Bon Ami 'Trick'

[jensen]

Hi,

just use mineral oil for running in for a few 100 miles, and then switch to synthetic oil to preserve the engine from further "runnung" in, just as stated in bill silvers CB72 / 77 bible.

Jensen

[simon r]

Hi all
A good friend of mine used to work for cosworth racing here in the uk,he swears blind that when they run up the dfv's on the dyno they used to flick a thumb nail size portion of vim (an abrasive powder type kitchen cleaner) down each throttle body to bed the rings in,and he's not the sort of chap that tells storys!
Simon

[e3steve]

Hi all
A good friend of mine used to work for cosworth racing here in the uk,he swears blind that when they run up the dfv's on the dyno they used to flick a thumb nail size portion of vim (an abrasive powder type kitchen cleaner) down each throttle body to bed the rings in,and he's not the sort of chap that tells storys!
Simon

Yup, I'd concur with that method. Back in the '70s, at the tender age of 17, I 'ported' my old man's Austin A60 Cambridge (groan!); it had a 1622cc BMC B-series engine á la MGB (1798cc) but with a single 1½" SU carb. I'd pulled the head because it was a bit smokey. There was no perceptible piston side movement in the bores and, not wishing to lift out the block, I opted for polishing the ports (inlets and exhausts...... I know: "why?"!) and popping the valve guides out for turning down a bit.

It still smoked a bit upon reassembly, so a slightly older chum who was just out of his apprenticeship at a local BMC dealer suggested the very same 'trick' to break the glaze in the bores, as the old man never drove the car over 60mph. Ya-know-what? It only bloody worked! It stopped smoking within a day or two. And it went like a train; well, as well as a tired '66, 60bhp Cambridge could, anyway!

Dad died the following year and we sold the car to an uncle who'd just 'retired' his Wolseley 4/44 after a rear-end shunt. It lived another couple of years without missing a beat or emitting a wisp of oil-smoke. But the front wings and chassis outriggers did rot away a bit more with each English rain shower!!

I bought a new Sierra Sapphire Cosworth, 10 Jan 89; chipped from the dealer (Hendy Motorsport), with a Detection Techniques engine management upgrade to 250bhp (from 204) and a 25mm suspension lowering. Now, that was a handful! The last of the rear-wheel drive Sapphires before the 4WD. Saw 168mph on the M3, taking a mate to Gatwick airport at 4am. Only for a short burst; you just don't know what that driver in the far distance, doing the legal limit (70mph), is likely to do as you approach him! Apart from sh1t himself, of course!

I never tried the Vim trick on it, though......

[G-Man]

Thanks for this thread. I really was sceptical but there seems to be enough evidence here to suggest that it works. I think I'll try it on someone else's motor first!

G

[Vince Lupo]

A friend of mine is going to try it on his CB500. Since he's gotta tear the motor apart anyways, he figured he'd give it a try, and then he might not have to do a teardown. I'll let you know how he makes out!

[rustywrench]

A recent conversation with a close friend (former Honda dealer/mechanic) has revealed an alternative to some of the previous tricks for aiding stubborn rings in the seating process.


Based on the principal that the rings are not seating because the oil will not let the ring and cylinder wall contact metal to metal; one can stop at the top of a steep hill and shut off the bike. Then close the choke most of the way to restrict most of the air flow. Change the trans to a higher gear for more RPM's, open throttle to full and get bike rolling. Let the clutch out and rotate the engine with ignition off for a couple blocks. This will allow the fuel in the cylinders washing the oil off the walls allowing the rings to run bare metal for a bit seating the rings. Ya wouldn't want to do this for more than a few seconds though.
Also you could remove the plug on one side ,start engine and run at a fast rpm for a bit then do the other side.

I have not tried this yet but will soon as I now have an engine that may need some help here. Some very experienced folks have told me it works so we will see. RW

[jensen]

Vince, G-man, steve,and others,

First of all happy new year to everybody,

Many remedies are suggested that purport to cure bore glazing. Mostly these involve tipping some sort of abrasive into the engine's air inlet to abrade the cylinder bores. . Any abrasion that takes place will be along the AXIS of the cylinder, allowing oil to pass the rings and therefore to consumption.

So, it's not wise to do this, there's no better way to destroy your engine. The positive effect on the rings is minimal, but the negative abrasion effect on the bearings is maximal.

The only real answer is to abrade the bores in a CIRCUMFERENTIAL direction, using either honing stones or abrasive papers. .This is clearly a bigger job than tipping powder into the air intake but it can be guaranteed to solve the problem with a modest outlay of cash.

Glazing occurs when the breaking in process is not done right. There are only two things that you can do, rebore and break in properly.

I always use this procedure described below, it works.

If the wrong type of oil is used initially, or the break-in is too easy, rings and cylinders could (read will) glaze and never seal properly. A fresh cylinder wall needs some medium to high engine loading to get the piston rings to seat properly for good compression but make sure you don't lug or overheat the engine. Use high quality, low viscosity oil, no synthetics, too slippery. If synthetics are used during initial break in the rings are sure to glaze over.

An engine's initial run should be used to bring oil up to operating temperature only, with little or no load, then shut down and allowed to cool to ambient temperature. This is important. After each run the engine needs to completely cool down to ambient temperature. After a cool down period, start it up again and take the motorcycle for it's fist ride.

This time give the engine light loads at relatively low rpm and stay out of top gear. Lugging the engine, i.e., low RPM with a lot of throttle (manifold pressure), is more detrimental than high rpm. Another key is too constantly vary engine load during the entire break-in period. A constant load is not ideal for breaking in bearing tolerances. This second run should last only 10-15 minutes before another complete cool down.

The third run should see slightly higher rpm with light to medium power loading using short bursts of acceleration to help seat the rings. Again 10-15 minutes of running should do it and again avoid top gear. A forth run should consist of light to medium engine loads with a few more bursts of medium-high rpm, and lasting just 10-15 minutes varying the engine load and again avoiding top gear. Next while the engine is still warm drain the oil and change the filter. This gets out the new metal particles that are being worn away. Most of the metal particles will break away within the first 50 -75 miles. To ensure the rings seat well, use the same high quality oil and don't be shy about short duration high rpm blasts through the lower gears after the oil has been changed.

A few more 15-20 minute sessions should be used to work up to the engine's redline gradually increasing the engine loads. After some definite hard running and 250-500 miles it's a good idea to check the valves. After 500 miles re-torqueing the head is suggested. Switch to synthetic oil but not before 500-1500 miles. Most of the engine experts warned of the danger of breaking in the engine too easily and ending up with an engine that will always run slow whether it is from tight tolerances, inadequate ring seal or carbon buildup. Engine load is more detrimental than rpm because of the head created internally, so avoid lugging the engine but rev it freely especially in the lower gears. Basically, be sure not to get it too hot but be sure to seat the rings properly.

So that's it, sure a lot different than keeping under 4000 rpm for 500 miles then under 5000 rpm for 1000 miles. Maybe bike manufacturers are being super cautious at the expense of your motor's performance? I think that they take the cautious route that works over time (1000 miles, or about 20 hours of break in) versus a faster route that can be more easily screwed up."

Cylinder bore glazing also results from prolonged light load running, particularly during the running-in process, and leads to the formation of a surface coating or skin derived from chemicals present in the oil and fuel. If glazed cylinder bores are examined, it is not unusual to see the honed crosshatch markings beneath a super-smooth, highly polished, varnish-like layer. Bore glazing occurs at low speed and light load operations, particularly resulting from blow-by in new engines. Exhaust gases passing piston rings in newly built or re-built bores can react with oil and wear products, forming a golden-coloured varnish glaze. Most engine manufacturers warn against the potential problem. Long periods of light or no-load running early in the engine's life may lead to cylinder bore glazing and high lub oil consumption.

For those who still think that running the engine hard during break-in falls into the category of cruel and unusual punishment, there is one more argument for using high power loading for short periods (to avoid excessive heat) during the break-in. The use of low power settings does not expand the piston rings enough, and a film of oil is left on the cylinder walls. The high temperatures in the combustion chamber will oxidize this oil film so that it creates glazing of the cylinder walls. When this happens, the ring break-in process stops, and excessive oil consumption frequently occurs. The bad news is that extensive glazing can only be corrected by removing the cylinders and rehoning the walls. This is expensive, and it is an expense that can be avoided by proper break in procedures.

You must achieve a happy medium where we are pushing on the ring hard enough to wear it in but not hard enough to generate enough heat to cause glazing. Once again, if glazing should occur, the only remedy is to remove the effected cylinder, re-hone it and replace the piston rings and start the whole process over again.

Jensen