SCCoA Super Coupe Club of America: Dedicated to the preservation and performance of the Thunderbird Super Coupe - 1989-1995

Google

Super Coupe Club of America > SC Literature > Ever wonder what changes Ford made to the standard 3.8 L engine to turn it into an SC?

submitted by Duffy Floyd
DuffyF56@aol.com

Here is a synopsis of the changes made by Ford for the Model year 1989 to make the standard 3.8L Engine into the SC version we all love (and hate at times).

To allow for the additional power generated by the engine there were new designs for reinforcement made on the following components:

Block
Main bearings
Crankshaft Bearing Caps
Crankshaft (Dura-cast initially and forged steel for the majority of the production run)
Steel crankshaft sprocket
Timing Chain
Cylinder head
Head bolts
Rocker arms

The throttle body was designed new for the SC motor.

Water routings in the engine were redesigned for the SC motor.

Intake Manifold:

Of course to accommodate the supercharger the intake manifold was changed to provide a way to mount all the upper engine components such as the SC, air bypass valve, inlet plenum etc.

Exhaust Manifold:

These to were redesigned for the SC version. Each side houses a Heated Exhaust Gas Oxygen sensor (HEGO). The use of the HEGO allows accurate sensing of O2 level in a lower temperature exhaust gas (200C- 392F) when compared to a EGO (unheated) sensor. On the SC the HEGO sensor on the right side is located in the exhaust pipe just downstream from the exhaust manifold for that side. On the left side the HEGO is located in the exhaust manifold itself.

Cylinder Block:

The cylinder block was redesigned and reinforcement was added to increase durability and strength of the block. The water passage opening locations were also moved.

Both the ATX and MTX camshafts (Automatic transmission equipped cars and Manual transmission equipped cars) were redesigned to allow for newly designed roller tappets. Roller tappets have the advantage of reducing sliding friction and improving fuel economy. Because of the choice made to include the roller tappets it was necessary to include guide plates and retainers to secure them.

The main bearing caps were made one inch taller and the cap bolts were increased in length to allow the caps to be secured properly to the block.

Initially Ford planed to use an improved method of manufacturing the crankshaft to add strength to the unit. It was referred to as Dura-cast. Due to production issues with the Dura-cast process, the vast majority of SC cranks were forged steel. Note that if you rebuild your SC Motor?the main journals can only be refinished to 00.25mm (0.010-inch) undersized and the rear main journal can not be refinished since it is already 0.010-inch undersized. The reason for the undersize rear journal was to prohibit any standard cast iron cranks being run down the line in an SC engine which would surely result in a warranty problem. If a standard crank would possibly be tried in a SC short block, the main bearing caps would not bolt down properly.

The balance shaft used on the standard 3.8 L (a feature used to reduce engine vibration) was eliminated and replaced by a spacer in place of the balance shaft drive gear.

A knock sensor was added to increase ignition performance. This is a piezoelectric accelerometer sensor that is designed to vibrate at the same frequency as the engine knock (pre-detonation). The sensor operates in consort with the EEC IV engine control system to retard ignition timing and hopefully eliminate the detonation before real engine damage occurs. If you ever have to replace one make sure you get the correct version since there are sensors made for at least 4 different frequency ranges depending on the application.

The rear main oil seal was modified to improve the sealing characteristics and to provide more durability. Some of you may have experienced rear oil seal failure in other Fords. Before approximately this vintage engine for Ford, the seals were mainly two piece and over time the rubber seal would actually wear a groove in the steel crank. The only true fix was to replace the crank. Now with this redesigned seal it is a one-piece unit which allows the use of a "sealing ring" which can be installed over the groove and allow a new seal to be installed and the leakage to be stopped.

Cylinder Head:

The cylinder head was redesigned to increase the bolt boss diameter and deck thickness. The water passages (between the cylinder head and block( were revised to improve the sealing between the two components. The valve springs were improved by strengthening and made smaller in diameter. The spring seats were changed to accommodate the new spring design.

The cylinder head bolts are larger and have been made stronger.

Crankshaft Damper Assembly:

The crankshaft damper was changed to a cast aluminum piece to reduce weight.

The rear of the damper was fitted with a cutter for the Distributorless Ignition System (DIS) system. It has three vanes which when passing past the block mounted Profile Ignition Pick-up (PIP) sensor generates a signal to both the DIS Module (mounted on the top of the engine beside the Ignition coil pack) and the Electronic Engine Control Assembly (ECA {EEC IV Module}) and gives the base spark timing.

Camshaft:

There were two different types of camshafts designed. Automatic and manual transmission cars each had their own unique camshafts. They were color coded yellow for the ATX version and pink for the MTX version. The paint was applied to the rear end of the camshaft.

Timing Chain Tensioner:

A tensioner and corresponding snubber were added to the engine.

Pistons:

The piston domes for the pistons were redesigned to increase the performance. The pistons were also constructed of high silicone aluminum (hypereutictic). The compression ratio was 8.2:1.

Oil Pan:

The oil pan was diecast to reduce noise and vibration.

The oil level sensor was modified to also double for an oil temperature sensor.

Oil Cooler:

A Modine oil cooler was added to increase both engine and oil life.

Valve Covers:

The valve covers were diecast from magnesium for weight reduction.

Platinum tipped spark plugs were added for increased life and performance concerns of the engine.

Download PDF of this article

Club email: scguys@sccoa.com
www.sccoa.com
Document Last Modified: 07/29/04 03:33 AM
  Copyright ©1996 - 2017, Super Coupe Club of America