25 replies to this topic

[MRA]

You need to run it lean when you're running it in.

 

Why ?

[Carlos W]

 

You need to run it lean when you're running it in.

 

Why ?

 

To avoid bore wash

[sonikk4]

130 psi is low for a new built engine, i would expect more than that to be honest.

[MRA]

 

 

You need to run it lean when you're running it in.

 

Why ?

 

To avoid bore wash

 

 

So avoiding bore wash you get holed piston/s and burnt valves ?   I'll have to disagree but add you want it correct, not lean or rich, however with rich it can be put right easier that if it is lean, you choose, Bye.

[Carlos W]

Come on, be real, no one should have there foot on the floor on a new engine!

I like them running with a hint of lean misfire at part throttle during run in.

AC

 

 

 

 

 

You need to run it lean when you're running it in.

 

Why ?

 

To avoid bore wash

 

 

So avoiding bore wash you get holed piston/s and burnt valves ?   I'll have to disagree but add you want it correct, not lean or rich, however with rich it can be put right easier that if it is lean, you choose, Bye.

 

Really, so people like AC Dodd are wrong?

[Carlos W]

Lean is king for running in. Part throttle fueling around 0.4 to 1.0% co gets the job done nicely.


To revise;

Lean = correct
Rich = rebuild again.

Ac

[MRA]

 

Come on, be real, no one should have there foot on the floor on a new engine!

I like them running with a hint of lean misfire at part throttle during run in.

AC

 

 

 

 

 

You need to run it lean when you're running it in.

 

Why ?

 

To avoid bore wash

 

 

So avoiding bore wash you get holed piston/s and burnt valves ?   I'll have to disagree but add you want it correct, not lean or rich, however with rich it can be put right easier that if it is lean, you choose, Bye.

 

Really, so people like AC Dodd are wrong?

 

 

I talk to people who test engines on a daily basis for the likes of Jaguar, Nissan, Ricardo..... are they wrong ???

[Carlos W]

 

 

Come on, be real, no one should have there foot on the floor on a new engine!

I like them running with a hint of lean misfire at part throttle during run in.

AC

 

 

 

 

 

You need to run it lean when you're running it in.

 

Why ?

 

To avoid bore wash

 

 

So avoiding bore wash you get holed piston/s and burnt valves ?   I'll have to disagree but add you want it correct, not lean or rich, however with rich it can be put right easier that if it is lean, you choose, Bye.

 

Really, so people like AC Dodd are wrong?

 

 

I talk to people who test engines on a daily basis for the likes of Jaguar, Nissan, Ricardo..... are they wrong ???

I talk to my engine builder for my mini engine is he wrong?

[MRA]

 

 

 

Come on, be real, no one should have there foot on the floor on a new engine!

I like them running with a hint of lean misfire at part throttle during run in.

AC

 

 

 

 

 

You need to run it lean when you're running it in.

 

Why ?

 

To avoid bore wash

 

 

So avoiding bore wash you get holed piston/s and burnt valves ?   I'll have to disagree but add you want it correct, not lean or rich, however with rich it can be put right easier that if it is lean, you choose, Bye.

 

Really, so people like AC Dodd are wrong?

 

 

I talk to people who test engines on a daily basis for the likes of Jaguar, Nissan, Ricardo..... are they wrong ???

I talk to my engine builder for my mini engine is he wrong?

 

 

I think you know my reply even before I do.....

Edited by MRA, 28 March 2016 - 09:00 PM.

[sonikk4]

This topic will remain open but i suggest both MRA and Carlos make no further comments at this point in time. The OP still needs assistance and bickering over who is right or wrong will not help here.

[Cooperman]

During running-in a new engine should not be damaged if it is slightly too rich or slightly too lean. The same applies to the timing being slightly advanced or slightly retarded from nominal.

The damage will be caused if it is FAR too rich or FAR too lean (or far too advanced or far too retarded). That is why there are specialist documents, e.g. David Vizards excellent guide, giving suggested initial needles/jets and timing settings.

Now someone with a new engine has a problem with conflicting advice. On one hand it is advised to do the initial start up and to run the engine at 3000 rpm for 20 to 30 minutes. During this time it is impossible to re-set the mixture and if a long way out damage is possible..

Now I've been building modified engines for over 50 years and my method is to get as close to the correct needles (talking SU's here) by ref to data sheets and experience. I set the mixture screws about 12 to 14 flats down from fully weak and the ignition at c.6 degs BTDC static. I start the engine and run it at between 2000 and 2500 rpm for 8 to 10 minutes. Then I switch off, check for leaks, inspect the plugs and re-start, setting the revs to about 1100. Then I set the mixture using the piston lift button(s) and, if twins, a carb balancer.

Then I drive it and maybe 'fiddle' with the distributor until it runs nicely without 'pinking'.

Before we had rolling roads that was about the best you could do, but now a trip to a rolling road after a couple of hundred miles is the norm.

I'm sure some will now tell me that all my engines will have been wrecked by doing it this way, but I've been doing it this way since 1963 and have worked on competition engines with no high-initial-wear issues ever and I've always done it this way.

Obviously if you start it up and it is running so rich after 8 to 10 minutes that the plugs are black or white, there is a problem and adjusting the mixture screw and checking by lifting the carb piston at 1100 revs will show this immediately and it must be corrected straight away.