Expensive-sounding noise, time for a Subaru? heh

[vwwestyman]

This time, NOT the '78 TDI!

Editing to add, this engine was originally from an aircooled Vanagon. In 2014ish, I bought the engine and swapped all the stuff over to make it go in the Bus. In 2016, I swapped the center-mount carb for factory fuel injection from a '78ish Bus. Also has an 091 transmission.

Was driving the '73 today, and as I left an appointment, it very suddenly started making a clacky, metallicky, expensive-sounding noise. Got it to a safe spot (in front of a friend's house, conveniently) and made 3 videos, and started walking to my office.

Will call AAA after work.

As I walked I set about uploading the videos to YouTube... I don't do that often, and it automatically grabbed all 3 clips and put them into one video, so sorry that that is kind of annoying. (Edit: Lord, I realized two of them are upside down! Oh well.)

No holes in the block, no massive oil puddles.

From the back, the sound seemed to be coming from the middle of the engine, but from up top the sound seemed to be more towards the transaxle. So I'm trying to be optimistic that maybe it's just something to do with the clutch, like maybe a bolt came loose or something.

I think the engine may die in one of the clips, and at idle it is a bit rough... That seems "normal" at the moment; the #3 plug will eventually foul over time, such that it seems to come offline at low RPMs, and kick back on as the RPMs go up, so most driving is fine enough. Eventually it gets annoying and I clean or replace the plug, and all is well for quite a while. It's time to do that again, which I sort of forgot until after I promised my 4.5 year old we could take it this morning. Recently did track down and fix some spark "leaking" from the spark plug wires (after the last time I drove it), so I am/was somewhat hopeful that will stop the plug from fouling in the future.

All that to say, the stumbly idle could be a red-herring if you weren't aware of that.

So, what is your call for what I find?


Link

_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[W1K1]

my guess is :: dropped a valve guide, and the bits are getting hammered in the combustion chamber
probably that #3 that was leaky
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http://www.thesamba.com/vw/archives/manuals/jim_martin_engine_build.php

1973 super
1965 squareback 1500E
1971 bay window westy- subi swap

[airschooled]

I would rotate the engine by hand in a quiet place and feel/listen. A half inch ID hose makes a fine stethoscope.

Or pull the valve covers and see which valve is doing the tango with its piston… My suspicion is your plug fouling was due to a sinking valve/seat that didn’t show up with self-adjusting valves.

Drive it home and put the tow money towards a Subaru.

Robbie
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[Wildthings]

A '73 would have the hole for the factory air injection system that are plugged one way or another. I am guessing that a plug failed and all you need to do is replug the hole.

[vwwestyman]

[Abscate]

It’s a cheaper, rod knock sound but it isn’t floating like a knock.

Have a good look at your exhaust manifold for cracks and fails
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[vwwestyman]

Just had this thought:

Though I drove it only a short distance, it *seemed* like the power was normal.

And when I was trying to get the videos, I one time did rev it up and I'm pretty sure that the one cylinder came "on line" as always when I did that.

Doesn't seem like those things would happen if it had dropped a valve, right?
_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Shonandb]

I had plugs (bolts) threaded into my emission ports/holes on my heads on my 73 Panel (1700cc) back in the 90s and one of the bolts I was using to plug the hole, somehow worked it's way in (threaded itself in further) and started hitting the valve and made a similar sound.

The engine ran fine as it didn't affect anything until the valve finally broke and then the engine stopped dead, luckily at an idle and didn't cause too much damage.

Mine wasn't as loud/pronounced as in your video and took a few days of driving before it broke. Yours sound like a much louder impact so I would recommend not running the engine anymore until you make sure it isn't something simple like mine was if I had taken the time to troubleshoot it better.

In my 76 Westy, I had a bad main bearing that was noisy but not the same knock as you are hearing for reference.
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*******************************
76 Westy with a 2.5L Subaru SOHC + Vanagon (010) Automatic Transaxle
Build & Trip Thread: https://www.thesamba.com/vw/forum/viewtopic.php?t=758760
Previous 1973 Panel Bus:
Click to view image

[raygreenwood]

Having heard it before...it does kind of sound like one of the exhaust air injection plugs has come out....BUT....when that happens there is exhaust and/or flame into the engine bay. You would see it in the videos.

But...that same sound can come from a really blown out head gasket (if you are still using gaskets)...where you have a burn through at the edge.

Also if for some reason a header pipe has come loose or seriously cracked.

Ray

[SGKent]

if it comes and goes, that can also be a valve seat. If so catch it now before it breaks the head off the valve and trashes more than a head. With these engines, anything is possible. That said, you could have a ten year old modern car and be facing a blown head gasket or dead transmission.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[vwwestyman]

The Vanagon motor wouldn't have had exhaust injection holes, right? Surely they didn't continue to build the heads that way and just plug them up...

I have no idea if there are head gaskets- I lucked into buying that motor for a good deal. Turned it over enough to feel compression 4 times and smooth rotation, and bought it. When I got it home, I only changed all the oil seals and removed the Vanagon specific parts and bolted on the Bus specific parts from the original engine. Put it all together and tried it out, and it ran well, so I ran it!

Engine hasn't been out since I installed the fuel injection in 2016. It's been a bit leaky and the foam seal is starting to get crumbly if you touch it so I have/had been intending to pull the motor sometime and fix all that stuff up. I guess if was going to drop a valve today, I'm sorta glad I didn't do that over the past winter like I'd hoped.

Was originally thinking I'd use AAA to tow it home, but then later in the afternoon today it did occur to me that this Bus was a tow-behind vehicle for the previous owners, and I have a tow bar for it! Duh.

So I'll plan to tow it home tomorrow or over the weekend and see what I find. May not get too far into it until Sunday at the earlierst but we'll see.

Besides the regular stuff, it sucks a little extra because we'd been using this Bus for transportation/a backdrop for our shave ice side-hustle business and it's just now starting to be that time of year!

_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Shonandb]

Sorry Dave, I didn't read the full thread to know that it was from a Vanagon but thought I should share my experience as it sounded similar.

If you need an incentive to do the swap, listen to my first start:


Link

_________________
*******************************
76 Westy with a 2.5L Subaru SOHC + Vanagon (010) Automatic Transaxle
Build & Trip Thread: https://www.thesamba.com/vw/forum/viewtopic.php?t=758760
Previous 1973 Panel Bus:
Click to view image

[SGKent]

I have a couple different models of this. They fit thru a plug hole. Makes for an easy diagnosis if it is a valve seat, and how much damage it has done.

https://www.amazon.com/DEPSTECH-Industrial-Inspect...1&th=1

https://www.amazon.com/Seesi-Endoscope-Waterproof-...amp;sr=1-1
_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[vwwestyman]

[Abscate]

[vwwestyman]

[skills@eurocarsplus]

if you juuuusssst give it a little throttle off idle does the noise go away?
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[airschooled]

It’s not combustion/exhaust related. The sound is happening once per revolution and not changing with throttle. Combustion/exhaust leak noises happen once every other rotation, and change with throttle.

You’re looking for an 800bpm cause, not a 400bpm cause. A cylinder drop test (pulling once injector wire at a time) would make the sound disappear if so.
Robbie
_________________
One-on-one tech help for your vintage Volkswagen:

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[timvw7476]

I've dropped an intake valve seat & driven on it to spare a tow $. They don't sound like that. The seat usually just wedges into the head as you limp to safety on three cylinders. That's a real machine gun sound you've got there. Check the valve springs. Probably find out The Dealio under those covers. : i

[SGKent]