Serpent 710
04-05-2004, 10:06 PM
#7816
Originally posted by markp27
On the subject of engine tuning.....I can get my engine tuned pretty ok these days, but one problem I often have is re-starting the engine when it is hot.
Does this indicate that the lower needle setting is too lean or too rich?
Cheers, Mark.
On the subject of engine tuning.....I can get my engine tuned pretty ok these days, but one problem I often have is re-starting the engine when it is hot.
Does this indicate that the lower needle setting is too lean or too rich?
Cheers, Mark.
1. Crank overheat. This can come from improper clutch settings or too lean engine.
2. Carb overheat. Basically it heat soaks from a too hot engine.
Both "boil" the fuel as it enters the motor and makes it impossible to start. You actually sometimes see the fuel retreat up the fuel line just after you prime the motor when very hot.
The condition means you are running too hot generally. You need to cut more body holes or richen your motor.
04-05-2004, 10:11 PM
#7817
Tech Addict
Re: Re: Re: Re: Re: Re: engine
Originally posted by AMGRacer
Yes. I say 1/4 of a turn to be totally safe but mayby 1/8th would be sufficient you need to get a feel for your specific engine. I usually do the middle needle when I am in a rush since you can access it easily through the rear window.
If your motor still has pinch at the top when hot without the plug it actually is not even run in fully yet.
To do a proper compression test you can do this:
1. Remove the motor from the chassis and remove pipe.
2. Spray a little fuel into the exhaust port and turn the motor over once or twice.
3. Roll the flywheel over while holding the exhaust port up to your ear. You should hear hissing which then stops as the piston nears the top of its stroke.
4. Hold it still before it fully turns over. You should not hear any hissing for at least 10 seconds. Less than 10 seconds is still OK but the motor is no longer in its prime.
Yes. I say 1/4 of a turn to be totally safe but mayby 1/8th would be sufficient you need to get a feel for your specific engine. I usually do the middle needle when I am in a rush since you can access it easily through the rear window.
If your motor still has pinch at the top when hot without the plug it actually is not even run in fully yet.
To do a proper compression test you can do this:
1. Remove the motor from the chassis and remove pipe.
2. Spray a little fuel into the exhaust port and turn the motor over once or twice.
3. Roll the flywheel over while holding the exhaust port up to your ear. You should hear hissing which then stops as the piston nears the top of its stroke.
4. Hold it still before it fully turns over. You should not hear any hissing for at least 10 seconds. Less than 10 seconds is still OK but the motor is no longer in its prime.
04-05-2004, 10:14 PM
#7818
Originally posted by AMGRacer
Problem is cause by two possible factors:
1. Crank overheat. This can come from improper clutch settings or too lean engine.
2. Carb overheat. Basically it heat soaks from a too hot engine.
Both "boil" the fuel as it enters the motor and makes it impossible to start. You actually sometimes see the fuel retreat up the fuel line just after you prime the motor when very hot.
The condition means you are running too hot generally. You need to cut more body holes or richen your motor.
Problem is cause by two possible factors:
1. Crank overheat. This can come from improper clutch settings or too lean engine.
2. Carb overheat. Basically it heat soaks from a too hot engine.
Both "boil" the fuel as it enters the motor and makes it impossible to start. You actually sometimes see the fuel retreat up the fuel line just after you prime the motor when very hot.
The condition means you are running too hot generally. You need to cut more body holes or richen your motor.
I'll try and collate the information here for the FAQ - it is sadly lacking an engine section at the moment.
04-05-2004, 10:14 PM
#7819
Originally posted by Profoxcg
how do you open an engine. Do I just inscrew the 4 screws on the back and close it when i am done? or do i need to take any special precations? or use any sealants?
how do you open an engine. Do I just inscrew the 4 screws on the back and close it when i am done? or do i need to take any special precations? or use any sealants?
Anyway, to access completely the internals of the engine, you need to take out the 4 screws bolting the heatsink. You need special tools (Hudy makes them) or find a slotted screw that fits very nicely the head of the screw. I don't know about Sirio engines but with all Nova engines, it comes with slotted head screw for the engine heatsink. Once that's off, you can access the button head where the plug is threaded. Be careful of the shims that come with it. Don't loose it !
Then unscrew the screws at the backplate. Before taking out the rear backplate, make sure your piston is at TDC (Top Dead Center).
If you're not sure, let your LHS guy take it out for you and watch him do it.
04-05-2004, 10:23 PM
#7820
Tech Addict
ehgine shims
My engine didnt have any shims in the head does that matter?
04-05-2004, 10:26 PM
#7821
Re: ehgine shims
Originally posted by Voodo_Magic
My engine didnt have any shims in the head does that matter?
My engine didnt have any shims in the head does that matter?
04-05-2004, 10:27 PM
#7822
Originally posted by InitialD
There were some good instructions on the RB website with pictures. But now I cannot find them anymore...
Anyway, to access completely the internals of the engine, you need to take out the 4 screws bolting the heatsink. You need special tools (Hudy makes them) or find a slotted screw that fits very nicely the head of the screw. I don't know about Sirio engines but with all Nova engines, it comes with slotted head screw for the engine heatsink. Once that's off, you can access the button head where the plug is threaded. Be careful of the shims that come with it. Don't loose it !
Then unscrew the screws at the backplate. Before taking out the rear backplate, make sure your piston is at TDC (Top Dead Center).
If you're not sure, let your LHS guy take it out for you and watch him do it.
There were some good instructions on the RB website with pictures. But now I cannot find them anymore...
Anyway, to access completely the internals of the engine, you need to take out the 4 screws bolting the heatsink. You need special tools (Hudy makes them) or find a slotted screw that fits very nicely the head of the screw. I don't know about Sirio engines but with all Nova engines, it comes with slotted head screw for the engine heatsink. Once that's off, you can access the button head where the plug is threaded. Be careful of the shims that come with it. Don't loose it !
Then unscrew the screws at the backplate. Before taking out the rear backplate, make sure your piston is at TDC (Top Dead Center).
If you're not sure, let your LHS guy take it out for you and watch him do it.
http://www.hpiracing.com/walkthroughs/engrebuild.htm
04-05-2004, 10:34 PM
#7823
Tech Addict
engine shims
I cannot see any and i have never had the head off before!
04-05-2004, 10:36 PM
#7824
Re: engine shims
Originally posted by Voodo_Magic
I cannot see any and i have never had the head off before!
I cannot see any and i have never had the head off before!
04-05-2004, 10:38 PM
#7825
Tech Addict
Re: Re: engine shims
Originally posted by PSI Racing
Usually there's one shim stuck to the head.
Usually there's one shim stuck to the head.
04-05-2004, 10:39 PM
#7826
Re: Re: Re: engine shims
Originally posted by Voodo_Magic
yea i thought so too but i run my finger over it to check and nothing moved! But now i think about it are they copper looking?
yea i thought so too but i run my finger over it to check and nothing moved! But now i think about it are they copper looking?
04-05-2004, 10:41 PM
#7827
Tech Addict
Re: Re: Re: Re: engine shims
Originally posted by PSI Racing
Some are copper and some are silver.
Some are copper and some are silver.
04-05-2004, 10:42 PM
#7828
They are like this:
04-05-2004, 10:43 PM
#7829
Re: Re: Re: Re: Re: engine shims
Originally posted by Voodo_Magic
well there was a copper looking one but it didnt move so i just left it as is
well there was a copper looking one but it didnt move so i just left it as is
I had a couple of shims that were stuck to the head.
At first look, it seemed like it was part of the head.