DIRTY STUFF
INEEDED an engine. One of Henry Ford’s cast-iron wonders: the sidevalve V8. Built in their millions in the US and Canada, mine was destined to drop into a 1949 frontengined race car, the remains bought in pieces and rebuilt to race again in Historic events.
These heavyweight mills, with their massive cranks, first appeared in 1932 and remained in production until 1954. I was after the last of the line, an 8BA, which powered 1949-54 Custom sedans. This had been uprated with larger conrod journals, shell bearings, newstyle water pumps, conventional-type valves instead of the mushroom foot pieces running in split valve guides, a front right-side distributor, and heads featuring front water off-takes. Small changes, except for the rear of the block, which was shortened to remove the integral clutch housing, and the oil pressure relief valve was now in the pump instead of the front of the block. With a bore of 3.187in and a 3.75in stroke, engine capacity was a moderate 239.4 cubes. I reckoned I would bore the cylinders to 3.312, fit a set of JP domed alloy pistons and add finned, high-compression alloy heads.
There are a couple of secrets to extracting double the stock power output of these engines.
Firstly, both the inlet and exhaust valves have the same-size 1.500in heads, and the inlets also have short 1.5in-diameter ports – probably Henry’s idea to keep manufacturing costs down. When rodding guys see these and how easy they are to get at, they attack with an internal grinder and open the holes right up. Wrong. This only loses power, because the speed of the incoming fuel/air mix drops right off, and the cylinders don’t fill. The easy solution is to fit 1.750in inlet valves from Holden’s 308 V8, which only need metal added to the ends of the valve stems to get the clearances right. That way, the charge speed in the ports increases, adding a bonus of more power.
Secondly, don’t grind the cam lobes. Apart from weakening the camshaft itself – where high revs and big spring loads will see the rear of the cam break and go out through the back of the block – sidevalve engines do not like big valve durations and small lifts, which a lot of tuners specify. The alternative is a lobe profile of 50 degrees overlap, with a valve lift as high as you can get. Otherwise, too much of the fresh charge will simply blow out through the open exhaust valves, and you lose power again.
How we do this is a bit messy, and expensive. The only way to increase valve lift (as the lobes work directly under the followers and these work directly on the valve ends), is to build up the lobes with satellite weld. Or you can organise a billet-steel cam, as Merv Waggott used to make years ago. The aim is to increase lobe lift to a max of .375in – the most Ford’s .998in followers will handle. Otherwise, lobe peaks will run outside the follower base circle and rip the tops off the lobes. I couldn’t find a cam lobe master of 25/65-65/25 with a .375in lift, so I settled for a Porsche grind of 37/73-73/37 with a .335in lift, which worked reasonably well.
I could have bought screw-adjustable lifters from Speedway, or even a manifold-mounted supercharger, but the purse was tight, so I declined. I got a pair of Offenhauser finned alloy 9:1 heads from a guy in Adelaide, and followed that up with stuff from Speedway Motors in the US of A, like valve springs that were not massive (as there’s not much weight in Ford’s valvetrain); an alloy cam gear, replacing the stock cotton phenolic piece; a Mallory twin-point distributor; and four twinbarrel Holley 94 Bug Spray carbs, which have .250in-larger venturis than either the famous 97s or the Chandler Grove units.
As the original race car had four inline carbs on an alloy manifold, I decided to go one better and made my own tube-and-plate inlet manifold. This was a pure ram manifold, with eight individual runners ending in fabricated carb-mounting plenum chambers. Which was one hell of a job!
Centre exhaust port splitters are essential and can be bought, but I made my own from plate and rod, which fitted better too. Three-into-two headers were also made from pipe and plate, and I took metal off the stock flywheel to suit a nine-inch clutch, tossed the original manual fuel pump and fitted a high-capacity electric unit. On cold-range sparkplugs, the engine fired first spin of my modified starter motor, and wasn’t too noisy via the open exhaust pipes.
I sold this old race car to Tony Osborne, after running three regularity events at Queensland’s Lakeside Raceway. Without a body, because I couldn’t find 25 grand to replicate the original alloy shell. Tony ran it on a chassis dyno in Melbourne, where the V8 pulled 190bhp running on seven cylinders, as one piston ring cracked and fouled a sparkplug. On eight, it should have made over 200 – double the output of an original stock engine!
CENTRE EXHAUST PORT SPLITTERS ARE ESSENTIAL AND CAN BE BOUGHT, BUT I MADE MY OWN FROM PLATE AND ROD, WHICH FITTED BETTER TOO