Tempo - Topaz Car Club of North America FAQs (frequently-asked questions)
Category: Main -> Ford Tempo / Mercury Topaz FAQ -> 2.3L HSC/HSO I4|
What is the 2.3L HSC/HSO?
The primary engine used in the Tempo/Topaz is called the HSC due to the cylinder head being based on a "High Swirl Combustion" design. Ford's theory was that a higher swirl rate would help to atomize fuel better at lower rpm's, improving both low rpm torque and helping with mpg's. Back to top
The HSO motor used the same basic cylinder block /bore and stroke, but a different cylinder head and camshaft were substituted. The HSO stood for "High Specific Output" and was the higher performance version of the HSC motor. The HSO cylinder head and camshaft typically display improved performance above 3000 rpm as compared to the lower revving, more restrictive HSC designs.
While one can substitute the HSO head for the HSC cylinder head ( or vice-versa ) on any year 2.3 Tempo / Topaz motor, the HSO camshaft can only be used with first ( 1984 - 1987 ) or second ( 1988 - 1991 ) generation HSC motors. This has to do with the fact that third ( 1992 - 1994 ) generation Tempo's & Topaz's make use of a cam position censor in the computer ( ECM or Electronic Control Module ). This sensor is missing on the HSO cams, making it incompatible for the last series of these cars.
Is the 2.3L HSC/HSO the same engine used in the T-bird TurboCoupe, Mustang and Pinto?
No. These are completely different motors even though they share the same basic metric measurement of displacement. Don't confuse the two, as very little ( if any ) internal parts will interchange without major modifications. Some external parts, such as the flywheel, etc.... may possibly interchange with some machining. This opens up the door for some potential high performance mods IF one is willing to do the research and spend the necessary money.Back to top
Can I swap the 2.3L OHC engine into my Tempo/Topaz?
A 2.3L OHC swap will be very difficult for several reasons. Conversion to rear-wheel drive (RWD) will be necessary, as the 2.3L OHC was never offered in a front-wheel drive (FWD) platform car and thus has no known transaxles that will bolt up. The 2.3L OHC is also longer than the 2.3L HSC/HSO by several inches, and installation will require alterations to the chassis. It is possible with enough money and time invested, but will not prove easy.Back to top
What aftermarket modifications exist for the HSC/HSO?
Due to the lack of professional or street racing interest in these motors and vehicles, very few "High Performance" parts were ever produced for them. Most of those that were produced have either been scrapped and / or sold by now, leaving very little available to purchase new at this point in time. Back to top
Like any other motor though, custom ground cams, headers, intake manifolds, etc... are available for them if one is willing to pay the cost. Due to the lack of mass production, modifying these motors can become costly, especially if one doesn't shop around.
Basic hot-rodding techniques, such as porting of the existing cylinder head, improving airflow into the motor via modifying the intake system, installing a higher flow exhaust system, increasing fuel flow into the motor, improving combustion efficiency through improved ignition parts, etc... can all add up to sizable gains in power production. Depending on the amount of money and effort that one wants to invest into and HSC / HSO motor, power levels of appr 125 - 175 HP appear to be well within reason. Figures higher than this are achievable, but typically at much greater expense.
My engine has no get-up-and-go. What can I do to get more power?
Is your maintenance up to date? Have you made sure that EVERYTHING under the hood and in the drivetrain is operating properly? Have you THOROUGHLY inspected ALL of the vacuum lines under the hood? When's the last time you changed the plugs and plug wires, set the timing, cleaned the MAP/MAF & Throttle Body, replaced your air filter / breather / PCV valve / Fuel filter, etc ??? Back to top
In many cases, these motors aren't running as good as they could due to a lack of maintenance over an extended period of time. One has to remember that the last production run of these cars were made over a decade and a half ago. As such, time, with the associated wear and tear, have taken their toll. This is especially true of cars that were used as "mules" or "beaters" i.e. daily transportation that never received the love due them. In such cases, it is not uncommon for the fuel injectors and / or Catalytic Converter to be thoroughly clogged. While the injectors can be thoroughly cleaned while still in the system, the Catalytic Converter would need to be replaced.
While you can't reverse damage that has been done to the motor and transmission due to a lack of proper maintenance, one can minimize any further losses and help to restore some of the lost power through selecting the proper parts and performing proper maintenance. Depending on the variables involved, each situation will vary. For specific recommendations, please check the forum archives first. If the answers to your questions can't be found there, post a question in the proper forum with as much specific info pertaining to your vehicle and the problem. Our members will do their best to share info that may help you to resolve the situation.
What about Turbocharging or Supercharging the engine? Is this feasible?
Applying forced induction to the HSC is a complex matter requiring serious planning, research, and money. The HSC/HSO is basically of limited power potential and will not accommodate a high level of boost. While forced induction of an HSC / HSO motor can and HAS been done, engine modifications include custom intake and exhaust manifolds, higher flowing exhaust, all of the necessary connecting and mounting hardware associated with the forced induction device being used, an intercooler, custom valvetrain parts, custom aftermarket pistons / rings, etc.... all add up to a LOT of work and expense. Should one choose to go this route, be prepared to run into a LOT of fabrication and expense. Back to top