<VV> Low vacuum

[Bryan Blackwell]

Hi Jim,

IMHO, a turbo'd 140 with a bigger than stock cam is doing pretty well to idle under 1000 rpm with 15" of vacuum.  Mileage looks fine too, I consider that a good measure of overall health.  One thing we all tend to forget in this day of EFI is that carbureted engines with big cams didn't idle very well back in the good old days.

--Bryan

On Aug 14, 2014, at 12:19 PM, James Cuneo via VirtualVairs <virtualvairs at corvair.org> wrote:

> All, I have a 140 w/turbo that has only 15" vacuum at idle. Also, vacuum gauge has rapid 1" fluctuations. No vacuum leaks, checked every thing 3 times.Engine has 1k miles since rebuild including pistons, rings, rebuilt heads with intake valve stem seals.OTTO TB-20 cam. Cam degreed and triple checked at 4 degree advanced recommended setting. Would this be in the range of normal vacuum for this combination.How does this compare to stock 180?Engine will not not idle reliably/smoothly below 900 rpm. Have tried stock as well as a modified Rochester 2g carb.I am getting 23 mpg @ 60 mph with AFR of 14.2/1 with 2g carb.Other than idle, engine runs great.Any thoughts?Thanks,Jim Cuneonorcal 65 corsa