Engine run-in requirements

[skippydiesel]

20 hours ago, facthunter said:

Only if you tramp on them and keep your foot to the floor. They Don't Need to and highway work is seeing just over 2,000 RPM on  them. They get good torque as low as 1400.   Nev

most car/engines just trundle along at highway speeds BUT if you want to get descent performance out of a buzz box (any 4 cylinder under 2.0 L) use the revs/gearbox.

 

A lot of Australians,  raised on big 6  8 cylinder donks (relativity slow revving engines) don't seem to understand that small 4's thrive on rpm

[facthunter]

Have YOU actually driven any of this stuff.? Plenty of LARGE VANS have only 2 litre motors. Have a drive of a Focus RS. Buzz box my arxx.   Nev

[IBob]

Nev, could you explain about the rings not bedding in and so burning more oil?
I'm not disputing this, I would like to understand it better.
Thanks.

[facthunter]

It's common knowledge in the reconditioning game. You don't hone the bores too smooth and you give it a few squirts if its been a re-ring job. Repco  Super X Rings says to do a few flat out runs through the  gears,  once it's warmed and aircraft engines at RNAC had the rings lapped before running to ensure they didn't get blow by in certain areas which would damage and warp the rings. Rings  have a deliberately rough  surface  where they contact the bores to aid bedding in.. On a new or reco motor it takes less than 10 minutes to get good compressions registering and that's how it must be to ensure satisfactory life  Nev

[old man emu]

Am I correct here: Chrome rings + chromed cylinders = a big No! No!

[facthunter]

Yes. Bad idea. So are stainless on chrome vanadium.   Nev

[old man emu]

Just something to be aware of, but more for apprentice AMEs.

[facthunter]

Choosing compatible metals that run against each other is Important. Some copper-lead bearings had Indium plated on them in the big radials. Valves and guides are particularly critical or they may GALL. Stainless is not a good thing to use as a wearing surface. IF it's a valve It needs to be nitrided . Hard chrome was often used on a valve stem.  Nev