How to run-in a newly built race engine

[Corollaman]

Hey PH,

I'm currently putting the finishing touches to my freshly re-built 4AGE Toyota engine. The engine which will be used for race purposes only was rebuilt with stronger internals, ACL race bearings, ARP head/main/big end bolts, hi-comp pistons, big cams, bike carbs, and a few other bits. It will also most likely be running at higher RPM's than standard. Being my first engine rebuild I have no experience in how best to run-in an engine to ensure optimum performance for its life.

Does anyone on here have any experience in this as i've had mixed advice from reputable mechanics who both have experience in building race engines. One says to keep it at low rpm's for the first 1000kms or so, and the other says drive it as it's going to be driven from the first start.

WTF do I do cause i'm sh!tting myself that i'll do the wrong thing and the whole build will have been in vain. Help !

[350Matt]

Hi

run it on cheap oil for the 1st 500 miles and gradually open the up throttle and revs as the miles pile up, don't use more than 2/3rd the 2/3rds the load for the first 500 miles then start exploring the upper ranges and post 1000 miles start giving it some abuse.

[CDP]

I was told to give it some welly by the builder. I didn't - I built up to it and kept coming back into the pits frequently to check for leaks etc. It's always possible to overlook something so it needs a good testing before really hard use.

[skid-mark]

1 when you start the engine for the first time with the car stod still you should hold the revs at around 2000rpm for the first 20 mins don't just let it idle you want the oil pumping round that engine to bed the cams and crank/ pistons in,
2 let it idle but then blip the throttle every few seconds/minutes but don't red line it keep it around 4000rpm do this till the coolant system is fully operational and the fans have cut in at least two of three times and that there's no air locks avoid OVERHEATING.
3 when you first start to drive the car always try to avoid labouring the engine ie pulling away in to much of a high gear, never red line your engine for first few months or 100 miles and try to keep it within around 4000rpm,
4 once this period is over with the car stod still start to blip the throttle going higher with each interval so that your happy the engine can reach its limit if there are no problems nasty engine noise should be ok to drive engine to it's higher revs 4000+.
if you avoid the run in period it may not cause any visable damage but engine will probably not last as long as you'd like. (point 1 is very important).

Edited by skid-mark on Sunday 8th March 01:07

[GreenV8S]

You have to put some load on it to bed the rings in, but keep it to very brief bursts so it doesn't get a chance to build up heat. Absolutely avoid low rev / high torque situations, do the bedding in in the middle of the rev range.

[CDP]

My engine had been on the dyno so the builder had probably done the bedding in work before installation. Hence his comment.

[skid-mark]

don't you just love it though the sound of a rebuilt engine firing up into life for the first time

[Drew SS]

just give it to her mate drive it like u stole it if its been built right it will handle andything afterall its a race engine

[MHM]

350Matt said:

Hi

run it on cheap oil for the 1st 500 miles ..... and post 1000 miles start giving it some abuse.

Bearing in mid the OP said it was for racing it should be nicely run in for the 2011 season.
Personally once you have done the initial start up etc, I like to turn tickover up, let it get warm, let it cool and repeat half a dozen times.