TecnoPower 21XM (M01)

I got a chance tonight to take down and measure the new TecnoPower 21XM. It uses a domed/dished type of piston, not a flat top. This makes for some what tough to measure the head clearance and volume. I gave it my best effort though. Here is what I found after inspecting it. Please remember that all of my measurements where taken with just a caliper. That is all that I had at home tonight. So Your findings may be just a fraction different than mine.



Head clearance with all shims: .029".

Head clearance with shims removed: .013

Head button volume: .20cc this is without including the squish area or the dish in the piston.

Head button volume including the piston dish but not the squish area: .23cc

Exhaust 170*

Intake 130*

Crank opens at: 209* ATDC

Crank closes at: 55* ATDC

Total open duration is 206*

I was vary pleased with the quality of the fit and finish. It is first class all the way! Thank you TecnoPower for making this Outboard Powerhead available to us.

Mark

Mark,

When is the inboard coming out?

It looks like a VERY NICE QUALITY ENGINE.

I hope Rody is thinking about a front exhaust engine in the future?

They would sell quite a few of them if available.

Thanks For Sharing,

Mark Sholund

mark, thanx to technopower is right, but THANX to you for bringing it to us!!! very nice looking fit & finish. you & tim need to come to the WTC & bring some with you, i'll bet they wouldn't be going back with you ....

I think you are vary correct Robin!

Here are the numbers according to Rody and Niklas from a little over a month ago:

Concerning the timings :

Crank : open/35 close/245

Exhaust : 170

ports : 130

STD and TURBO button volume with 0.3mm headshim and piston in TDC : 0.29633cc

V1 TURBO button volume with 0.3mm headshim and piston in : 0.22433

I also think it is safe to say this engine is produced with the intentions of being an easy to tune, reliable, and good running engine. There is more power in it, and Rody has confirmed, but that will always lead to a tighter needle window, and effect reliability (in terms of finishing heats). There have also been talks of releasing a 'sport' version of this engine, once they see how things go with the powerhead only version. So, keep your fingers crossed, the guys across the big pond are answering our calls for newer engines and they are expecting honest feedback. We need to support their efforts if we indeed dont want to see our OB Tunnel racing sport die out due to lack of equipment.

A huge KUDOS to TecnoPower, and all their associates. The tunnel heads appreciate it.

~ James

topfuel443 said:

Here are the numbers according to Rody and Niklas from a little over a month ago:

Concerning the timings :

Crank : open/35 close/245

Exhaust : 170

ports : 130

STD and TURBO button volume with 0.3mm headshim and piston in TDC : 0.29633cc

V1 TURBO button volume with 0.3mm headshim and piston in : 0.22433

I also think it is safe to say this engine is produced with the intentions of being an easy to tune, reliable, and good running engine. There is more power in it, and Rody has confirmed, but that will always lead to a tighter needle window, and effect reliability (in terms of finishing heats). There have also been talks of releasing a 'sport' version of this engine, once they see how things go with the powerhead only version. So, keep your fingers crossed, the guys across the big pond are answering our calls for newer engines and they are expecting honest feedback. We need to support their efforts if we indeed dont want to see our OB Tunnel racing sport die out due to lack of equipment.

A huge KUDOS to TecnoPower, and all their associates. The tunnel heads appreciate it.

~ James

Click to expand...

Hey James,

BTW, is she still at the baby-delivery-house or @ home with new jr?

The lakes are still hard here but I need to order some new tunnel props from Mark. James, can you give me some of your ideas on what props I need for booth "stock" and "open" classes for these babies...? Booth the way we race (short 3-leg course) and on ovals.

shoboat said:

Mark,

When is the inboard coming out?

It looks like a VERY NICE QUALITY ENGINE.

I hope Rody is thinking about a front exhaust engine in the future?

They would sell quite a few of them if available.

Thanks For Sharing,

Mark Sholund

Click to expand...

We are looking into some solutions but this takes time... The easiest would be to make a different crankcase but this costs a lot of investment and before doing this we need to know if this is worth it.

shoboat said:

Mark,

When is the inboard coming out?

It looks like a VERY NICE QUALITY ENGINE.

I hope Rody is thinking about a front exhaust engine in the future?

They would sell quite a few of them if available.

Thanks For Sharing,

Mark Sholund

Click to expand...

Mark,

I can turn them into a rear exhaust inboard engine if anyone would like one. I have the parts in stock to do so.

Mark,

So how much to turn the exhaust around?

Let Me Know Please,

I may have a few others to turn around also.

Thanks,

Mark Sholund

231.590.3023

Email is: [email protected]

shoboat said:

Mark,

So how much to turn the exhaust around?

Let Me Know Please,

I may have a few others to turn around also.

Thanks,

Mark Sholund

231.590.3023

Email is: [email protected]

Click to expand...

mark,

i believe hes talking about just reversing the crank rotation from outboard to inboard..

Why you want to go do that. Use it as is and run of the PTO. Pipe comes out neat in the center out the back. I've always wanted to use a OS XM as an inboard but the hobby shop wont sell motor alone must buy leg too.

Cobus

Hesco Racing said:

Why you want to go do that. Use it as is and run of the PTO. Pipe comes out neat in the center out the back. I've always wanted to use a OS XM as an inboard but the hobby shop wont sell motor alone must buy leg too.

Cobus

Click to expand...

Yup, I've seen that done a while back. It's a neat setup.

Hesco Racing said:

Why you want to go do that. Use it as is and run of the PTO. Pipe comes out neat in the center out the back. I've always wanted to use a OS XM as an inboard but the hobby shop wont sell motor alone must buy leg too.

Cobus

Click to expand...

I've got an older novarossi long stroke set up with an O/B crank and cut down PTO to use in an inboard configuration with a straight header. The square drive in the PTO is broached to take a 3/16" square drive cable. No need for a ferrule or a flex hex. B)

From a manufacturing perspective, It would be much cheaper to manufacture those existing parts a little further ( removing the excess off the PTO housing and opening up the PTO shaft to accomodate 3/16" square) and add a suitable belt start flywheel rather than a cone type flywheel, than to tool up for a new crankcase, crankshaft, inlet valve etc. An advantage is that it is still able to maintain a long crankshaft to fight bearing and crankpin distortion without the extra drag of an added rotor valve.

Also FWIW, I recently tried to get those low timed "buggy" numbers working in an inboard boat, and just couldn't get enough rpm without raising the timings. The torque was fantastic, but not as useful as rpm. 3.5cc Marine motors like similar numbers to On-road car engines. Exhaust in the low 180's and the transfers in the 128 - 130 region.

Cobus,

You would have no trouble at all selling a complete OS leg. They are the best leg for mod engines and F/E conversions in my opinion.

Hey Tim, Could you send me a picture of your OB turned IB. I am thinking of doing this to some engines. also is that realy a 3/16" square? if it is on a 3/16" flexshaft I think the square would be in the .150" range.????

Thanks,

Mark

lights said:

Hey Tim, Could you send me a picture of your OB turned IB. I am thinking of doing this to some engines. also is that realy a 3/16" square? if it is on a 3/16" flexshaft I think the square would be in the .150" range.????

Thanks,

Mark

Click to expand...

Mark, you are correct. (.150) I did a quick mock up in one of my .21 hydros. I just turned a motor around to see where the flywheel would be, in relation to the rear boom. If i used a shorter CMB black inboard flywheel, i could move the motor ahead a little more, so i wouldnt have to change the motor mount location. This was done with a nova, and a stock nova flywheel. Richard D

lights said:

Hey Tim, Could you send me a picture of your OB turned IB. I am thinking of doing this to some engines. also is that realy a 3/16" square? if it is on a 3/16" flexshaft I think the square would be in the .150" range.????

Thanks,

Mark

Click to expand...

Hi Mark,

The crank is now residing in an O/B engine that is attached to a new tunnel I'm putting together, so it's no longer in that config for me to take a pic of. The actual dimensions of the square isn't 3/16's as such, but an Octura 3/16" square-drive flex cable fits in it. So does a K&B 7.5 flex cable. I could measure the cable square dimensions if you want? I can take a pic of the cut-down PTO if you want, but it's nothing special - just the outer mounting parts cut off to a similar size to an inboard backing plate.

Tim

I have a pretty good picture of it in my head. Thank you Tim.

No problem Mark!

Question for you if I may - do you broach, EDM or use some other method to put the square in your PTO shafts? I really find the manufacturing processes for things like that fascinating!

Hesco Racing said:

Why you want to go do that. Use it as is and run of the PTO. Pipe comes out neat in the center out the back. I've always wanted to use a OS XM as an inboard but the hobby shop wont sell motor alone must buy leg too.

Cobus

Click to expand...

I'd take the leg if you just want the motor!!!!

kroggs said:

Hesco Racing said:

Why you want to go do that. Use it as is and run of the PTO. Pipe comes out neat in the center out the back. I've always wanted to use a OS XM as an inboard but the hobby shop wont sell motor alone must buy leg too.

Cobus

Click to expand...

I'd take the leg if you just want the motor!!!!

Click to expand...

Sounds like a chicken joke.... Are these motors available right now? Price with header....