need a Hoover?
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 3,128
Likes: 3
From: Deltona (son of Deland and DAYTONA) FL
need a Hoover?
I'm not so sure my stroker will support my vacuum headlights, brake booster and vents. Headlights are opening really slow, the A/C is blowing from the floor and the brakes are hard to push if I idle too long.
Everything functioned OK with the old L48.
Is anyone using an electric vacuum pump? What are my alternatives?
Everything functioned OK with the old L48.
Is anyone using an electric vacuum pump? What are my alternatives?
Race Director
Joined: Apr 2000
Posts: 17,665
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
What's the duration and type of cam, you can get a vaccuum canister at Jegs, never used one but could work, also make sure you don't have any vacuum leaks 
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 3,128
Likes: 3
From: Deltona (son of Deland and DAYTONA) FL
Custom solid cam: 238/248 degrees @.050, .525/.540 lift.
Don't we already have a vacuum canister up near the headlamps? Or is the one from Jegs powered?
Hmm, maybe there is a leak that I could have created when I swapped motors. Either that or there is a pre-existing one that didn't show up because the L48 made more vacuum.
Don't we already have a vacuum canister up near the headlamps? Or is the one from Jegs powered?
Hmm, maybe there is a leak that I could have created when I swapped motors. Either that or there is a pre-existing one that didn't show up because the L48 made more vacuum.
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 3,128
Likes: 3
From: Deltona (son of Deland and DAYTONA) FL
I think the vacuum leak theory is right. The motor is pulling 10 inches at idle. I re-plumbed some vac lines and got the headlights operating a little better. The A/C will blow through the vents after a short time at 1500 rpm. The brake booster is still a little hard after idling a while while at a light.
Are there any vac lines running to the charcoal canister or are those all just vent lines. I have it completely disconnected from the carb.
Are there any vac lines running to the charcoal canister or are those all just vent lines. I have it completely disconnected from the carb.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
why not plug all vacuum lines and get a good vacuum reading from your motor....then start to reattach items and see if it drops....look for the leaks with the last item you attached...the vacuum pumps are like $220 big ones.... i would check for bad lines and lose connections first...
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 3,128
Likes: 3
From: Deltona (son of Deland and DAYTONA) FL
Bob,
I unplugged all vac and capped all but one port. The motor makes 10" at idle. My L48 was 12-15. I re-routed some stuff and the headlamps inproved, the A/C will eventually come through the top vents when the motor gets some revs going. The brake booster is still a tad hard if I sit at a light idling for a while.
I unplugged all vac and capped all but one port. The motor makes 10" at idle. My L48 was 12-15. I re-routed some stuff and the headlamps inproved, the A/C will eventually come through the top vents when the motor gets some revs going. The brake booster is still a tad hard if I sit at a light idling for a while.
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Team Owner
Joined: Jul 2004
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From: Redondo Beach, California
FYI....
Stainless Sreel Brake Corporation and also GM Performance sell electric vacuum pumps to accomodate people with long duration cam shafts and vacuum operated brakes. They're not particularly cheap but I think they're a good idea. (I would guess there's other sources of these electric vacuum pumps.)
On a two lane mountain road, I momentarily had trouble with my Richmond 5 speed ( I got it stuck in neutral..they're hard to shift when new) and the engine died!!!!!!!!!! Whoa... no vacuum brakes. Coming into a turn in the road and not being able to slow down, I was forced to shunt onto a dirt lane that fortunately just happened to be at the turn. Very exciting!! I'm sure my wife will always remember that incident also. She was screaming when I had to shunt off into the dirt road. I'll always think about putting an auxiliary vacuum pump the next time I run with a long duration cam shaft in a car that needs power brakes..
Stainless Sreel Brake Corporation and also GM Performance sell electric vacuum pumps to accomodate people with long duration cam shafts and vacuum operated brakes. They're not particularly cheap but I think they're a good idea. (I would guess there's other sources of these electric vacuum pumps.)
On a two lane mountain road, I momentarily had trouble with my Richmond 5 speed ( I got it stuck in neutral..they're hard to shift when new) and the engine died!!!!!!!!!! Whoa... no vacuum brakes. Coming into a turn in the road and not being able to slow down, I was forced to shunt onto a dirt lane that fortunately just happened to be at the turn. Very exciting!! I'm sure my wife will always remember that incident also. She was screaming when I had to shunt off into the dirt road. I'll always think about putting an auxiliary vacuum pump the next time I run with a long duration cam shaft in a car that needs power brakes..
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by isosceles
Bob,
I unplugged all vac and capped all but one port. The motor makes 10" at idle. My L48 was 12-15. I re-routed some stuff and the headlamps inproved, the A/C will eventually come through the top vents when the motor gets some revs going. The brake booster is still a tad hard if I sit at a light idling for a while.
I unplugged all vac and capped all but one port. The motor makes 10" at idle. My L48 was 12-15. I re-routed some stuff and the headlamps inproved, the A/C will eventually come through the top vents when the motor gets some revs going. The brake booster is still a tad hard if I sit at a light idling for a while.
not sure on this but i think 10" is probably pretty close to the bottom threshold for making vacuum accessories work...next step...pull out credit card, call Jegs, order vacuum pump and cha ching problem solved!!!!!!!