engine build and break in procedure...myths?

[Jscobey]

so i built up my "street" VTR engine a while bike with STD bore JE pistons. now i am doing the same with my "track" VTR engine and 2 things have come to light that i wanna run past you fine folk.

the 2 problems i have uncovered

1. Honing Cylinders is POINTLESS and actually HARMS your engine; the only exception being on damaged/rebore to OverSize cylinders.
Article to support this :
http://www.snowvalley.20m.com/bikes/dnthone.htm

2. "Easy" break-in on the new rings is bad and results in burning of oil and loss of power leading to overall damage. For example "taking it easy" for the first 600 miles, as per the manufacturers recommended break in procedure results in improper ring seal leading to problems and poor performance. the theory is that to properly seal new rings, which do not rely on spring tension to seal as they have minimal spring tension, but rather the gases getting underneath the rings and forcing them out against the wall helping them to seal properly. the only way to achieve this is through running the engine hard on acceleration and deceleration, loading the engine both ways. during decel, the vaccum created sucks out any particles rather than them getting get between your rings and piston and eventually causing damage to the cylinder wall.
Article to support this:
http://www.mototuneusa.com/break_in_secrets.htm

Now neither of these articles are where i learned of these so called automotive "myths". Rather i learned of them on a recent trip to the Monterrey Rolex Historic's AKA Vintage car racing. I am close with a few of the drivers and there mechanics which build and rebuild these motors all the time. so this is coming from knowledgeable people who do this professionally. Now the premise of these practices being refuted is that engine's are made to a much better quality, with much finer tolerances, and higher quality parts than motors of decades past and these "ancient ways" are not only unnecessary, but down right bad.

ahhh but again you say if these old techniques dont apply to new engines, wouldnt the teams racing vintage cars, still abide by the laws of the past? NO because even though the car is old, the motor is new. i recant what i said, most of the cars really arnt even the cars they are suppose to be. they usually are the body of the car, and by that i mean a fibreglass replica with flared wheel wells and all, but underneath is usually a tube chassis with purpose built race engines. usually the tail lights are about the only thing these cars share with the car they are replicating.

so my "street" engine build, i did the traditional "easy" break in, as well as a simple hone on the cylinders. but on my "track" engine, i will do just the opposite. NO hone at all, and a hard break in. i will then compare results via 1.leakdown test 2.compression test 3.Dyno runs to measure power and torque.

now i have before and after dyno runs (thanks to my mates over at ducati) of the "street" engine pre and post piston install with NO other changes.
i will do the same with the "track" engine, the only difference being no hone, and a hard break in. then i will compare the % of either increase(hopefully) or loss of power due to the changes in the build and break in procedure. the compression and leakdown should tell alot of the story as well.

should be interesting, but ive come to find out that my ducati dealer uses the "hard" break in procedure and all freshly out of the crate bikes INCLUDING the $70,000 1199 Superleggera AND in their shop, purely on Re-Ring jobs that have no damage to cylinder walls, they DO NOT hone the cylinder. they simply check for tolerance specs, and if all is well, re-ring and button it up. a number of the bikes that come through the shop have been upgraded with low friction 2 ring pistons which require changing more often. so this info is consistent with what i learned in Monterrey. hence why i am trying it all out.

i know some of you will call me stupid, and that i will destroy my engine, but i wanna know for myself what the truth is in these matters and its a risk i am willing to take. from the research ive done, and the people ive talked to, id be stupid to hone the bores, as well as loosing on power if i run the engine in easy. so we shall see! would love to know what you guys make of all this!

[mik_str]

FWIW, I had the shop that rebuilt my engine do the MotoTune break-in..... BTW, I did a fair amount of research (Google) and most of what I found supported the hard break-in principle.....

[Jscobey]

Good to hear Mik. I had done some research prior to building my other engine but wasn't sure enough in the concepts to try it. Now that I've heard substantial backing and done my homework I feel that these are the best way to go about it.

[grumpyfrog]

I know fec all about this subject, but was there not recent problems with the 'blades that were softly run in burning gallons of oil? would support your process of giving it all from the start.

[mik_str]

Looking forward to seeing how you make out.... Go git 'em

[VTRDark]

Fantastic post Scobey and what an interesting subject. Respect to you for being willing to give it a go and doing it properly with dyno print outs. Like yourself I have read lots of info on the subject. The thing is there are so many various ways of doing things and who's to say what's right and what's wrong. A bit like with Porting, should one go bigger or smaller. Then there's things like Somander Singhs grooves. Basically all I'm saying is... who know's until one tries so good on ya. I hope it works out.

Personally I would have thought a hard break in is for max performance, bad longevity and a slow break in is for not quite so good a performance, good longevity. So basically performance verses longevity.

One thing I have noticed over the years is that all engines get used to a particular way in which it's being used. For example you could have someone ride your bike around for a few months like miss daisy. You get on the bike and it feels a little chocked up, not as responsive as normal. After a while of you thrashing it around, the engine loosens up a bit and becomes more responsive and back to it's old self. It's like an engine will adapt to the way it's being treated.

(:-})

[Jscobey]

The thing is there are so many various ways of doing things and who's to say what's right and what's wrong. A bit like with Porting, should one go bigger or smaller.(:-})

i totally agree with that carl. whats the old saying? theres more than one way to..... ahhh heck i cant rememeeber

i understand the thought process of easy break in = longevity, hard break in = performance but suffers longevity. but remember im not talking about a brand new engine here. only new pistons, rings, wrist pins, and big end bolts. everyting else in the motor is already broken in. so the whole point of the hard break in is to try to get the best seal possible from the piston rings. loading the engine both on accel and decel to force gases underneath the rings and push them out against the cylinder wall. so good sealing rings = better performance but also longevity. without a good seal your burning oil. your allowing oil into the combustion chamber causing build up on your piston, cylinder head, valves, etc.... well also getting harsh chemicals leaking down past pistons into the rest of the motor which includes acidic by products of burning gas and oil. these chemicals damage bearings, clutch plates, gaskets, etc... not to mention the huge risk of burning to much oil with refiling it, causing your motor seize.

as for as honing goes, the SAE (society of automotive engineers) says that an engine that is within tolerance on the bores, and has no damage, should NOT be honed before it is re-ringed. it was once thought that you had to "break the glaze" for the new rings to bed in. glaze being thought of as foriegn material which has been deposited into the cylinder wall. the hone was to, and very crudely i might add, scratch this off and cause peaks and valleys for the new rings to wear into. its been since discovered that a highly polished and smooth surface is the best thing for the new rings to seal with. the hone only makes for more piston to cylinder gap, looser tolerances, and therefore alll the downsides that come with a not properly sealed combustion chamber.

so in a nut shell both of these theories are in order to try and get the maximum seal, and longevity from the engine.

[VTRDark]

Just read that article on Honing. Very interesting and makes perfectly logical sense to me. I must admit I have always wondered what the thought process behind Honing is. You look at a cylinder and it's smooth and shiny. So why go roughening it up only for the rings to make it all shiny again. I also expect in the old days the machining process would have been a bit more......what's the word I'm looking for, course, not as precise. Hand driven even Older tech!!! Nowadays we have computer generated machinery and cutting materials which can make a cleaner more accurate cut leaving next to nothing, no rifling. Now there's a good word.

(:-})

[turbo_billy]

I always understood that the hone was not so much for the rings to wear into the peaks and valleys but to cause a rough enough surface for a thin layer of oil to be maintained on the cylinder bores.
As an aside, when I put the 0 mile engine in the "Legends" SP, I took it out with all good intention of breaking it in gradually. About 25 miles into the ride the right wrist got a little spirited and there ended the gentle approach........

[Furrybiker]

Not sure if this is directly related but some years ago I went round the Triumph factory. They took just assembled bikes and ran them to max revs to ensure they produced the correct power and torque figures, each and every bike. Then of course you and I cosset them for the first 600 miles.....

Ford ran Fiestas up to 80mph on a rolling road, probably just to see if they went bang! The newly built cars were filled with warm oil and then run up to speed.

Surely they aren't going to do this if its likely to cause a problem in the future.

[lumpyv]

The thing is there are so many various ways of doing things and who's to say what's right and what's wrong. A bit like with Porting, should one go bigger or smaller.(:-})

i totally agree with that carl. whats the old saying? theres more than one way to..... ahhh heck i cant rememeeber


"skin a rabbit"

good topic

mechanic told me once that you should always give diesel engines the beans right from new?

[tony.mon]

So could you not merely take the rings off the standard pistons and fit them to high comps?
After all, they're already nicely worn to the bore, if you don't hone....

Annoyingly, I read this after I'd honed the bores on mine, well, I'd bought the hone, anyway......
But is only just touched the surface, no measurable bore difference when I measured it.

Very interesting thread, or should I say myth-information....

[Jscobey]

or should I say myth-information....

ahahahaha best thing ive heard all day!

and rings are a service parts, as you know, they need replacing over time. now unless you could position each ring in the exact same spot around the circumference of the bore, you wouldnt get the same seal.

the only reason for honing is to "deglaze" and thats the basis of the "honing myth" as there is no such thing as glazing. just a highly polished bore, which is in fact good for ring sealing. and even though there isnt a measureable difference of the bore, its the microscopic level which we are referring to.

but i am just a guy who doesnt know very much. some much more experienced engine builders are the basis for my "research"

hope all is going well with the JE install. hope that last bolt isnt giving you to much trouble mate

[Stephan]

Interesting, I had similar thought. If I have engine withing tolerance, so I can use std piston bore, isn´it contraproductive to grind out some material by honing?

Now solved, in the case, I will just measure the clearance and put new pistons and rings in, thanks :-)

[Jscobey]

Interesting, I had similar thought. If I have engine withing tolerance, so I can use std piston bore, isn´it contraproductive to grind out some material by honing?

Now solved, in the case, I will just measure the clearance and put new pistons and rings in, thanks :-)

Stephan, expect the bores to be slightly more out of round at the top then the rest of the way down. this is due to the cylinder being unsupported at the top. as long as your within spec you should be good to go.