Honda GX160 5.5HP OHV Metallic Pinging Noise

[SmallEngine H.P]

Ok so i have this Honda GX160 engine that came with a Murray Outrage Go-Kart frame which i bought off a guy in my town for $100, So time to get down to it. I started it up with fresh gasoline and the old oil which looked good enough to use for a little bit before replacing a day later, I started it up, lowered the idle a bit, and it sounded fine so i decided to rev it up to hear it run and around 4-5K revs i started to hear a pinging noise that got louder as i revved it up but it stopped as soon as i let off the throttle. I replaced the oil with a new bottle of Pennzoil HD 10W-30 and half a bottle of Johnsen's oil treatment i picked up at my local Big Lots. I started the motor up and i revved it up when the motor had gotten operating tempature and it still knocks. It doesn't do it at idle but only at speed, i don't know what to make of it. Spark knock maybe? :shrug:

 

[JamnJM]

Dentonation you mean? Try higher grade of fuel.....

Head been milled?

Flat top piston?

 

[SmallEngine H.P]

No mods, bone stock running 91 oct. fuel.

 

[minibikin']

No mods, bone stock running 91 oct. fuel.

Stock shouldn't need more than 87 octane even with the factory 4 deg advance.

Sent from my DROIDX using Tapatalk 2

 

[SmallEngine H.P]

Haha guess what i found out today upon inspection when i removed the OHV cover :laugh: Both the intake and exhaust valve rocker arms weren't tightened down all the way to the stock lift specs and they were so loose you could move them left and right with the push rod still on the rocker. Lol hopefully all of the internal components are still intact i don't wanna take apart the engine and find loose con rod bolts lmao

 

[Newoldstock]

Haha guess what i found out today upon inspection when i removed the OHV cover :laugh: Both the intake and exhaust valve rocker arms weren't tightened down all the way to the stock lift specs and they were so loose you could move them left and right with the push rod still on the rocker. Lol hopefully all of the internal components are still intact i don't wanna take apart the engine and find loose con rod bolts lmao

Stock Honda engines in my opinion can be run with ZERO lash.
Just tightent them by touch.
Bring the rocker to the lash cap so its touching but still loose enough to wigle and move.

Now set them again to the factory spec and you will see just how much difference that is in lash.

In practice thety can't reliable set the lash to near zero but you can if you take the time to see its correct.

As the engine warms up it will actualy open up more and you will get some lash back maybe .002 or so....

This makes not real difference in performance that you can feel but it does make the engine quieter ( if you can hear it ) other noises that crop up are not masked by that particualr tick.

Others may disagree.
My Grandfather was one such man.
He insisted he be able to hear lash.
He was deaf as a stone though.

There was a point however when that is how he would set the lash on engines. He did it by ear....
It was very close and it was done warm and under load in a large stationary diesel generating plant.
At that time he was quite in tune to his engines and listend to them all the time.

Probably what made him deaf too....

 

[SmallEngine H.P]

Ok so today i set the valve clearance today, but when i adjusted them to specs they started ticking loudly? And all of a sudden the crankcase seal started leaking oil? lol guess i'm going to have to take it apart and inspect the components tomorrow...