7MGTE Headgasket Problems

**Mundoolun** · 17-11-2006, 12:21 AM

I own a 1989 MA-70 Supra with a blown headgasket. It seems to be leaking in cyclinder number six through both the water jacket ( eaten out) and through the gasket it self. I am currently loosing around two litres of water a week. I have but chemweld and diminerialised water and it seems to hold temperature. I have a new headgasket and inlet and exhaust gaskets but known it will need to welded up and pressure tested. I am wondering if it may just be easier to but either a new 7MGTE or should I step up to the Mighty 1JZGTE frount cut?

**haison** · 17-11-2006, 12:26 AM

It kinda depends on your budget. If the back of your block is rusted out you'd be better off getting a new 7M in there. Or if you have the ability, just get a new bottom end and rebuild everything over to that yourself. It'd be too expensive to get someone else to do it. By that stage you could just go the 1JZ halfcut. 7M's are getting a bit long in the tooth so whichever way you go with them there'll be extras involved with freshening them up again.

**BigWorm** · 17-11-2006, 12:26 AM

A 7MGTE with a BHG??? You gotta be kidding!

It's a big decision, 1Js rock, & 7Ms can sometimes rock harder, but there's always the risk of another BHG hanging over your head. Sometimes they can live long & fruitful lives, & sometimes they can die again & again. A 1J is usually pretty trusty, and if you get a JZA70 cut it should be easy too.

Otherwise if you want a project with huge potential, go 2J. Reliability of a 1J with the cubes of a 7M. Best of both worlds!

**EldarO** · 17-11-2006, 01:34 AM

been there done that.

my advice, if you dont have the time or money to invest in refreshing the 7M properly, go 1J.

ive spent near $22k on my MA70, about 7-9k was all thrown down the drain on repairing the 7M, and i bought a 1J after it happened again.

my problem was that i didnt have the time to be without the car, and it resulted in a couple of half-assed bodge jobs to get the car back to me quicker.

i received my 1J cut, had the engine in the car and running in 11 days, including 1 weekend, and working on it after work.

mine was auto-manual conversion too.

Eldar.O.

**rob_85** · 17-11-2006, 01:35 AM

replacing the gasket yourself would be the cheapest option.......

but maybe not the best option

all depends on your budget

**doobs** · 17-11-2006, 08:13 AM

I was in the same situation as you... I replaced my head gasket and put in some ARP studs, seems to be fine now.

But I want more power, and at the moment, im tossing up between working the 7M or putting in a 1JZ...

Working the 7M includes rebuilding the bottom end, putting on a metal head gasket and most likly a new turbo, which will be close to the cost of the 1JZ but would probly be "eaiser"... give me the performance I want, and I know the engine is in good nick...

Make the choice sooner, rather than later, unlike EldarO...

**millsi** · 17-11-2006, 07:22 PM

if it can be fixed then get some arp studs and a cometic gasket and get it fixed professionally (lightest of light skimming to get a good sealing surface).

**EldarO** · 17-11-2006, 09:28 PM

Originally Posted by doobs

I was in the same situation as you... I replaced my head gasket and put in some ARP studs, seems to be fine now.

But I want more power, and at the moment, im tossing up between working the 7M or putting in a 1JZ...

Working the 7M includes rebuilding the bottom end, putting on a metal head gasket and most likly a new turbo, which will be close to the cost of the 1JZ but would probly be "eaiser"... give me the performance I want, and I know the engine is in good nick...

Make the choice sooner, rather than later, unlike EldarO...

i usually couldnt help but feel a little offended if this comment was made,

but now, i can wholeheartedly agree.

that said, ive never complained, obviously if i lost 9k in cash, id slit my wrists, but i guess if you do it once, do it right, you wont need to complain

Eldar.O.

**doobs** · 28-11-2006, 08:32 AM

Originally Posted by EldarO

i usually couldnt help but feel a little offended if this comment was made,

but now, i can wholeheartedly agree.

that said, ive never complained, obviously if i lost 9k in cash, id slit my wrists, but i guess if you do it once, do it right, you wont need to complain

Eldar.O.

Yeah no offence intended, just that if I were in your shoes, and put big $$$$ into a motor and it packed up on me I'd be pist. But I guess I'm already heading down that path :S, just that I've only spent $500 on the motor, just heaps of down time...
Thinking about it, I should have put the MHG on when I had the motor out, and replaced the pistons and rings... but thats a bit of time and money... and well, touch wood the cars going sweet atm. Gives me something to look forward to in the future anyway

All that's left to do for me, is get my daily driver, wind up the boost on the 7M and sit tight and wait for the inevitable...

**EldarO** · 28-11-2006, 08:56 PM

Originally Posted by doobs

Yeah no offence intended, just that if I were in your shoes, and put big $$$$ into a motor and it packed up on me I'd be pist. But I guess I'm already heading down that path :S, just that I've only spent $500 on the motor, just heaps of down time...
Thinking about it, I should have put the MHG on when I had the motor out, and replaced the pistons and rings... but thats a bit of time and money... and well, touch wood the cars going sweet atm. Gives me something to look forward to in the future anyway

All that's left to do for me, is get my daily driver, wind up the boost on the 7M and sit tight and wait for the inevitable...

oh, im pissed, dont even think that i aint! im fucken fuming! bye bye HKS T3G kit!

the thing with the 7M is, (my opinion) if its over 70-100k k's, you NEED to pull the motor out, strip the block down and get the block machined flat, then get the head completely reconditioned if you want ANY reliability when your modifying it.

naturally there are exceptions to this, but this is from my experience.

for a reliable semi-stock 7M (not upgrading turbo/boost) you should be fine with the stock gear after a freshen up, if you do the proper prep work.

but if your planning to modify it later, your better off saving up for 6 months longer, taking the car off the road for a month or two (if your working full time) and pull it all apart, and put it all back together, so that when its all together, you've got a basically new engine.

backyard fixing a 7M without any machine work (on the head at least) is asking for trouble, and boosting it up (over 13 or so PSI from my experience) without making sure the block is flat is also asking for trouble.

thats why i never complained, i didnt do the proper work, and i ended up eating it, to be expected! just dont make the same mistake!

that said, if you've got the cash for the 1J cut, you've got the cash for the 7M freshen up/build, the time is the main deciding factor.

just have a look at Disturbed1's soarer, running 11.8 on stock internals + MHG and BPU mods.

the motors are strong as fuck once the head gasket and oil flow problems are remidied (oil flow only for track work, should be ok for drags IMO.)

Eldar.O.