7m-gte repair...which way to go?

[Bowlsclubboy]

Ok...so the missus' 7m supra just let go for the second time in about 3 or 4 years (BHG) and i need some advice on the best course of action to get the car reliable.

I should have had the block machined last time but was time poor, bad excuse i know.
Anyway, last time it happened, it recieved a basically full reco head, head gasket kit and i reused the studs at 68ftlb or something.

I caught it early this time, engine never ran out of water and never seemed to get hot, there are no marks on the head to indicate damage, only on the gasket, am yet to put a straight edge on the block or the head. Funny thing was, it blew through cyl 3 and the water jacket, as opposed to 5+6 where the damage from the last BHG was still in the block.

I have the following things available to me.

Stock 7m-ge from my 220,000km cressida, could possibly just retorque the HG and throw the turbo gear on this considering my gf drives like a nanna?

Have the block and head of the BHG engine torn down and machined (new bearings/seals usually done at the same time?) Any idea on how much i would be up for to have this done?

Purchase a used 7m-gte from a mate which is of unknown condition but comes complete and with a microtech, clutch and flywheel for $1100? Done know wether to tear this down also if i get it....

Keep the car off the road for longer and save for 1j manual half cut.

I have ordered a top end gasket set from the states for about $90 with 3 day shipping. Repco was $250 and Gen Toyota was $150 or so...FOR THE FUSKING GASKET ALONE!!!
Will order some ARP studs with my next driftmotion order also if i choose the 7m path.

Anyone else been down this path and have some imput?

[petergoudie]

I'm fixing a 7mge now and I'm beginning to think the coolant is eating the gasket material. It has degraded on cylinders 4, 5 & 6 after 85,000k. A cylinder head repairer said the 50/50 mix was too much. I doubt if anyone knows what the real problem is but I do know the head should be retorqued about 600k after it is fitted as the bolt torques drop off dramatically.

[AKSA]

Peter,

I'm faced with exactly the same decision, my '92 Grande has 214k kms, two years since a complete reco.
As I see it the alloy of the head softens on these motors, and after 18 years its marginal. With the 7mm bridge between pots, this seems to lead to BHG and it's a design flaw.

If the car is in good nick, two options comes to mind. A 2JZ, which would be around $2k5 for engine, gearbox, ECU and loom, or maybe even a LSx Chev, which for a crate motor is around $5k for a L76, but $2k more for a decent gearbox and more again for fitting and ECU, loom. You still have quite a few wiring issues with the 2JZ, and below 2000 rpm, you do not have the torque from this engine you had with the 7M, leading to significantly higher urban fuel consumption. The V8 would be marginally lighter, too.

It's a tricky one. Fixing the existing 7M is far cheaper, but won't last......

Difficult decision.

[Kedderz]

Buy the rebuilt + bored out 7mgte for sale in the for sale section, $1200 shipped to your door.
Dont put the turbo stuff on the 7mge, its already higher compression than the turbo motor and the ecu wont know what to do with the timing when the engine comes on boost and will detonate.

[andrew_mx83]

if it didnt get hot and the head was machined last time, prep the surfaces, slip another gasket in and off you go. was the head hardness/crack tested last time?

if you want to do it properly then strip the block and deck its surface and you wont have a problem again. replace rings, bearing shells and seals and you ill basically have a fresh motor.

remember to use hylomar on the gasket when it goes back together and that good surface preparation is the key.

[boxh34d]

Hey Troy, long time no see. (It's Lee from Wang BTW).
I would stick with the 7M. It saves dicking around with wiring and trying to source appropriate sumps / cross members etc. The recently rebuilt one here sounds like a good deal, but as always with a second hand engine, you don't know 100% what your getting.
If you want some guestimates of my newly built engine, shoot me a PM.

[petergoudie]

Andrew, I looked up Hylomar and there are several different types (blue, red, M, af etc). Which one do you use?

[Cuzzo]

Could you put a 2jzge in for 3-4K? never have to worry about it again?

[andrew_mx83]

the one i use is blue and in an aerosol can, around $15 from burson/autobarn etc from memory

[Shifty]

Buy the rebuilt + bored out 7mgte for sale in the for sale section, $1200 shipped to your door.

Good idea... sounds like the best option. I will say though that a bored out 7M is interesting... a 7M really needs closer bore spacing

Dont put the turbo stuff on the 7mge, its already higher compression than the turbo motor and the ecu wont know what to do with the timing when the engine comes on boost and will detonate.

yourmumsayswhat?

Sorry dude but that's all wrong. The computer has NFI what static compression the engine is running and this has no impact on ignition timing at all. At a stock(ish) boost level with all the turbo gear on it ignition timing will absolutely not be a problem. Sure if you're running 15psi but 10 or so and you'll have no problems. Run plugs one step colder and premium unleaded and it'll be sweet as.

[Kedderz]

the compression comment is in relation to boost, which on a the NA motor is higher compression, adding boost will kill it, happens all the time with na+t conversions without aftermarket ecu.

ignition timing is retarded on boost on the 7mgte, the 7mge computer will not accomodate this and cause detonation.

[GRANDE]

if it didnt get hot and the head was machined last time, prep the surfaces, slip another gasket in and off you go. was the head hardness/crack tested last time?

if you want to do it properly then strip the block and deck its surface and you wont have a problem again. replace rings, bearing shells and seals and you ill basically have a fresh motor.

remember to use hylomar on the gasket when it goes back together and that good surface preparation is the key.

what is 'hylomar'?

[wilbo666]

what is 'hylomar'?

Gasket dressing...

http://hylomarpl32.com/FAQ.htm

http://www.hylomar.co.uk/index.php?o...cman&Itemid=76





Cheers
Wilbo

[andrew_mx83]

yeah dat da one.


awesome stuff

[Shifty]

the compression comment is in relation to boost, which on a the NA motor is higher compression, adding boost will kill it, happens all the time with na+t conversions without aftermarket ecu.

ignition timing is retarded on boost on the 7mgte, the 7mge computer will not accomodate this and cause detonation.

The OP said using 7MGE engine with all 7MGTE stuff, so I take from that manifolds, injectors, ecu, etc.