fyrstormer

iTrader: (1)

Ah. Your comment about "no load on the conrod" made me think it didn't use the conrod at all.

I find myself wondering if I could make something similar using a spare motor mount magnetically attached to the side of an open-top container like a coffee can, with the crankshaft turned by a power drill. Obviously it wouldn't be anywhere near as fancy as this, but it might get the job done.

1fastmxcn

Hello, I tell you for a fact that the ebis machine is well worth the money. I have used mine now a few times and its a work of art. Leaves the finnished piston and sleeve perfect. Cant wait to run the engines.

Roelof

Get a mini deep fryer.
http://www.coopersofstortford.co.uk/...-prodst09288i/
place it under a drillpress....

fyrstormer

iTrader: (1)

Interesting idea, but I just threw away my mini deep fryer. Also, I have no space for a drill press.

Would something like this break-in machine even be useful for RTR-grade engines like the Losi 3.4? If not, I'm probably wasting my time considering it.

Roelof

For engines with a higher pinch it is more usefull than for engines with a low pinch. RTR have mostly a lower pinch. It also depends how many engines you use, with one a year for only RTR performance you probably better can stick with normal break in procedures.
But I have done LRP .28 pull starter and it did show a same break in mark as with the race engines I have done.

fenton06

iTrader: (24)

Why not use castor oil for break-in since it's used in the fuel? Not thin enough?

fyrstormer

iTrader: (1)

Yeah, castor oil is pretty thick. I suppose you could mix a little alcohol with it to thin it out, if you really wanted to use castor oil for break-in. But you're going to thoroughly degrease the engine before reassembling it, so it won't matter if the break-in oil is compatible with castor oil.

Roelof

Yes, have tryed Eurol Racing 1 with a viscocity of 21 at 100 degrees Celcius and Castrol A7474 with a viscocity of 17 at 100 degrees. Both wil show small scratches on the piston but still will do the job.

Because there is no speed the oil needs to be thin enough to crawl between the piston and sleeve

T_Lee

iTrader: (17)

Nice work, piston looks really good. Does this cause any problems having the whole crankcase and everything at the same temperature compared to the different temps everywhere when running? Does the exhaust side of the piston normally expand much more than the intake side?

Roelof

You may think the break in is compleetly wrong because the cooled and heated parts of the engine in a normal situation the piston and sleeve will take a different shape. That is true, but because the piston is not heated to combustion temperatures there is still enough room to shape it right with only a short break-in process when firering up the engine.

As a discussion about my Ielasi 9CL piston some pages back that it was compleetly done wrong by only touching the upper edge is showing a perfect used piston after the first rod replacement and the engine is still going strong after 15 liter of use.

Lets say this process brings the engine into a perfect matching piston/sleeve set which can not be done by any machine when manufactured.

After break in:



Here the pic after the 1st 5 liter of use:
http://www.rctech.net/forum/attachme...d-dsc_1456.jpg

T_Lee

iTrader: (17)

Ahh very nice, thanks for the explanation.

1fastmxcn

Hello,roelof, i also have one of these engines and must say, it took alot of time in ebis to get pinch that was acceptable. Still prefer OS engines fit bettet than nova. From the pic, your squish is set perfect. I bet its pretty low, thats how i find them to work best and maybe, machine the bowl to put trapped compression close to where it is stock. Good job roelof

Roelof

The engine had seen my bench for just 4 hours and needed 2 tanks on the track to go on full performance. I use Shell 0W20 oil in my break in bench.

The engine did come with the 16% head button and I am running the stock shims with Runnertime 16% and as mentioned the engine is running strong.

rbakker

'

Foodie

Roelof: Do you have any experience with LM produced engines and their pinch? I have an engine that has seen 1 hour at 90 degrees, 1 hour at 80 degrees and 3 hours at 70 degrees, but the pinch is still incredible hard... The piston looks a bit like the picture of the OS from earlier in this thread.

The Novarossi's does not behave like that and have much less pinch after 4 hours at 90 degress.

Edit: RPM's was set at 400...