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Discussion Starter #1 (Edited)
Hi:
In addition to upgrading my known-good 3.8L N/A engine that's in my lemons car with a splitport intake/heads, I've decided to cobble together a spare engine using the 3.8L engine I acquired from my 89 supercoupe donor car (I bought it for the manual transmission).

My plan is to do this as cheaply as possible so I will take the single port intake manifold from my "known good engine" and throw it onto this SC block.

The goal is to put together something I can quickly drop into the lemons car should something bad happen mid-race.

Right now, I'm hoping to learn more about the differences between the two engines. Please correct me if I'm wrong/misguided here on any of these statements/plans
* I understand that the 89SC has forged Crankshaft and Connecting rods. That's nice but not particularly relevant for me.

* However, the SC has a lower compression ratio (8.2:1) compared to the NA engine (8.8:1). This is a backup engine for me so I don't care about the slightly lower HP (some HP is better than nothing).

Allegedly, the SC compression ratio is lower than the 3.8 because the pistons use a larger dish. (confirmed by SCTbird1994)
http://3.7mustang.com/vb/f5/sc-na-94-98-mustang-3-8-99-mustang-3-8-compression-questions-262671/#post4535284

* I plan to do a mild polishing/gasket matching for the single port intake manifold and heads. Nothing drastic. It might be labor intensive, but hey, it's a project.

* 89sc engine turns over when you spin the crank but I'm not sure if the head gaskets are good. Since I will have the top of the engine off anyway (and i want to take a look inside the block so I plan on swapping out headgaskets anway)


* SC vs NA Heads: valve sizes are the same but casting is slightly larger for a thicker deck surface and therefore less prone to warpage (see below)
I will go with re-using the SC heads.

* Crank Sensor: TBD

* Timing Belt Cover: different shape and different crank sensor mount position on the early SC vs NA.


* Water pump: the water pumps are different from the SC and the N/A engine so I will need a new water pump if I'm going to convert this engine to N/A.

http://www.sccoa.com/forums/showthread.php?t=124224

* I plan to have a 95 return style fuel rail and injectors pre-installed on the 89SC block and ready to rock since I already have a spare fuel rail and that stuff is easier to install with the upper intake manifold off.

* Accessories: I don't plan on buying a spare alternator, PS pump, A/C delete bracket, distributor/ignition system, and tensioner so all of that stuff will be carried over from the N/A splitport engine should something bad happen.

QUESTIONS
Q: For this 89SC engine converted to N/A, should I just re-use the heads from the 89SC or should I use the heads from my 95 Tbird N/A?

Q: Are there any other differences I should be aware of that I will need to buy in advance or carry over during a race-day swap? Example: oil pan?

Q: While I'm swapping out injectors, I probably should swap out injector seals as well. I see a bunch of different options for seals and the packaging is different.
Is the best option just buying qty six of SK Products #SK57 (includes cap,2 o-rings, and washer)? Or, can I just buy 12 o-rings (2 per injector).

Thanks,
-g
 

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The SC Crankshaft and Connecting rods are Forged, the pistons are the standard Hypereutectic aluminum / alloy.

Compression ratio is different due to the piston dish, this is correct. Head combustion chamber volume is the same between the NA and SC heads.

I have read there is a slight difference between the valve cover mating surfaces, so if you are using the 95 valve covers, you may prefer the NA heads so they wont leak.

The Knock sensor is on the side of the block behind the passenger motor mount.

SC water pump has extra coolant ports so these will need to be dealt with.
 

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Discussion Starter #3
I have read there is a slight difference between the valve cover mating surfaces, so if you are using the 95 valve covers, you may prefer the NA heads so they wont leak.

The Knock sensor is on the side of the block behind the passenger motor mount.

SC water pump has extra coolant ports so these will need to be dealt with.
1) If I don't care which valve covers I use, the heads are the same (SC vs NA)?

2) SO this means that I can re-use the timing cover (or whatever you call the lump the water pump bolts onto)?

3) I plan on buying a new WP anyway ($20-30) so the 95 N/A engine will get a fresher pump and this SC engine will get the 95's used NA pump. Problem solved, right?


-g
 

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1) If I don't care which valve covers I use, the heads are the same (SC vs NA)?

2) SO this means that I can re-use the timing cover (or whatever you call the lump the water pump bolts onto)?

3) I plan on buying a new WP anyway ($20-30) so the 95 N/A engine will get a fresher pump and this SC engine will get the 95's used NA pump. Problem solved, right?


-g
NA water pump wont bolt to the SC timing cover. They are different shape. Also the early SC timing cover doesnt have a mounting point for the Crankshaft sensor - it is bolted to the block instead of the cover, the NA timing cover has the mounting location for the sensor.

Valves are the same size. Heads are very similar, but like mentioned above, the SC heads are thicker casting.
 

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Discussion Starter #6
NA water pump wont bolt to the SC timing cover. They are different shape. Also the early SC timing cover doesnt have a mounting point for the Crankshaft sensor - it is bolted to the block instead of the cover, the NA timing cover has the mounting location for the sensor.

Valves are the same size. Heads are very similar, but like mentioned above, the SC heads are thicker casting.
Thanks for all this useful info, Dan. I have updated my original post.

I will re-use the SC heads
I will buy a new N/A waterpump.

I need an NA timing cover. This guy's post is quite confusing so I'm not 100% sure which cars I can get one from
http://www.sccoa.com/forums/showpost.php?p=980389&postcount=5

Q: Do I need to do something about the crankshaft sensor or will be compatible from the 89SC to my 93/95 ECU (depending on which I use).

Q: Finally, what about the injector rings?
Is it typical just to swap the two o-rings per injector or should I get the 4pc party pack (2 orings, pintle cap, spacer)

-g
 

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As long as the existing pintle caps aren't broken, you can just change the O-rings. If several of the pintle caps are broken, then it would be worth it to get new ones since that would likely mean the plastic will be pretty brittle on all of them.
 

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Q: Do I need to do something about the crankshaft sensor or will be compatible from the 89SC to my 93/95 ECU (depending on which I use).
I dont have an EVTM for the 1989 Tbirds, but I have 93 and 95.

The 93 SC uses a crankshaft position sensor with the DIS and the 93 NA uses a Hall effect sensor for the ignition module on the Distributor engine. The 95 Tbird also uses the Hall effect .. I recall reading that the early SCs used a Hall effect also, I guess it really depends on the type of harmonic balancer used and if the timing cover has the mounting points for the sensor.

The SC balancer is 0 balanced, and the NA are counterweighted - but you are already using the SC flywheel, I cant recall if it was the early style with the counterweight or the 0 balanced one.
 

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Discussion Starter #9
I dont have an EVTM for the 1989 Tbirds, but I have 93 and 95.

The 93 SC uses a crankshaft position sensor with the DIS and the 93 NA uses a Hall effect sensor for the ignition module on the Distributor engine. The 95 Tbird also uses the Hall effect .. I recall reading that the early SCs used a Hall effect also, I guess it really depends on the type of harmonic balancer used and if the timing cover has the mounting points for the sensor.

The SC balancer is 0 balanced, and the NA are counterweighted - but you are already using the SC flywheel, I cant recall if it was the early style with the counterweight or the 0 balanced one.

It should be early style because the flywheel, transmission, and engine all came out of the same donor car, right?

Unless you tell me otherwise, I guess I should start looking for a crank position sensor + timing cover...
 

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It should be early style because the flywheel, transmission, and engine all came out of the same donor car, right?

Unless you tell me otherwise, I guess I should start looking for a crank position sensor + timing cover...
Just look at your balancer and the sensor ring behind it .. if it looks the same as the SC one, youre OK .. but if the SC timing cover doesnt have the mounting point, you'll need to switch it or look for another one.

I cant remember, the early production 89 SC's had the duracast crank with the external balance and midway through 89 they changed to the forged crank and internally balanced components with 0 balance flywheel and balancer.
 

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I cant remember, the early production 89 SC's had the duracast crank with the external balance and midway through 89 they changed to the forged crank and internally balanced components with 0 balance flywheel and balancer.
Cool, didnt know this. I thought all SC engines were 0 balance.
 

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<-- hoping I don't have a duracast crank
 

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I have put a 28 oz flywheel on a zero balance engine...it vibrated alot until I figured out what was going on :)
 

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I have put a 28 oz flywheel on a zero balance engine...it vibrated alot until I figured out what was going on :)
I had a buddy with a 95 SC .. another shop mis-diagnosed his blown rear differential and replaced the clutch and flywheel - an 89 counterweight SC flywheel, it had a wicked vibration around 2000-3000 RPM, rattled the whole car, broke the motor mounts and the power steering leaked all over which took out the suspension bushings also. I had a hunch it was a flywheel problem, but didnt find out until I actually tore it all down to replace everything.

Chris - If you take your flywheel off, and it has an AA suffix on the part number its a Duracast crank setup.
 

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I had a buddy with a 95 SC .. another shop mis-diagnosed his blown rear differential and replaced the clutch and flywheel - an 89 counterweight SC flywheel, it had a wicked vibration around 2000-3000 RPM, rattled the whole car, broke the motor mounts and the power steering leaked all over which took out the suspension bushings also. I had a hunch it was a flywheel problem, but didnt find out until I actually tore it all down to replace everything.

Chris - If you take your flywheel off, and it has an AA suffix on the part number its a Duracast crank setup.
Unfortunately my new to me 89-92 engine has no balancer and no flywheel. Anything else to look at?
 

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Unfortunately my new to me 89-92 engine has no balancer and no flywheel. Anything else to look at?
Not unless youre going to take the crankshaft out and check for balance. I have the part numbers for the Duracast Harmonic balancer, Crankshaft pulley, and the Flywheel only if you had any of those parts.
 

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The 89-93 Crank sensor uses a 3-vane setup and the 94+ uses a 36 minus one tooth (if I'm thinking right ) just like the 4.6.

The 89-93 must use the Cam sensor to know which plug to fire (without it will guess till gets it right) but the 94+ knows only with the crank once it notices the missing tooth.
 

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Not unless youre going to take the crankshaft out and check for balance. I have the part numbers for the Duracast Harmonic balancer, Crankshaft pulley, and the Flywheel only if you had any of those parts.
If I take the pan off (which I need to anyway to reseal the pan) would I be able to visually identify the differences between the duracast and forged crank?
 

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If I take the pan off (which I need to anyway to reseal the pan) would I be able to visually identify the differences between the duracast and forged crank?
Chris - I dont think so, but I would turn it over a few times and look for part numbers, stamping ID's, etc .. usually the crankshafts with the internal balance will have some holes drilled in the counterweights also, look for those.

Bowez - The vehicle in question has no cam sensor, it uses a distributor instead.
 

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Chris - I dont think so, but I would turn it over a few times and look for part numbers, stamping ID's, etc .. usually the crankshafts with the internal balance will have some holes drilled in the counterweights also, look for those.
Thank you.
 
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