NR .21 DD

[David Ashcroft]

Anyone using the NR .21 DD having fuel draw problems my tanks and lines seem fine ,engine runs but its a bit hit n miss at times...I thinking no fuel...

David

 

[namba276]

Gotta run it rich,rich,rich...

 

[ALLAN YUEN]

I think your ops pipe No good because it is too small Glenn said better NR 21 muffled pipe Good Luck!

 

[David Ashcroft]

Allan yes I was thinking maybe pipe ,,,I will change pipe today and test with the Mac and the NR pipe...

Will also take some cup out of the 442 ...

 

[Brian Sorgente]

what exactly do you mean hit or miss? what does it actaully do?

 

[David Ashcroft]

Brian I was think my prop maybe ...I was told it is a rpm engine but probably better for hydros...I will mod the 442 more

 

[Glenn Quarles]

David, these are typically not "rpm" motors...they have really good torque too! Have you set the head clearance? They come from the factory way to high and you will need to remove /replace shims to get it down to around .006". Once you do that you will be able to richen up the needle and burn enough nitro to get plenty of torque.

GQ

 

[RodneyPierce]

would also like to know what you mean by "hit or miss".

 

[David Ashcroft]

would also like to know what you mean by "hit or miss".

Just a bit of slang...

 

[David Ashcroft]

David, these are typically not "rpm" motors...they have really good torque too! Have you set the head clearance? They come from the factory way to high and you will need to remove /replace shims to get it down to around .006". Once you do that you will be able to richen up the needle and burn enough nitro to get plenty of torque.

GQ

Glenn ok ,,yes its at .008 ,at moment,,I am testing today with pipes and props ,,will let know..

David

 

[David Ashcroft]

Well I went to the lake just a short session didn't change anything except the pipe,,,I put the spp NR .21 pipe on and it come alive..started at 9". Then 8.5" was turning the 442 like nothing .. ...will go back tomorrow and try shortening more ...I will leave it at .008 for now ,,want to try my sholund chopper also...

David

 

[RodneyPierce]

I also had an issue with it sagging on the straight, and then picking up under load in the corners. But no matter how much prop I tossed on it could never get it to clean out down the straights. Im trying .18cc on the button this year and hoping it helps. Thing has GOBS of torque. I had very good results with the Novarossi pipe, but am currently going to run the SPP NR21 carbon pipe on mine and see where it gets me this year.

 

[David Ashcroft]

Rodney I am getting a brass button made ,,I drilled the NR.21

Stinger to .355 to test on Sunday ...

David

 

[RodneyPierce]

I have never had luck with the brass buttons. But then again I run very little water cooling so dont have any issues getting heat in the chamber either.

 

[shoboat]

Fellas,

You need more load to burn the nitro it sounds like.

David,

If that is your stinger I.D. .355" ? That is way too big for a 21 motor.

Rodney,

I think you need to recheck the numbers on your motor?

Thanks,

Mark Sholund

 

[David Ashcroft]

Delete

 

[David Ashcroft]

Fellas,

You need more load to burn the nitro it sounds like.

David,

If that is your stinger I.D. .355" ? That is way too big for a 21 motor.

Rodney,

I think you need to recheck the numbers on your motor?

Thanks,

Mark Sholund

Mark I correct myself I measured wrong I drilled to .315 and not .355....

David

 

[shoboat]

David,

Why do you think you needed to open up your stinger outlet size?

Believe it or not ? .284" to .290" are good pipe stinger numbers for a 21 engine.

Curious,

Mark Sholund

 

[David Ashcroft]

I am curious too ,,seeing what happens with changes,to stinger diameter,mine as stock was .278 thanks for those numbers..

David

 

[David Ashcroft]

Another session this morning and it went well..I got some warmer plugs RB #6 and the nova liked them.Running at .008 with a 8-1/4 " NR pipe using a sholund chopper.theseaducer was starting to move very well..I pinched the water also as it was a cool morning,this engine is still new and tight so I am looking forward to more performance yet...more testing tomorrow....

David