Alcohol Fired Mustang Small Block Engine - Revving Unto Caesar
Probe Builds An Alcohol-Fired Jalapeño Small-Block For South Of The Border
From the June, 2002 issue of 5.0 Mustang & Super Fords
By Tom Wilson
Photography by Tom Wilson
Where do you start when trying...
Where do you start when trying for more than three times stock 5.0 power output? Probe begins with its Dominator short-block, which for $1,860 gets you a stock block, a 3.400-inch stroker cast-steel crank, and all the happy stuff connected to it. To handle power pushing the four-digit range, owner Caesar Castro went an extra $2,000 for this stout R302 Ford Racing Performance Parts block with its humongous bearing bulkheads, four-bolt main caps, and extra metal meat everywhere.
If you've been anywhere in the real Mexico-by that we mean away from Cancun and other tourist fleeces-then you know Mexicans are seriously into a good time and don't waste life on bureaucratic nonsense. We can only imagine the high jinks this engine is going to get itself into.
Blower here, stroker there, it's all sort of the same after awhile. Occasionally something different pops up, such as a 347 running on alcohol-in Mexico. The call on this one came from Probe Racing Components in Torrance, California. The company was sort of building, freshening, and upgrading the unusual small-block all at the same time, and calculating its alcohol fuel ought to be good for something unique. We figured a gander over Probe's shoulders would be worth it.
Stroker crankshafts are even...
Stroker crankshafts are even easier to find these days than are stockers. Even for a big-power engine, Probe went with its normal cast-steel 3.400-inch stroker crank for the 347-inch displacement. Probe notes these cranks come off the boat with nitrating, but it added a heat treatment hardening process as well. To reach the required 28-ounce balance, Probe ground off some of the outer circumference of the counterweights. It would have taken drilling big balancing holes otherwise, so clearancing some of the outer counterweights was easier.
Engines such as this are always good for a story anyway. The tale here is the Mexican owner, Caesar Castro, lives in Hermosillo, Sonora, and enjoys participating in local contests of automotive machismo. The rumor is these events take place on barricaded public streets, which we can easily understand given the liquidity of petty local regulations in La Republica. But having not spoken directly with Señor Castro, we're not precisely sure exactly what sort of contests these are. Clearly they require plenty of noise and torque, as Caesar's other engine is a 572-inch 460 stroker-both the big-block and the 347 small-block we're looking at here doing duty in the same '72 Mustang. Given the voracious alcohol consumption of these powerplants, we surmise mano-a-mano drag racing not too far out of town is the duel in question, but you never know.
We can also safely postulate Señor Castro is no small fry. In a place where many citizens are happy the busses continue to operate, he has somewhere approaching $20,000 in this engine, which ought to guide you in your desires to replicate it.
When clearancing a 347 package...
When clearancing a 347 package in the more confining R302 block, there's just that much more metal to grind. Here's the deeper-than-usual 347 rod-bolt-to-cylinder-wall grind job on Caesar's block.
Because alcohol is consumed...
Because alcohol is consumed at just about twice the rate of gasoline, hot-to-trot alky motors can have some fairly serious fuel pumps. These are invariably crankshaft driven, leading to the gilmer belt drive sprocket and extension shown here with Caesar's Romac harmonic damper. These parts previously ran on his Brodix-headed small-block.
Naturally, the connecting...
Naturally, the connecting rods are Probe 5.315-inch, steel H-beam TrackMasters. As with the crankshaft, they are Chinese imports, which explains their low cost. Alcohol fuel explains the rust spots on the beam-the super-clean-running alky is like running an engine on solvent. Parts come out of running engines clean and have a tendency to pick up light surface rust quickly. Clevite 77 H-bearings are used; the H stands for Hard. That means the bearing has a steel shell, a larger fillet radii, and more heat-resistant materials. They are designed for big power engines that can really lay the crank and rods against the caps. Naturally, these cost more than the usual inserts. Rod bolts are ARP 3/8-inch L19 upgrades-good for the 9,000 rpm this engine may see.
In light of the high rpm anticipated,...
In light of the high rpm anticipated, Probe moved down from 0.150-inch piston pins to these 0.120-inch wall units. That's nothing radically lighter, but a little diet for the reciprocating weight without going to short-lived 0.090-inch wall pins as used in engines with 20-run lifespans.
Do we really need to say these...
Do we really need to say these are Probe custom pistons? The moderately tall domes look racy and are needed to get the desirable 14:1 compression, but they aren't the last word in smooth flame front travel. Probe went to a low-tension 0.043-inch Childs & Albert ring package from the more common, but heavier, higher-drag 1/16-inch stuff common on street engines. A little more gap is needed for the hot alcohol burning, and the siamesed R302 cylinders were filed in too. Assembler Roy Baird said he could really feel the lack of drag when rotating the crank on the engine stand. He said it felt like half the torque normally required with 1/16-inch rings.
Everyone has to save money...
Everyone has to save money somewhere, and when you're just having fun with your amigos, popping the big bucks for a dry-sump oiling system is a bit much. Caesar's engine will do its thing with a simple Melling high-volume, high-pressure oil pump and Probe driveshaft.
Caesar cut no corners when...
Caesar cut no corners when it came to cylinder heads, opting for a fine set of Blue Thunder small-block race heads. Designed strictly for big-power small-blocks, the Blue Thunders are full of raised ports and big valves to ensure maximum power. Considering their excellent construction and power potential, these heads are affordable at $1,800 a pair. For many customers, they'd work just fine out of the box. While the water passages work with nearly any Ford block and intake, the header bolts and valve covers follow Cleveland patterns. Caesar uses big Hooker 4-into-1 headers.
We are also reliably informed that some of this engine-at least a few surviving bits-once resided in, appro-priately enough, a Mexican block. Fitted with Brodix heads, a Cola billet crank, a 51/48-inch steel main girdle, and a Track Dominator intake, that engine split its block like a dry corn tortilla. Therefore, Caesar wanted to move up to a Ford Racing Performance Parts R302 block this time around, along with new Blue Thunder heads in an effort to make more power as well as greater longevity-or at least more noise.
Another interesting aspect of the engine, but one we unfortunately do not have a photograph of, is the Flying Toilet injection. This is an aftermarket injection system not uncommon in NHRA drag racing. Ron's Fuel Injection Systems [(800) 513-FUEL] in Tucson, Arizona, is the source on these nonelectronic, high-volume, constant-flow designs that use their own throttle bodies and a four-barrel intake manifold fitted with port fuel injectors. On Caesar's engine, the Toilet, as it's affectionately called, flushes atop a Probe Industries custom sheetmetal intake for sewer-like airflow.
At press time, the tequila burner had yet to fiesta with an engine dyno, but George Klass guessed 900 hp and kept a straight face, so we'll tell you he said that. Could be, too, as alcohol is simply gorgeous racing fuel, offering 120 octane and frigid induction temperatures, so the compression can be sky high-it's 14:1 here-and the airflow packaging is helicopter like. The camming is aggressive in the extreme, with more than 0.800 inch of intake valve lift. So, with as much as 9,000 rpm on tap, this one really ought to wiggle the worm. Heche la!
On The Flowbench
Minimal porting gets the Blue...
Minimal porting gets the Blue Thunder heads flowing up there with Hoover Dam. Probe worked the exhaust port and blended the bowl; the intake received just bowl blending to reach 285 cfm on the exhaust and 395 cfm on the intake ports. Otherwise the heads are out-of-the-box.
Caesar's Blue Thunder heads posted some nice numbers on West Coast Cylinder Heads' flowbench. As these heads are relatively new, we thought you'd like to see an independent look at how they flow. The intakes were cleaned in the bowl; the exhausts received some port work as well.
|Valve Lift||Intake (cfm)||Exhaust(cfm)|
|0.100|| 82.2|| 64.5|
Note: Lifts are in inches, flow in corrected cfm at 28 inches of water
Now here is some real he-man...
Now here is some real he-man sport. Probe's custom grind for Caesar boasts some eye-watering numbers to bandy about the cantina. How about 0.830 inch of intake valve lift and 276 degrees of duration at 0.050 inch of lift? The exhaust is also open all night, spec'ing at 0.797 inch of lift and 279 degrees of duration. Nasty!
A great reason to choose Blue...
A great reason to choose Blue Thunder's head for an alcohol engine is that pipe plug sitting above the spark-plug hole. It opens to a partially drilled passage leading to the intake port. It's designed to be drilled through by the customer to allow port injection on alcohol engines. Caesar will be using this feature, instead of the modified injector mountings in his old Victor intake manifold.
Rather then stick with one...
Rather then stick with one manufacturer, Probe went catalog raiding for Caesar's valvetrain. The rockers are Probe 1.8 aluminum rollers, the solid lifters are by Isky, and the pushrods are 8.00-inch-long, 3/8-inch Manleys. And that cam-it's a custom mechanical roller from Cam Motion.
Blue Thunders come with either...
Blue Thunders come with either 70 or 50cc combustion chambers. Obviously, Caesar and Probe opted for the high-compression 50cc version to get 14:1 compression. This allowed the moderate piston domes to provide all the squeezing-the heads are unmilled. The Manley stainless steel, hardened tip, swirl-polished valve package uses 2.200-inch diameter, 6.600-inch overall length intakes with 1.710-inch diameter, 6.380-inch overall length exhausts.
Probe first fitted Caesar's...
Probe first fitted Caesar's Blue Thunders with Probe stud girdles as shown here. The engine was not run in this configuration, and later Probe went to a new shaft rocker system custom made to fit the Blue Thunders-and now available from Probe. In any case, the springs are garage-door stuff from Isky. Duals with dampers, they provide 275 pounds at their 2.00-inch installed height and a pushrod-straining 750 pounds at their 1.200-inch open height. Max lift was given as 0.800 inch, which means the intakes are living on borrowed time. Then again, valvesprings in this league tend to lead short, happy lives. Manley 10-degree retainers and keepers are used. The retainers are raised 0.100 inch to clear the tall-spring-installed height.
Probe offers several sheetmetal...
Probe offers several sheetmetal intakes and matching offset distributors built for them by Woods Engineering. Caesar's engine took the single four-barrel intake top to match the Flying Toilet throttle body. Dual four-barrel tops are available. The distributor is an MSD billet unit sawed in half and fitted with an internal belt drive at the offset.
While we missed the fully...
While we missed the fully dressed engine, some of its accessories were on-hand during our visit. These include the Meziere billet water pump and the alcohol fuel pump.