So I am buying an 89 sc..

I am picking up a bird tomarrow, sc, 800$, has 100k on the clock.

What should I look for for general maintince?

The guy says the car makes some noises, but, should be fine for awhile.

I never had an sc, and, this would be my 4th mn12.
I have had an 89 cougar, 3.8, never replaced the HG's, sold it with 202k on the clock, car still runs on stock gaskets.

My other 3.8 bird took a big dump, leaked oil everywhere, tranny went out at 160k.

My current bird, 93 lx 5.0, is still getting some work done on her

Anyways, I never owned an sc, I hear the crank shaft bearings are well known for going out. I would like to replace them b4 they do. What kind of cost would be associated with the parts? I would do the labor myself.

Is there anything I need to do with the sc? Change oil/bearings?

I need this car to be super reliable. It has a 5 speed in it, has a small scratch from 1st to 2nd, I am not too worried about that, a lot of my friend's 5 speeds scratch, and work fine.

I know replacing the bearings willnot be easy, as the lower sub frame is in the way, I did not really look at mine when I was working on it, how easy can it be removed to drop the pan?

I am also considering doing the ehad gaskets and maybe getting the ehads freshened up a bit and maybe some porting.

The cats on it have been gutted and the the resonator has been removed.

I will be driving 5hrs one way to pick it up tomarrow, I want to know what to look out for, it would suck for something to go out on the way home.

Also, how much work is it to rebuild my old rear end from my 5.0 bird, and put some diff gears and add trac-lok? I recently put in a frpp 3.73 pumkin i the 5.0 bird...

All 89 SC's had trac-lock rear ends in them.

Bearings? The lower end of the SC block is one of the strongest V6 lower ends available. Stock it's good for 350hp, no problem.

Changing head gaskets is a good idea if it hasn't been done yet. Port match the lower intake and all the gaskets while your at it.

Inspect the harmonic balancer on the front of the crankshaft. Over time they tend to fail and when they fail they can fail catastrophically. You can still get them from Ford, or go with a much better unit from BHJ.

The SC block is neutral balanced, so any pulley's you replace or flywheel or any such thing must also be neutrally balanced.

Probably one of the bigger issues you can run into is issues with the anti-lock breaks. Changing out the fluid is a good idea. If you find the ABS light coming on too easily (slam on the brakes and the light comes on) you could have an accumulator that needs to be replaced (about $100). There is a relay for the ABS pump as well that you might just replace as a preventative measure.

The 5 speeds are notchy when new and don't get any better as they age. Common issues are worn synchros or blocker rings. Parts are still available, but not commonly.

You might be o.k. to drive it home. The one thing I worry about with used cars are the rear wheel bearings. An SC that is run hard and at the drag strips tends to wear the drivers side rear wheel bearing. They are pressed into the rear suspension knuckle.

The supercharger itself shouldn't make noise. You may want to pickup some SC oil from a GM dealer before you head out there. Bring some tools along so you can check the level of the sc fluid. If it's low, top it off before you leave. The snout seal may have blown out allowing the fluid level to get low. It's not hard to replace but it's not good to run the SC low on fluid. That gear train in there runs at high rpms.

Then there is the typical used car stuff with 100k miles on it. Water pumps, p/s pumps, alternators, tensioner pullies. Stuff like that.

Good luck.

I got the car and everything seems to be fine, it just idles kinda hard, I am thinking it could be plugs and wires, it is almost like it is missing, and, I would bet that they are the orig plugs/wires.

Are there any sensors that should be checked/replaced?

I want to replace the blancer when money permits.

So the lower end of the motor should be fine? Someone told me that when you have a sc'd car, the bearings don;t hold up as long...

I would like to build up the top 1/2 of the motor so I can put on a larger sc

sc0tty8 said:

... it just idles kinda hard, I am thinking it could be plugs and wires.

Are there any sensors that should be checked/replaced?

Someone told me that when you have a sc'd car, the bearings don;t hold up as long...

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I would guess plugs and wires if the wires look old. Plugs & Wires are overlooked because they are a pain to change. When I got mine it had a tiny miss at highway speed. I changed the wires and plugs and it has run fine ever-sence. (I suggest you use ONLY double-platnum plugs. It will eat anything else).

The blocks on our cars are pretty beefy and the bearings hold up well as long as you keep the oil hanged. This is because the block was designed to take the supercharger. It is NOT the same block as is in the N/A V6's

The only sensors I can think to check ar the crank and can sensors. Generally, if it is running the sensors are OK. (I'm not an electrical guru so there may be other thoughts on it)!

Exactly. The motor was built by ford for a supercharged application. So don't sweat the bottom end unless you know it's had coolant in the oil before.

The only sensors that are preventative replacement might be the oxygen sensors. Old oxygen sensors can really impact fuel economy. Otherwise, ya just drive it until a sensor fails.

Certainly plugs and wires. Stick with the Auto-Lite double platinums or an irridium plug. Choose your wires wisely as well. Ask in the tech forum what people have had sucess with. The Stock wires from Ford are plenty good.

Bigger SC? Bigger how? The M90 is plenty big and other than the Whipple that some people are putting on now, there isn't much bigger to fit. I think someone is trying to get the lightning blower on their car. But that's some major work.

I am after mroe power. I am considering buying some used heads and send them to a local machine shop to get them cleaned up and maybe ported a little larger, maybe get some better springs in them for more lift.

I have a desire for more power that what ford had intended me to have

sc0tty8 said:

I am after mroe power. I am considering buying some used heads and send them to a local machine shop to get them cleaned up and maybe ported a little larger, maybe get some better springs in them for more lift.

I have a desire for more power that what ford had intended me to have

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If you have a desire for more power, be prepared to spend some money!

Most of us that have gone looking for power have dropped a few thousand and then realized for about a few thousand more we could get what we wanted out of the car !!!! (aka. No matter what you spend, you can always buy something else to shave off a few more tenths at the track).

You can gain a fair amount by adding a cold air intake system, larger MAF, larger Throttle Body and a low restriction exhaust system. After doing the exhaust, you can also swap out the stock SC pulley with a 5% or 10% overdrive pulley.

When you do the exhaust, you COULD replace the exhaust manifolds with a set of headers too.

Just these modifications will run you $1500.00 + to buy. (If you shop around).

At any rate, best of luck in your quest for power.

I know that power does not come cheap. For headers on my v8 bird, that costed me 350$, usually they where 440$ from summit.

I am not new to the mn12 platform, just new to the mn12 sc platform.

I have been looking at texas thunderbirds at parts, I have been looking at a few other places, I am well aware parts are not cheap, and, I know that with power comes a price.

I really do not think there is much restricting on the exhaust now, except for the stock headers, after I give the car a tune up and a good looking over, I will worry more about performance parts, I do not plan to put much money into parts yet, as I am stillg athering info.

I am thinking jan-feb I will start to throw some cash into it, I am thinking to the tune of 2kish

Any suggestions on places to look for more reasearch? I want more boost, but, I understand that the m90 can only take so much, so I am thinking maybe I will have to upgrade the blower, maybe the ic, larger injectors...I am unsure yet..

sc0tty8 said:

I know that power does not come cheap.

Any suggestions on places to look for more research? I want more boost, but, I understand that the m90 can only take so much, so I am thinking maybe I will have to upgrade the blower, maybe the ic, larger injectors...I am unsure yet..

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I got a lot of my stuff from Paul at BTM (see banners ads on this site). He helped me out alot.

I also spent alot of time cruising the Tech BBS' and looking at other cars to see what they were doing.