Need some P220G experts... Got a tap/knock

[bc.gold 3,406]

Tap tap, possible causes, loose flywheel, broken crankshaft, bad connecting rod bearing or a bad wrist pin.

[1990Onan520-H 15]

54 minutes ago, bcgold said:

 

Worn timing gears would give a distinctive whining sound with the engine running,

 

What were the metal particle found in either the disassembled filter element or from the oil you drained from the engine, those metal particles have  story to tell.

 

When a wrist pin goes astray often the cir-clip falls out thus allowing the pin to float from side to side inside the cylinder, the image below is not of your engine type its facsimile showing damage.

 

 

 

No metal found in pan or filter. Timing gears feel sharp which I believe is good and means they aren't worn.

[1990Onan520-H 15]

25 minutes ago, bcgold said:

Tap tap, possible causes, loose flywheel, broken crankshaft, bad connecting rod bearing or a bad wrist pin.

The flywheel popped when i took it off, so dont think it was loose. Keyway also looks good. No loose magnets either. The tap tap goes away when I hold the camshaft gear in one direction and rotate the engine. I'm starting to think this tapping is normal? It just sounds like a lot of play but again, I'm new to steel all gear driven timing sets.

[1990Onan520-H 15]

Here is the rear cylinder. No question water was in there at some point. But other than that looks ok for a 1000 hour machine, again, compression was 85 psi in each cylinder so I don't think this pitting is hurting anything. The other cylinder looks brand new.

 

Now that im looking at it, could that scoring on the right side of that picture be a wrist pin mark?

 

Edited February 1, 2020 by 1990Onan520-H

[bc.gold 3,406]

Rotate the engine clockwise bring that piston into the position you see it now, magic marker place a mark onto the cylinder wall gently back the engine up just the distance of the backlash in the timing gears.

 

If there was any wear in the wrist pin the piston would have stayed stationary.

 

The low compression is probably from stuck piston rings.

[1990Onan520-H 15]

5 minutes ago, bcgold said:

Rotate the engine clockwise bring that piston into the position you see it now, magic marker place a mark onto the cylinder wall gently back the engine up just the distance of the backlash in the timing gears.

 

If there was any wear in the wrist pin the piston would have stayed stationary.

 

The low compression is probably from stuck piston rings.

My intake valves were leaking slightly. Very very slightly. But they were being held open a hair. Just enough for brake clean to every so slightly leak through. Think that would drop each cylinder to 85 psi? Or should I pull both pistons out to check the wrist pin clips and clean the rings? The engine is very clean and seems to have been well maintained so I would be surprised if the rings were stuck.

[lynnmor 7,815]

I would pull that piston, the cylinder looks bad enough to me.  Freshening the valves is a good idea, I have seen compression restored in engines with just the slightest valve wear.  The fact that all valve clearance was lost needs further investigation. 

[bc.gold 3,406]

12 hours ago, 1990Onan520-H said:

My intake valves were leaking slightly. Very very slightly. But they were being held open a hair. Just enough for brake clean to every so slightly leak through. Think that would drop each cylinder to 85 psi? Or should I pull both pistons out to check the wrist pin clips and clean the rings? The engine is very clean and seems to have been well maintained so I would be surprised if the rings were stuck.

 

Leaking intake valves, was the engine spitting gasoline out of the carburetor.

 

Easy test for leaky exhaust valve, take a business card and put a fold in it to act as a hinge, place the paper over the exhaust pipe if a valve is leaking the paper will be drawn back against the pipe hard enough that when it makes contact you'll hear a blip, blip sound.

 

Exhaust valves that are seating properly will continuously push the paper away, without the audible blip, blip.

 

Pull the pistons you either have stuck or broken piston rings.

 

This afternoon my Onan died while blowing snow, A lesson from my father, no spark no gas no run.

 

Plenty of gasoline just filled her up, and the electric fuel pump is pushing fuel, checked for spark and found none at the plugs, checked for power at the coil and found it live. So the problem is with the ignition points but the way the engine died without warning I suspect the condenser is shot or maybe a shorted wire inside the ignition box.

 

 

 

[lynnmor 7,815]

7 hours ago, bcgold said:

 

This afternoon my Onan died while blowing snow, A lesson from my father, no spark no gas no run.

 

Plenty of gasoline just filled her up, and the electric fuel pump is pushing fuel, checked for spark and found none at the plugs, checked for power at the coil and found it live. So the problem is with the ignition points but the way the engine died without warning I suspect the condenser is shot or maybe a shorted wire inside the ignition box.

 

 

Just curious, what old Onan are using that has points?

[tom2p 2,394]

20 hours ago, 1990Onan520-H said:

My intake valves were leaking slightly. Very very slightly. But they were being held open a hair. Just enough for brake clean to every so slightly leak through. Think that would drop each cylinder to 85 psi? Or should I pull both pistons out to check the wrist pin clips and clean the rings? The engine is very clean and seems to have been well maintained so I would be surprised if the rings were stuck.

 

if you have future plans for the tractor - at this point might be good idea to pull the remainder of the engine apart and complete a rebuild  ?

 

you have the knowledge and ability - as displayed by your documented progress 

 

parts won't be inexpensive - but you got the most expensive part :  labor 

 

maybe the pistons and crank don't require replacement ...  ??? ... (provided not too much cylinder wear) ... but just about anything / everything else including rings, bearings, gaskets, seals should be replaced  

 

... hone the cylinder bores ... fix the valve issue (and ensure seats are ok) ...

 

???

If I had this/your ability - I would consider pulling the 1000 hour P216 from my one 416-H and do a rebuild 

last time I pulled an engine apart to do a rebuild I had much more hair and much less stomach  lol

[1990Onan520-H 15]

15 minutes ago, tom2p said:

 

if you have future plans for the tractor - at this point might be good idea to pull the remainder of the engine apart and complete a rebuild  ?

 

you have the knowledge and ability - as displayed by your documented progress 

 

parts won't be inexpensive - but you got the most expensive part :  labor 

 

maybe the pistons and crank don't require replacement ...  ??? ... (provided not too much cylinder wear) ... but just about anything / everything else including rings, bearings, gaskets, seals should be replaced  

 

... hone the cylinder bores ... fix the valve issue (and ensure seats are ok) ...

 

???

If I had this/your ability - I would consider pulling the 1000 hour P216 from my one 416-H and do a rebuild 

last time I pulled an engine apart to do a rebuild I had much more hair and much less stomach  lol

 

This issue is the tractor itself is not worth doing a full rebuild. Its hardly worth resealing and assembling the engine. I have to do this as cheap as possible. I'll pull both pistons and check for broken/stuck rings and loose wrist pins and go from there. I'm starting to think it's the end of the line for this one. Which is a shame because the engine is actually in good shape other than that cylinder pitting.

 

This is my snow blower machine so gets very little use. If I can assemble it enough to run and blow snow 15 to 20 hours a year that's really all I need. It's not really even worth grinding the valves on. I'm not after maximum power or even no oil consumption. Just to have it run and spin a 2 stage snow blower.

Edited February 2, 2020 by 1990Onan520-H

[tom2p 2,394]

bummer 

rear cylinder pitting is odd 

 

from valves on one cylinder ?  head gasket ?

 

what did the motor oil look like ?

 

possible the pitting was result of broken down oil ... condensation acids etc in the oil when engine is run infrequently and or for short intervals in low temps (and even more so with certain types of oil)

but ya wonder why only one cylinder 

[1990Onan520-H 15]

7 minutes ago, tom2p said:

bummer 

rear cylinder pitting is odd 

 

from valves on one cylinder ?  head gasket ?

 

what did the motor oil look like ?

 

possible the pitting was result of broken down oil ... condensation acids etc in the oil when engine is run infrequently and or for short intervals in low temps (and even more so with certain types of oil)

but ya wonder why only one cylinder 

Yeah very odd. I don't know the history. I bought this machine and 2 weeks after owning it, it just died which lead to this. Thankfully I didn't pay too much because I would have been more upset than I already am. I don't think the previous owner thought it was going to die, seemed like a decent enough guy. Things happen, we deal with it and move on.

 

Engine oil was clean, but I actually sort of know who owned it before the guy I got it from, and that gentlemen passed away. I also know it was kept in a dirt floor barn. So very possible it sat for years unused after he passed.

Edited February 2, 2020 by 1990Onan520-H

[bc.gold 3,406]

Forgot to add another possible cause for tap tap, if the cylinder became so badly worn oversize there would be a ridge left at the top of the cylinder. Each time the piston reached top dead center the top piston ring would slam into the ridge making an audible sound.

 

During an overhaul this ridge had to be removed before the piston could be removed from the block, looking at the picture you provided appears there is no ridge.

 

 

Edited February 2, 2020 by bcgold

[bc.gold 3,406]

1 hour ago, lynnmor said:

 

Just curious, what old Onan are using that has points?

 

Cast iron CCKB 19.5 HP, Onan from 1975, pressurized oil system, forged connecting rods with replaceable bearing inserts available in STD, 0.010", 0.020" and 0.30".

 

If your engine requires a lot of parts I would suggest you keep an eye open for an Onan generator having the same engine, these engines make excellent donors as most have very few hours on them.

 

Most gen sets used the gen head as the starter so you may not find a ring gear installed to install your 12 volt starter you'll need to use  the oil pan from your old engine and some of the tin cowling.

[Darb1964 1,119]

The scoring looks like that motor was ran on starting fluid with low oil,or old oil. I think the scoring is not good,but not catastrophic. I think you clean it up and the rings are working right. Make sure the valves are adjusted and seating. The timing may be the culprit that renders the engines to much money to make it worth fixing. The gear should have rounded teeth not sharp. Put it back together fresh oil,and fuel, I would put a good amount of marvel oil in the fuel and oil. Let it warm up good and put it to work, what do you have to lose?

[1990Onan520-H 15]

I don't feel any ridge on the cylinders. Maybe an ever so slight one on the "damaged" cylinder, but I'm questioning if it's even there.

 

I stand to lose a bunch of time and probably $75-$100 in gaskets and seals if I do. Kind of a toss up. Guess I'll start by pulling the pistons out and checking the rings and such.

[bc.gold 3,406]

27 minutes ago, 1990Onan520-H said:

I don't feel any ridge on the cylinders. Maybe an ever so slight one on the "damaged" cylinder, but I'm questioning if it's even there.

 

I stand to lose a bunch of time and probably $75-$100 in gaskets and seals if I do. Kind of a toss up. Guess I'll start by pulling the pistons out and checking the rings and such.

 

Would like to see some pictures of those pistons.

[1990Onan520-H 15]

13 minutes ago, bcgold said:

 

Would like to see some pictures of those pistons.

You mean in the bore or after removed?

[bc.gold 3,406]

Removed, I'm placing odds the skirts are scored.

 

As for my CCKB Onan it just needed a rest, was working the old girl pretty hard putting a huge demand on the ignition system that the condenser just could not handle.

 

Today with a cold engine she fired right up, but the park at the plug is orange, good indicator to replace condenser as the spark should be lightning blue.

 

[bc.gold 3,406]

On 2/1/2020 at 12:52 PM, 1990Onan520-H said:

No metal found in pan or filter. Timing gears feel sharp which I believe is good and means they aren't worn.

Probably look like sludge, did you pass  magnet through the oil

[1990Onan520-H 15]

1 minute ago, bcgold said:

Probably look like sludge, did you pass  magnet through the oil

No magnet through the oil no and oil was clean as in recently changed. Found no metal in the filter. That said there was some sludge on the bottom of the pan but not anything crazy. Rear cylinder didn't look to have any bad burn marks in the valve area, so I assume it wasn't overhested either.

[Mudrig150 330]

You most likely have bad cam bearings, and the excessive play has caused the gears to get chewed up. 

 

At this point, if you aren't willing to put forth a couple hundred toward the engine, then you're outta luck. 

[1990Onan520-H 15]

37 minutes ago, Mudrig150 said:

You most likely have bad cam bearings, and the excessive play has caused the gears to get chewed up. 

 

At this point, if you aren't willing to put forth a couple hundred toward the engine, then you're outta luck. 

I don't feel any up and down play in the cam. Is there any way to check that or is the cam easy to remove?

[Mudrig150 330]

8 minutes ago, 1990Onan520-H said:

I don't feel any up and down play in the cam. Is there any way to check that or is the cam easy to remove?

Should be pretty easy, just tedious. Remove valves or get something to hold them open, push the tappets in, and then you should be able to just pull the cam out.

If need be, pull the gear off.

 

We only own 2 B-series, but that should be the process.

Edited February 4, 2020 by Mudrig150