Community Forums

Doc Vegas · 10-16-2015, 01:26 PM

Hi Folks: On this trip, my Onan 5500 GAS generator will hit 1,000 hours. I read the thread on "how many hours", so it sounds like I am fine. I had the oil changed by a professional shop and the plugs look like they were replaced. But, i want to be proactive. The manual says to check the valve lash and possible "replace the heads" at 1000 hours. What's the story here? Valve lash I get, though I may not be able to do it myself...??? But inspect and replace the heads...., really?

What's the scoop? The generator had 900+ hours on it when I got the rig. Seems to start up OK and run fine. What would you do?

Thanks

scooterbob · 10-16-2015, 02:56 PM

If the plugs are good, the filter and oil changed, and it runs good I would leave it alone..

Doc Vegas · 10-16-2015, 03:40 PM

Quote:

Originally Posted by scooterbob

If the plugs are good, the filter and oil changed, and it runs good I would leave it alone..

Thanks, I like that! Will be curious if others talk about valve lash adjustments. I had a BMW motorcycle and this was part of the routine maintenance, maybe similar on the Onan? Cheers

vsheetz · 10-16-2015, 09:39 PM

Keep the plugs, oil, and filters changed per schedule. Then if it ain't broke don't fix it.

Doc Vegas · 10-17-2015, 09:29 PM

Sounds good, I will be doing the oil in a week or so. Thanks again

LETMGROW · 10-18-2015, 06:44 AM

Anyone would have a tough time convincing me to replace a perfectly good cylinder head for no good reason. Adjust the valve lash maybe as parts do wear and tolerances can change. If you don't hear any audible clicking noise in the valve area I'd leave it alone.

Pirate · 10-18-2015, 05:51 PM

Quote:

Originally Posted by Doc Vegas

Hi Folks: On this trip, my Onan 5500 GAS generator will hit 1,000 hours. I read the thread on "how many hours", so it sounds like I am fine. I had the oil changed by a professional shop and the plugs look like they were replaced. But, i want to be proactive. The manual says to check the valve lash and possible "replace the heads" at 1000 hours. What's the story here? Valve lash I get, though I may not be able to do it myself...??? But inspect and replace the heads...., really?

What's the scoop? The generator had 900+ hours on it when I got the rig. Seems to start up OK and run fine. What would you do?

Thanks

Took mine to an authorized service center once, regular freighliner/onan place. They giggled when I suggested the valve adjustment. Like others said, they too said if it runs great, leave it alone. I have around 1300 hours on mine now. I do oil, filters, plugs once, that's it.

LVJ58 · 10-18-2015, 08:45 PM

If it works, leave it alone, if it quits, get it fixed..

Good luck & Safe Travels

FORTRIDER · 10-19-2015, 05:51 PM

Quote:

Originally Posted by LETMGROW

Anyone would have a tough time convincing me to replace a perfectly good cylinder head for no good reason. Adjust the valve lash maybe as parts do wear and tolerances can change. If you don't hear any audible clicking noise in the valve area I'd leave it alone.

I would rather hear ticking, that means the valves are loose. No clicking valves are too tight and subject to burning and pitting. Just my 2 cents.

Redapple · 10-19-2015, 08:53 PM

It is just breaking in...you good, change the oil, filters and run it on a regular basis.

Doc Vegas · 10-19-2015, 10:14 PM

Thanks again all!

LETMGROW · 10-20-2015, 04:34 AM

Quote:

Originally Posted by FORTRIDER

I would rather hear ticking, that means the valves are loose. No clicking valves are too tight and subject to burning and pitting. Just my 2 cents.

I agree with that but in a running engine if the valves or valve seats are worn that badly you would soon hear a skip in the engine from compression loss. This could be verified with a compression test.
By this time the damage has been done already and the heads would have to come off and be repaired or replaced.
Leaving the valves too loose can ruin parts in a hurry. As the clearance is taken up the valve stem is slammed and rockers and valves can be quickly worn.
Lynn