Hammerhead .21 Build

[Hammerhead]

Ready to run. Look forward to running with all you Namba8 guys on the 10th at Twin Lakes.

 

[57fairlane500]

Looks good Marty, cant wait to see it Saturday.

 

[Hammerhead]

Kelly, Yours as well. You sure did a clean build on that JAE.

 

[Hammerhead]

Well the boat rides nice, but the 35+ is givin me a headache :wacko:

 

[RodneyPierce]

Well the boat rides nice, but the 35+ is givin me a headache :wacko:

whats wrong? Perhaps we can help.

 

[shoboat]

Marty,

What sleeve do you have in the motor?

194* or the 182* exhaust numbers?

Thanks,

Mark Sholund

 

[RodneyPierce]

Marty,

What sleeve do you have in the motor?

194* or the 182* exhaust numbers?

Thanks,

Mark Sholund

good lord, I hope its not the 194*. Thats up there!

 

[Hammerhead]

Yep! That's where it's at. I'm having Jim grind on it this week. Hope that turns it on.

 

[RodneyPierce]

Yep! That's where it's at. I'm having Jim grind on it this week. Hope that turns it on.

its got a 194* exhaust? What are the transfers at? IF you can get it to work (will be high transfer timing) that sucker will be an RPM monster, but torque will be nearly non existant. Small diameter prop, less pitch and spin it to the moon would be my advise.

If I remember correctly (and I could be wrong) but isnt the 35+ one that you cant lower the liner on very much due to sub induction? Perhaps Jim can weigh in on this. I may be way off in left field here, as I have never messed with a 35+, just thought I had read somewhere here fairly recently about it. Like I said, I could be way off base. Let us know how it turns out.

 

[Hammerhead]

From what Jim says, I would be able to lower it 4 degrees without getting sub induction. That will bring it down to 189. It's at 193 now. You can tell it isn't drawing enough fuel on the bench; even with the needle way out. I'm not sure what the transfers are at.

 

[RodneyPierce]

Ok, so it is the one I remember reading about then. Cool.

 

[Jim Mamaril]

Yeah this is the 194* sleeve and it can not be lowered much, I think I can get it to 188 but I need to measure it again to make sure. Dropping it to that may help but it is a balancing act at best.

 

[RodneyPierce]

Yeah this is the 194* sleeve and it can not be lowered much, I think I can get it to 188 but I need to measure it again to make sure. Dropping it to that may help but it is a balancing act at best.

Hey Jim! I was hoping that you would chime in as well. And I agree. It can be made to work though. I was running a 190* exhaust/130* transfer timing in my sport 20 with good results. Im not going to say it wasnt a little picky on needle, but it worked, and worked quite well. I had to keep the prop diameter down and be careful with pitch. Really let her spin up. It didnt have any torque so to speak of, so if I let off it and tryed to cruise at a slower pace it was a crap shoot if it would come back up or not. But when it was up on plane and at WOT it went pretty well.

(this was in a sport 20 as well, so I can only imagine that it would work better in a lighter/less contact area rigger)

 

[Glenn Quarles]

Yeah Hammerhead and I had this talk when he bought the motor...the high timed 35+ motors either work great for some guys or not at all for others. We have since talked about the different ways to make it better.

Jim, if you are going to do some cutting on the motor for him, I lower my sleeve .013" without subport and it made a big difference.

Hammerhead let me know if you can't get it working and we will come up with another plan.

GQ

 

[Hammerhead]

Will do, Glenn. Thanks for the help. Just wish it would run as good as my .12.

 

[shoboat]

Marty,

The car sleeve at 182* is another option remember.

Good Luck Testing,

Mark Sholund

 

[Hammerhead]

Mark, I think I'm leaning in that direction. I don't know if I will use a 182 P/S. Jim has something up his sleeve. I'm going to let him give it a go first. I know this boat will compete in heat racing just fine. Just need to get the bugs worked out of the power source. The props you made for me will definately work fine.

Glenn, Don't take offense. I guess I didn't know what I was getting into. The way the engine was set up at the beginning, just was a bit above my pay grade and designed for something other than I intended. I love NRs. Always have, always will. This one though, has proven to be much more of a challenge than I expected. Live and learn.

 

[Tim_Duggan]

Dropping it 4 degrees will make a noticable difference - it's my opinion that it's the transfer timing that is the problem and too much transfer is not a good thing on a small 21 engine in a rigger.

From memory the sleeve was dropped 0.013" on mine by turning down the lip and went from having no torque and nearly impossible to tune, to being able to pull a H7 with 3.75" on a rigger with no rear ski. This was on 50% nitro. More Liquid torque may have helped, but I had tank capacity issues on 50% that would have been impossible to live with on more nitro.

I hated the 35 Plus at first, it was way down compared to the older NR's I had, but once the sleeve and head were adjusted, it's now my #1 engine (and I have quite a few NR's to choose from)

 

[Hammerhead]

What's your head clearance, Tim-san?

 

[Tim_Duggan]

0.008" Hammer san.

The head depth was adjusted after altering the sleeve height.

Mine likes OD-77t plugs. I'm not using the original cooling jacket either. It weighs a tonne and has massive water passage area.

I hope all this helps you out my friend. Any Q's, you know how to reach me.