<VV> advice for what to tune up....

[Sethracer at aol.com]

In a message dated 4/18/2009 7:16:14 PM Pacific Daylight Time,  
fly2xs at gmail.com writes:

Hello  all, this is my first post to this list.
I inherited my mothers 1962 Monza  900 Convertible in November.  Yesterday
was the first time it has been  driven in a long time.  A number of years 
ago
the entire drive train  (engine to wheel bearings) was rebuilt and there is
only 340 miles on the  odometer now.

It took a bit of time but it is now running and sounds  good.  I have a
Couple of issues I am hoping to get some insight  on.

1. On deceleration and Idle, the engine will backfire softly. No  backfiring
on acceleration or maintaining speed.
2. When the engine is  cold it will not idle by itself.
3. Acceleration is rough except on wide  open throttle.
4. Gen/Fan light glows during idle and is very very faint  while driving on
the highway.



Brett - Almost all of the above symptoms are indicators of Carb issues.  
Sitting for a long time is tough on the inside of Carbs and the rest of the 
fuel  system as well. I suppose you have cleaned out the tank and the lines, 
so the  carbs are being supplied with enough clean gas. The Corvair carb is 
one of the  easiest carbs to rebuild. If you pick up a couple of rebuild kits 
and thoroughly  clean out and systematically rebuild the carbs, that is a 
good first step. Two  things that can trip up a first-timer with the Corvair 
Carbs is setting the idle  speeds and the choke alignment. While removing 
the carbs, check to see if the  choke springs provide a good spring-loaded 
vertical thrust to the rods. It is  easy to misalign these and have them catch 
inside the passage in the head. When  cold, those choke springs should 
provide plenty of upward thrust to push the  chokes closed and raise the idle. 
(The chokes are only pushed closed when the  throttle has been pushed open.) 
When the motor warms up just a bit, those  springs relax and the rods are 
pulled down, unloading the chokes and dropping  the fast-idle cams away from 
the throttle arms. Setting the idle speed, and  balancing the idle between the 
two carbs is a procedure that you would be best  consulting the shop 
manual. It usually involves a special tool such as a vacuum  gage or Unisyn to 
measure flow. You will need to disconnect the link from the  throttle 
cross-shaft to the drivers side carb during the idle speed  balance setting. 
Otherwise, your adjustments on one carb are fed across via the  shaft linkage and 
tweak the other side settings. The trick is to get  both carbs passing the 
same amount of air at idle, the idle down to a  reasonable RPM - this depends a 
bit on the transmission type - and the  engine to idle with no vacuum 
feeding to the vacuum advance unit. It is a  balancing act.  
 
You can check the real charging voltage by measuring the voltage at the  
battery during Higher RPM running, or in a pinch, on the road. There is no  
charge at idle with a generator, but the voltage should go up as the engine 
RPM  increases. If it doesn't, start looking at the regulator or Generator as 
the  culprit, but always clean the battery cables well as the first step. 


Any  insight would be greatly helpful.  I am in the Seattle Area and hope  
to
see those in the area at future meet ups!
There is a great group in your Backyard (Don't run and check - I mean  
figuratively).  Corsa Northwest has a history of Corvair help. And there is  a 
great Corvair event coming up - a bit East, but worth the drive. It is the  
NorthEast Econorun.   
>From their information page:
"The dates are Friday June 12th through Sunday June 14th. More information  
about the show and the Econorun is available here:  
http://www.corvair.org/pdf/2009EconorunRegistration.pdf
If you can make it,  it should be quite a weekend.

Enjoy driving that car, Brett. If it has really old tires, do a thorough  
check on them before driving much.

 
Seth  Emerson

C's the Day! - Corvair, Camaro, Corvette



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