1.01 cmb burning holes in pistons

[Buckshot]

You'll notice how fast the temp drops at the end of the run.

IR temp guns after a run are only good for guessing.

IR temp guns are a great tool on the bench for tuning along with the good 'ol ear.

I assume that you slowed down a couple of time in the run? Also great data.

Yeah some of that I was milling around. I guess my GPS unit didn't like Northern Indian because it didn't log at the Masters or I'd be able to show the speed trace along with the temps.

 

[dwilfong]

Takes time for the GPS to find its self if you go more than say 300 miles away from the last time it loged on.

 

[steve wood]

Here is a snap shot of my Eagle Tree head temp readings from a run in open water at Hobart 2012.

which one was inside motor/outside?

 

[Buckshot]

Here is a snap shot of my Eagle Tree head temp readings from a run in open water at Hobart 2012.

which one was inside motor/outside?

I'll have to check for sure but I think it was set up where Thermocouple_A was the inside motor and Thermocouple_B was the outside motor.

The laps it made from 110sec to 130sec is where the motors where synced up real nice.

I have all the junk to log both motors for RPM also but never put it in the boat, that will be nice to see someday.

 

[Ty Faust]

Good data Buck! Very helpful with the twin

 

[dwilfong]

Buckshot test your resistors with a ohm meter. make sure you get two that read the same.

You will get a beter picture of what is going on.

 

[dwilfong]

Have a brain storm I will throw out there.

Some talk about using a long length of fuel line to help with a lean over.

Well how about a float chamber between the needle and carb?

When full it will act right on the needle. now get a load on the eng and it will suck from the chamber.

 

[Tom Foley]

But if the amount it can suck is not controlled it will go rich ..then lean as the bowl emptied !

 

[ids987]

Have a brain storm I will throw out there.

Some talk about using a long length of fuel line to help with a lean over.

Well how about a float chamber between the needle and carb?

When full it will act right on the needle. now get a load on the eng and it will suck from the chamber.

As long as the flow to the float chamber can keep up (by pipe pressure or other means eg pump), the level of fuel in the float chamber is very nearly constant. The engine runs in suction feed mode all the time, and the head of fuel available is very nearly constant.

 

[dwilfong]

That what I am thinking the chamber will be full all the time from the pipe pressure and the needle will control as it always dose.

but when the eng needs more fuel it will have a surge tank to pull from.

Never sucking the needle dry.

Basically the same thing thy use over seas but the needle in front of the tank.

 

[phill fields]

That what I am thinking the chamber will be full all the time from the pipe pressure and the needle will control as it always dose.

but when the eng needs more fuel it will have a surge tank to pull from.

Never sucking the needle dry.

Basically the same thing thy use over seas but the needle in front of the tank.

David you're exactly right with the float chamber and pressure tank. We use them with fsr-v boats in Europe. The pressure pipe from the exhaust feeds into a small header tank to the left of the engine. That header tank feed pressure into the main tank. The main tank feeds fuel to a float chamber infront of the engine. The float chanber then goes to the fuel needle in the carb. It works perfectly

Phill

 

[Tom Foley]

Phill , David is talking about a surge tank after the needle different to your setup . The needle still has to set to the highest need / richest setting to be functional or the engine will run lean the way I see it .

David your boat sure is going to be a Guinea Pig for a lot of tech this season !!

 

[dwilfong]

this is what I'm talking about.

http://madmodder.net/index.php/topic,2456.75.html

 

[phill fields]

That's so cool. Same principle but engineered about a thousand times better!

 

[Tim_Duggan]

Phil,

Do the FSRV 15cc boats have any issues with burning holes in RS91 pistons? What % nitro is the most common in that class?

Tim

 

[dwilfong]

That is bad!!!!!!!

If I was just a better machinist.

 

[phill fields]

Phil,

Do the FSRV 15cc boats have any issues with burning holes in RS91 pistons? What % nitro is the most common in that class?

Tim

Tim, yeah there have been a few. But i've only seen a handfull of cases in the past 2-3 years. We run 15-25% nitro in them. We run 30 minute races so the problem comes from fitting enough fuel in to last. I run 25% in my 15cc v boat and my hydro though. We find the bearings are the worse problem

 

[Tim_Duggan]

Thanks Phill,

Good info to know!

Tim

 

[Ian Inverarity]

Tim, yeah there have been a few. But i've only seen a handfull of cases in the past 2-3 years. We run 15-25% nitro in them. We run 30 minute races so the problem comes from fitting enough fuel in to last. I run 25% in my 15cc v boat and my hydro though. We find the bearings are the worse problem

Both bearings? I have had issues with the bearing at the flywheel end.

 

[Bob Morton]

Wow that was a super illustration of fine maching to say the least. I need to put my hammer and chisel away .

A simple hopper tank and a data recorder is the answer as seen by Bucks chart. I am referring to a twin application.

Nails.