lol.
The only reason would be to lower the compression ratio all the way down to a regular gte, which most people agree is too low for the fuel these days.
The GE pistons are just as reliable as the TT, and with a TT headgasket you will be around a 9.1:1 which is still very boost friendly (what most na-t run on pump gas including myself).
If you are running e85, you could just use a stock ge headgasket and enjoy closer to 10:1 compression and have a torque monster all day with no problems at all (except finding a e85 station before you run out of fuel).
Either way I would have to agree with blk&blu and you should install arp headstuds while you are in there.

baconbomb

Thanks guys. Im not sure what clutch im using id have to look up the receipt. But Ive personally only started the car 5 or 6 times so i feel like it was a preexisting condition. I have a few more questions.

1. How do you route the oil and coolant for the turbos? The same as you would on an NA-T setup is what im assuming.

2. The 1j I have has ARP headstuds and a new head gasket. I dont think i can but can i reuse the headgasket since its literally been running for only 30 mins tops? Or is it crushed and I need a new one. Im fairly certain I can resuse the ARP headstuds. Am I correct?

Thanks for all youre help. Cant wait to get this thing running

spoolxexo

iTrader: (4)

Wait, wait.

Where did this 1jz of yours come from? A Supra? A Soarer? A Chaser/MKII?

baconbomb

Its from a soarer. Why does that matter though?

spoolxexo

iTrader: (4)

Because 1jzs don't just crankwalk for no reason.

IT seems the earliest Supra and Soarer have this issue. I'd like to know why it happens. This happened a lot on the 4g63's back in the day.

xspsi6

iTrader: (31)

Yes correct and the main culprit was aftermarket clutch sets and the fact that you need to push the clutch in before you start the car so as long as you disable that feature they would last, This alone could most likely be the cause of your crank walk.

INTIMAZY

iTrader: (5)

Any particular reason why pushing in a clutch at startup causes so much stress? Just curious. I don't understand why clutch disengagement at startup would cause more strain than pushing in the clutch when just shifting gears.

scoobySC3

iTrader: (1)

The way my feeble brain understand it is that when the engine is running you have oil pressure, which the main and rod bearings "float" on, but with the engine off, you have no oil pressure, so the bearings are in direct contact with the crank as they do not have the oil as a buffer. So when you push in the clutch with the engine off you are moving the crank, and putting more stress on the bearings, then you turn the key/start the engine with the clutch depressed and you get a moment of no oil pressure and the engine internals rotating with all of that stress from the crank not being in good alignment, so it would put extra wear on all of the bearings. Now with the car running and the clutch depressed, you have that oil pressure/buffer so it should not put as much stress on the bearings, but probably still not ideal to have the crank move forward/aft at all.

Does that sounds right lol?
Thanks,
Rick

ArmyofOne

Pretty much nailed it!

SEXC

iTrader: (2)

I have never heard of this happening to any other motor besides the 2jzgte. Like stated before the supra community lowered the chances of this happening by doing the clutch bypass mod. Hope you get your problem sorted out and come back stronger. Good luck