[FC] Diagnostic confirmation needed

[J R Read_HML]

Seems like you would have found a dropped seat (the symptoms seem to 
indicate that to me) when you reset the valves.  The number of threads 
showing should be roughly equal across the board and one (on # 2?) would 
have been way off from all the others.

Since it sounds as if the left side is overly rich (I took your comment to 
mean all 3 plugs were fouled), is the secondary leaking fuel?  Needle and 
seat not closing?  I'm not sure which carb you rebuilt, but assume the 
primary.  The "drum sound" could possibly be detonation from hot carbon 
igniting the fuel too far before the piston reaches TDC.

Is this a high mileage engine (since the "new" pistons)?  What's the oil 
consumption like?  Blowby?  Worn valve guides?

Anyway... you don't have to remove the entire drive train to get a head off. 
You can pretty much do it with the engine in - just lower it at the rear 
mount.  Might have to remove the long studs for the carbs, but might not.

Later, JR


----- Original Message ----- 
From: "Garry Parsley" <geparsley at sbcglobal.net>
To: <corvanatics at corvair.org>
Sent: Monday, April 30, 2007 7:23 PM
Subject: [FC] Diagnostic confirmation needed


> Hi all,
>
>  Recently developed a problem I'd like to bounce off all to see if I 
> missed something or if you agree with my assessment. My 65 Brier has a 140 
> / PG, the pistons are forged .060 oversized, has just recently started to 
> run rough, like on five cylinders. Thought I had a flooding carb on the 
> left side, as indicated by head temperature, so rebuilt the offender. No 
> difference, next changed points (pitted), condensor and coil (just to be 
> sure). No difference. Pulled the plugs, and as suspected the left bank was 
> extremely fouled, right bank was textbook perfect. Changed plugs and 
> wires, still no difference. Since I'd had problems (real or imagined) in 
> the past with the valve adjustment on the left side, I reset the valves 
> again, just to be safe. I could not detect any problems with the valves 
> while doing this (side-to-side, excess noise, etc.). No difference. Okay, 
> some of the symptoms includes: as stated before it seems to be running on 
> five cylinders. With the air breathers
> off, the left side has a sound coming out of the carb that sounds like 
> hitting a 55 gallon drum with the side of your fist. The choke pull-off on 
> the left side chatters, while the right side is rock solid. PCV valve 
> chatters like a woodpecker. My belief is that #2 cylinder is the offender. 
> No difference when that plug wire is pulled. I've decided to pull the 
> drivetrain and yank the head off for a close inspection. I haven't done a 
> compression test yet, but intend to before the drivetrain is dropped. 
> Before I do drop it, is there anything else y'all would recommend I try 
> based on these symptoms? Best guess on actual problem?
>
>  Thanks,
>  Garry Parsley