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Help: 1990 Toyota Supra Turbo


Tomcat0403
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1990 Toyota Supra Turbo

90,000 miles

extremely clean exterior and interior

brand new hydraulic clutch, tires, other stuff

Driven very easy

Anyways I'm buying this car from my uncle for $1000. It's a great car but the engine keeps going through head gaskets or something of the sort. Problem is that coolant keeps on getting into the oil and the engine. Also there is an oil leak somewhere, which could be the same problem. My uncle spent close to 12 grand trying to fix this problem through Tansky and AA engine service and they completely screwed him over. Through the fine print they were justified, but they told him different from what the paperwork said.

Anyways, point is my mechanic friend thinks that the problem might be the type of head gasket but it could be something major. Does anyone have any experience with these supras or have any good advice?

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Have you looked at the turbo?

If you keep blowing head gaskets, then that would often mean higher than normal compression pressures - being a turbo, it's likely too an overboost situation. Has the wastegate and turbo been rebuilt? You might have a sticking spring or something in the wastegate that causes pressure spikes in the intake when you let off the gas, continually stressing the head gaskets until they finally give.

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Supras are fairly notorious for head gaskets. Even the non turbos. If the head gasket was done properly, you should be fine. FelPro Gaskets are generally better than factory issue, so unless they found some really shoddy gaskets, you should be fine there. However, if the problem is recurring even after head gasket job, I would assume you either have a cracked (Possible) head, or warped (Very likely) head, as the straight 6 configuration gives a long flat head which tends to warp badly if ever overheated, and the turbo would just make things worse.

If your getting coolant in the oil, AND your sure its the head gasket (There are other ways that can happen, for example an oil cooler which is coolant based, many turbo japanese cars have these) then you are going to need to pull the head back off, and have it checked for cracks and warping. If its been done repeatedly, I would think there is a crack somewhere that is only opening up when it gets hot enough for things to move around a bit, and to be safe I would replace the head.

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Thanks

It has a boost gauge stock, and i have not driven it. It has been sitting for three years now because last time it had a problem it overheated. Our family mechanic took a quick look and told him the same thing, probably a head gasket. He had it towed to his shop and when they started it up it smoked up the whole shop with the oil/coolant mix and he hasn't cared to fix it since then.

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As far as i know the head has not been resurfaced, and AA said the head was fine, but neither my uncle or I trust what they say for shit. So the list right now is....

Cracked or warped head

oil cooler

overboost from the turbo

bad spring or similar to cause the wastegate to stick

miss anything?

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most, maybe not all, stock "boost gauges" are not actually measuring boost but rather the ECUs estimation of boost given certain conditions. Theoretically, you could unhook one of your IC pipes and have no pressure but the gauge would still read normal pressure.

No matter what, you really want to have a boost controller and real gauge.

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I've built a Supra or two in my day. You need to take the head to a reputable machine shop and have them measure it. If you can have some surfacing done you may be fine but on the turbo models you can't shave too much.

I recommend a metal head gasket and ARP head studs. I installed a HKS head gasket on my '89 Turbo and never had another issue. I ran about 17 PSI of boost with no worries. I'll try to find a couple links for you... BRB.

I agree. Having built several MR2 Turbos. Expect to spend money. Though if you keep it stock it shouldn't be too bad. Look at a Coumetic Gasket as well as an HKS. ARP studs definitely an option. Spending 12 grand .. should never happen. You can buy a practically new motor for waaaay less from Japan..

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At this point i'm just going to keep the car stock...Its a nice car and i want to keep it in the family, my uncle loves the car to death but he has a mental block about spending any more money on it. He's also not the best with the mechanics of cars. Like i said he babied the car. I might just by a new engine, but i would have to sell my 99 Wrangler. That is a money pit right there, i have the choice of dropping two grand on the Jeep to get it fixed, or spending possibly the same amount on the supra and having essentially a brand new car...hrmmmmm

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if you got a garage ill come pull the motor out for you or take the head off which ever route your going. I have a machine shop here i love and use religously if you want me to get the head done for you

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Depends. If the head hasn't been baked to hell and back you should be able to surface the face. The head has to be smooth' date=' flat and within thickness tolerances. If not, you'll have nothing but problems. Also, the face of the block is important. If it's had the shit beat out of it you're kind of up stream without a paddle.

I bought a JDM engine from a company in New York for $1400. It had about 40K miles on it. You may want to go that route.

Here's one place to look into...

[url']http://www.jdmenginescorp.com/engine_details/toyota_jdm-7m-gte-3.0l-v6-turbo-toyota-supra-1986---1992-engine-only--

I was looking at the other engines they have and i saw a twin turbo from another supra, have you had any experience dropping a different engine in 1990 or similar?

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The MKIII Supras are notorious heagasket eaters like everyone has said, but they are all missing a key element here. The bottom end is cast iron and the head is aluminium, so when most people do repair jobs like decking the head and block they dont get the right RA finish on it. Much like sand paper the RA number is smoother the lower the numeric is and the MKIII's require an extremely low/smooth RA finish, other wise the head moves the gasket and block eats the headgasket even on stock boost. While ARPs and a copper headgasket ( not recommended) is a quick fix or even an MLS gasket it wont last long. My suggestion would be to go talk to Mike Phillips at Phillips racing engine in Grove City and see what he recommends, they do quite a few import motors and even some of my personal things.

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The MKIII Supras are notorious heagasket eaters like everyone has said, but they are all missing a key element here. The bottom end is cast iron and the head is aluminium, so when most people do repair jobs like decking the head and block they dont get the right RA finish on it. Much like sand paper the RA number is smoother the lower the numeric is and the MKIII's require an extremely low/smooth RA finish, other wise the head moves the gasket and block eats the headgasket even on stock boost. While ARPs and a copper headgasket ( not recommended) is a quick fix or even an MLS gasket it wont last long. My suggestion would be to go talk to Mike Phillips at Phillips racing engine in Grove City and see what he recommends, they do quite a few import motors and even some of my personal things.

is there anything you can't fix on a car.... you sir are awesome...

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