Clicking sound and very loose valve

[pdx6169]

Hello!

Long-time reader and first-time poster. I'm about a year into my Beetle journey and have found this forum to be very helpful. I'm hoping the expertise here can help me diagnose an issue with our 61 convertible that popped up yesterday.

We were driving yesterday, leaving a parking lot, when the engine very suddenly started making a loud clicking noise in sync with the rpms. The car also started backfiring. The issue went away for a bit as we drove, then came back sounding even worse with some engine stumbling. After we pulled over for a while, we started the car back up, and were able to get her the last few miles home. Sounded ok, not great, definitely a little off still.

I checked the valves this morning and all were in adjustment except #3 exhaust which was way loose. There was a huge gap, like 1/8". I had to turn in the adjustment screw in pretty far, much farther than the others, to get the gap at 0.006. You should be able to see this in the below pic (far left). My Spidey sense told me something didn't seem right about having to make a huge adjustment like that, so I haven't tried to start the car.

What could be going on here? My initial thought is stuck or collapsed lifter, but I'm still a novice with these cars. Thanks for any insight!

[KTPhil]

No hydraulic lifters on these cars. Solid lifter.
With the gap so much larger, it's time to pull the rocker shaft and examine the #3 exhaust pushrod. (Set to TDC for that cylinder first).
If you are lucky it's a pushrod failure, with nothing else out of whack. This is rare, though; usually something ELSE wrong makes the pushrod fail (stuck valve or lifter).
Do not drive or even run the engine until you investigate further.

[6T5 square]

I second Phils assessment. VW had a couple of styles of pushrods back in the day. I had the end snap off one on the way home in my Squareback. Take the arms off and I'll bet you have your answer
_________________
John
65 square 1500S (weezer) sold but always on my mind
60 beetle (Ned)

Quoting John Muir -- Open the rear boot. Get out the stool and sit down. Contemplate the air-cooled beauty before you. - How to Keep Your Volkswagen Alive -- Step-By-Step Procedures for the Compleat Idiot

[pdx6169]

Thank you both for the quick reply. I went ahead and pulled the rocker assembly off. The pushrod is not bent. The surface of the #3 exhaust valve is noticeably lower than the other three. With a straight edge, #3 intake and the #4s are level with each other. The #3 exhaust sits a good 1/8" lower. Is this a stuck valve?
_________________
1961 Type 1 Convertible
1969 Type 1 Sedan

[KTPhil]

How about the #4 exhaust valve lash? It uses the same cam lobe, so if it's good, then its a lifter or valve, stuck or worn.

[pdx6169]

[splitjunkie]

Possible that the #3 exhaust seat is working it's way out of the head preventing the valve from returning to it normal position. If that is the case, running the engine is a very bad idea.

The engine will probably have to come out and that head will need to be pulled to inspect the valves and valve seat.
_________________
Chris

You know, a lot of these scratches will buff right out... Jerry Seinfeld

[67rustavenger]

[pdx6169]

[67rustavenger]

[pastellgreen]

To me it seems, you have a 1200 with cylinder heads with round bosses, but converted to short studs. Clearance should be 0.004 then, according to the workshop manual describing the process for this kind of conversion. With the the short studs, clearance increases when the engine warms up.

[pdx6169]

[KTPhil]

[glutamodo]

In late 1971, VW retconned the valve adjustment specification for all "short stud" heads to .006" regardless of what the original owner's manual stated. That included converted round boss heads and even 36HP engines.
_________________
Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[pdx6169]

Thanks all for your help. Looks like the car is grounded for now and I have myself another summer project. This will have to wait a bit as I also have a 69 sedan that I need to get back on the road once parts come in next week. Luckily no engine pull there (yet!), just putting in a new pedal assembly. But of course the clutch cable wingnut was seized and the guide tube was missing altogether, so that put a halt on what should've been a single afternoon job. The fun never ends!
_________________
1961 Type 1 Convertible
1969 Type 1 Sedan

[pdx6169]

[tcoop1100]

Try here:
https://www.thesamba.com/vw/classifieds/detail.php?id=2419321
Good guy, mostly OG parts.
_________________
Aloha,
Tim
January '57 Sedan with April '64 40hp big bore

[pdx6169]

[glutamodo]

The photo above shows rockers held on with SAE head bolts. That means it has already been converted to short studs.
_________________
Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[pdx6169]