Page 1 of 1
Brake & Clutch Vaccum low
Posted: Sun Feb 27, 2005 4:56 pm
by legsx1
Having made my transplant of my V8 corvette, I find the vaccum pressure is down 5 inches on what the Nissan 4.2 diesel had, which affects brakes and clutch. Does anyone have any clues on how one can increase this
Posted: Sun Feb 27, 2005 4:59 pm
by bazzle
Put the diesel alt and pump back on??
Increase idle speed?
Bazzle
Posted: Sun Feb 27, 2005 6:56 pm
by TUFF MAV
Are you running a bigger than normal cam in the new motor ?
Kyle
Posted: Mon Feb 28, 2005 5:33 pm
by legsx1
No its the standard 96 Corvette injected motor
Posted: Mon Feb 28, 2005 5:35 pm
by legsx1
Bazzle, I have the alternator, but did it have a vaccum pump attached or what, mine was a 97 Safari
Posted: Mon Feb 28, 2005 5:58 pm
by ozy1
97. i think had a motor fitted vac pump, the earlier had alt fittedvac pump, bazzle will correct me if im wrong
Posted: Mon Feb 28, 2005 6:14 pm
by TUFF MAV
Have you connected the vaccum hose to the proper point on the manifold ? Pull the hose off at the booster & see how much vaccum you have at idle.
Kyle
Posted: Mon Feb 28, 2005 6:22 pm
by bazzle
TUFF MAV wrote:Have you connected the vaccum hose to the proper point on the manifold ? Pull the hose off at the booster & see how much vaccum you have at idle.
Kyle
Good question..
Also ensure a one valve is correct way around
if it doesnt make good vac at idle you may benefit from a small reservoir after valve side.
Bazzle
Posted: Mon Feb 28, 2005 8:11 pm
by TUFF MAV
Good question..
Also ensure a one valve is correct way around
if it doesnt make good vac at idle you may benefit from a small reservoir after valve side.
Bazzle[/quote]
That was going to be my next sugestion about the valve & air tank. Could just be a lack of vacuum at idle.
Kyle
Posted: Tue Mar 01, 2005 5:28 am
by legsx1
At idle it has about 20 inches of vaccum, aftyer revving it up and backing off the throttle the vacccum rises to 25 inches and then drops back down to 20 inches at idle again.
I have removed the reservoir and the one way valve, but are now considering putting them back again as at motor shut off = no vaccum
Ozy1 you are correct, mine had a vaccum pump different setup to the alternator
Posted: Wed Mar 02, 2005 6:03 pm
by TUFF MAV
You may need to run an extra reservoir after the one way valve.
Kyle