Cylinder number one running lean

[skiter8198]

All of a sudden it sounded like I had an exhaust leak. After a little poking around I found that when I remove plug wire found number one cylinder it stops. I pulled the plug and it looked like it running lean on that one cylinder. I adjusted the valves (they did have some play in them). And it made no difference, if anything it got worse. The engine is a 1679 with a 34 pict 3 carburetor and a pertronix svda electronic distributor.

[modok]

So.... fix the exhaust leak.

Or it's leaking at the head/cylinder, not so easy to fix, but maybe re-torquing the head studs would help.

[skiter8198]

@modok I can’t find an exhaust leak, that’s what’s puzzling me. I’m hoping it’s not leaking between the cylinder and the block.

[67rustavenger]

[VW_Jimbo]

[skiter8198]

Ok, so after looking at it again I found the issue (not sure how I missed it the first time). The exhaust stud backed it way out. These are new heads from aa performance with only a few hundred miles on them. The studs came installed in the heads when I purchased them and I never removed them and installed loctite. I installed a new stud with loctite and problem solved. Also I when through and checked all the others and found most a little lose, some more than others.

The next time I buy new heads and they came with studs already installed, I will remove all the studs and reinstall with loctite.

[67rustavenger]

Well, that'll make it pop on decel.

Good on you for looking closely.

Buying a set of heads, with the studs uninstalled. Is no guarantee that the studs will stay where you install them.

I bought a set of US made heads a few years back. After using red loktite on the studs. They still backed out when I was removing the exhaust nuts.
Those heads had less than 1K miles on um.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!

There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!

[bedlamite]

[modok]

It fell out because it was loose.
Threadlocker or locknuts are not going to fix that problem.

[oprn]

I find that on new exhaust gaskets I need to check them several times in the first heat cycles. The gaskets seem to continue to crush for a while. Also I like the copper exhaust nuts. They don't tend to seize on the studs so the studs stay in the heads. No lock nuts for me, I would rather have the nuts come loose than the studs. Loose studs wiggle out the holes in the head and then the next thing that happens is the studs pull out of the heads!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[mikedjames]

If they came undone they were probably not torqued up enough to properly crush the gaskets, so vibration performs the crush and then everything is a bit loose.
_________________
Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy