Race Engine Forum UK

Kill the engine in first gear instead of turning off the ignition switch so the engine does not diesel because of the high idle speed. I'm not sure if you use the term diesel but it is the condition where the engine continues to run after the ignition is turned off.

Not trying to be cryptic. You have the car idling at a higher rpm than usual during break in. It should be high enough to keep oil constantly being thrown on the cam. That will make the engine run on after the ignition is turned off. To stop the engine have the trans in first gear with the clutch depressed. Press firmly on the brake pedal. Let the clutch out slowly so it will drag down the engine rpm until it stops. With a little practice you can do this so seamlessly that a passenger in the car would not even notice. Many of the race engines I deal with idle between 1500-2000rpm for one reason or another. Have been stopping them this way for a long time. Once the engine has some miles on it turn the idle back down. I do not have cams go flat doing this high idle regime

To add a little variation to the theme of running in rings. in my opinion you could do the acceleration runs as often as you like on the first drive. Just make sure you give the engine some time to deal with the heat you just generated locally on the rings and bores. Do a few full acceleration runs, then do a few "light" ones. Just make sure you're not cruising but give the engine something to do. Keep it easy in the "cooling down cycle" so it can transfer the heat away from the rings and bores. One or maybe two minutes for the cooling down should do, if you're on an empty road going anywhere between 60 and 100 km/h (with an Alfa 33 8V, other speeds may apply to other cars). Once the temperature has settled again, you can do more acceleration runs and repeat until you're out of time, gas or inspiration. Keep a close eye on engine temperature and if possible, oil temperature and pressure. Once the rings get bedded in better, you can do more acceleration runs per stint, since less heat is generated that may cause the damage you're trying to prevent.

Try this - it's my regime if a dyno is not used, ignore the bits about the oil accumulator:

GUY CROFT RACING ENGINES

data issued May 11

GENERAL ENGINE START-UP INFO – READ ALL THE WAY THRU - BEFORE STARTING ENGINE!

1ST START-UP

1. Ensure sump plug is secure. Check all oil and water hose connections and oil filter for security. Fill cooling system with 50% genuine Fiat Paraflu mix.. Fill engine oil to level on dipstick. If engine is new use a non-synthetic 10W/40 oil for break-in eg Castrol GTX. Semi-synthetic is OK. It is recommended for initial start-up that the feed to the oil pressure accumulator (if fitted) be closed off via the manual valve as the solenoid valve will permit oil to be drawn off from the sump even with no current feed to it. This can lead to a low oil level in the sump. (The accumulator will not however discharge unless current is applied). The additional oil for the accumulator can be added later and the system connected up and wired up.
2. Competition cams should be liberally coated with a good brand of cam lube or smeared with molybdenum disulphide grease. Use engine oil to fill the camboxes, the oil filter, cooler, remote filter and as many of the oil lines as practicable..
3. Remove spark plugs. Disconnect the electric fuel pump and the ignition coil live feed. You must ensure the oil pump is wetted and primed by removing the oil filter housing - or - accessing the feed from the oil pump and squirting oil down the gallery to the pump. You must NOT hook up oil lines until oil backs up from this gallery or hose line from the pump when the engine is cranked or aux d/s spun.
4. Once you are sure the pump is primed and functioning correctly crank up main engine oil pressure with the plugs out and the throttle wide open. Do not crank the engine for more than 7-8 secs continuously and for more than 20sec altogether, the oil pressure should easily come up by this time. Do not start the unit until oil pressure registers on the oil pressure gauge. An excellent method of priming is to spin the aux driveshaft with a high-torque electric drill, although this does mean removing the cambelt.
5. Connect the fuel pump, allow the system to fill and check for fuel leaks.
6. Connect the ignition system and check that it generates sparks when the engine is cranked, by holding the main feed from the coil to the distributor 0.5cm from an earth point.
7. Fit the plugs. GC supplied NGK race plugs can be used for break-in.
8. Prime the carbs by several applications of full throttle to actuate the pump jets.
9. Start engine with minimum application of the throttle. If new cams have been fitted it is vital to keep the engine running at 2000 -2500 rpm for 10 minutes to allow cams to bed in. If engine will not run comfortably at this speed without overheating turn off and investigate the cause.
10. Adjust idle speed to 800 rpm and strobe/set ignition timing (usually 10 deg +/- 2 deg at 800 rpm is about right). Do this immediately and as quickly as possible.
11. You have just run the engine for the first time - so double check that everything from the silencer to the alternator belt is secure!

Note: If an accumulator is fitted, the sump needs to be overfilled depending on its capacity. The unit will automatically draw off this extra oil after the engine starts.


2nd START-UP

1. Check cooling system for leaks.
2. Check oil level and top-up if required.
3. Start engine, check oil pressure and run at 2000 rpm to allow cams to bed in if not already done., When the engine reaches 75 deg C, throttle back and adjust idle speed screw to give 800-850 rpm, then adjust idle mixture to give optimum running, balance carbs if used. Switch off.
4. Accumulator equipped models: connect live feed (it should ideally be wired so as to be activated by the ignition switch) and fill engine with additional oil. Restart engine and run at idle for 2-3 mins to allow unit to fill. The unit should register the same pressure as the engine oil pressure gauge at any given speed. The air precharge is far more compressible than oil, and it may well be full even though the gauge reading on the accumulator shows a relatively low pressure.
5. Run engine at range of speeds to max 3000 rpm to warm up and check cooling system integrity and temperature. The engine should respond normally when the throttle is blipped lightly. You can now drive the vehicle but for no more than 1/2hr and only at low load and speed, or leave it idling for 1/2hr, but do keep a careful watch on temperatures and make sure the cooling fan cuts in by 90 deg C max.
6. On models where the head gasket is required to be retightened it should now be retightened but you must first leave the engine to cool overnight. Get the torque setting direct from GC – settings depend on bolt and gasket type.


BREAK-IN PERIOD BY DRIVING IF ROLLING ROAD NOT USED

1. For the 1st hour do just local driving and do not exceed ½ throttle and 4500rpm. Use the gears very freely and at all costs avoid ‘high-gear – low engine speed’ as this will lead to heavy bearing load with low oil pump output. Stop frequently and check the underbonnet region for leaks and problems. Make sure oil pressure and engine temp is OK and stop immediately at any sign of overheating. Test the engine response on a quiet local circular route void of traffic lights and congestion and don’t venture too far, as the engine jetting may be wildly wrong. Do periodic spark plug checks; the plugs should be pale brown to grey around the outer body of the plug with insulator nose pale brown to yellow-white. If the mixture is too lean the engine will overheat and if the mixture is very over-rich, terminal piston ring and bearing damage may result. If the engine shows any sign of labouring switch off and recover the car by towing or trailer.
2. After the first hour of light running you can carry out a compression test. Typically the low compression engine (7.2/1) will give 180 psi or over and high compression units 210 or more. There should be no more than 5% variance between cylinders.
3. Continue the break-in phase and extend throttle to 3/4 and 5000rpm. Ideally the engine requires to be driven at a range of speeds within these limits for a further (say) 200 miles to fully bed in and prove-out the new installation*, but make sure that increased speed and load is accompanied by periodic plug checks to confirm mixture or damage may occur.
4. Do not attempt full-throttle runs until you have put the race oil in the engine.


For all GC engines race grade oil must be used, eg: Selenia Racing 10W60 or similar. GC strong recommendation is use oil with not less than 50 high temperature viscosity rating.

After any break-in period and major overhaul - change oil and filter. Remember that a remote filter set-up requires a filter with an anti-drainback valve.


The engine may need a confirmatory rolling road power run to check jetting.
On the rolling road, make sure your coolant and oil temps do not exceed:

Coolant: 75-80 deg C
Oil: 80-90 deg C

* just as important as bedding in the rings I can assure you. Most 'new' engines that fail do so due to second-rate installation eg: cooling system leaks - hoses & clips...

Never take spark plugs out of an aluminum head when hot.

I do not usually take compression tests. If there is something amiss with the running of the engine I am working on I use an infrared thermometer to determine which cylinder is under performing. By reading the temperature of the individual tubes at the header flange it is easy to detect which cylinder is lacking because it will be much cooler than the rest. Then using a leakdown tester will show more about what is up with the cylinder in question. As a side note this is a good way to help tune multiple carbs at idle. Synchronizing and mixture show up as heat. Get all the tubes the same temperature and then adjust for afr. It is not quite that simple but it does make the process much faster.

Did anyone tell you to always put anti-seize on the spark plug threads before you install them in the cylinder head?