rippinwater
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What is the proper head clearance for NR .12 5 Port?
HEAD CLEARANCE ON NR .12 5 port
- Thread starter rippinwater
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Hi Craig it should be between .004"-.006" for 60% nitro.
GQ
GQ
rippinwater
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Thanks Glen I will see where its at, as I have never checked clearance on this engine. The engine has been eating glow plugs when it has a really good run. I have been running 50% in this engine, will these numbers be ok for that? Is there a noticeable difference between 50% and 60% in this engine from a performance standpoint?
Thanks -Craig
Thanks -Craig
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Craig, these motors come with very high clearances from the factory. This is what is causing you to kill plugs! The only way to get the nitro to burn is to lean it down and it's the lean run that takes the plug out. When you increase the compression you will be able to burn more nitro and the richer needle will keep the plugs alive. Most folks think the plug is being taking out from the compression, but it is really the lean needle settings required with the low compression. You will also see a large increase in torque with the lower head clearance!!!
GQ
GQ
rippinwater
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Thanks Glen I will make the necessary adjustments.
rippinwater
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Took me a while to find the needle (and a couple of glow plugs) but its finally performing at the level I would expect..Thanks Glen--------------Craig
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Sounds great Craig!!! Oh yeah, I forgot to mention that you should not be running any water cooling (maybe just a touch if there is not much airflow around the motor)! Making sure the motor is running warm enough is crazy important!!!
GQ
GQ
Norm,
We run O'Donnell 277's or the T-77's in all of our 12's and 21's.
The hotter plug will help you burn the Nitro with a more complete burn.
There is a small advantage running the Turbo Plugs also, about 250 more RPM.
Have Fun Testing,
Mark Sholund
We run O'Donnell 277's or the T-77's in all of our 12's and 21's.
The hotter plug will help you burn the Nitro with a more complete burn.
There is a small advantage running the Turbo Plugs also, about 250 more RPM.
Have Fun Testing,
Mark Sholund
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Hey Norm! Like Mark says, the hot 77's work well if they stay alive in your setup. I use a lot of the Nova 5 and 6's and really like them. In general, the hottest plug you can run is best.
GQ
PS, the turbo plugs are the real deal in the small motors!!! I don't ever run a .12 motor without them!
rippinwater
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Glen-I'm running the air cooled head that they sell on novarossiusa marine. I was having trouble finding a needle on the engine during open water. It was smoking and not coming up on the pipe very easily if at all, so i kept leaning until it came up and had a good strong run, but it ate the plug, so I richened it up a little and told my son (who was the driver) to keep the rpm's up between the pits and the launch (really get the heat up) and when I launched it hit the pipe very quickly and never missed a beat the whole race (so yes these things do really love their heat) and it returned with the plug in perfect shape.
