running in procedure

[petejw]

i was going through one of my old text books
"automotive mechanics" and came across this
for running in an engine


"Do not allow the engine to idle on first start up after assembly.
Accelerate it immediately to a speed comparable to a road speed ofnot less than 40km/h and maintain this speed until the engine temperature reaches approximately 80oC.
It is a bad practice to allow the engine to idle slowly during the first warm up period immediately following the assembly of the engine. At idle speeds there is insufficient oil thrown onto the rings, pistons and cylinder walls to adequately lubricate them duriing the engine running in period.
The recommended engine speed will ensure sufficient lubrication to prevent ring scuffing during this critical period.
Whenn the engine is properly warmed
Accelerate the car on the road several times in top gear at full throttle from 40 - 50 km/h.
This procedure allows full gas pressure to build up behind the top ring and thus provide sufficient load to cause rapid seating of the rings on the cylinder walls.
The chrome compression ring responds particulary well to this quick seating treatment and the chrome surface provides added assurance against any initial scuffing.

Driving procedure during first 300kms
1.Avoid full throttle operation in top gear at low speeds in order to prevent overloading of the rings and
2.avoid prolonged top speed operation to prevent damage to the rings by overheating.
for best results drive normally, but not at speeds in xsess of 60% of top speed during the first 300kms.

Ive put this up for anyone thats interested.

[dbeardslee]

Pete - very timely. I've got another member's SF out in the mancave right now and I just finished reinstalling the head and buttoning it up. First time I start that sucker I'm going to follow your advice. Another mechanic had redone the rings and the head, and when he first got on it he reved it too high and blew out the head gasket.

When I reinstalled the head, I torqued it to spec and let it sit overnight. It was about 90 degrees when I torqued them, and the next morning I went out and retorqued them after the motor had a chance to expand and contract a little. I was amazed that I got almost a full turn more on the four inner nuts, about 1/4-1/2 turn on the center nuts, and the outside were fine. The head gasket that failed, failed on the #2 cylinder, and I'm thinking without the overnight retorque it may well have gone again had I started it like that.

I'm going to hang the exhaust and carbs today, and hopefully later I'll be able to warm it up properly, let it cool once more, and do a final retorque on the head nuts. If you want to get good results, it's important to follow the correct procedure. Thanks for the heads up.

[petejw]

hey Doug,

what i liked about it was the way they described
the reasons for doing what they did, the textbook is
over 25 yrs old but thought it could still be relevant.

"Accelerate it immediately to a speed comparable to a road speed ofnot less than 40km/h"
im not sure how you would determine this, but when we used to run in new cams or bearings the engine would run at a fast idle around 2500- 3000rpm,
for around 15 - 20 minutes.

its always a good idea to retorque the head after the intial
cool down, just remember to retention the cam chain.

[81xsproject]

I subscribe to THIS school of thought.

[petejw]

ive read that too, tho ive never done it that way,
i intend to next time, the article i put in is pretty
similar, the article states to have the engine at
a fast idle for initial warm up tho, it still says to rev the engine out
to red line which that guy states.
the article also said not to run the engine for extended periods at a high rpm
for the 1st 300k's but this was written over 25 years ago,

when i eventually do mine, ill warm it up at a fast idle, but run it in
the way the guy does in your link.

i used to run in hwp cars, but the problem was by the time we received the vehicles they had been started at the factory taken to a dealer and then driven to the yard by the time we received the cars theyd have a couple of k's on them and had been started several times.
but we'd pretty much take it to a track (eastern crk raceway wasnt to far away)or the freeway and just fang them, the majority of the times the cars
flew and were run in well, on the odd occassion you'de get a lemon.
then they'd be serviced immediately again.

[dbeardslee]

the article also said not to run the engine for extended periods at a high rpm for the 1st 300k's

300,000 miles?! Now that's a break in . It's all good stuff, fellas. I won't be doing the break in on this one - just getting it running for its owner. I'll pass this info along to her, though.

[petejw]

lol only got another 150ks to go then .

Hey '81,
have you run in an engine using his methods?