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Old 07-13-2017, 09:36 AM   #21
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I thought it was keyed as well, the only engines with gears I've seen were keyed, hence my question.

My Cummins book is on the boat, is it possible that the valve train is assembled incorrectly? Have you set the timing pin to check correct valve settings?
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Old 07-13-2017, 01:09 PM   #22
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Yeah, thanks for keeping me honest. I'm really learning as I go here, but that's the way I roll. Would usually rather puzzle it out myself than outsource to a pro. I was focused on cylinder #1 yesterday and didn't find any lash in the intake valve at pinned TDC and then made a leap too far :-). Lash had been within spec when I did my initial inspection. After barring the motor over I found that the rocker doesn't unload at any point on that valve. Do valves seat during break-in? I had sort of assumed that lash would maybe need adjustment after running for a few hours. Not going to sweat that right now unless someone tells me I should. Doesn't seem like the core narrative.

I keep coming back to timing, and am going to narrow my focus to the fuel pump removal, service and reinstalls.
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Old 07-13-2017, 01:34 PM   #23
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I admire your determination and effort Jeff! Good luck getting this resolved.
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Old 07-13-2017, 01:53 PM   #24
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Do I now understand that one or more valves never close all the way as demonstrated by there never being any clearance? That could explain quite a bit.

No, the clearance should not change on running the engine, though most manufacturers call for resetting clearances after 1000 to as much as 5000 hrs. But the gap shouldn't close up.

When you set the valves, are you sure you were at the top of the compression stroke and not the top of the exhaust stroke? It would be an easy mistake to make, either now when rechecking, or before when you set them initially.

And is it just me? I would really want to know where that nut came from, and where it is now. Unauthorized metal objects inside an engine is generally a bad thing.
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Old 07-13-2017, 02:39 PM   #25
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Do I now understand that one or more valves never close all the way as demonstrated by there never being any clearance? That could explain quite a bit.

No, the clearance should not change on running the engine, though most manufacturers call for resetting clearances after 1000 to as much as 5000 hrs. But the gap shouldn't close up.

When you set the valves, are you sure you were at the top of the compression stroke and not the top of the exhaust stroke? It would be an easy mistake to make, either now when rechecking, or before when you set them initially.

And is it just me? I would really want to know where that nut came from, and where it is now. Unauthorized metal objects inside an engine is generally a bad thing.
Thanks. Agree on the nut. Can't even say for sure that's what it was as I only caught a glimpse of it. I should have been more deliberate in removing the cover, but assumed it would drop into the bilge. Can only assume it went into the oil pan since I didn't find anything under the motor. I may disconnect my oil removal hose and try fishing around the pan when I drain the oil. I did poke around the oil drain at the bottom of the front gear case with my pickup stick but didn't get anything. Assume it's pretty much a straight shot from there to the pan. Its path appears to have started out on the motor side of the IP gear, and my workspace hygiene is generally not great, so I'm willing to accept as a working hypothesis that it was my doing.

Re valves, I haven't actually made any adjustments. At this point I'm looking more, doing less :-). Will continue, and your comments help.
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Old 07-13-2017, 03:03 PM   #26
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Do I understand that no.1 has no lash? If the valve is held open there would be no compression and that would explain the making oil.
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Old 07-13-2017, 05:08 PM   #27
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Thanks. Agree on the nut.

What might that nut have been attached to? Or what was it attaching to the engine, if anything? Is that widget still attached? Properly affixed? Sans nut?

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Old 07-13-2017, 05:43 PM   #28
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Is your oil pan steel or aluminum? If AL, you may be able to move nut with a strong magnet to somewhere you can grab it.
X2 on are you sure you are on the right stroke for TDC. Compression is right, exhaust is wrong.
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Old 07-13-2017, 08:01 PM   #29
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You can tell if you are on the right stroke by barring engine over and watching rockers. Rotate til intake valve opens then closes, then turn about another 120deg. No valves should be moving and that is comp stroke.

Also another hint is that 1 and 6 pistons move together, 2 and 5, and 3 and 4 same. The piston of each pair is always in the same place, but in opposite strokes in the cycle. So roll over til 6 exh valve closes and intake just starts to move. Now you are at #1 tdc firing or very close to it.
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Old 07-13-2017, 08:33 PM   #30
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engine won't run 180 off and blowby would not be affected by cam timing.

the video audio sounds like a very unhealthy bottom end to me.
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Old 07-13-2017, 10:05 PM   #31
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engine won't run 180 off and blowby would not be affected by cam timing.

the video audio sounds like a very unhealthy bottom end to me.
That was my thought as well.

Only a few of ways to get combustion gasses into the crank case...

Past a piston, through a blown head gasket, or through a valve seal

Diluting oil with diesel, enough to "make" oil is indicitave of a cylinder not firing.

High blow by is indicative of a cylinder problem.

My opinion is to pull the head and take a look see at what is happening. This is assuming that he has already pulled the valve covers and visually checked everything out.

A valve or valves being out of adjustment (tight), while in the extreme can cause a cylinder to not fire due to no or low compression, they won't typically cause a blowby issue since a valve remaining open does not create a path from the combustion chamber to the crank case.
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Old 07-13-2017, 11:57 PM   #32
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Well actually a valve held open will stop that cylinder from firing, the fuel will run down the cylinder walls into the crankcase (washing off oil too) and the gases will exit by the open valve into the valve cover and pressurize the cc through the oil return passages. Blowby in a Cummins is a given but what that video shows is oil smoke coming out the valve cover. I'm pretty sure it would be darker if it were combustion gases.

Check and correct all the valve clearances first. If all the oil has been washed off the cylinder walls it might be damaged too.
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Old 07-13-2017, 11:58 PM   #33
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What might that nut have been attached to? Or what was it attaching to the engine, if anything? Is that widget still attached? Properly affixed? Sans nut?

-Chris
It didn't originate in the gear housing. I did a complete inventory of widgets and fastenings. I think I dropped it in. Had stuff spread out around me and was going through some contortions getting the pump back in.
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Old 07-14-2017, 12:38 AM   #34
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Thanks to all.

I should recap and update.

All timing is fine. I've learned a ton about how these things are put together. Basically worked my way out from the crank through the cam and out to the valves. And IP timing. I really wanted to eliminate as much as possible the possibility that I did unknown damage from the front gear intruder.

Valve train had four intake valves that had no lash. Couldn't find a gap. So I got all the intake valves to spec. Exhaust were close enough and I didn't touch them.

My one nagging doubt is injection pump timing. Everything else I have complete confidence in.

I appreciate the discussion on blowby. I'm well aware of the conventional wisdom. Killed my BT last year. But I think this is a special case.

Remember that this is a motor that sat on a bench for 25 years. Virtually zero hours. Went through a teardown with new rings and gaskets in preparation for commissioning. IP rebuild and injectors tested. And then the motor a dwent through a troubled birth mostly due to my bumbling and fumbling.

So now we're about 25 hours in. I've never been able to get more than maybe 80 hp from it. The blowby as near as I can tell is not cylinder specific.

My take on this is that there's a good chance that if I can get up to full power without much more dicking around the blowby issue is going to disappear. If not we all can agree on the remedy.,

I should also say the the fuel dilation issue appeared to have almost disappeared the last time I was out.

Getting back to injection timing. Tomorrow I'm going to change the oil and filter, clean up, and go out for a quick jaunt around the bay. I've got fully charged batteries, ticking off one of the poor starting checklist boxes.

If i don't see a dramatic improvement I'm going to shut down, lock the IP to TDC, and go back to the pump shop and have them confirm timing.

Hmm. Tomorrow's Friday. Better set an alarm.
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Old 07-14-2017, 12:44 AM   #35
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Hmm. Tomorrow's Friday. Better set an alarm.
Some people here call Friday "Poets Day" (Piss Off Early Tomorrow`s Saturday).
I hope you solve your issues. I guess we have many many Cummins engined boats on TF, but right now there are 3 with significant issues, that we know about. Probably means nothing.
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Old 07-14-2017, 12:52 AM   #36
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Some people here call Friday "Poets Day" (Piss Off Early Tomorrow`s Saturday).
I hope you solve your issues. I guess we have many many Cummins engined boats on TF, but right now there are 3 with significant issues, that we know about. Probably means nothing.
Actually my pump guy usually works Saturday mornings. 75 years old, same shop for 45 years. I dunno whether they like seeing me coming, but I've enjoyed my several visits there. They now let me near their machines :-)

I really can't blame my issues on the manufacturer, so I think we've got a very low confidence level in any sort of correlation here.
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Old 07-14-2017, 12:56 AM   #37
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Well actually a valve held open will stop that cylinder from firing, the fuel will run down the cylinder walls into the crankcase (washing off oil too) and the gases will exit by the open valve into the valve cover and pressurize the cc through the oil return passages. Blowby in a Cummins is a given but what that video shows is oil smoke coming out the valve cover. I'm pretty sure it would be darker if it were combustion gases.

Check and correct all the valve clearances first. If all the oil has been washed off the cylinder walls it might be damaged too.
No disagreement with anything you posted except where highlighted.

A valve stuck open will either allow combustion gasses into the exhaust manifold, or the intake manifold, not the crankcase.

A valve seal could be a path between the valve cover area and the combustion chamber but not a valve being held open.

At least thats my armchair troubleshooting from 8,000 miles away
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Old 07-14-2017, 01:10 AM   #38
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Thanks to all.

I should also say the the fuel dilation issue appeared to have almost disappeared the last time I was out
Just to expand on this - the last time I was out was just before I started this thread. Immediately before that I had reseated the #1 injector. Think I talked about that already. That cylinder had up until then been underperforming the others. It now appears to be better. So there was a noted issue in one cylinder but I think that's been resolved.
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Old 07-14-2017, 01:23 AM   #39
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It didn't originate in the gear housing. I did a complete inventory of widgets and fastenings. I think I dropped it in. Had stuff spread out around me and was going through some contortions getting the pump back in.
Actually could it have been my 15 mm 1/2" socket? That's really the only thing that I've lost during the commissioning. Wow. Don't think what I saw was that big. But it was definitely shiny.

If I get up early enough I'll do some fishing around during the oil change. Not really fussed about having it (presumably) in the pan, but your questions have rekindled my curiosity.
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Old 07-14-2017, 03:36 AM   #40
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Pretty sure 1/2" corresponds with 13mm, but it`s still a hard shiny metal object. Maybe the experts can tell if it could get sucked up by the oil feed, and what might happen. I`m never keen on assuming coincidence, if something unusual happened, and a previously well tested engine is doing something unusual, there might be a connection? OTOH maybe it never even made it to the sump.
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