2jz vs 7m reliablity? hope this isnt too noob of a question.

[1986.5supra_kid]

so this topic has been beaten to death but lets say someone was looking for a reliable 450-500whp supra,cressida. i already have the 2jzge na-t but i have been reading about crank walk and how it destroys a motor. i havent seen this on a 7m yet.. but lets say you have a 450-500hp 7m and 2j. what are the weaknesses of the 7m?

2jz-crankwalk......7m-BHG...... Bhg sounds like easy fix if it wasnt over cooked. keep in mind cost of parts 2jz block($200-$500) (bearings maybe $100) and whats the work on a 7m(machining $100)(MHG $100)

Asking this in the future of a the next project build.

thank you

 

[GrimJack]

Crankwalk is due to single plate clutches that need a lot of pressure... which you certainly will *not* need to hold 500rwhp, so it's a moot point.

I'd suggest sticking with what you have, with the biggest consideration being that you already have it.

 

[91Supra313]

Personally I know a lot of people that would like to find out where you are getting a MHG for $100.... I paid way more then that..... As far as reliability, yeah 7Ms have a HG problem, but if you take care of it ( HG ) then you wont have an issue. Every motor has problems, most of the time it is the owner that is the problem, but as long as you build it right the first time then chances are unless you are racing it, you won't need to rebuild it. I went 2JZGTE in my Supra simply because of availability of parts, especially just down the road at Autozone.

 

[1986.5supra_kid]

hmmm i appreaciate the input fellas. i have done the bypass on the clutch switch just to help prolong the life of my 2jz. just hate for there to be a major butt porking with moving and stationary objects inside the engine.
i have the ACT HD PP and street disk but the disk is starting to slip under high load 4th gear on ramps and such. so maybe a twin disk would be wise?

 

[Beals]

also how does the machining only cost you a 100$ they only charge you an hours labour or what? as for the clutch slipping it kind of seems odd, maybe another problem?

 

[leezymk3]

I think a 2jzgte is more reliablity,up to 800HP tune,so 500HP is nothng to that motor
I vote for 2jzgte.

 

[1986.5supra_kid]

never had machining work done so i was ball parking what i thought it might be worth. thought maybe someone would chime in as say well my friend so and so done his for this amount. it only slips when its a 2f2f kinda shifting. dogging it.

 

[Poodles]

Was the clutch broken in properly? Is you clutch pedal freeplay adjusted?

 

[GrimJack]

And how old is the clutch? If you've got 100k miles on it, then it's not unreasonable.

 

[1986.5supra_kid]

maybe 5,000miles. i would like to think its broke in correctly. i drove the 2jzge around for 3,000 miles to break in the motor and clutch before the turbo installation.

 

[Insidious Surmiser]

from what I've seen the 7m is less prone to get crank walk, I was talking with my buddy about this the other day. way I see it your best option would be a three-parter

1. use a centerforce PP (less initial load, more load applied as rotation causes weight to shift onto the diaphram)
2. disable neutral safety start switch (don't hold clutch on start-up)
3. don't stand on your clutch at lights ect.

as for me, I'm still going to use my ACT clutch. people have run these things on 7m's for ages with no issues, seems like if you treat the clutch right you shouldn't have any issues.

as far as reliability hp wise... the 7m will live @ over 700whp w/ just cams for a LONG time. same would be said of the 2j w/ cams except that would be @ over 900whp.... of course a wore out engine will shit the bed whenever it feels like it though... no way around that.

 

[Nick M]

from what I've seen the 7m is less prone to get crank walk,

What is it that you have seen, and where is that you saw it?

 

[grimreaper]

^ must be because the 7 bad headgaskets eat the other bearings before the thrusts wear out.

 

[Poodles]

It's ironic since most of the people pushing that kind of power are smart enough to go with a multiplate setup. It's easier to hit those numbers on a 2J and there are single plates made for those cars that can handle the load (supposedly).

Just because there are more cases, doesn't make it more common

 

[1986.5supra_kid]

@ Insidious Surmiser
Another member recommended those counter weighted pressure plates too. and i have done the clutch switch bypass. and im making it a habit to be in neutral at a light w/out clutch disengaged.

At times i wish i had gone from 7mge to 7mgte or even 7mge na-t because now that i have a 400whp car its plenty fun to drive. the 7m is so industrial looking i could go on and on...i may need a second MA70. or at least a 7mgte in my 88 pickup

 

[Insidious Surmiser]

What is it that you have seen, and where is that you saw it?

figure of speech my friend. I've never seen either engines get crankwalk.... I've seen firsthand PLENTY of built 7m's... usually the cause of engine failure will be a poor tune, or fatigued engine (or both) bearings let go and then maybe you get to throw a rod... simply put I've never even HEARD of a 7m getting crankwalk, but I've heard of 2j's getting it more times than I'd like to count.

@ Insidious Surmiser
Another member recommended those counter weighted pressure plates too. and i have done the clutch switch bypass. and im making it a habit to be in neutral at a light w/out clutch disengaged.

At times i wish i had gone from 7mge to 7mgte or even 7mge na-t because now that i have a 400whp car its plenty fun to drive. the 7m is so industrial looking i could go on and on...i may need a second MA70. or at least a 7mgte in my 88 pickup

indeed. sometimes I feel like I need 3 or 4 a70's -_-

It's ironic since most of the people pushing that kind of power are smart enough to go with a multiplate setup. It's easier to hit those numbers on a 2J and there are single plates made for those cars that can handle the load (supposedly).

Just because there are more cases, doesn't make it more common

this is an astute observation. could be a simple matter of 2j's more commonly being pushed harder, or it could be that they are simply handled by more careless (or clueless) individuals. no telling really. although I will note that even guys running rps triple plates have gotten crankwalk w/ their 2j's... I'm glad someone's using their head though, instead of trying to harass me for making a comment on the information I've been able to gather.

^ must be because the 7 bad headgaskets eat the other bearings before the thrusts wear out.

and so the tired song is sung again.... 2j's blow head gaskets too, but for painfully obvious reasons, not anywhere nearly as often.

BTW I've seen numerous m series engines w/ over 500k miles on them, never have I seen a JZ series like that. not saying it's not possible, but the M was a workhorse for almost 3 decades for good reason. JZ, almost 2 decades. I still wonder why they stopped making the JZ series TBH

 

[1986.5supra_kid]

indeed. sometimes I feel like I need 3 or 4 a70's -_-

It will be funny when these $1k-$5k cars gain value in the future because there antique.

Any how I wish to make my 2jz thrust bearings last as long as they can. any recommendations on motor oil?

 

[Insidious Surmiser]

yeah, i guess time will tell....

I'd say just run the recommended 10w30.... also the thrust bearing isn't pressure fed, so it just gets lubed from oil spilling off from other areas in the engine. (that's why you don't want to stand on the clutch on startup, or while sitting) I've personally always ran walmart supertech, never had any issues. ironically the only thing I ever buy from walmart. someday I'll make the switch to something else, but the day hasn't come. I'll probably go w/ rotella though...

 

[1986.5supra_kid]

wonder why its not pressure lubricated? i was thinking rotella t6 5-40w..but i have one more gallon of 10-30w gtx castrol here.

 

[Nick M]

^ must be because the 7 bad headgaskets eat the other bearings before the thrusts wear out.

Don't you have radiator caps to jack up?

I've never seen either engines get crankwalk....

That would be the best thing you could have said.

but I've heard of 2j's getting it more times than I'd like to count.

And they do something else to their car that 7M owners don't usually do. It is not the engine.