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16 hp Onan welsh plug leaking

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56hotrod

The cam is not tight in the rear bearing. There does seem to be more movement forward and backward of the cam in the rear bearing than up and down.

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sorekiwi

There does seem to be more movement forward and backward of the cam in the rear bearing than up and down.

I would hope that you have less than .048" of bearing clearance!!

If you have the valve springs still installed, it will be hard to see how much wiggle there is in the camshaft. They will tend to load the cam over one way or the other. Cam to bearing clearance is only .0015-.003" so you shouldnt be able to feel much movement. Having said that. on that rear (splash fed) bearing a little more clearance might not be a bad thing - bigger gap for some oil to get in there.

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sorekiwi

There does seem to be more movement forward and backward of the cam in the rear bearing than up and down.

I would hope that you have less than .048" of bearing clearance!!

If you have the valve springs still installed, it will be hard to see how much wiggle there is in the camshaft. They will tend to load the cam over one way or the other. Cam to bearing clearance is only .0015-.003" so you shouldnt be able to feel much movement. Having said that. on that rear (splash fed) bearing a little more clearance might not be a bad thing - bigger gap for some oil to get in there.

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56hotrod

Ok, I've been away for a while but got the engine all back together with the new plug installed. I used red loctite around the edge of the plug, installed it and dented the center with a 3/8 drive extension, then put permatex around the edge. Put the engine back together NO LEAKS after 30 minutes of cutting grass. I adjusted the valves according to the manual and now they are tapping. I did them .005 on intake and .013 exh, engine cold and adjusted both cylinders at TDC. Why are they still tapping?

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sorekiwi

Why are they still tapping?

Wild guess here, but I just went and looked at a P220 lifter and adjusting screw.

On the top of the adjusting screw, where the valve contacts it there is some wear (- obviously the diameter of the valve stem). This makes a little "bowl" in the top of the adjustment screw a couple of thousanths deep. I just checked 8 lifters I could easily get to, and all of them had .002 or .003" of wear)

When you stick your feeler gauge in the gap, I bet you are actually measuring the gap between the valve stem and the unworn part of the adjuster screw. The gap from the valve stem to where it actually contacts the screw is a couple of thousanths bigger than what you are measuring...

The right way to fix this would be to grind the top of the adjustment screws flat again so you can measure the gap, but since your motor is back together again, this probably wont happen.

If it were me I'd try setting the valve clearances a couple of thou tighter than spec, see if that quietens it down. (and hope this doesnt cause it burn a valve! :) )

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Redline69

 This is a subject I've been wondering about on my machine also.

 

Here's a picture of the offending plug on my 416. The engine oil leaks out the bottom of the plug.

 

DSCF5104_zpsc770537b.jpg

 

 I think you can picture it, just above the PTO cover plate.

 

I wish the member who had those pictures could reload them. I know Photobucket has been a real pain in the butt recently,and changed platforms, so maybe that's why the pix won't load.

 

 

 Should I try and order a new plug from an WH dealer, or could I just measure the hole,and see if I can find a generic automotive frost plug?

 

 

 Any more assistance on this topic would be appreciated.

 

 Frank

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Redline69

Thought I might get a bit more feedback on this issue?

 

 Still wondering about whether or not a stock size auto frost plug might work in this situation.

 

 

 Appreciate it.

 

 

 F.

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Redline69

 No other experiences with this issue?

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gwest_ca

I doubt Onan had special plugs made for them when there has been every size available for years. Two types I am aware of - shallow (dished) and cup (with straight sides)

 

Garry

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Redline69

Hi Garry,

 

Not sure I follow what you mean by...

 

"there has been every size available for years."

 

 So these are an Onan only part?

 

 Thanks.

 

 Frank

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gwest_ca

I do not think it is an Onan only item. Expansion plugs have been used in gearboxes for years and Dorman have supplied the automotive industry back to 1918. Onan would have sourced them from someone like this. They are a standard hardware item like nuts and bolts to an engine maker.

http://www.dormanproducts.com/

Concave plugs

http://www.dormanproducts.com/gsearch.aspx?type=keyword&q=expansion+plugs+concave

Cup type plugs

http://www.dormanproducts.com/gsearch.aspx?type=keyword&q=expansion+plugs+shallow

 

I don't know what type you need or the size.

 

Garry

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Redline69

Thanks for that follow up,and the additional links.

 

 Appreciate it!

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