Ford six. Very cool!

[Steve.k]

https://m.facebook.com/157130251058147/ ... 662528823/. This is some ingenuity here.

[midnightbluS10]

That the one with the chopped up Cleveland heads on it?

[JoePorting]

That is cool. Thanks for posting. Would like to see the deck side of the head.

[Cubic_Cleveland]

I though the guy who built this ls headed version was a memeber here?

https://www.engineswapdepot.com/?p=4014

[Truckedup]

Cutting up two V8 heads and welding them together for use on inline 6's is done on Chevy 292 inline six cylinder engines also..

[mag2555]

Is that heck of long crankshaft a billet?

[Steve.k]

Yes modded cleveland heads. There was also a guy in Saskatchewan canada had a car Srapper 2 setup similar.I thought the stock 300 crank is steel they put it through a lightening process?

[Keith Morganstein]

Yes modded cleveland heads. There was also a guy in Saskatchewan canada had a car Srapper 2 setup similar.I thought the stock 300 crank is steel they put it through a lightening process?

Only the HD crank is steel (medium duty trucks).

[Steve.k]

Thanks Keith that's what I ive seen to.The only ones I've been around are out of trucks.

[grandsport51]

Bruce Sizemore Preparation H
Sorry no Pic from Car Craft 1971Eleven-Second Six
By Don Green

Ford's failure to release a V8 Maverick in 1971 (in a year when they approved the use of a 302-inch V8 in the new Comet, Lincoln-Mercury's version of the Maverick) was a definite cause for disappointment to small car fans. This was especially true because everyone had known since its original release hat the car was designed for a V8 (all, the necessary mounting holes were already in place on the chassis). Also, rumors had been circulating for a full year about the soon-to-be-releasedV8-powered Maverick, but 1971 announcement time came and went, and no V8 was to be had. Only the clunky standby sixes.

But apparently things weren't as bad as they seemed. Especially if you asked a group of Detroit area racers who were long-time proponents of straight sixes and eights. The group, numbering four, was in the process of preparing a six-cylinder Maveric for H/Modified Production, and a more unlikely group of guys to be racing Fords would be hard to find. Frang Prayg, an employee of General MotorsMotors Styling. Bot White, a Parts Manager at an Oldsmobile dealership. Art Keyes, a machine shop foreman; and their ace-in-the-hole. Bruce Sizemore, and employee of the Ford Motor Company, comprisedthe foursome. At that time Bruce was working in the now-defunct Performance Events group. He provided technical advice and is to a great degree, responsible for the construction of the engine.

The car is now running and running well. Driven by C/Stock record holder Tom Schumacher of Columbus Ohio, the Maverick was the H/MP class winner at the 1970 Indy Nationals. The best performance to date for the 2810-pound car is a very creditable 11.92 at 114 mph (the current National Record is 12.06 seconds). Theclass the car falls in, H/MP, understandably explains the car's name. "Preparation H", but the car's performance prevents it from being the butt of suppository-oriented jokes.

Anyone who has ever tried to make a six-cylinder engine competitive knows the myriad problems associated with an engine that was designed to be an economical workhorse rather than a racer. If nothing else, the vibration that in-line engines develop at certain rpm can frustrate and overwhelm all but the most serious engine builders. But Sizemore, Prayg, and others have been there before. They've repeatedly solved these problems on many different types of engines and were able to make the Maverick engine perform with the best with what appears to be very little effort. They were also very happy to discuss their approach to in-line engine building using their 11-second six as an example. But they were quick to stress that despite how the current engien runs, it is far from the final answer. Through their experience, they were able to develop a combination that worked well the first time.. And since the season was in progress when the car was first run, very little of the trial and error as experimenting has been done to improve the cars performance. When the racing season begins again in the Detroit-Ohio area, permitting more development work. Sizemore is confident that the Maverick will run 11.7's.

The engineis based on the 240 cubic inch six that was released in 1965 for use in the large bodied Ford passenger cars, Econolines and light trucks, and is commonly used in Taxis. With exception of the crankshaft, this engine provides all the basic raw material. The stock 3.18 inch stroke 240 crank is replaced by a heavy-duty crank from a 300 cubic inch Ford truck engine. The 300 crank, part number C5TZ-6303-D, has a 3.98-inch stroke and is made from forged steel with flame-hardened rod and main journals. There is also a 300 light-duty truck crank, but the heavy-duty version is the one to use. Bruce has the mains grooved by the Moldex Tool Company (the steel is so hard that the crank cannot be cross-drilled). Naturally, the crank should be checked for straightness. Use the 300 truck crankshaft damper, part number C5TZ-6312-K. When installing it, make sure both crankshaft snout and the inside of the dampner are perfectly clean. A particle of dirt could burr the shaft, throw the damper out of position and cause vibration. The damper should be torqued to 130-140 lbs-ft. It is also a good idea to mark the front of the damper to let you know if the outer half has slipped in relation to the inner half, as this would make your timing mark inaccurate.

The 240 engien block is a thinwall casting with a 4.00-inch bore and is identical to the 300 block. The first engine Sizemore built for the Maverick was overbored .060-inch. The large bore proved satisfactory for a couple of months of competition, but the walls of two of the cylinders finally cracked from teh strain. In the future no more than a .040-inch overbore is planned. The group align-bored the mains to insure accurate crankshaft fit. Bruce installs the crank with .003-inch clearance on the mains, using Clevite 77 bearings. The thrust is set at .006-inch. The block's deck surface should also be O-ringed using any good grade copper or stainless steel wire. The o-ring grooves should be cut with a diameter of 4.375 inches around each bore, and should allow the wire to protrude approximately .008-inch above the surface of the deck.

Sizemore uses 240 rods which are longer than those used with the 300 crank. The 240 rods have a center-to-center length of 6.79 inches, while the 300 rods are only 6.21 inches long center-to-center. The longer rods were selected to allowthe pin hole to be placed higher in the piston, hopefully reducing any possible tendacy for the pistons to rock in the bore. Naturally, the longer rods also reduce the rod angle and thrust.

The deicsion to use the longer rods was based on past experience. Also, Bruce was able to draw some parallels between the six and the successful 428's 4.13-inch bore, and both have an identical 3.98-inch stroke, so he sought a rod length comparable to that of the race-prepared 428. At this time he has not tried the stock length 300 rod for comparison.

The 240 rods were manufactured in two versions. Those made in 1969 and later have an oil squire hole drilled in a heavy boss on the rod's big end that srays oil from the crank journal toward the piston pin. Those rods prodcued in 1968 and earlier do not have the oil hole and boss and are therefore lighter. The '68 and earlier 240 rods (part number C5AZ-6200-A) also have smaller diameter, lighter wrist pins(.9121-inch compared with the '69 and later .9752-inch pins).

The rods should be prepared by grinding the forging lines from the sides of the rod's I-beam section (all grinding should be done lengthwise on the beam section) and drilling a 1/8-inch oil hole in the top of the rod to help lubricate the piston pin. The hole should be chamfered slightly after drilling. These operations hsould be followed by a complete deburring and a throough shot-peening for both the rod and cap. Bruce uses Clevite 77 rod bearings with .003-inch clearanc. The side clearance should be adjusted to .022-inch.

The pistons are J.E. forgings with the pin hole relocated to compensate for the longer 240 rods used with the 300 crank. Only two ring grooves are used in teh pistons; the single compression ring is a .017-inch step Dykes with a .012-inch end gap; the three-piece oil ring is from either Perfect Circle or Sealed Power. The cylinder block's deck height is cut to place pistons .010-inch down in the bores. When used with a head gasket having a compressed thickness of .038-inch this gives compression ratio of approximately 12.0:1. The cylinders walls are honed to a 600 micro-inch finish with .007-inch piston-to-wall clearance.

The cylinder head is a 240 casting with porting work done by Crane. The combustion chambers are cleaned and the valves unshrouded, increasing the combustino chamber displacement from 67 to 70cc's. Cran experimented with a variety of port configurations, buth round and square (see photo), with the square ports proving to be surperior. in airflow testing, the Crane head has shown a 40% increase in flow over the stock 240 head. Surprisingly enough, this has been accomplished without a great change in the cross sectinoal area of the ports. Rather, the increase has been provided by the reshaping of the ports and runners.

The head is currently fitted with stock 327 Chevy intake and exhaust valves (1 15/16 and 1.600 inches, respectively), but later airflow tests have shown a slight improvement from the use of reworked 427 Ford valves. The valves are the lightweight hollow-stem versions and require that the stems be shortened and the head diameters be turned down to allow their use. New keeper grooves must also be cut in the stems. The advantage of the 427 Ford valves over the 327 Chevy valves at least from an airflow standpoint, lies in the contourof the underside of the valve head. The ford valve has a steep, smooth angle of approximately 23-degrees from the stem to the seat while Chevy valve has a more abrupt angle of apporoximately 10 degrees from the stem to the seat. Sizemore emphasizes, however, that the advantage has only been indicated in airflow testing, as they have not yet had a chance to actually try the Ford valves in the engine. The basic 427 Ford valves that are required for the modification are the 2.195-inch hollow-stem intakes (part number C5AZ-6505-N) and the sodium-filled 1.733-inch exhausts (part number C5AZ-6505-N). Be prepared for the much greater initial cost of the lightweight Ford valves as compared to the Chevy valves, not to mention the additional labor.

The valves are cut with 45-degree seats, while the heads get 44-degree seats for a 1-degree interference fit. The intake seats have a width of .040-inch; the exhausts have a width of .060-inch. "Preparation-H" uses General Kinetics valve springs with a seat pressure of 120 pounds, hard anodized aluminum retainers and Isky hardened keepers. Sizemore uses Sharp 1.6:1 needle-bearing, roller-tip aluminum rocker arms mounted on screw-in rocker studs from a high performance 289. Use the stock, silver-colored McCord matrix head gasket, part number C5AE-6015-B. The factory stocks two similar gaskets for these engines -- be sure you get the gasket marked with a small stamped-in "Mc" and not one with a stamped-in "V". Secure the cylinder head to the block using a hardened steel washer under the head of each bolt. Watch the length of the head bolts to avoid bottoming if you have milled either the block or the cylinder head surfaces. Torque the head bolts to 70lbs-ft, retorquing them after the engine reaches operating temperature.

The camshaft was purchased from General Kinetics and has 310 degrees of duration, a .372-inch lift at the cam (multiplied by the 1.6:1 ratio rocker arms, this gives a lift of almost .600-inch at the valve) and 90 degrees of overlap. Bruce isntalled the cam with split overlap which required the use of an offset 4-degree advance key supplied by Mr. Gasket. Stock 289 solid lifters are used with Smith Brothers' 3/8-inch O.D., heavywall, chrome-moly pushrods. The stock timing gear set should be discarded and replaced with a Cloyes gear set. The stock fiber cam gear has many small teeth that shear easily compared with the larger, much stonger teeth on Cloyes aluminum cam gear.

Bruce recommends two ways to go for ignition, either a Mallory Rev-Pol dual-point distributor or an Accel ball bearing dual point conversion kit for the stock 240-type distributor should be set to give 20 degrees of crankshaft advance (10 distributor degrees) at 3000 crankshaft rpm. Initial timing should be set at 18 degrees for a total of 38 degrees of advance. use Autolite BF-22 plugs gapped at .030-inch.

The exhaust was constructed from 1 3/4-inch O.D. tubing, with each pipe having a length of 34 inches from the flange to the beginning of the collectors. Cylinders, 1, 2, and 3 are grouped into one collector, whiel cylinders, 4, 5, and 6 are grouped into a second, separate collector. The collectors themselves have an inside diameter of 3 1/2-inches and an overall length of 9-inches. Sizemore again emphasies however that these particular headers are not a result of trial and error. They are the first onand only ones that have been tried on the car to date, and wil most likely be improved upon in the coming season.

The intake manifold, like the headers, was constructed of 1 3/4" tubing. The length of the tubing was cut accordingly to allow an overall length of 18 inches from top of the carburator horn to the intake valve seat. Using three 48mm, two-barrel Weber downdraft carbs, the tubing manifold was constructed to allow one carburator barrel to feed each of the six cylinders. No lenum chamber is used. The Webers are fitted with .170-inch main jets and .140-inch air correction jets.

The six lubricated by a stock oil pump that has had the pressure relief spring shimmed to provide 70 pounds of oil pressure. The oil pan sump was lowered to increase the capacity to nine quarts (less filter), and the oil pump pickup was lowered accordingly and positioned in the center of the sump. Valvoline 40-weight is used as lubricant.

The clutch and flywheel are all Schiefer units originally designed for 289-302-351 cubic inch V8's. The forged aluminum flywheel and 11-inch, 2800-pound forged aluminum pressure plate are both coated with a .010-inch sprayed steel surface for heat dissapation. The disc, part number 50-40128, is a special Shiefer item designed especially for Ford four-speed applications. Because of the six-cylinder's vibration, Bruce uses Locktite to secutre the 1/4x20x3/4-inch Schiefer bolts that hold the flywheel to the back of the crank. The entire clutch unit is housed inside a Lakewood 289 (6-bolt) scattershield.

The four-speed transmission is a small-input 2.32:1 low gear unit of the type used on 289's and low performance (Widson) 302'2. If you're shopping around for a used trans, you should be aware that there is an almost identical four-speed that was used with the 390 engine. It has the small diameter input shaft and the same gear ratios, but the pilor on the main shaft is 5/8-inch shorter than the pilot used on the 289-302 transmissions. This difference will not allow the main shaft to seat properly in the rear of the crankshaft adn will ruin the clutch as well as the pilot bearing. Use the roller bearing developed for LeMans engines; either a Fafnir number 9103KDD or a New Departure number 773L03. The trans is equpped with a Hurst Competition-Plus shifter.

A shortened 428 Cobra Jet driveshaft connects the trans with a '69 Mustang rearend. The stock width rearend carries a 9-inch diameter ring gear in a 4.89:1 ratio, a Detroit Locker and stock 31-spline Mustang axles. The rear springs are stock six-clinder units used with adjustable Koni shcoks and 34-inch long tractino bars.

"Preparation-H" has shown that a six-cylinder engine can be built at at reasonable cost, developing enough power to move a 2800-pound Maverick well into the 11-second bracket. In its current form, the engine is putting otu approximately 400 horsepower -- and more on the way.

THE FRENCHTOWN FLYER
VIP Member
Posts: 5533
Joined: Sat Nov 09, 2002 9:25 pm
Location: FRENCHTOWN
Re: Preparation H article
Post #2 by THE FRENCHTOWN FLYER » Fri Dec 04, 2015 1:44 pm

CoupeBoy wrote:
...Ford's failure to release a V8 Maverick in 1971 (in a year when they approved the use of a 302-inch V8 in the new Comet, Lincoln-Mercury's version of the Maverick) was a definite cause for disappointment to small car fans...

[grandsport51]

D2FD6ECE-256A-44BF-9716-BE4442ADD9D6.jpeg

98231C66-EFB0-495D-8D92-D58EB34C3736.jpeg

95689884-8725-4182-82AF-CD631763A211.jpeg

30639200-6FAF-4AC4-95A7-40F20CF84D2F.jpeg

9E68D05D-91A7-47EC-A932-CD3D296A2D64.jpeg

Sorry for long posts but we knew Bruce and CJ
TRUE RACERS AND INNOVATORS.
Dave B,

[pamotorman]

there was a dirt track modified that raced near here using the 6 cylinder ford engine that whipped up on the chevy V-8s pretty regularly.

[Steve.k]

Thanks Dave very good read. Those guys were ahead of the curve no doubt about it. That ingenuity impresses the hell out of me! For sure!

[SchmidtMotorWorks]

If someone really wants to run a 6 cylinder, the DOHC engine that came in some Chevrolet trucks might be worth looking into.
Perhaps a Jaguar DOHC, some Jaguar engines had very nice lower-end parts.

[Tuner]

there was a dirt track modified that raced near here using the 6 cylinder ford engine that whipped up on the chevy V-8s pretty regularly.

I remember an article 35-40 years ago in "Stock Car Racing" or "Circle Track" about a guy (I think ASA in Wisconsin, but ?) who was successful in making power with a 300 Ford Six but the bottom end wouldn't hold together, the forged steel truck cranks he was using would crack. When he finally ran out of forged steel cranks he used a cast iron crank and had no more failures (at the time of the article). The opinion was the cast crank was easier to make with the counterweights in more ideal locations, the castings could have more strategically located counterweights.

In the early '70s I tuned some 500 2bbls on a 300 Ford for a drag racing deal that the flywheel came loose in just a few passes, time after time, better bolts, lock tabs, nothing would keep it tight. The guy finally tack welded the flywheel bolts and it still came loose. Another was '70 240Z Datsun that after it got the cam and headers treatment when the RPM went north of 8000 a few times the flywheel would get loose and start clunking. The '70 240Z crank has no counterweights at all, same as a 4bbl. Pontiac OHC 6, just bearing journals. The 1bb. OHC Pontiac crank has counterweights. As I recall you can tell a 6 cyl. OHC Pontiac crank from other GM 230 and 250 sixes because it has scallops in the counterweights to clear the block where the accessory drive housing mounts for the distributor, fuel pump and oil pump.