UPDATE - VANARU CONVERSION - IT's ALIVE!

[Navy_Flyer]

After a very nice weekend camping about 150 miles from home, started up and headed for home. Engine gauges all in the green. After about an hour at 60 mph on the highway decided to get off and top off the gas. Still, everything normal. Quick check of oil level, right in the middle. Started up, and heard a light tapping. I thought it might at first be a lifter, then as we got back on the road it didn’t go away, and I thought, ok the valves may need some adjusting. Then, it happened - loud knock knock knock from the engine. Slowed to idle and pulled off into a business parking lot. All gauges still green. A check underneath, no leaks anywhere. Shut it down and got a tow the rest of the way home.
It sure is acting like a rod or rod bearing. At least I think so. Guess I have to drop it and open it up. Engine mileage is unknown - I put this engine in from an 88 Vanagon that only had 60K on the clock, but no validated history other than what I was told. The engine has been almost trouble free for 3 years and gave no warning at all of this. I’ve put about 6K on this engine since I put it in. I’ve read here, somewhere, that the connecting rod stretch bolts are known to fail at higher mileage. True? Maybe that’s what I have here. Since I shut it down right away, is it salvageable with new rods/bearings?
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1987 Westfalia, Automatic. EJ25 VANARU Conversion

[DanHoug]

since you have an auto trans, it COULD be a flex plate that has cracked. they sound nasty too and can mimick a rod. do you have an oil pressure gauge? oil buzzer system come on at all?

-dan

[wcdennis]

Lots of things can knock. Even an exhaust leak can sound like a knock. Drain the oil and see if any bits of a bearing come out.

[Navy_Flyer]

[Zeitgeist 13]

If you quickly blip the throttle, does the engine knock more as it's decelerating?
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Wildthings]

Less than 100K miles would be pretty young for the notorious rod bolt stretching syndrome. I would go with the lifters leaking down as the lifters on these engines don't like a thick oil like a 20w50 even when they are hot and the oil has thinned. Rotate the engine like you were doing a valve adjustment and see is any of the pushrods have end play. If so your problem is most likely a lifter that leaked down.

[IdahoDoug]

I'm going to assume a mechanical ability here in the top tier and that you have something worse than a lifter situation.

I like the flex plate comment and I also wonder like you do about the connecting rod bolt stretch. You are describing exactly what happened to me except my oil alarm DID sound and I pulled off immediately.

If you have a stretching bolt it would have dropped your pressure enough to trigger the alarm. How confident are you in the system working as desired? That's one question I have.

I would drain the oil into a clean glass container. Of all the times to actually secure a large gallon glass container, this would be the time to go literally buy one because you want to maximize the chance of a correct diagnosis. Drain your oil into it and set that aside to settle. If you've cooked a bearing, you will easily be able to see it. If you heard it, and a bearing was the noise, you're going to have some sparkly oil.

Next, I would in a quiet garage with good hearing, rotate the engine by hand with a wrench on the pulley bolt, or pull the spark plugs so you can do it with the pulleys. You'll want to firmly move the engine back and forth, listening for a deep clunk of a loose con rod. You'll feel/hear it. It's an obvious a slack feeling especially if you rotate 90 degrees past TDC for each piston and play the crank back and forth at this point of maximum crank arm rotational movement.

If you get nothing in the oil - good news. Ditto if its back up by no discernible clunk. Now move on to the flex plate and I dont have a good way of checking that. Anyone?

I'd also check the CV joints as those rascals can mimic a lot of much more serious ills. Loose bolts on these can create a broad spectrum of sounds and such though I think you are getting your clunk at idle with the car still, eh?

Doug
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Abscate]

A rod knock will definitely Change on float, you can run this at idle , unloaded, to help diagnosis only...don't load it by driving.

You can even try lifting a spark plug connector to try isolate the cylinder in question and confirm rod, valve lifter over flex plate or exhaust.

Well done getting the beast back on deck...OK underline
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.ssS!

[Navy_Flyer]

Thanks for all of the great comments and suggestions. Since this just happened last night, I have not yet been able to do any more diagnosis except to confirm that the knocking sound was present with the car sitting still - so it is not the drive shafts. As for the oil pressure light/buzzer - it works. I installed new sensors (low and high) when I installed the engine. I validated the operation when, after the new transmission was installed this summer, we took it on a ride to West Virginia - through the mountains. The engine did get hot, but nothing the fan and cooling system could not handle, and I did not push too hard - but one steep hill a car pulled out directly in front of me and I had to quickly get off of the gas and onto th brakes. At that point the light and buzzer DID go off for only a couple of seconds, then turned off. At first safe opportunity, I pulled off and checked everything - was OK. I investigated when I got home and learned that the mechanic had done a courtesy oil change for me, and used 10W-30. In summertime. In the mountains. I think it was too thin and pressure just dropped for a second during the extreme maneuver. I replaced it immediately with 20W-50 after that.
After the tow home on the flat bed, I started it up to get it into my driveway (the flatbed could not maneuver to my property). I kept it at idle and coasted downhilll into my driveway - engine running only to retain power brakes and steering. It only 'tapped' this time - the engine had been off/cooling for about two hours at this point. I revved it, and it did make noise, but no where near the level it did on the highway. I cannot fathom a lifter with noise like that - or one that leaked down and did not immediately pump back up - can they fail? Could a pushrod fail? There was no smoke or other indications - just the noise. Just throwing out less catastrophic 'hopeful' possibilities.... I know I will have to likely drop the engine, but just hoping I can find something definitive before I do.
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1987 Westfalia, Automatic. EJ25 VANARU Conversion

[Navy_Flyer]

[Navy_Flyer]

[Wildthings]

The tiniest piece of dirt can cause a lifter to leak down and/or fail to pump up. If a lifter has gone soft you should be able to detect it by setting the engine at TDC compression for each cylinder in turn and seeing if the push rod or rocker is loose and/or if you can push in on the bottom of the rocker arm to see if the lifter is soft.

A quart of Marvel Mystery Oil may quickly get a lifter working right again. Backing the adjustment off to give a little lash will help in getting a lifter to decide to pump up again.

20w50 oil will cover up the warning signs that a rod bolt is ready to fail. I have always used more conventional weight oils like 10w30 or 5w40 in my WBXer engines and have gotten high miles out of them. On my '91 it began to have a flickering oil light at around 180K miles and thus I took it out of service before the failing rod bolt let loose (I hadn't even heard of the rod bolt issue at that time but knew something wasn't right). Had I been running a 20w50 oil I may well have destroyed the engine.

[Navy_Flyer]

If I remove the three flex plate to torque converter bolts, thereby disconnecting the engine from the transmission, can I safely start the engine? If so, that may eliminate the flex-plate as the problem - or confirm it.
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1987 Westfalia, Automatic. EJ25 VANARU Conversion

[Wildthings]

Since the teeth that mate with the starter are on the torque converter there is no way to start the engine at t his point.

[MarkWard]

Someone suggest killing one cylinder at a time. You can use a simple test light to short out the sparkplug wire by probing the boot or as suggested you can pull a plug wire one at time be careful not to shock yourself.

If you have a rod knock, keeping that cylinder from firing should take the load off and you should hear a reduction in noise.

A rod bearing failure will fill the oil quickly was lots of shinny stuff. Draining the oil you will see the particle dust when a bearing has failed.

Carefully cutting open the oil filter will also give you a chance to look at the element for engine parts.

When a rod bolt fails, it is usually pretty spectacular and unlikely it would even crank over. Bummer.
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☮️

[Abscate]

[AtlasShrugged]

[Navy_Flyer]

[IdahoDoug]

I vote for the oil drain into a clear container. You have a mechanical ear and you've said twice that it's not the same as a lifter noise. I think you should trust yourself and confirm by observing your oil. I think you will have a definitive answer. How many miles on this oil? Cutting the filter open is a pain unless you have access to the proper tool, btw. I've tried a couple times and made a serious mess and nearly sliced myself due to the oil, tool pressure/force required and the like.

That would be my suggestion - drain it.

The water is a cool idea - putting that in my bag of tricks.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Abscate]