Engine
The original engine, most of which came with the car was a 140 but as with any race car it has been changed a number of times. The main race engine is still 140 based but with various mods to make more power and be reliable at the same time. There is a fine line here! This is the current example
The current heads have been prepped based on flow bench numbers and all the tried and true race modifications such as deep seats and bronze guides. Much time was spent making sure all the casting flash was removed.
A through porting, small stem custom intake valves, stock exhaust valves and a three angle grind to the sealing surfaces was done. Springs are Isky 235D racing springs with inner damper with Comp Cams steel caps and locks.
I use roller rockers and a stud girdles from Clarks on both my race and my backup engine.
All this gets covered up with a set of deep cast valve covers from The Shop.
I replaced the bolts with 1/4-20 studs to hold them on.
The angle port exhaust stacks are 1 ½” with custom flanges from Stinger Motorsports. Clean thoroughly!
The cam is a custom Schneider grind and I use a set of Isky hydraulic lifters with a Clark’s aluminum gear and retention ring.
The crank shaft is a race prepped stock unit cut to a .010 under bearing size and is polished, balanced, magnafluxed, deburred, oil holes chamfered and has the cam gear welded. A set of .010 over Clevite triple layer bearings hold it in place. Clean thoroughly!
A set of custom aluminum oil push rod tube splash baffles as shown in “ How to Hot Rod Corvair Engines” are used under the lifter bores held in place by screws and Loctite.
The block cylinder studs were were replaced with ARP heavy duty studs. The case bolts are also ARP’s from Clark’s. I only use the two inner bolts for extra stability as the case has factory locating studs on the ends. The oil pick up is an extended model to reach the bottom of the Clarks finned and baffled aluminum deep oil pan. I use Clarks’ finned oil aluminum pans because they add about half a quart without hanging too low and are strong enough to act as a skid plate. Clean thoroughly!
The oil pressure regulator resides in the side of the cover. This needs to work smoothly. The bypass relief hole is enlarged to 3/8” and the plunger spring pressure is increased by adding a 5/16” ball bearing or spacer to the spring. This will give around 50 psi. Clean thoroughly!
The oil pump I use is the Clark’s Pro Flo high volume unit. Some say you do not need one but, with a remote filter and long remote cooler lines I think you do. Most racers use one.
As stated previously the stock idler shaft has to be removed as the new pump has a longer one. Also the end cap has reliefs for the gear shafts to ride in which will keep the gears stable. A pinning kit comes with it to locate the spacer. There is a bit of fettling with everything to make sure there are no interferences with the rotating parts but I like this kit.
The oil filter adapter which bolts to the top of the rear cover is another piece that needs a lot of detailing and modifying. Before cleaning I cut the stock oil filter mount off and tap the holes for pipe plugs. This can be welded over and I have used both methods. When using pipe plugs one must be very careful not to split the thin area on the bottom or you will have a big leak. Don’t ask me how I know this! The stock oil bypass valve is also removed. No plugging is required here. I usually remove the web for a little freer oil flow but it’s not necessary.
To plug the stock fuel pump boss I use a 15/16” freeze plug installed from the bottom. Then I grind down the aluminum around it.
The gasket area is another place to use the plate and sand paper honing to get it smooth and even. With the fuel pump rod sleeve removed I grind down the aluminum boss below the gasket area to make it easy to hone the gasket surface.
Carburetion
For vintage racing I use the four single barrel carbs with racing mods. Big bore carbs have have enlarged venturis, extended cluster arms, 1 1/2” throttle plates,side jets, float bowl vents, and a general smoothing of the air horns. I still use two primary and two secondary units with the great Roger Parent Heim joint linkage.
Also I use a spacer setup from Norm Latulippe under the carbs with equalizer hoses which is purported to add a few HP. Not sure if it does or not but I run it. The fuel inlets all have -6 AN fittings.
For air cleaners I usually run K&N mounted on stacks made from exhaust tubing but, I do have some nice stainless mesh filters on velocity stacks made from aluminum drinking glasses for show.
Ignition
The distributor is stock Corvair from a 102 HP standard engine for the more aggressive curve, modified with a sleeve to limit mechanical advance and timed around 32-36 degrees total. Points trigger a MSD spark box mounted on the package shelf.
I run a set of NGK Racing R5674-7 or 8 plugs gapped at .045. A set of Seth’s Wires carries the fire to the plugs with a MSD Blaster coil.
Since I run a total loss system the alternator is gutted and runs a stock pulley which frees up a few HP and helps keep the belt on. The battery is a Braille AGM racing type.
Cooling
Engine cooling air is from a stock fan with ½” cut from the outer diameter and rebalanced.
cut down fan driven with an aluminum pulley. The crank pulley is a deep groove indexed racing model with timing marks engraved in the outer ring.
I normally use a NAPA belt
Oil cooler and filter
Since the stock engine oil cooler and filter are not up to racing standards a remote oil cooler and filter is a must.
A Mocal 17 plate cooler is mounted in the front compartment and plumbed with -10 AN fittings and PushLok hose. I use ½” nominal steel EMT conduit pipe for the runs in the tunnel to and from the engine. I welded steel male AN fittings to the ends. The cooler is ducted so all air passes through the cooler and out the bottom of the trunk.
In the engine compartment we have the Canton cartridge type remote oil filter and a Mocal thermostat which is partially closed until the oil temp reaches 180 degrees before opening all the way.
This makes engine warm up quicker, keeps some oil flowing through the cooler and keeps from shocking the engine with cold oil.
To prevent lack of oil flow on startup there is a 2 quart Canton Accusump mounted beside the driver seat with a T handle to remotely operate the valve. The T handle is activated to pressurize the engine with oil during startup plus if you suddenly lose oil pressure at speed it will keep the oil flowing long enough to shut down and hopefully save the engine.
The connection at the engine is a modified stock oil cooler adaptor with male -10 AN fittings welded to the in/out openings
For the oil pressure senders I used a piece of 1/8 steel brake line tubing with adapters and a flex hose from a grease gun to mount a remote manifold with tees on the side rail. It has the electric sender for the gauge and an adjustable snap switch set at 20 psi for the low pressure warning light on the dash and the connection for a mechanical gauge in the engine compartment.
Back to Race Vair
Jugs are Clark’s full fin 60 style repros ordered with a .004 clearance. After degreasing and cleaning thoroughly with hot soapy water, I paint them with high temp flat black, using several light coats. I use copper head gaskets and stock bottom gaskets to shim the jugs to get the pistons to valve clearance needed.
On the top side I used a thicker (.040) stock baffle under the blower cover with the corners of the louvers radiused to prevent vibration cracks caused by the high revs destroying the baffle. This is an often missed but very important mod for a racing engine as the crankshaft is very close to the bottom of the baffle and can contact it if the baffle breaks up. Clean thoroughly! The top cover has a second crankcase vent installed on the opposite side as the stock one. It exits into its own catch tank as does the stock vent.
The rear engine cover is another important piece of the engine where I do a lot of detail work. I first heat and remove the stock fuel pump rod sleeve using a tool I made from a bolt and rounded nut to drive it out. I do the same with the oil pump idler gear shaft as it will be replaced with a longer one. Heating the area helps with removal. I then smooth and level the three gasket surfaces by using a flat plate surface, 400 grit wet or dry sand paper and WD40 as a lube. Clean thoroughly!
All the internal oil passages have been smoothed and radiused as well and the stock oil bypass valve removed. The bypass valve is replaced with a plug made from a nickel filed down to fit, edges peened over and sealed with JB weld. This is in preparation for the remote oil filter. Clean thoroughly!
Click to see more photos.
Click to see more photos.
Click to see more photos.
Pistons are Clark’s forged .040 inch over with stock pins individually gapped Total Seal rings. Rods are stock lightened and balanced units with ARP bolts. Pistons need notching due to cam lift to clear valves. I used a special piston notching tool to do this.