Looking to advance the timing on a GX390 that I’ve converted to natural gas to get it to run a bit better. Any tips on how much advance I should start with and do you have any tips on how to dial it in and make sure I’m not over-advancing the timing?
I have a stock predator 212 hemi and removed the governor, upsized my main jet to a #37 and installed some 22# valve springs and it breaks up at full throttle. Would love some feed back as to what I missed👍 Also still have stock flywheel installed
Is the piston hitting the stop right at top dead center? I know where top dead center is and how to find it, but I get lost as soon as ya put the stop in.
Don DeLaire no. It hits just before, then turn it the other way and it hits just after. between the two is tdc. I have a better way of showing this now. I may redo the video
Don DeLaire it's difficult to describe something like this via text. pictures and video work best. I'll see what I can do for a new video in the coming week.
I was just wondering, if the camshaft meets up with the driveshaft cam so the dots meet, and the flywheel goes on the shaft key, why is finding the timing important?
I know you can advance the timing with diff shaft keys, but if you buy the proper parts, shouldn't it run right? I'm building up a predator 212 with billet aluminum, better cam, and 18 lb springs.
Don DeLaire Good questions! Knowing where you're timing is at helps with diagnosing an engine that won't run. Flywheels can slip even with a key installed. In racing applications timing is extremely important in order to get the best performance. When you buy an engine new, used, our freshly rebuilt you don't know for sure where the timing has been set. Timing is as important as knowing what cam you have and what is best for your application. Timing would be different if you're using gas vs alky or if you're using the engine for general use vs racing...By the way, this same process to set your timing as well. offset keys are okay. We never use them. Our flywheels are set without them. We feel the pose a greater risk of the flywheel slipping. Instead of a key we lap the flywheel onto the crank, set the flywheel where/when we want the plug to fire, and torque it to 60 ft-lbs.
Thank you for your help, that totally cleared it up for me. As I'm getting all new parts, I opted for a performance cam that's 32 degrees btdc with the corresponding billet flywheel that's keyed 32 degrees btdc. I found the 32 lb springs the cam calls for and just need to find retaining rings and rockers strong enough, and stainless steel valves.
Don DeLaire We set our stock racing engines at 36 degrees. We have the SS valves, aluminum retainers and keepers for those springs. We don't carry the rockers. A great website to find info and parts is Poboys Greasy Nails Club on Facebook.
What differences are there from 32 btdc to 36? I'm putting my Predator hemi on a 26" bicycle, so I don't need the crazy torque of a race cart, I'm just trying to achieve awesome acceleration and top speed.
i have a greyhound 6.5 motor and i can get it to start but only with the choke on even after it is warmed up it wont start without being choked and when i do get it to start up and am able to take the choke off and it stays running but when i use the pedal to accelerate it cuts off but if i throttle it up with my finger on the governor lever it works fine but bog's out when i use the pedal and shuts off i have already gone through the carb and the tank and fuel line and fuel filter checked the spark plug and it is fine but still wont accelerate using the pedal what could it be
Sounds like a fuel problem. Possibly an air leak or maybe the gasket is blocking the low speed circuit. Recheck the gaskets and check for leaks. Also, what's the history on this engine? Has any work been done to it?
Not sure it came with a go kart I got and it had that problem already but I've checked the gaskets and they look new so did the carb inside and it's getting plenty of flow from tank to bowl but seems like it starving for gas when I accelerate the pedal but not when I do it from the governor it does fine
The throttle is hooked up with a spring to the governor arm and the arm is connected with a small rod and spring to the carb and it won't accelerate either way off the ground or under load but if I move the governor arm it will accelerate that way
The light I get, the math and the wheel I get, how ya get the timing from 28 shown here, to 36, I don't get. Thank you for all your time by the way, I'd really like to have this figured out before I start ordering everything, because I have to do the whole build on plasma donation payouts, and a meager tax refund coming soon.
Don DeLaire rotating the flywheel while keeping the crank still changes the timing. turning the flywheel clockwise makes the spark occur sooner (which is what you want). you do need a degree wheel.
Really good video upload..The best tuitorial on timing and finding TDC I've seen..I can do it now...Thanks Mike
Great video ! The ending put a smile on my face lol
Looking to advance the timing on a GX390 that I’ve converted to natural gas to get it to run a bit better. Any tips on how much advance I should start with and do you have any tips on how to dial it in and make sure I’m not over-advancing the timing?
I have no idea on natural gas. Sorry!
This got me more confused than before; too many unexplained loose ends for me.
Outtakes were hilarious !
I have one a small engine the Pistons not move what is the problem
thanks for the tips. good stuff man.
I have a stock predator 212 hemi and removed the governor, upsized my main jet to a #37 and installed some 22# valve springs and it breaks up at full throttle. Would love some feed back as to what I missed👍 Also still have stock flywheel installed
It may be going lean. Check for air leaks. The plastic spacer, if you're using one, can crack. Stock muffler?
You'll need to change your timing as well.
Mike Allen stock muffler yes. Plug keeps fowling so doubt lean condition. So I'm assuming adjusting timing to 36deg is solution?
charles janssen i would set timing at least 28 degrees btdc.
@@MrParafaxTHIS IS A dumb question but what is bottom top dead center? Top dead center i understand . Is it where the ignition sparks? Just below tdc?
Would you know the valve lash for 212cc non Hemi with 18lb Springs?
.000" up to .003"
Is the piston hitting the stop right at top dead center? I know where top dead center is and how to find it, but I get lost as soon as ya put the stop in.
Don DeLaire no. It hits just before, then turn it the other way and it hits just after. between the two is tdc.
I have a better way of showing this now. I may redo the video
( ; ) ) I'll subscribe and keep muh eyes out for it.
Don DeLaire it's difficult to describe something like this via text. pictures and video work best. I'll see what I can do for a new video in the coming week.
Thanks, Mike, for all the help.
Don DeLaire any time, Don! Hope you have a great night! Keep me posted.
I was just wondering, if the camshaft meets up with the driveshaft cam so the dots meet, and the flywheel goes on the shaft key, why is finding the timing important?
I know you can advance the timing with diff shaft keys, but if you buy the proper parts, shouldn't it run right? I'm building up a predator 212 with billet aluminum, better cam, and 18 lb springs.
Don DeLaire Good questions!
Knowing where you're timing is at helps with diagnosing an engine that won't run. Flywheels can slip even with a key installed. In racing applications timing is extremely important in order to get the best performance. When you buy an engine new, used, our freshly rebuilt you don't know for sure where the timing has been set. Timing is as important as knowing what cam you have and what is best for your application. Timing would be different if you're using gas vs alky or if you're using the engine for general use vs racing...By the way, this same process to set your timing as well.
offset keys are okay. We never use them. Our flywheels are set without them. We feel the pose a greater risk of the flywheel slipping. Instead of a key we lap the flywheel onto the crank, set the flywheel where/when we want the plug to fire, and torque it to 60 ft-lbs.
Thank you for your help, that totally cleared it up for me. As I'm getting all new parts, I opted for a performance cam that's 32 degrees btdc with the corresponding billet flywheel that's keyed 32 degrees btdc. I found the 32 lb springs the cam calls for and just need to find retaining rings and rockers strong enough, and stainless steel valves.
Don DeLaire We set our stock racing engines at 36 degrees. We have the SS valves, aluminum retainers and keepers for those springs. We don't carry the rockers. A great website to find info and parts is Poboys Greasy Nails Club on Facebook.
What differences are there from 32 btdc to 36? I'm putting my Predator hemi on a 26" bicycle, so I don't need the crazy torque of a race cart, I'm just trying to achieve awesome acceleration and top speed.
i have a greyhound 6.5 motor and i can get it to start but only with the choke on even after it is warmed up it wont start without being choked and when i do get it to start up and am able to take the choke off and it stays running but when i use the pedal to accelerate it cuts off but if i throttle it up with my finger on the governor lever it works fine but bog's out when i use the pedal and shuts off i have already gone through the carb and the tank and fuel line and fuel filter checked the spark plug and it is fine but still wont accelerate using the pedal what could it be
Sounds like a fuel problem. Possibly an air leak or maybe the gasket is blocking the low speed circuit. Recheck the gaskets and check for leaks. Also, what's the history on this engine? Has any work been done to it?
And Merry Christmas!
Not sure it came with a go kart I got and it had that problem already but I've checked the gaskets and they look new so did the carb inside and it's getting plenty of flow from tank to bowl but seems like it starving for gas when I accelerate the pedal but not when I do it from the governor it does fine
How is the throttle hooked up? Are you revving the engines under load (ie. Sitting in the kart) when throttling with governor and pedal?
The throttle is hooked up with a spring to the governor arm and the arm is connected with a small rod and spring to the carb and it won't accelerate either way off the ground or under load but if I move the governor arm it will accelerate that way
Glenn Curtiss, V-8, 40hp, 148mph.
The light I get, the math and the wheel I get, how ya get the timing from 28 shown here, to 36, I don't get. Thank you for all your time by the way, I'd really like to have this figured out before I start ordering everything, because I have to do the whole build on plasma donation payouts, and a meager tax refund coming soon.
Don DeLaire rotating the flywheel while keeping the crank still changes the timing. turning the flywheel clockwise makes the spark occur sooner (which is what you want). you do need a degree wheel.
So I just order the 32 cam, and springs and such to spec, and adjust the flywheel?
Yes, sir.
clockwise=sooner=increase in number from btdc? Yes? I think I follow now.
Don DeLaire yes. the spark will fire sooner burning more of the fuel.