10 Tips for Engine Survival
by Don Terrill – RacingSecrets.com ©2003
1.) Less RPM – This is the number one killer of an engine. If you can make enough power at a lower RPM you should do it. Don’t forget missed shifts, now that’s a real killer.
2.) Optimal Coolant Temp – Both running an engine under power with too much water temp and too little temp can be harmful. High temps are the worst, with blown head gaskets one of the first signs of trouble. I’d say between 160′ and 210′ is best, never over 240′.
3.) Optimal Oil Temp – Low oil temp lowers oil flow. Higher oil temp breaks down the oil and gives way to the chance of metal parts coming into contact. Drag Racers usually race with the oil temp too low and stock car racers too high. Try to get near 200′.
4.) Less Compression – I’m a real fan of less compression. If you don’t need the extra power then there’s no need having the engine on melt down. If you’re in a competitive class then you have no choice. I’d keep it under 12 if you don’t need the power.
5.) Proper Ignition Timing – Too much timing leads to pre-ignition, which is like hitting the piston with a sledge hammer. Too little timing can lead to extremely hot exhaust valves. What happens if an exhaust gets too hot? The head eventually falls off. The only way to know the right timing is by dyno testing, track testing or reading the spark plugs.
6.) Tighter Lash – The weakest link in most engines today is the valvetrain and nothing kills it faster than too much lash. Just adding .010″ of lash can double the force on the valves. The only negatives to tight lash is usually less torque and the chance of holding the valve open if you go too far. Consult your cam maker for a usable range.
7.) Optimal Oil Level – You probably think I’m going to say too low is the problem, well if someone is going to make a mistake on oil level, 90% of the time it’s going to be too high. Too much oil can lead to the crank and rods whipping it up and adding air — not good. Most applications are very safe at 6qts.
8.) Proper A/F Ratio – Too rich a mixture can cause problems, for example carbon build up and washing the cylinders down. The real risk is from too lean a mixture. Just like ignition timing the only way to know the right mixture is by dyno testing, track testing or reading the spark plugs.
9.) Proper Clearances – Rod bearing clearance, main bearing clearance, piston to wall clearance, lash, etc., all are extremely important. You’d be shocked to know how few engine builders know exactly what these specs are. My advice, buy the tools and learn how to assemble your own engine.
10.) Proper Startup – I can’t tell you how many times I’ve seen this, someone starts their racecar completely cold and proceeds to rev the engine between idle and 7000 RPM. All engines need time to warm up. Better yet, how about oil and coolant heaters?