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Discussion Starter #1
Ok I searched and found a few reasons for my friends 87 MKIII but I'm still not sure.

The other night he bought a 87MKIII Turbo with the Targa top ***drools @ Targa top*** And I was the one with the honors of driving it home (He's still not good with a 5speed yet).

The queer he bought it off of (Yes this guy was as gay as could be) had all the service papers for everything on the car... 2 years ago he had a BHG and had it replaced as well as having a re-man turbo put in at the same time. So I was driving this thing back... I know it blew a hg again cause it's shootin some white smoke from the tailpipe so I'm keeping an eye on the temp guage. We got about 15miles up the street and i hear this loud "clang!" and the cabin fills with sweet smelling smoke. All I can see is a Exxon sign so I steer twords the sign, brushed the curb and blew out the driver front tire...no biggie... it was bald to start with. Once I parked it I popped the hood open and I was astonished!

Some how the system over pressurized the blew the neck of the radiator! We were now on the very outskirts of Washington DC still in a ghetto region though...good ol North West DC has lots of gang issues etc. We leave it parked there over night, surpised they didn't tow it by the time we returned in the morning. Popped the spare on it (which btw the gay guy didn't have the tire iron or a jack in the car...just the tire). There was a indian guy working the gas station who drove a Corolla but that bastard wouldn't let us use his tire iron :mad: So we had to find a parts store to get a 4way bar cause we drove there in my Chevy beater car that has 19mm lugs....19mm won't fit a 21mm too well =-p.

What we're tryin to figure out is wtf causes the system to get that much pressure in it.

We're going to pop a new radiator in it and thermostat for the time being... with the Supra you all say leave the cap off at idel and have it up on some ramps? If that's the case well give it a shot. He's going to order a stock motor from this place called M.M.R who sells nothing but slightly used JDM and other import motor...it's like $600 w/o turbo. Then going to start getting his motor with a BHG taken apart, get the block bored and trued out as well as a headjob (this one has a good ammount of valve rattle) We're jus scratching our heads tryin to figure out why all this happened
 

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if it has a bad BHG, then the pressure from the combustion chamber leaking into the water jacket can overpressurize the cooling system, causing such a failure
 

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:imwithst:

The majority of the time when they do decide to go, it's usually on the water jackets on the exhaust side. And the majority of the time, it's on #5 & #6 cylinders. "Occasionally" it's on #1 & #2 cylinders as well, but that's if it's REALLY bad & the leak was in multiple locations.

When my 5MGE went, it was in the usual #5 & #6 cylinders at the exhaust water jackets.

WOW!!! This was REALLY pressurized if it blew the radiator neck off!!! Didn't happen to me, but instead it blew the cap off of my coolant overflow tank. Good thinking for babying the motor as much as you could when you first saw the signs of the BHG.

Bill, in this case a bad radiator cap is not the problem, unless it was the wrong pressure spec (pressure spec on the cap is too high). In this case, the cap should have been doing it's job & venting coolant & air into the overflow tank. Problem is that when the system get's this overpressurized, the cap can only relieve so much.

2slow.. Tell your buddy to park this car, until he can get the replacement motor in!!! That motor is not going to go very far in it's current state, no matter how much you burp the system.
 

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Discussion Starter #5
Well that pretty much explains everything... it was at night so I couldn't exactly access the whole car. I knew it had a BHG cause it was blowing some sweet smelling whitesmoke..Yes it did smell sweet =-p. It funny that 2 years ago he had the HG done at the dealership... they probaly didn't true the head out or if not that he didn't take it back after a few miles to have the headbolts re-torqued. But I do agree with CJ and funky about cylenders 5 & 6 cause a decent ammount of smoke was comming off the back of the manifold on the rear of the motor.

When the neck completly blew off it was about 5miles away from it's resting spot but still sitting on the beltway. The Park Police said that they were going to tow it back to his place for $75 only to find out that the towing compay the police used took it back to the companies lot. Yea he was pissed off in a major way cause now he has to have them tow it back to his house from the towing companies lot.

I hate to sound like an ass but... My MKII is sitting on the lift at work... so I know where it's at =-D Maybe his mishap will work out in my favor... I'm still undecided on my swap. If I go with a 350 Chevy motor I'll have to build a bulletproof LSD, 7MGTE...I hate having to re-wire anything with a passion. Since his motor is comming out... Maybe I can give him $100 for his block and rebuild the bottom end and make a 6MGTE (Yeah, I'm getting a CT-26 reguardless) due to time and money more than likely I'll end up building a 6MGTE :twisted:
 

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It funny that 2 years ago he had the HG done at the dealership... they probaly didn't true the head out or if not that he didn't take it back after a few miles to have the headbolts re-torqued.
It was done at the Toyota dealership??? That explains a few things... More than likely they did deck the head to make sure it's straight & flat, BUT.. More than likely when they tightened the headbolts, they went to the stock setting of 58 ft lbs.

Retorque the headbolts later??? Unlikely!!! Remember!! Toyota AND the TSRM says that the headbolts are supposed to be done @ 58 ft lbs on a 7M. And they won't tighten it more than that!!! Remember... Toyota to this day STILL deny's that there is even a BHG problem on the 7M's!! But if you have a full size pickup truck or 4 Runner w/ the V6, they have no problem admitting there is a BHG problem. And from EVERY horror story that I've read on the SOGI list from years ago (prior to 96), Toyota has come up w/ other excuses.... (You've neglected/not maintaining the motor, you're being too abusive w/ your driving habits, all of these "performance mods" are what caused the BHG, yada yada..). Back then the only saving grace you had, is if you bought the car used from them & you also purchased the 72K miles extended warranty, then they would fix it. If the warranty was up, then you would have to eat the repair cost.

More than likely, Toyota followed the rules on what the repair instructions said & did not do anything above & beyond. Even if it meant this was the correct fix (that the rest of the Supra community knows about)
 

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Discussion Starter #7
Why only 58ft/lbs?

I mean damn... The heads on my old ass s-10 required like 90ft/lbs... I almost killed myself tighting my heads on it... and I went back in after that short 100mile breakin to retorque... And I followed the sequence the service book said to do it and to this day the motor runs like a dream.

Since the temp pegged out and it blew off the neck of the rad. I think it's safe to say that the head is officaly toast and would need a massive/expensive mechining....which means I get his blown motor for the block and bottom end =-D
 

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To this day, I have no idea why Toyota recommended 58 ft lbs on their later M series motors. My 5ME manuals says 58 (and I'm assuming the 4ME manual says likewise), it's the same for the 5MGE (and most likely the 6M as well).

Head: In this case, it would depend on the amount of warpage that occurred when it overheated. A machine shop could make that determination & they would know if the amount that they have to take off would exceed the maximum amount. If it goes beyond that, well...... Then you will have a very nice 3 ft long paper weight.. And you would have to get another 7M head.
 

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2slow4you said:
I'm still undecided on my swap. If I go with a 350 Chevy motor I'll have to build a bulletproof LSD, 7MGTE...I hate having to re-wire anything with a passion. Since his motor is comming out... Maybe I can give him $100 for his block and rebuild the bottom end and make a 6MGTE (Yeah, I'm getting a CT-26 reguardless) due to time and money more than likely I'll end up building a 6MGTE :twisted:
If you use a 7M block, you'll end up with a 57M-GTE, not a 6M-GTE.
hint: do a search for 57M-GTE


(I'm known for being pedantic)
 

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Discussion Starter #10
Really... a 57M-GTE?

I was under the assumption that a 6mgte was a 7MGTE block with the 5M head with turbo and turbo manifold... I'll go on a limb and guess it's jus the 7MGTE bottom end (crank, piston rods and pistons) inside the 5MGE block and hit +turbo?

Pen*dan*tic:Characterized by a narrow, often ostentatious concern for book learning and formal rules: a pedantic attention to details

I try not to use books... Yes there's a right time and place to use books but others you use the knowledge from life exp.

And Ross... Sorry that I called you an ass...no one seemed to understand what I was saying and got blown way the hell out of proportion. I gotta learn to control my temper... Life's a Beoch but I'll try to step up and be a man about it to admit I was wrong for throwin an insult... But you could in theroy make a custom wiring harness for a LT1 ECM with adding a few wires to a Toyota harness... Jus takes time and patience =-p
 

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Nope...

The above is correct. When you have a 5M block & head w/ the 7M crank, THEN you have a 6M. 7M block & crank w/ a 5M head is still a 57M
 

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Discussion Starter #12
Ok, I'm about to rip his 7MGTE apart...I'm sure the head is gonna e warped as hell and if the mahine shop can't fix that one I kno a guy at work with a head from a non-turbo... To the best of my knowledge they're the same motor jus one is N/A and the other is turbo...will the N/A head work with a turbo setup jus in case they can't fix the one that's been over heated a few times?
 

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Heads from a GE & a GTE are identical. Should work fine. We just had a thread going last week, where several peeps have said that the GTE exhaust cam is slightly different (this is supposed to be a slight advantage, others have said it does not make a difference), otherwise it's the same.
 

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a 6M is basically a 7M bottom end, but, the pistons have 2 valve reliefs cut in them rather than 4 for the 7M.

the 5M block has to have some machining done for the 7M crank to fit.

it's all the same either way I guess.

on the early 7M heads, I've heard from 10-30 HP differnce on the exaust cam differnces... none of which I've see confirmed by any real data.

after 89 I understand the cams are the same in the GE and GTE.

Mike
 

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2slow4you said:
And Ross... Sorry that I called you an ass...no one seemed to understand what I was saying and got blown way the hell out of proportion. I gotta learn to control my temper... Life's a Beoch but I'll try to step up and be a man about it to admit I was wrong for throwin an insult...
It's OK, it's all good now.
 
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