May 1, 2007
Where is all this budget building leading? Take a look at the engine shown here. This is where we ended up with the first full build. This great-looking, aluminum-headed 5.0 cranks out power in the mid 300s. Cost, as seen here, is $2,289 plus hard work.

If you like the lead shot, be aware that we don't get to that stage of the build until next month-although you'll need to follow what is done here to get there. Maybe we're jumping too far ahead, so let's backtrack to where we left off on the last installment of the saga of the Comp Cams special budget-build project.

Working with select students from the University of North Carolina at Charlotte (UNCC), the plan is to build an all-purpose race car that, while performance is a priority, having fun with it and limiting costs is equally as important.

We started with an '88 manual-shift 5.0 already equipped with a number of basic speed parts, but with a really tacky interior. Race cars don't generally have interiors, so our 5.0, sourced by Dale Sciranko of Custom Performance in Concord, North Carolina, was acquired for the princely sum of $2,800. After detailing it and overhauling the limited-slip diff, we made a best pass at Mooresville's eighth-mile strip of 9.044 seconds at 77.2 mph. This equates to 14.13 at 96.7 in the quarter for a total cost of $2,862.

When a Zex nitrous system jetted for 75 hp was added, our best went to 8.77 at 81.9 mph (13.57 at 100.7 mph), but torque-induced wheelspin was very much a limiting factor. The cost, including the Zex upgrade, brought our total to a little less than $3,400. Everything done engine-wise came under the heading of maintenance or bolt-on. The car was capable of bettering such a performance, but traction from old tires was a major handicap and our first problem to address. But on with the engine-with its high mileage, it was time for an overhaul.

If the bores have no measurable ridge, as is often the case with injected 5.0s, then a cheap and easy-to-use glaze buster can be used to recondition the bores to accept new rings.

Budget Block Build
It was entirely practical for us to overhaul the engine currently in the car, but with deadlines and such, it was far better for us to get a complete junkyard motor and start from there. In fact, to make life easier, we started with two junkyard engines and did tests on one or the other, but we will deal with them as if we were working on a single unit. Because you can go with what's already in the car, we are not counting the cost of our junkyard-sourced long-blocks, which, by the way, typically cost $150 apiece.

One of the assets of 5.0 fuel-injected engines is that they do not wear out bores at the rate of a carbureted engine because fuel wash on the bores is almost eliminated. This means far less metallic junk in the oil. As a result, crankshafts last much longer even if the bearings don't. Tear down a few 5.0s and you will find that, for the majority of them, a rebore or a crank grind is far from mandatory. This has been the case with the last four out of five engines I've torn down.

The first job was to drain the oil, then wash off the engine. To clean the entire engine, there is little substitute for a few cans of Gunk and a 1,000-psi pressure washer. After a couple of hours, we had a pretty clean engine, but my 10-year-old daughter, Jacque, and I looked more like we hit pay dirt on an oil-drilling rig.

Other than lifting off the intake, heads, and crank, we had this engine stripped to the bare block in about three hours. Block inspection showed near zero bore wear and that a three-leg, spring-loaded glaze buster (about $25 from NAPA) would fix those bores in next to no time. But first the block had to get down to bare-metal clean.

At this point, you need to take the block to your local engine shop and have the cam bearings removed. The cost to remove and replace cam bearings after the final cleanup (including a set of low-cost bearings) is typically about $50. For a bare-metal cleanup, a really good job can be done for the price of a couple of cans of barbeque-grill cleaner and an electric drill and wire brush. After this preliminary heavy-duty cleaning, redo the job with a stiff brush, Gunk, and a high-pressure hose. The Gunk leaves a thin film on the block that stops it from rusting right away, giving you the time needed to wipe down and blow the block dry with compressed air.

KB Performance Pistons has an extensive range of both cast (above) and forged pistons suitable for moderate-to-high performance use. Since nitrous is on the menu, we elected to use a set of the new low-cost, high-performance forged pistons (right).

You are now at the point where a glaze-buster hone can be used to lightly clean up the bores. Don't worry that you are doing this without the benefit of a deck plate. Ford does it all the time, and the bores you are redressing are probably out of round by a half-thousandth anyway.

Next on the agenda is to go through all the threaded holes in the block with an appropriate tap. The head-bolt threads are especially important to clean out as this will ensure all the parts are properly tightened when they are installed.

Now is the time to do the final cleaning. The Gunk and a hose are once again your allies. Once it is absolutely clean, dry the block and apply WD-40 to all the machined surfaces, bag it, and take it around to the machine shop that removed the cam bearings for new ones to be installed. When you get it back home, wipe down the surfaces to be painted with lacquer thinner, then prime and paint them.

Crank, Rods, And Pistons
About the time you take the block over to the engine shop to have the cam bearings knocked out, consider what might need to be done to the crank. At the least, it should have the journals polished if they are still perfectly round and to size. Most engine shops can check the size of the crank and polish it for as little as $20. Ours, as is so often the case, was still within manufacturer's original tolerance and exhibited no measurable wear.

Here is our KB-equipped short-block assembly as it was received from Speed-O-Motive. With everything done to bring it up to a competition spec, this assembly cost $2,175.

Now we had to fix the rod and piston assemblies. With the old rings removed, we performed a good cleaning, using barbeque-grill cleaner for the first round. While the Ford forged pistons may not look the raciest, they are tough and wear-resistant. The chances of these being non-reusable are slim. Just be sure to check that the ring grooves are still clean and square as they tend to wear tapered as the miles mount up. Use a new ring and check the clearance with a set of feeler gauges. If the clearance shows parallel and is less than 0.003 inch, then they are good to go for another 100,000 miles.

All our rotating assembly parts checked out, as did the oil pump, so all that was needed to rebuild this otherwise-stock bottom end was a full engine gasket set, rings, and bearings. You can source these parts as a kit from Speed-O-Motive for $199, or from Summit Racing or Jegs for a few more bucks. With the rings gapped and bearing clearances checked with Plastigage, the bottom end of our motor went back together.

Because the original heads suffer from poor flow due to sharp turns and the like, the ports, both intake and exhaust, respond well to even the simplest port mods.

Of course, while things went well for us, it could be that your engine's block is not in good shape. If this is the case, you will either need a different block or have the necessary machine work done. We had just such a deal with one of our engines, so it became necessary to recondition the short-block to the fullest extent. This could not have happened at a better time editorially, as KB Performance Pistons had just come out with a line of forged street pistons designed to hold up against the rigors of racing as a weekend warrior. These pistons, said to be fine with up to 150 hp worth of nitrous, are intended to be no-frills, tough pieces. These pistons were shipped to Speed-O-Motive, where the boss, George Ullrich, built us a new short-block assembly. Because of shipping costs to and from North Carolina to Speed-O-Motive's shop in West Covina, California, it proved more convenient for us to get a complete short-block assembly sourced from Speed-O-Motive. If you live in the Los Angeles area, then you can save a few bucks by taking over your existing core to be reconditioned.

The block was equipped with new bolts and was line-honed, bored, decked, deck-plate- honed, and enameled. The pistons were equipped with Total Seal rings, rods were reconditioned and fitted with ARP bolts, the crank was ground, and the complete rotating assembly was balanced. This makes it about as race ready as you can get short of using an aftermarket forged crank and rods. Assembled ready to this spec, the total is $2,175, or you can assemble it yourself and save $425.

A carbide cutter was used to reshape the guide bosses and to take out the larger irregularities on the short side of the ports. The rest was done with 60- and 80-grit emery rolls.

Cheap Power Iron Cylinder Heads
If the existing heads on the engine are good, then they can be given a basic do-it-yourself porting job that will use up about a couple of weekends of time. But be aware that 5.0s tend to wear out valveguides, so if the odometer has more than 100,000 miles on it, you have only a one-in-four chance of owning heads with guides fit for further use. Our spare heads needed guides, but the original heads on this test engine did not. Because of this, we are not including the cost of the seat and guide job here, but chances are you will need to consider this option.

Getting fresh guides can be done one of two ways. The first option is to have K Line guide liners or regular brass/bronze guides installed and the seats recut. Expect this to run in the neighborhood of $180, and if the valve stems are good (as is often the case) they can be reused. Your second option is to use the oversized stem, stock replacement valves, sold to the trade by Engine Tech in Carrollton, Texas. These valves have a +0.015 stem and a +0.030 valve head on both intake and exhaust. To convert will cost about $220, but your heads will now have oversized valves, which is a plus. Also, note that these valves have the keeper grooves about 0.030 inch lower, so if you intend to use higher lift than a stock cam and stiffer springs, they will need to be used with +0.050-inch keepers to regain installed spring height.

Here's our budget long-block assembly equipped and ready for a break-in and dyno test on our DTS engine dyno. The electric water pump, carb, intake, and distributor will be swapped out for fuel-injected counterparts when installed in the car.

Back to the porting. Nothing other than reducing the obstruction caused by the valveguide bosses and blending in port irregularities was done on these heads. The main body of either port was not enlarged other than what it took to clean up major bumps in the casting with a 60-grit emery roll (you will need about two dozen of them). Close attention was paid to blending in the port pocket with the valve seats. The valves had the sharp edge formed between the seat, and the back face of the valve was rounded off so the back transitioned into the seat progressively. Check out the graph (Fig. 1) and you will see that extra flow is achieved right off the seat. This is due to the smooth blend of the ports into the seats. Because extra air is now accessible by the engine throughout the lift range used by even the stock cam and valvetrain, we can expect a decent return in output for the time invested.

With 0.030-inch shims under the springs to increase the spring force, the spare ported heads were assembled and set to one side, ready to swap out with the stockers when we go to the dyno.

Meanwhile, the rest of the engine was rebuilt using the head gaskets in our Speed-O-Motive gasket kit. After they were cleaned, the cam, lifters, and pushrods all went back in the same position they came from. A note here concerning head bolts. We managed to get the threads smooth by using a wire brush in a drill press. The threads must be smooth so they do not have excessive friction, otherwise the clamping loads on the head gaskets will be below par. As such, the head gaskets will blow easier when nitrous is used. If there is any doubt about the usability of the bolts, replace them with new ones.

While on the dyno, Mervyn Bonnett ran some lifter preload tests. Because roller lifters have a tendency to collapse, they usually produce best results when adjusted toward the bottom of the preload. However, some brands of lifter do not lube the rockers well when adjusted like this, so check oil flow at cranking speed before running the engine.

Engine Dyno Break-In
To break-in our engine and check that all was well before we installed it in a car, it was run on our DTS engine dyno. Since (at that time) the dyno was not equipped to run a fuel-injected 5.0, the long-block was fitted with an Edelbrock Performer intake manifold and a Barry Grant 650 Speed Demon carb along with a mechanical distributor supplied by Performance Distributors. After a two-hour break-in, the carb and timing were optimized and the figures in the chart (Fig. 2) were achieved. For an otherwise-stock engine, this unit was putting out some good numbers, but we knew some of that power would go away when the fuel-injection system was fitted after engine installation in the vehicle.

After break-in and servicing, the engine was installed into the car. Remember, the car has BBK long-tube headers. Just for the record, on the chassis dyno these have repeatedly shown a 17-20hp increase over the stock headers on near-stock engines. With the timing set to 14 degrees at idle, the Comp Cams Special's engine turned in rear-wheel output figures as shown by the blue curves in Fig 3. The increased output from the rebuild amounted to some 15 lb-ft and 10 hp in terms of peak numbers, but the low-speed torque was up as much as 20 lb-ft of torque. All this came with a glass-smooth idle, better throttle response, and an engine with zero blow-by.

Changing out the stock heads for our ported ones shows just how much these engines are starved of air. Compared to a set of aftermarket heads, our ported iron ones are still down on flow. Also, the stock fuel-injection intake can hardly be considered much better than mediocre, so getting the full benefit of the heads is not practical at this stage. Even so, the heads boosted torque by 10 lb-ft at peak and over 20 lb-ft at 5,800. Power increased by over 20 points, and the engine hung on longer at the top-end, thus allowing a shift point about 300-400 rpm higher.

On The Track
With winter fast approaching, the opportunity to run the car at this spec did not present itself. This was compounded by the fact that our second engine was about done and waiting in the wings. What we will need to do here is get some numbers from our computer simulation using the rear-wheel power curves generated from the chassis dyno test. With the original 225 rwhp we managed a best-on old and not very grippy drag radials-of 9.044 for the eighth-mile at 77.2 mph. Assuming no other changes except our fresh powerplant, the car's computed performance was 8.86 seconds at 79.45 mph. The sad part is that the extra power available would still not have returned a 60-foot time under 2 seconds. This is proof positive that tires have to be high on the priority list. Maybe that will happen next month, along with the upgrade to aluminum heads and such as seen in our lead engine shot.

COSTS SO FAR
(ROUNDED TO THE NEAREST DOLLAR)
No. 1 engine
Speed-O-Motive engine O/H kit $199
Cleaners, Paint, and Misc. Supplies $33
Nuts and Bolts $12
Accel {{{5000}}} Series 8mm Cable Set ${{{80}}}
Spark Plugs $18
Distributor Cap $12
Cam Bearing R&R plus Bearings $50
Crank Polish $20
Total $394