Hi,

I always used to let the engine cool down to ambient temperature after each tank. Unfortunately this takes a lot time.

Now I've read a few break in methods in the net (e.g. Josh Cyruls, and Uriahs).

Can I run several tanks in a row for example after the 3rd tank to speed up the break in proccess or should the engine cool down after each tank?

Thanks in advance.

I always let it cool down in between the first tanks (first 7-8). It helps the materials achieve their proper fit.

Remember your engine will last as long as the time you dedicate it on break-in.

Quote from Ron Paris:

Heat cycling stabilizes the metal and allows mating parts to fit better against each other. Keeping the piston out of the upper portion of the cylinder (which is smaller in diameter than the lower portion in order to create a better seal during combustion) will allow the cylinder to properly contract as it cools—without interference from the piston.


You can read about his break-in method and tuning method here:
http://monster.traxxas.com/showthread.php?t=474587

Break-in method is the 4th post.

Todays materials and engines are produced in small tolerances that there is no issue with fitting the materials. The only thing what realy happens is when cooling down there is a little bit grow in the piston.
When running in with the heatcycle the grow will taken care of with the next tank and at the end the piston will be a tiny bit looser than when going to run it in all the way without stopping. If you do that it will take a while when the piston becomes realy loose.

Thanks for your replies.

In this particular case I'm going to break in an O.S. Speed XZ engine. I think I read somewhere that this engine is set up for 30% nitro fuel. I'm going to use/race 16% nitro fuel.
The manual says that there are two head gaskets istalled (0,2 and 0,1mm). For low Nitro fuels the 0,2mm gasket should be removed. I guess they mean with low nitro fuels 20% nitro an less, right?

Doesn't the compression grow when removing gaskets? Since I've read that O.S. Engines are build very tight (Piston/Sleeve) isn't it better to leave all the gaskets in for the first few tanks an remove them later?

Hmmm, know I've found this:

This would mean my 0.3mm would be just fine

That numbers given are the head clearance, not the thickness of shims.
Head clearance is the distance between underhead and the top of the piston when the piston is all the way up.

Ok, so leave all shims in for break in period and remove them later or remove them directly?

Once the shims are installed for break-in, you do not remove them. The proper shims should be installed no matter if you break-in an engine or racing. The only time you add or remove shims if you are planning on going to a higher or lower nitro content.

I always let my engine cool down between each tank. Just like the earlier post. Take your time "If you rush this process... your engine will rush it's performance."


Pass you soon...

Are the moderator in this forum able to create polls?

I would like to have a poll with the most popular break in methods to see which one is used most often.

You want 1000+ brake-in methodes in a poll ???????

Just do the one you like, at the end all brake-in methodes will work and the results are always different even with more engines using the same methode due the different tolerances the engines have.

I'm just curious and I didn't say "all", I said the most popular. I for example only know 3 or 4, so I think creating a poll with that question wouldn't be such a big deal.

However, in fact I'm not sure if I should stick with my old break in method or should I switch to WOT.

My old method was: Driving the car directly with moderate revs for the first tanks and then increasing the rev till tank no. 10 or something like that, depends on the engine. Always kept the temperature over 80 and below 120°C.
Never let the engine idle 1 or 2 tanks (in my opinion an engine killer method).

A lot guys of my RC Track use the WOT method.
On one hand I think it's a good method (because much fuel/oil is always covering the piston) on the other hand a lot people tell me that race engine should been broken in under "load" which with the WOT method during the first few tanks isn't given (in my opinion).

So I'm a little undisclosed

Stick with your routine, it's good.

I sometimes do WOT when it has to be quick, but if not done right it can kill an engine in a NY minute.

Cooling down between tanks gives the internals the chance to expand and shrink and settle down structurally.

Never idle on the box. As you said it kills the pinch and the rod.

What is WOT??

Search for wide open throttle break in method.

OK, it means that.. No need to search, tried it before. It's not a method for my likings.