Natural Gas Engine
Natural Gas Engine
(OP)
Hi guys,
I have a Natural gas engine made by Waukesh that keeps detonating.
I have tried cleaning and regapping the sparks this didn't help. I then replaced the sparks and the engine ran good for about 500 hrs. then it started detonating again - I found
a sticky valve on cylinder #2 so I replaced the head, now, about 1000 hrs down the road the engine is detonating again. I have checked my valve gaps, check O2 checked my carbs,
checked the intake temps and jacket temps all looks fine. with the one exception that when this is happening, the intake manifold pressure increases by 2 lbs.
Any thoughts?
Thanks guys.
I have a Natural gas engine made by Waukesh that keeps detonating.
I have tried cleaning and regapping the sparks this didn't help. I then replaced the sparks and the engine ran good for about 500 hrs. then it started detonating again - I found
a sticky valve on cylinder #2 so I replaced the head, now, about 1000 hrs down the road the engine is detonating again. I have checked my valve gaps, check O2 checked my carbs,
checked the intake temps and jacket temps all looks fine. with the one exception that when this is happening, the intake manifold pressure increases by 2 lbs.
Any thoughts?
Thanks guys.





RE: Natural Gas Engine
Intake manifold pressure could be your issue though. I suggest checking that everything playing a role in this... throttle, wastegate, air bypass (if present).
Is there an electronic control? If so, is it trying to tell you anything... e.g. check engine light?
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
RE: Natural Gas Engine
Yeah, my book just says to clean and regap the plugs - it didnt change anything, but changing out the plugs cleared the fault.
Throttle and wastegate are all operating as they should - throttle is electronically controlled while the wastegate is mechanically.
I get no check engine lights or anything. This is a big 18 liter generator, all I see is that it jumps around on its skid and the Hz fluctuates a bit, but not much.
It seems that changing the plugs usually helps - this is the third time I had to do it and it cleared the fault, but the plugs only get about 500hrs on them while rated to 1400 hrs.
My dealer doesn't really understand why that is and neither do I.
RE: Natural Gas Engine
The occasional severe misfire suggests perhaps you have more sticky or leaky valves.
Mike Halloran
Pembroke Pines, FL, USA
RE: Natural Gas Engine
You need to check the detail part number.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Natural Gas Engine
Another possibility, for instance, is that one cylinder is dying off at high load (i.e. ignition issue), and the control is increasing charge pressure in order to maintain the same output distributed among the remaining cylinders that are still functioning properly. As above, this will push the combustion closer to/into knock.
Just some ideas. The reality is probably something else.
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
RE: Natural Gas Engine
je suis charlie
RE: Natural Gas Engine
RE: Natural Gas Engine
I described my problem and I was told to check for "weak Ignition" as Theblacksmith says. They were pretty certain it had nothing to do with the plugs that I use at all.
I am supposed to check the resistance in each coil and I am supposed to check for 140-160 VDC on the G-lead coming off the ignition module - this should tell me if my ignition module is bad or if
I have a bad coil.
RE: Natural Gas Engine