ENGINES

Engine Casting Decoder

To translate Casting Codes - Dates are determined by the last digits - thus D122 translates
as April 12th 1942 or 52. C234 is March 23rd, 1954. (Single digit for year) Month is determined by the first letter - A = Jan., B = Feb, C = Mar., D = Apr., etc. This is true for all CWC (Campbell Wyant and Cannon) engines. The "unknown "foundry uses the full date, 1-15-54 no code involved. Translation of date codes = MO/DAY/YEAR

Hudson Engine ID Codes1

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Cast Iron Crack Repair

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All HUDSON ENGINES are Prone to cracks in the block as well as the manifolds Repair of these cracks is a daunting task for even the most experienced shop.  PERKINS REPAIR has mastered the art of saving the cracked Hudson engines, heads and manifolds.

Perkins Repair Service, owner Jeff Perkins, over 25 years of experience in Cylinder Head reconditioning, head & block surfacing and Cast Iron Crack Repair at affordable rate. This shop provides quality service to the vintage auto and tractor enthusiast at an affordable price Call Jeff or the staff at 317-847-7446 or jphudson49@people.com 

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The Original Hudson 7X Engine - Created by Bernie Siegfried

Starting with the block, .015" was milled off the top deck, intake ports were enlarged to take 2 1/16" valves with 30 degree seats, exhaust ports to take 1 3/4" valves. All ports were polished. The block was fully contour slope relieved to the Hornet gasket shape. The slope finishing about 3/32" below the block top. Head bolts were 1/2" diameter. A Pacemaker Aluminum head was drilled to for 1/2" bolts and relieved to accommodate the larger valves. Bores were honed to "C" size. Pistons were "A" size. Piston heads were sloped at the valve facing side the width of the block relief and the relief depth. Piston pins were finish ground on the inside diameter and this diameter tapering from the enter to the pin ends. A set of the lightest of the 40 weights of connecting rods were used by Hudson had .020 straddle milled off both sides of the big end. A rods were semi polished as was the crankshaft. Crankshaft bearing surfaces were made to allow .001" - .0015" additional bearing clearance. The tappet oil holes were plugged. The rod squirt holes were closed. This was done to permit a continuous flow of oil at pressure from the relief valve through a copper coil oil cooler. As an after thought I removed the upper ring pin and cut the pistons off at the lower ring groove. Overall I reduced the weight of each piston and rod assembly by slightly more than 1/4 pound. All pistons, pins, rods and crankshaft were microbalance. I semi polished the inside of a Twin_H manifold. "Somehow" word of what I was doing got our to the various suppliers at Hudson and all the vendors got into the act.

The Carter representative supplied me with two carburetors with increased CFM capacity, Federal Mogul provided precision heavy duty bearings, and the MacQuay-Norris man with a set of low friction quick setting rings.

With the exception of the block deck milling and the crankshaft balancing, all the work was done on the engine was accomplished by me in the basement of my house with tools acquired in the 20 years I had been tinkering with racing engines.

With the added relief area in the block, the head and the piston slope, the Pacemaker head produced a compression ration of 8.25:1 which I knew would work well with the 92 octane fuel Pure Oil Company provided.

Bernie Siegfried - Hudson engine test engineer

• Hudson's Pinned Rings & Fluid Clutch
• Letter to Mr White from Bernie about Hudson engines
• My Years at Hudson Part One
• My Years at Hudson Part Two
• 1972, The year for Number 43 about Bernie's Stock car
• Tales From the Hudson Motor Car Company
• Hudson Engine Conversions - The FIRST 7X engine is born

  • Page 1 , Page 2, Page 3, Page 4

My son Joseph with Smoky @ 1999 Nashville HET National Meet

Narrow block Hudson engines

There are two Post War Hudson Big Six Blocks, the "Narrow Block" (1948-1950), discussed here, and the "Wide Block" (1951-1956). Both engines used the same basic architecture: Chrome alloy block, L-Head, 4 main bearings. The later block was introduced to rectify and strengthen any weaknesses shown in severe usage. The Narrow Block engines used mechanical valve lifters during its production life.

NARROW BLOCK 232 and 262 CID (Cubic Inch Displacement).

Hudson introduced the "Big Six engine" line in 1948 as a 262 CID version only. It was called the Big Six because it was actually larger in CID than the "Big Eight" which was only 254 CID.  The 262's bore is 3.5625" and the stroke is 4.375". This is called the Narrow Block engine to differentiate it from the "Wide Block" so named because the crankcase is wider.

The Narrow Block  was produced as 262 CID in 1948, 1949 and 1950. In 1950 a 232 CID version was introduced for the Pacemaker model Hudson. The 232 CID block has the same bore as the 262 but used a 3.875" stroke crankshaft. Aside from the crankcase width, the Narrow Block engines have different cylinder head water passages, and the lower oil pan rail is straight from the front engine plate to the rear engine plate.

The Narrow Block 262 engines produced in 1948 and early 1949 used an aluminum 2-barrel intake manifold. All 232 versions used a 1 bbl intake manifold. Cylinder heads were available in either aluminum or cast iron and were unmarked in 1948 and 1949. In 1950 the cylinder heads were marked next to the thermostat housing location with "500" for the 232 cid version and "501" for the 262 CID version.

L-Head engines have their valves in the block, not the head. Valve sizes for the 262 and 232  were 1.8125" for the intake and 1.5625" for the exhaust. These sizes were the valve size through the entire production run from 1948 until 1950.

All Big Six engines received hand-fitted pistons and bearings during production. As such, the size information for each piston was hand-stamped into the block behind the lifter and valve covers on the right hand side of the block. Hudson's attention to detail like this resulted in excellent power for a L-Head engine as the engines were assembled with the utmost care (almost blueprinted) when assembled at the factory.
 
The crankshaft flywheel flange uses 7/16" bolts pressed into the crank, and with a special lock plate for the nuts. These smaller size bolts have been an issue since the beginning of production, sometimes resulting in the bolts shearing from the engine's torque. Flywheels for both stick and Hydra-matic transmission cars must be sealed to the crankshaft using good, high quality sealer to prevent leaks .

All Narrow Block engines are suitable for stock and mild performance rebuilds, but are not recommended for high performance usage. Cylinder heads and oil pans do not interchange with the 1951 and later Wide Block Big Six engines.

Cylinder Heads. 
An aluminum cylinder head was optional on all three engine displacements during this time. In most cases, the aluminum head upped the compression ratio by 0.5 and did give a slight increase in horsepower. Head gasket retention with the aluminum cylinder head was, and is, an issue due to warping and differing expansion rates of the head and block. (If buying a used aluminum cylinder head, be sure to ensure it can be machined back to straight and true).

Camshafts.Camshaft duration changed several times over the years. The standard factory cam for Hudson 232, 262 and 308 engines is Part # 306344. The lift is 0.356".

The performance camshafts Hudson used in most Wide Block engines were the "742" and the "040" cams. They can be fitted to the Narrow Block engine. Both of these camshafts started out as 7X racing camshafts, but are suitable for daily driven Hudsons. The "742" camshaft had the ramp opening and closing rates altered in 1955-56 for use with hydraulic lifters and yet work very well with mechanical lifter engines for street performance.

The actual specifications for these two camshafts have never been accurately listed except for the lift. The "742" has .354" valve lift and the "040" has .390" valve lift and 268 degrees of duration. Both lift specs are at zero lash. New reground camshafts are still available that offer better performance than these two cams.

Crankshafts.
1948-1954 232 and 262 CID Crankshafts and reciprocating assemblies will interchange between the 232 and 262 cid engines, however the 308 CID crankshaft will not fit in the Narrow Block.

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When replacing the timing chain cover make sure the crankshaft Spacer is not worn. The diagram above shows how the seal wears the spacer. The spacer can be reversed to provide an unworn surface on which the new seal will ride.

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Stroker Crankshaft and Rods

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HOW TO BUILD A "7X" ENGINE By Sloane F. McCauley

Sloan died a number of years ago, but his talent and love for Hudsons lives on in this paper. He was A.H.R.A. National Record Holder Formula 4, B/A and D/A racing a Hornet powered Jet.

Most Hudsonites have heard of the magical 7X engine, but a great many of them do not really understand what it is nor what modifications have been performed to make it a true 7X In this article we will show you what is required to 7X your own 308 engine. Of course, it will be necessary to remove the engine from the car and completely disassemble it so at rebuild time would be a good time to 7X your engine. The basic differences in the 7X engine and the stock Twin-H power 308 are the larger valves, the wider and deeper relief area, the hot cam, the dual exhaust manifold, and the high compression head. The 7X engine has 2" intake valves and 1 11/16" exhaust valves. These valves can be easily installed in the stock 308 block. The valve pockets must be enlarged and then hand ground to achieve the venturi /effect under the valve seat which is so important to obtaining max flow through the valves. These oversize 7X valves are available from Jack Clifford as is the 311040-7X cam, which is reasonable in price and affords a good performance boost over the stocker. The 7X cam is set at .016 H and the timing specs are intake opens 14 degrees BTDC, intake closes 62 degrees ABDC, exhaust closes 56 degrees BBDC, exhaust opens 20 degrees ATDC Gross lift is .390. The 232 head is used on the 7X engine, giving a compression ratio of 8.7 to 9.2-1, depending on the variance in hand machine work in the relief area. Horsepower of the 7X engine is rated at 180 and torque is 305 ft-lbs. at 3,000 rpm. The 7X dual exhaust manifold helps in the back pressure-relieving department but these are becoming very scarce items. The stock exhaust manifold can be split and dual exhausts installed if a genuine 7X dual exhaust manifold cannot be obtained. The stock Twin-H power intake system is also used on the 7X engine. Of course, the heart of any good 7X engine is the relief area. This is the area of the block across which the mixture must flow from the valves to the cylinder. This area must be deepened and widened to achieve full 7X status. The first thing to do is get a head gasket and some machinist's dye. Paint the block surface with the dye and put the head gasket on the block. Now take a scriber and scribe a line, following the head gasket. This will show you what must be removed in order to widen the relief area all the way out to the head gasket. Also, the edge of the relief area should be radiused where it meets the head gasket to afford greater flow. The relief area should be deepened right down to the edge of the valve seat and cut all the way out toward the bore. The counter bore that the valve sits in will be eliminated and you will have a flat plane surface from the edge of the valve seat to the cylinder. The best way to cut the relief area is to use a milling machine such as a Bridgeport along with an end mill tool. This is the easiest way to remove the bulk of the material and then the block can be hand finished and smoothed. It is possible to grind the complete 7X relief by hand, but I would not recommend it. I believe you would be better off paying a machinist even at $10/hour because the work is not precision type work and can be roughed out quickly and easily on the machine and then hand finished and polished. I would estimate that I have nearly 100 hours work in the block in my race car, mostly hand finished This is only my second block in five years of racing this car, and is far superior to The first one, which was lost when a piston exploded and the rod wiped out the cylinder wall and went right out through the side of the block. Needless to say, if my present block were damaged beyond repair, I would cry a lot. The block is the critical part of a flathead racing engine. Unlike an OHV, in a flathead, all the power is produced by the breathing ability of the block in which the valves are located, as opposed to the easily replaceable head of an OHV engine. One thing to remember, however, is that just because an engine is advertised as being a 7X does not mean that it really is. It has become fashionable to call any mildly souped 308 a 7X engine. In reality, the 7X engine was a dealer-installed option (which means built by the factory racing team) the specs of which were set forth in a Hudson factor3~ technical bulletin dated 2/2/52. The true 7X engines were generally hand built for racing purposes and it is doubtful that many of these original 7X engines are still around. A high altitude engine was produced by the factory, which included some 7X parts, such as the oversize valves, 232 head, and hot cam, but were not true 7X's in that the relief area was not deeply machined and hand finished. The later model '55 and '56 blocks have deeper stock relief areas than the earlier blocks which make them more desirable for a stock engine, but if the relief area is to be machined to 7X specs, it makes no difference which block you use. The second-generation 7X engines, such as mine, are also hand-built units utilizing Clifford parts. Don't let anyone pawn an engine off on you as being a 7X without First pulling the head and checking for sure, as a tremendous amount of hand preparation goes into creating a genuine 7X engine. Well I hope this gives everyone a general idea of what a 7X engine really is, and if you are planning on rebuilding that tired old 308 anytime soon, l'd definitely recommend 7X mods as the performance increase per dollar spent is fantastic. Now we will discuss how to 7X your block and we will delve further into proper block preparation as applied to a racing engine.

Correct block preparation is a very exacting science, the details of which are often overlooked by the amateur hot rodder. The major rule in block preparation is "cleanliness is next to Godliness." I assembly my engines in hospital like surroundings, and if you want your engine to last, I'd advise you to do the same. The first thing to do with an old block after disassembly is to have it placed in a hot caustic solvent tank to clean out the din and sludge The cam bearings must be installed after caustic cleaning because the vat would devour them for its dinner. The block should be milled about .020 to insure a straight and level deck. The top edge of the cylinder bore should then be chamfered in order that the rings will go in easily without breaking. Many hot rodders advocate align boring the main saddles of the block but I have found this to be unnecessary on the old Hudson blocks. The Hudson engine was a precision product and all tolerances were very closely held. Besides, align boring is a very difficult operation which requires extremely expensive equipment to perform correctly. Some of the cheaper align boring rigs are nothing but junk, and they can really butcher a block.

The lifter bores should be smoothed and polished with fine emery cloth. On other engines, a brake cylinder hone can be used for this job, but the Hudson lifter bores are too narrow. The head bolt holes in the block should be slightly chamfered at the top of the block surface to allow for any distortion caused when the head bolts or studs are torqued down. .. The block should be honed on a Sunnen CK-10 honing machine. The old hand-held drill-operated corncob hone is junk and can never deliver a professional ring seal. For best results, a honing jig should be made from an old head, which can be torqued down, on the block to distort the cylinders. The hone can then be passed through the holes cut in the old head and hone the block with it distorted as it would be with a real head installed. Cylinder wall distortion can and will run as high as .003 to .004 so this is the only way to get a topnotch professional quality ring seal. The block should now be completely de-burred and smoothed. All edges should be chamfered, the rough spots in the ports should be smoothed out, and any loose casting slag should be ground away. The inside of the Hudson blocks is already painted orange with special paint which is good, in that tiny nicks and cracks are sealed and the oil can flow back to the pan easier. The main oil gallery is plugged with welch plugs at each end of the block. When oil pressure is raised above 50 psi, these plugs tend to go away, so the fix is to thread the oil gallery front and rear and install pipe plugs. This prevents any chance for oil leakage, and the pipe plugs can be easily removed for cleaning at rebuild time. Another little tip I can pass along to you is that the front main bearing cap should have another oil return hole drilled in it to allow for greater flow of oil from the timing cover back into the pan. I experienced an oil buildup problem in this area early this year due to increased oil pressure, which was causing the front timing, cover seal to leak. After we drilled the second oil return hole on the other side of the main cap, we had no more problems. Now we come to the most important part of block preparation: cleaning. Simply vat cleaning the block is not good enough. The best way to really clean a block is to take it to the 25-cent car wash and soap the hell out of it. Stick the sprayer in all the oil gallery holes and blow detergent through them until the flow is clean. Also clean the entire block inside and out. Splurge and spend a couple of bucks here, as it will pay off in the long run. The next step is to get some small bristle brushes, such as gun cleaning brushes, and run them in and out of all the oil passages in the block and crank, using soapy water as a cleaning solvent. You'd be surprised how much dirt you can still get out of the block with these brushes, even after it has been cleaned in a vat and soaped at the 25-cent car wash. You will need to use an extension in order to pass the brush through the main oil gallery, which runs the length of the block. Brush all the oil galleries until they come clean, then rinse off the block and crank. You are now ready for assembly. I do not have the space to elaborate on proper assembly methods, as this article deals with block preparation. However, the main thing to remember is "keep it clean". This does not mean a disorganized, hurried assembly on a dirty garage floor. I like to assemble my engines on a pair of sawhorses upon which the block can be placed. This gets the engine off the ground and can easily be wrapped up in cellophane after assembly is completed to protect from dirt. Take your time in assembling the engine. Be sure all the parts are operating room clean and wash your hands often

Don't get in a big hurry, and above all - THINK!