xjqkz

Every engine I get, I make sure to open it up first take out p/s and give it a nice spray bath with carb cleaner then wd40 and mm oil it before putting it all back together. Then I seal the back plate with high temp rtv and also the carb. Needles I use green slime.
I've never found any big shavings of metal but every once in a while I'll see tiny aluminum dust, I guess thats all it takes to mess up a sleeve.

Back to the topic... I agree with MattVid that During breakin those 2 steps need to take place. Every breakin method that I've seen/heard of does the same job pretty much in multiple tanks. But inside of the engine these 2 steps is whats going on in everyone of those breakin methods even fuelman's method.

Lot of people associate WOT with high RPM's thats not necessarily true. When JBlaze said WOT he also said to rich the engine to the max, what that does is slow the rpm's down, thus does not stress the con rod, infact with that much fuel/oil going through the engine and the sleeve being super lubed up it pretty much minimizes the stress. Unless if there is a factory defect in the rod it should run like normal.

downunder

There are really only two parts in an engine that need to be mated (run in) together. Fortunately the best way to do this is much the same for each although the time needed is different. Manufacturers of very high performance engines (Jett for instance) say that the rod needs 20-30 minutes before it's got the final polish and fit required. The rod of course depends on having a continuous film of oil between the bushing and the crankpin so it can "water-ski" on the oil film. So you don't want too much load on the rod or it can squeeze out that film and give metal to metal contact. To help avoid squeezing out that oil film you need an oil that likes to stick to metal (that's called a polarised oil) and most synthetics are not polarised but castor is. That's why castor is recommended when running in an engine. When an engine is running, only the upper half of the lower rod bushing feels any load and that's the part that gets polished, the bottom half will keep its original machined finish. Of course the reverse is true for the top bush but that one's a bit hard to see . So in general for the rod we need a reasonably light load but enough revs to keep it "water-skiing".

Now the piston/liner. Although modern machining makes them look perfect, they're not. To make things worse, the simple act of tightening the head onto the engine can distort the liner by a minute amount and it's no longer perfectly round (even if it was to begin with). Like the conrod bush, the piston depends on a continuous oil film to keep it seperated from the liner but any imperfection can break through that film giving metal to metal contact which means friction which means heat. Too much localised heat upsets the piston composition. I think most know that the piston in an ABC has a lot of silicon in it which is what stops it expanding too much from heat. But this silicon is in grains which is why a piston can look speckled. A localised hot spot can heat the piston enough (in that tiny area) to melt these silicon grains back into the alloy and then that part of the piston no longer has the same expansion rate as the rest of it. Which means that part of the piston will then expand slightly more giving more friction heat and a larger localised overheating which gives....well, you get the idea . So to run in as best as it can, the piston needs to gradually get hotter and expand gradually to let any high spots be polished down rather than scrubbed off. Once again, an oil that likes to stick to metal is helpful in keeping down any friction heat. Should I say castor again? The time taken to do all this properly isn't all that long, less than it takes to run in the rod, but basically it needs to start fairly rich (which means the piston gets more cooling than the liner does) then slowly leaned out to let the piston warm up and grow a little each time. It may seem strange, but the softer piston will actually polish the much harder chrome on the liner without doing anything to the piston itself.

kersplat

My main concern with break in is using a good amount of castor oil in the mix and take care of the real work horse in the engine, (the connecting rod). This means pre heating the engine before the first start of break in, and keeping the revs below the high end. Running the engine close to 300F will not hurt it during break in, an ABC engine will tollerate heat well if you are using additional castor oil during break in. I have engines with 40 liters of fuel run through and the pinch is good and the bottom end of the rod is still an intimate fit. You do not need an elaborate break in process, just run the buggy and don't be heavy on the throttle until you've burned about ten tanks.

Falconeer

I have done a lot of reading and have found this method to be the most sensible.

I will definately stick to this. Now just waiting for my Picco to get here lol.

veedub

How can i tell if im running my engine to lean? will it be fairly obvious to the ear that its screaming to loud at high rpms? low? i just got a new motor and havent broken it in yet, I feel much more confident i will be able to break in a well running motor with the information you have posted here and on your website.

rccheech

I would like to see a video in full detail on how the WOT break in is done, anyone have any links???

mabuecker

My Feedback: (8)

I talked to blaze right after i got my turbo s5 in nov. and just didnt have the sak. iv broke in a handfull of engines since and everytime it crosses my mind but that caution he has at the tops scary. a vid would be awsome.

j_blaze

here is a link to show you the wide open rich section of the breakin, josh cyrul himself, when temps hit 120 you lean it 1 full turn and the wheels spin some and temps go up. just lean rich lean rich over and over to the right temps for the full bottle. it works, i did another motor today, worked flawless. the metal pinch is almost gone but it turns over on the box without having to preheat. it helps to use a hot plug during this break-in, it helps the idle stay consistent and have no flameouts.

http://www.youtube.com/watch?v=FAhO3ohjT2Y

rccheech

Yeah I seen that one... just a step by step video would be nice, I'm gonna give it a try anyway...... so you go to idle only when refueling right???