Tinkering with an engine

[Micropuller]

Little update on what I'm up to:

One of our clubmembers approached me to do some work on an engine he bought. It's a 2.5 Cu/In weedeater engine, which originally ran on gas. He wanted it converted to nitro and in general produce a bit more power.

I started with cutting of the top of the heads and replacing them with new head-buttons with a higher compression ratio. Next I made a new heatsink which fits over both the cilinders. I ordered a couple of Walbro alcohol carburettors for which I made some tuned intake manifolds.
We hope to do a try-out this saturday. When all goes according to plan, the next thing to do is add a couple of custom made tuned pipes, and just to see if it works, this:



Here's what it looks like now:

[trickedoutTLT06]

wow. you really need to get into crawling, i bet you could make everything yourself!

[skidooguymxz550]

are you going to put the rc nos on it? that thing would be sweet in a sleeper

[xjman]

That kinda reminds me of one of Bob Shores engines. You may want to go with a bigger flywheel.

[Micropuller]

The test run went OK. I got about 7800RpM with a 20x10" prop, which equals about 5.5HP (stock was 3.2HP@8500RpM)

Here's a short vid of it running: http://home.hetnet.nl/~cyril-wichers/images/Robin5.wmv

[ColquittCustom405]

Sweet work man.

[Cole82]

Tune pipes will almost double the the HP on that engine. You have to have BP to get power.

[xjman]

Are you putting it in a car or truck?

[TMXONR]

Is the prop just for testing the engine or is it going in a plane. Either way nice work, that thing is sweet.

[NorCal 2500HD]

very nice...Id love to have one of those in a MHZ cat hull.......crazy how all the cool large scale boat stuff comes from europe.....

[Micropuller]

Yep, tuned pipes are next on the list. I just needed to see how the engine performs under load, so I can do the calculations (I make my own pipes) Double the HP is a bit on the high side IMO, but a gain of 20-30% should be possible. And then ofcourse, there's the nitrous...

When all the modifications are done and I'm satisfied with the performance, this engine will -ofcourse- go into a puller!

[xjman]

If you are using it on the ground I would go with a heavier flywheel, itll help keep rpms up and a more constant rpm. Have you decided what type of axle that is going to attach to? Will the crank hold up to the strain of a puller? I really would like to see this thing go once its together.

[sambmx]

I thought this was a nitro motor! Lets get some bigger jets and nitromethane.
92% nitro 8% 2 stroke oil if you have spare parts that is a supercharger on that would be rad.

Anyways sweet build keep us posted

[Micropuller]

New test-session tomorrow:

[slobin3d]

that has to be the coolest thing ive seen in a long while. What size prop is that? any ideas of what kindof power this thing is going to make

[xjman]

He said further up in the thread. Its producing 5.5 hp, with the tuned pipe a few more ponies will be unleashed. I'm still interested how the internal parts hold up to the added strain.