7MGTE build up questions.

[boxh34d]

Ok, in the new year I'm planning to rebuild a 7MGTE to swap over into my MA71.

I am aiming at about the 300 odd RWHP mark and trying to keep as much response / torque in the thing as possible.
The plan is a full rebuild and making sure everything runs straight and true. Balancing, resize rods, linishing, machining, bearings, slugs etc etc. The head will be rebuilt also, and have any major casting marks cleaned up, as well as the ports matched to manifolds etc. Just the basics.
I have a few questions which I have searched and searched for answers, but info that I have found is either not definative enough, here-say, conflicting or just plain outright bullshit.

So, My questions are:

At what point ( HP or pressure ) is a steel shim head gasket ( HKS etc ) needed over a Multi Layer Steel jobbie such as those from Cometic?? Or will either be fine?? This will be held down by ARP head bolts / studs, not sure what the difference is when it comes to the crunch.
The same question can be asked of the pistons. At what point does aftermarket slugs become a good idea??

For my HP level, what turbo would be suited to the job?? Some people will say highflow CT26, some TO4 or GT35 or something, and some have said that the standard turbo will get there ( I am doubtfull of this one ).
Will the standard manifold and a highflowed CT26 be up to my goal??

Intercooler is obviously getting upgraded as well. I was 'thinking' a second hand stock replacement such as those from ARC or TRUST, that fit in stock brackets, and use mostly stock plumbing. . I am assuming the cooler will be up to the job, but will the stock plumbing start to show a problem at this level??

And lastly head / cams. I know there are plenty of big 7M's out there pushing big numbers with stock head and cams. Is doing some porting work worth the dollars involved, or is it just as effective to use a bit more artificial air to get the required flow??
And, are different cams worth it??
I have some NA cams here that came with one of my heads. I know it has been said that its not a huge upgrade and maybe not worth it if you have to buy the cams etc. Mine were free and I have them, is it worth chucking them in??
Are aftermarket cams / regrinds something to consider??


Like I said, I know there is info out there, but a hell of a lot of it is quite vague and a lot is contradicting to other info.
Any other insight / advice / opinions / info is welcomed. Any thing I have forgotten??

The only exception to this of course is if someone wants to say "Just put a 1JZ in it and be done with it".
I have picked up most of these parts for 3/5ths of stuff all, and for the cost of the rebuild, I will have a brand new motor there for less than the cost of a conversion.

Thanks in advance everyone.
Lee.

[haison]

G'day, I'm doing pretty much the same thing right now so hopefully I can help a little.

Are you rebuilding your current motor or getting another one? Which ever one you are building, get the head off and check for corrosion at the back of the block. A lot of them these days are rotting out quite severely. Some of them get fractures between the water galleries and bolt holes as well so keep an eye out for that too. Provided that's all good and you do the correct torqueing and re-torqueing a MLS h/gasket should be fine.

The stock internals can take up to around 400hp comfortably so just give them a good clean up and check, replace all the bearings etc and you should be fine. New pistons would be a good idea though. One thing I'd definately recommend if the engines a dirty one is to get the plugs out of the crank before you hot-tank it. Other wise after the cleaning the grit inside the ports will soften up and get into your big-ends.

Power wise, have a look at Whatthe?'s old engine. He netted 250rwkw with intercooler, hi-flowed turbo, SAFC, SITC and the 1UZ afm w/bigger injectors by memory, he can probably enlighten you further on that.

I can't help you too much in terms of the head work, I'm just giving mine a good cleanup and making sure there aren't any restrictions but not planning for big cams or anything just yet. Most of your aftermarket cams out there will require a bit of head work to put them in, not many 'plug n play' setups around so it comes down to cost factor.

Sorry if I'm being a bit vague. None of this has been tested as of yet as my engine is still in bits but I'll keep posting up things as I think of them. For the moment 200-250rwkw is my aim but I want this engine to be able to take more power if I choose to without having to tear it down again and rebuild it.

Kudos to you for putting the work into building a proper 7M!

[Danners]

I was using NA cams on my 7MGTE. There was an article in HPI ages ago, i think they gained a few extra kw's out of them.

[deaf_rattle]

I wouldnt waste my time with stock i/c piping

Get the engine rebuilt (even if its just with stock bits)
run lexus AFM with 550cc injectors
upgrade exhaust
upgrade intercooler
HKS mhg
Upgrade turbo
upgrade fuel pump
more boost and done

check out my build in the members section.
im going abit more hardout, 300plus rwkws

But yeah any questions feel free to ask.

cheers

[boxh34d]

Haison: good to see someone else is heading in the same direction I am.
Thanks for that info. Regarding block condition, I have seen more than enough 5M and 4M blocks with the water gallery eaten out on the rear intake side of cylinder 6 to figure its just an M trait that happens if not maintained.

Danners: Re that HPI, do you still have that article, or even the issue it was in?? As I would be interested to see it.

Deaf Rattle: I was after the specific info regarding the limits of the said parts, as I the general build sequence is fairly well sorted. Can you narrow it down any more?? I had a look at your thread, and can see parts etc that you have used, but have you found when and under what circumstances things start to suffer.

Thanks for the replies so far, keep em coming peoples.

[haison]

It's not actually lack of maintenance that rots out the block, well not entirely. It's actually from electrolysis, i.e. bad grounding. We're looking into better points on the block to ground it when the engine goes back in. Oh one more thing. Grab a screwdriver and try and scratch the filling in the plugged up holes in the water galleries on the exhaust side (i think). They should be as hard as the rest of the metal, but if it's beginning to corrode those bits get really soft.

[EldarO]

to make big numbers from a 7MGTE, you need a flat head (with good conditioned alloy) and a flat block.

from there:

a metal head gasket, a big turbo, an exhaust, a cooler, and metal IC lines.

Eldar.O.

[whatthe?]

Yep, as haison said my old 7M was making 245 rwkw (or about 330rwhp). The mods were as he listed (and with a factory graphite headgasket!) + 2.5" steel IC piping, a reasonably big custom front mount and a 3" turbo back exhaust. The CT26 in stock form struggled to reliably provide 13-14 pound of boost so the hi-flow 60-1 wheeled CT26 upgrage was well worthwhile and is certainly good enough for the power levels youre chasing. Mine pushed out 16-17 psi without any issues

I am currently building a pretty serious 7M myself, so when it's back in and dynoed perhaps it'll make an interesting comparison against what my old essentially stock engine was making

Edit - Oh, and whilst I wouldnt try and talk anyone out of big power p00, it'll definitely work out costing more than you think..... My new engine has now passed the 11k mark (long motor only, no manifolds, turbo etc )

[haison]

11k!!! You is teh mad!

[whatthe?]

Yes, don't I know it. Coulda had a vvti 2J cut with a getrag for less than that . Ah well, it'll be something unique!

[wiseco7mgt]

im currently in the process of a 7mgt build just waiting on my wiseco forgies to come, i wont be running lexuus maf instead ill be useing a MAP ecu and highflowed 440 cc dynoed to suit,also waiting on h/f ct26,be interesting to see the performance difference between Map ecu and lexus maf.ill post up dyno sheet after christmas break when it all goes together.

I am aiming at about the 300 odd RWHP mark and trying to keep as much response / torque in the thing as possible

cant see torque being a problem with a 7m and hitting 300 hp isnt a problem with stock pistons either provided the motor is tuned well.goodluck with it

[boxh34d]

whatthe: That is exactly the kind of info I was after. Thanks. My only question is, did you run your first set up with stock I/C plumbing and find that it was not up to task, did you research that it can only hold so much pressure etc, or did you just make the call to upgrade it?? Just out of curiosity. Also, what did your fuel system consist of??

Eldaro: I don't mean to be a smart ass, as you took the time to post in this thread, but I have to ask, did you even read my first post asking questions??? You have not even come close to answering any of them. Any dickhead knows to make big power you need a big turbo and intercooler. . .
( end rant )

wiseco7MGT: I would be very interested to see the results of that one. Thanks.

[whatthe?]

No, mine had the custom steel IC piping from day one (in an MA61, so there were no standard pipes to begin with), although my girlfriend's MZ20 has all standard piping plus a small bolt in ARC cooler and a HKS 3" turbo back exhaust and makes 200rwkw with standard CT26 at 12psi (I suspect that this is coming close to the pipework's limits however).

My fuel system consisted of a walbro 255 lph pump and a rising rate FPR

[doobs]

Ey fellas,

First of all, sorry for a bit of a thread hijack, but its kinda relevent

Seems like a few of us are building up the 7M's atm... Mine is getting very tired, and I'm planning on a full rebuild in about feb/march next year. While my goals are not so high (anything around 250rwkw would be great) I'm trying to build in abit of reliability...

I'm interesting in finding a decent machine/engine shop in Victoria? I'm in Geelong, so a drive to Melbourne isn't out of the question. I'd also like the crank and rods tested, so a place that can do it all at once would be good.

Another big question I have is concerning the pistons? Are any forged aftermarket items fine, or should I be looking for a certain brand?

Cheers boys

[whatthe?]

Can't help you with machining shops in Vic, but as far as pistions go I've heard good reports from people using CP, arias and wiseco. I'm personally using HKS, I'll let you know how they go