Running in - adding oil to fuel

[Macbeth]

I’m close to starting the new engine & going for some short rides - I’ve read 554686 pages on line on many old bike forums & understand the objective

I came across this factory recommendation page in our forum & it was the only time I’ve seen this suggestion of adding an egg cup full of oil in the fuel surprisingly.

Do you guys do this oil / tank add with new engine builds  ? 

I’ve absolutely zero experience on a fresh motor & frankly it’s 30klm of city traffic just to get to a curvy country road (a common suggestion) & heat on a new air cooled engine is a very pertinent concern

[Triton Thrasher]

Looks like useless advice.

[Rex]

Counter-intuitive- you want the rings to bed in ASAP, not add more lube to prolong the bedding-in process.

[Swarfcut]

 Back in the day your local  service station offered a product called REDEX, punted as  "Upper Cylinder Lubricant" In effect an expensive slug of magic oil added to the fuel. This was supposed to lubricate the valve stems and guides, back when valve stem oilseals were not even thought of and blue smoke on the over run was an accepted trait on engines of the 1950's.

 So in effect that recommendation is doing just that as well as adding oil to the combustion chamber. I'll agree with Rex on this.

 As for running in, modern top brand oils with their anti friction additives are cited as causing problems with piston rings failing to bed in. As a first fill, cheap oil is fine, but allowing a new build engine to idle for long periods contributes to poor bore sealing. Light loading and varying speeds is the best compromise. As stated, the rings need to bed in and this requires a certain amount of load and friction.

 Other folks may hold a different view, but it's worked for me.

 Swarfy.

[limeyrob]

I read somewhere that the Harley engineers had done some tests and on the side valve race engines where the cylinder would distort they put the engines together with dry bores and thrashed them straight off.  They got much better ring sealing.

Its not clear what running in is for.  Modern shell bearings fit and run straight away, and if you have bronze bush that need's 500 miles of slow running before its OK you have other problems.

I think the big worry is piston / bore fit. I rebuilt my 3.3 Perkins and it was tight, its taken 2000 miles to really loosen up but there was no way of setting the piston skirt clearance.

[Triton Thrasher]

Internet wisdom persuaded me to try the rough hone, bigger second ring gap, cheap oil, dry assembly and immediate acceleration method of “running in.”

I’m sure it gives better compression.

But I may be about to read the very opposite, in subsequent replies!

[limeyrob]

I think it gives better compression too.  Once the rings are glazed and the bore smooth wear will be very slow.  If it wasn't we be changing rings every ear or two.
The same applies to brake linings, brake as hard as you can repeatedly as soon as you set off with new linings.

[Rex]

The pre-war engine tuner Hartley (Ariel and Norton) used to recommend leaving the rebored cylinder out on the lawn overnight to gain a rust film, then reassembling with a lightest smear of oil and revving it a couple of times as the best way to break in an engine.
Never tried leaving the cylinder out in the garden, but the rest of the procedure works well, I've found.

[limeyrob]

Don't forget to pee on it too:
Racing folklore has it that M12/13 cylinder blocks were hand picked from production M10-powered cars that had covered over 100,000KM. The theory being that any issues that could arise from manufacturing defects in the casting process would have shown themselves by that point. The folklore then takes a stranger twist; supposedly, BMW engineers would then leave these blocks outside, subjected to the elements for months at a time and then urinate on them for good measure! Paul Rosche apparantly described these blocks as “well-hung meat”. There is evidence to suggest that urine can have a sort of nitriding effect on ferrous metals. Indeed, swordsmiths of old would often quench their swords in urine – so it may not be as far fetched as it sounds. Either that or someone at BMW was just taking the p…

[berger]

Bryan Donkin company used to leave castings for big industrial valves and cylinder liners outside for years before machining them. chinesium lathe beds are probably machined while still warm then settle as time goes on, my brother had to sort out his big chinesium lathe to make it into a good machine. as for running in i use straight grade cheap oil and don't over rev or labour it he says letting the berger build rev it's nuts off when the ferrule jumped out, i also use bursts of throttle and shutting off never just sitting there at the same throttle opening.

[muskrat]

G'day Macbeth.
I put it together pretty much dry, just a little oil in the bore to get the barrels on then wipe off. NO added oil to the fuel. As said use a cheap non friction modified oil to run in, say 100 miles and a little load at varying revs. Change the oil to your preferred brand then ride it like you stole it 
Cheers

[Macbeth]

G'day Macbeth.
I put it together pretty much dry, just a little oil in the bore to get the barrels on then wipe off. NO added oil to the fuel. As said use a cheap non friction modified oil to run in, say 100 miles and a little load at varying revs. Change the oil to your preferred brand then ride it like you stole it 
Cheers

Yep.  I’ve arrived at what you said is best  👍

I think my only real tentative issue is riding it for its first few klm in traffic. So will initially just get a bit of heat in it before I start on a few city blocks at a time between cool downs & keeping it off idling & lugging. I’ve got plenty of Motul SAE50 classic on hand before I eventually swap it over to fleet oil like the rest of my bikes

I mentioned it to my 93 yr old dad who always had bikes since the 1940’s & he went straight to “get yourself some Ajax - a good fistful” (as expected) 🤣🤣 I think his last build was on our horizontal McDonald milking engine. I’m careful not to mention moth balls near him either.

[muskrat]

G'day Macbeth.
  I have "run in" a few race motors with Ajax. Start'em up 1/2 t0 3/4 revs and throw an egg cup of Ajax into the carb  . Best if the oil return line is into a bucket then change the oil twice. Usually done on a Saturday night before Sunday races.
Cheers

[berger]

Ajax? shove some grinding paste in it

[muskrat]

Ajax? shove some grinding paste in it

G'day Bergs.
No, too messy
I wouldn't do it to a road motor. A race motor will be rebuilt on Monday. A race motor gets "run in" on the warm up lap 
Cheers