<VV> Plug Secondaries (140hp only)?

[Bruce Schug]

I have run my 140 with the secondary linkage disconnected for short 
periods of time. Here are my observations.

On Jun 9, 2004, at 6:30 PM, N. Joseph Potts wrote:

> OK - that was a nice thread about 140hp vs 150/180hp.
>      Now, I've got a question that is a bit more realistic for a guy 
> who has
> a 140, but no other Corvair. This concerns secondary carburetors 
> Yes/No.
> This does NOT concern changing heads! Assume KEEPING the 140 heads and
> blocking off the bases for the secondaries, perhaps changing the 
> crossshaft
> to a two-carb type.
>      My own limited experience with running in this mode leads me to 
> expect:
>
> * Performance as smooth as with 4 carbs (properly jetted/adjusted)

Performance will be smoother since you won't have that "spot" where the 
secondaries open. That "spot" is an identifying feature of 140 
performance. With fuel injection or anything else I'd miss that slight 
hesitation/bog/surge whatever it is.

> * SOME improvement in gas mileage (how much?)

It depends on how you drive. If you drive easy and don't use the 
secondaries there won't be any difference. If you enjoy that rush of 
the tach needle as you get into the secondaries you'll save some.

> * Presumably some reduction of performance (how much?)

Again, it depends on how you drive it. If you drive easy there won't be 
any difference. However, if you get into it there will be a huge 
difference! The 2-carb setup will just run out of carburation, just 
like any 2-carb engine does. It's that mid-range and high-end that will 
be gone, that wonderful surge that you feel in a 140 as the tach sweeps 
up over the 3,000 rpm mark on the tach.

> * Possibly some impairment of cooling at the ends of the heads where 
> the
> secondaries were (?)

I don't know. I don't know why there would be a difference here.

>
>      Anyone who has experience running his 140 on its primaries only is
> requested to chime in with reports of experience, particularly anyone 
> who
> has done so deliberately rather than as a matter of expedience 
> (secondaries
> not working, can't afford ANY reduction of gas mileage, etc.).

I have done this by choice. If you want to really appreciate a 140, 
disconnect the secondaries for a week or so. Then re-connect them. 
You'll know why you love your 140!

(If you disconnect the secondaries, remove the secondary linkage, don't 
just disconnect it, leaving it to possibly jam and leave you with a 
wide open throttle or something.)

Bruce

Bruce W, Schug
CORSA South Carolina
Greenville, SC
bwschug@charter.net

CORSA member since 1981

'67 Monza. "67AC140"