Procedure: (long form)
- I said plug in the oil and water heaters at the top of the page because it can take as
long as 2 hours for everything to warm up. At the racetrack, the first person in the garage
in the morning always plugs them in, even before turning on the coffee pot. They often
consist of 115 volt Watlow heating pads glued to the oil tank and the bottom tanks of the
- If the engine is freshly rebuilt, you will have also plugged in the heater on a separate
pressure pre-oiler, often called a hot oiler. Don't confuse the hot oiler with the coffee
pot. Hot oil will taste to you like garage coffee, but the engine won't like java in its veins.
- If you're in doubt about the state of charge of the batteries in the starter cart, put
the charger on it.
- If the fuel pump has sat a long time, take off the output hose and pour some 3-in-1
oil into the pump to prime it.
- Remove the spark plugs.
- Make sure the car is out of gear and the ignition is off.
- If the engine is a fresh rebuild, attach the hot oiler. Look for a dash 2 or so fitting
installed in one of the main bearing oil galleys in the bottom side of the crankcase. Open
the valve on the hot oiler and watch for pressure on the oil pressure gauge on the
car's dashboard. Turn the engine over by hand 2 or 3 revolutions with the engine turning
tool to distribute the oil better. Turn off and disconnect the hot oiler, and be sure to put
the plug back into the hot oiler line and the cap back on the engine's oil galley fitting.
- Disconnect the fuel line at the barrel valve on the injection and put the line into a
- As a general rule before cranking with the powerful starter motor, to keep from
hydraulicking the engine, put the engine turning tool in the back of the
transaxle and turn the engine over several revolutions by hand. If it won't turn over, a
cylinder is probably full of fuel. The Hilborn toilet bowl injection can leak a lot of
fuel into the engine. Lots of people have hydraulicked Offys.
- Bump the engine over with the starter. "Bump" means crank in short bursts, letting the
engine stop briefly each time. When the oil pressure gauge starts moving up, crank
continuously. Look for 150-200 PSI oil pressure and fuel coming out the fuel line. Check
that the fuel in the container is clean.
- Release any fuel cell pressure by pushing down the manual fill dry break.
- If the engine is a fresh rebuild, let it sit a while longer with the heaters still
plugged in, as much as an hour, then crank again to circulate the warm oil from the oil
tank through the engine.
- Release fuel cell pressure again.
- Check the container again to see that the fuel is clean. Reconnect the fuel line.
- Crank the engine until a fuel fog is shooting up evenly into the air out of all four
spark plug holes. If it's not even, an injector(s) is plugged.
- Install the warmup spark plugs, with antiseize on the threads. Tighten them *very*
lightly, or they will jam when the engine heats up. Getting them back out has a good
chance of stripping out the aluminum threads in the cylinder block.
- If the exhaust pipe points at the mechanic holding the starter motor, the hot exhaust
will remove the arm and facial hair of the mechanic. Such a car should have with it a
tool consisting of a tight radius 90 degree bend of 4 inch tubing on a stick that is held
over the exhaust pipe to direct the flames (these engines run very rich) off to the side.
The tool is called a beard saver. The mechanic holding the beard saver should be aware
that if the engine backfires, he needs to keep the beard saver from hitting the face of
the guy with the starter motor. Hold it tightly against the exhaust pipe.
- Crank the engine with the ignition off. When you see oil pressure, turn on the ignition.
It's OK to play with the throttle a bit to get it started, but don't let it do a hard
start with a lot of throttle opening, you want it to start at an idle. Often, the engine
will start then quit, and if you've already pulled the starter out, you'll have to wait
for the starter to wind down before reinserting it. Since the engine is to start at idle
speed, keep the starter in and on until the engine is running continuously. I know of one
driver who winged an Offy when it started, and it broke two fingers on the hand of the
mechanic when the starter, which was a ground reaction leg type, spun around violently.
- If the engine backfires loudly through the exhaust repeatedly, the mag might be
installed 180 degrees out of phase, an easy mistake to make. I had this happen to me once,
and it was VERY loud.
- When the engine starts, everyone should be looking for leaks. Someone should be
assigned to look under the car for leaks. The solid-mounted engine shakes so badly,
you can look over the whole car while it's running, looking for loose hardware. Loose bolts
and nuts will be spinning from the vibration. Rookie Janet Guthrie told Dick Simon the
engine shook so bad when she was driving there were 4 or 5 images of the other cars around
her. She asked, "How do you tell which one is the real car?" Dick said, "You'll learn which
one is real."
- As soon as it starts, if the engine is missing, feel the individual exhaust pipes to
see which one isn't warming up like the others.
- Feel the cam covers. If there's a hot spot, you have a bad cam bearing.
- Don't let the oil pressure go over 200 PSI, or you'll balloon the oil cooler.
- Do not rev the engine for show like some lowbuck lowlife. It doesn't serve any
purpose on this expensive engine that's worth more than your life.
If you wing the engine to impress your girlfriend, the chief mechanic will throw a
wrench at your head (he won't miss) and the owner will fire you (he won't miss you).
Using the linkage on the injection setup, repeatedly raise the RPM slowly from idle
to about 4,000 RPM then lower it quickly.
- If the engine is a fresh rebuild and the oil pressure isn't right, adjust the pressure.
The adjustment is a screw and locknut among the four engine mount bolts at the lower front.
- If the engine is a fresh rebuild or the mag has just been installed, check the ignition
timing. The timing marks are on the clutch.
- Run the engine till the coolant temperature is 80 to 100 degrees centigrade.
- Each time you back off the throttle in the manner recommended, there will be a mild
backfire and about a foot and a half of flame out the exhaust. At night, the spectators
love this. Since the exhaust of a methanol burning engine stings the eyes, it's usual
to back the car partly out of the garage. At Indianapolis, Hal Sperb used to back his car
all the way out and up against the chain link fence so he could roast the fans who would
try to get as close as possible. (These folks were called "fence hangers", and they
were considered ripe when their knuckles turned white. Then a chief mechanic who shall
remain nameless would help the prettiest girl over the fence by climbing up on the
500-gallon refueling tank parked alongside the fence.)
- Turn the ignition off. Then watch out. On one of the cars I worked on that had
a low-mounted turbocharger and a long tailpipe, there would be a 3-second delay after
the engine came to a stop, during which the spectators would gather closer, then
there'd be a moderately loud backfire and a 3 or 4-foot flame that would incinerate
the spectators. Hey, you have to give them something to tell their two-headed grandkids!
- Install the race plugs, again with antiseize and very light tightening. If you
leave the warmup plugs in, they'll overheat under boost and cause preignition, which
will burn a piston.
- It's about time to give the car to the driver. If it's a cold day, you may need to
put tape over the radiators or their inlets, otherwise the engine may never get fully
warmed up. Fancy cars and later cars will have different bodywork pieces to restrict
the inlet(s) or outlet(s).
- Let the driver have the car. Believe it or not, the warmup is not complete; the
driver has to follow his own procedure in the first few laps before he can stand on
the gas. Driver and author Patrick Bedard described the process well:
Throttles open; throttles closed.
Each time he shuts down, the rich mixture detonates in the exhaust
like cannonfire. There is a terrible tension in the sound, palpable conflict, the Offy's
bark being restrained by the turbocharger's muzzle. Spectators hang on the fence
outside, riveted in place.
The garage is filling with methanol fumes that sear the eyes. Everyone
backs away. Only Gene Thrall stays with the car, leaning over the Offy, working the
throttles. He is alone, like the man stoking the blast furnace, somehow able to stand in
its pink glow when others cannot. Emotionless. Only sweating.
A handful of wrenches laid on the monocoque are now visibly dancing,
high-stepping to the tune of the Offy, marching to its vibrations. I notice they are
backing away, just as everyone in the shop has done. The black car is sinister, forbidding;
part rapid oxidation, part voodoo. ...
... The Offy is an irascible old lump. Its oil has to
be heated before starting. Then, once it's running, it sounds like a Maytag working out on
a bucket of lock washers. I keep thinking it is on its last legs. But
Marvin, one of the engine builders, says no, Offys have been
sounding like that for 40 years.
The warmup process is an ordeal. Can't idle it at constant speed: rattles
the cam gears. Can't drive it at constant speed: might be in a lean spot in the fuel
injection. Can't turn any revs: oil pressure will go to full murder. So I ease out of the
pits in first gear, straight into the Seismic Zone - a ferocious vibration period at about
2600 RPM ...
... The plan was to creep around in first gear until
the water came up to 70 degrees centigrade. That would take about three-quarters of a lap
if there was plenty of tape on the radiators. Then shift to second and work the engine
against the brake. Working the engine is the only way to thin the oil so the pressure
will come down. It has to be down to 160 PSI before I can leg it. Getting it there
requires, finally, running some boost in the higher gears - say, 40 inches on the manifold
pressure gauge. but higher gears mean more speed, and therefore more air through the
radiators, making the water cool off. This cajolement never takes less than five laps, and
when it drags out longer the temptation is just to throw the boost to it, give it the full
statutory 60 inches, the way you'd give a mule a two-by-four.
Copyright Car and Driver Magazine September 1981
- The running oil pressure should be about 125 PSI, and the running water temperature
should be 80 degrees centigrade.
- If you are restarting the engine after it is warmed up and it vapor locks, blow
vigorously into the fuel cell vent tube that's usually wrapped around the rollover bar.
That will force some fuel through the system. After the engine starts, release the
fuel cell pressure. If it still doesn't want to start, put some 3-in-1 oil into the
fuel pump. Don't use shop air to pressurize the cells,
that's too much. I've heard of one car that was split at the seams this way. The crew was
up all night putting a thousand rivets back in the tub, and Goodyear and Firestone were up
all night patching the cells.
- If you are restarting the engine after it is warmed up, you don't have to put in warmup
plugs if you can feel any warmth in the cylinder block.
- If the engine isn't going to be rebuilt right away like it would after a full race,
and is going to go into storage for a while, spray fogging oil into the air intake before
shutting the engine off for the last time. Run the engine at a fast idle and spray lots
of oil in. The goal (not always attainable) is to foul the plugs and kill the engine, that
means there's plenty of preservative oil in the areas most likely to corrode.