Vaccum pumps
08-27-2002, 10:16 AM
#1
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Join Date: Jun 1999
Location: TEXAS
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Vaccum pumps
With out just reposting it in this section I thought I might see if I get any more responses on this section.
http://web.camaross.com/bb/Forum2/HTML/008417.html
Your thoughts?
http://web.camaross.com/bb/Forum2/HTML/008417.html
Your thoughts?
08-27-2002, 06:50 PM
#2
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Join Date: Mar 2000
Location: 51°N 114°W, 3500' elevation
Posts: 2,037
Your best bet with a belt driven pump is the Moroso one.
You could try adapting a smog pump but you need to find one from a Ford or Toyota that has an inlet port. The majority of all smog pumps pull unfiltered air from behind the pulley to inject into the exhaust. There's no way to pull the crankcase down into a vacuum with this type of smog pump since there's no way to connect to an inlet port. After you find the smog pump (pulleys interchange so you can find a GM pulley with the proper belt groove) you then need to fabricate your own mounting system. The smog pump will pull too much vacuum. All the crankcase needs is a maximum of 12". The smog pump can pull 28" in a well sealed crankcase. If you decide to use one you either need to create a vacuum leak to keep the level down, install a vacuum relief valve or install a vacuum regulator. By the time you're done it might be cheaper to just buy the Moroso system.
I have no experience with the electric pumps used on Caddys or late model f-bodies. Apparently they're supposed to work fine. I've experimented using the electric vacuum pump from an early 80's Cavalier. Although it will pull a well sealed crankcase down into a vacuum it doesn't pull enough volume. At an idle it works fine but when the engine is under a load, the pump can't pull enough air out of the crankcase and the crankcase will go from a vacuum to a boost. My experimenting was able to blow the engine dipstick right off the tube.
After all the experimenting I currently have no crankcase evac system on my race car. Not even a header evac system. I get a bit of oil slobber on the valve covers from the breathers after every run but not enough to leak down onto the headers.
------------------
Stephen's racing page
or check out the race car
87 IROC SuperPro race car
461 big block
Best ET on a time slip: 11.349
Best MPH on a time slip: 119.7
Best corrected ET: 10.983
Altitude corrected rear wheel HP: 480
Best 60 foot: 1.546
Member of the Calgary Drag Racing Association
You could try adapting a smog pump but you need to find one from a Ford or Toyota that has an inlet port. The majority of all smog pumps pull unfiltered air from behind the pulley to inject into the exhaust. There's no way to pull the crankcase down into a vacuum with this type of smog pump since there's no way to connect to an inlet port. After you find the smog pump (pulleys interchange so you can find a GM pulley with the proper belt groove) you then need to fabricate your own mounting system. The smog pump will pull too much vacuum. All the crankcase needs is a maximum of 12". The smog pump can pull 28" in a well sealed crankcase. If you decide to use one you either need to create a vacuum leak to keep the level down, install a vacuum relief valve or install a vacuum regulator. By the time you're done it might be cheaper to just buy the Moroso system.
I have no experience with the electric pumps used on Caddys or late model f-bodies. Apparently they're supposed to work fine. I've experimented using the electric vacuum pump from an early 80's Cavalier. Although it will pull a well sealed crankcase down into a vacuum it doesn't pull enough volume. At an idle it works fine but when the engine is under a load, the pump can't pull enough air out of the crankcase and the crankcase will go from a vacuum to a boost. My experimenting was able to blow the engine dipstick right off the tube.
After all the experimenting I currently have no crankcase evac system on my race car. Not even a header evac system. I get a bit of oil slobber on the valve covers from the breathers after every run but not enough to leak down onto the headers.
------------------
Stephen's racing page
or check out the race car
87 IROC SuperPro race car
461 big block
Best ET on a time slip: 11.349
Best MPH on a time slip: 119.7
Best corrected ET: 10.983
Altitude corrected rear wheel HP: 480
Best 60 foot: 1.546
Member of the Calgary Drag Racing Association
08-28-2002, 12:20 AM
#3
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Join Date: Jun 1999
Location: TEXAS
Posts: 329
Well I have low tension rings in the car right now (I think I would change them next time I go in the motor) and she is having a little bit of a problem sealing I think. It got a lot worse when the D1 blower went on the car. The only way the crankcase is really getting any vacuum at all right now is the 1/2" tube coming from the PCV Valve in the intake to the blower inlet pipe. With as much air as its flowing right now it might be sucking way to much thru that way becuase I am getting some oil in the blower piping.
The only other thing I had ever heard about to help with low tension rings on race cars was to go with a vac. system and just cap off the PCV system all together. I wouldn't think it should be using as much oil as it is or smoking like it is and the only major change was the blower.
Its going on a LT1 car and I do not have the stock elec. AIR pump anymore, I was just planning on making a bracket and putting the Moroso pump were the A/C would have been..there is a idler pulley there right now
------------------
1994 1LE Z28 T56
383, 6.0" rods
GTP Stage III heads
4:10's
Hooker LT's
blah blah blah.....ATI D1 15psi Intercooled
http://members6.clubphoto.com/anthon.../guest-1.phtml
The only other thing I had ever heard about to help with low tension rings on race cars was to go with a vac. system and just cap off the PCV system all together. I wouldn't think it should be using as much oil as it is or smoking like it is and the only major change was the blower.
Its going on a LT1 car and I do not have the stock elec. AIR pump anymore, I was just planning on making a bracket and putting the Moroso pump were the A/C would have been..there is a idler pulley there right now
------------------
1994 1LE Z28 T56
383, 6.0" rods
GTP Stage III heads
4:10's
Hooker LT's
blah blah blah.....ATI D1 15psi Intercooled
http://members6.clubphoto.com/anthon.../guest-1.phtml
08-28-2002, 11:55 AM
#4
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Join Date: Jul 1999
Location: craplanta ga
Posts: 212
Well personally i have mixed feelings about vacc pumps..In your case its not the way to go..Better off fixing your rings if thats the problem..
The pump if you use it will help seal the engine and many engine builders feel that the negative pressure under the piston frees up power..That seems to be true from my experences with them..Gained 35hp on a turbo 4 banger and about the same on my mazda current setup..One thing that many forget is that the engine must and absolutely must be sealed up completely..That means no pcv no vents anywhere and even breathers..Use good o rings on the oil fill cap etc etc..
trade offs are the when dissconnected from the crank case ive seen the pumps suck 25 hp from the engine when pulling max vac..Something to think about..
ive also talked to a few top engine builders in the country and they all seem to think that fixing the rings is a better way to go..Still in my case "meth buring street driven small block" i still run the pump..
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FLUCK A SPELL CHECK<I CAN SPELL REALLY GOOD< IT'S JUST THE TYPEING THAT STINK AT!
http://phillyfabanddesign.tripod.com/parts4sale/
http://phillyfabanddesign.tripod.com/phillyfabricationanddesign/
http://phillyfabanddesign.tripod.com/PhillyFabsLT1RX7/id1.html
88 RX7 GTU, 97 Lt1/700R4,10" 3K stall, 4.30 gears,285CFM heads,12.4-1 compression, custom cam and 2700lbs...Daily driven!
The pump if you use it will help seal the engine and many engine builders feel that the negative pressure under the piston frees up power..That seems to be true from my experences with them..Gained 35hp on a turbo 4 banger and about the same on my mazda current setup..One thing that many forget is that the engine must and absolutely must be sealed up completely..That means no pcv no vents anywhere and even breathers..Use good o rings on the oil fill cap etc etc..
trade offs are the when dissconnected from the crank case ive seen the pumps suck 25 hp from the engine when pulling max vac..Something to think about..
ive also talked to a few top engine builders in the country and they all seem to think that fixing the rings is a better way to go..Still in my case "meth buring street driven small block" i still run the pump..
------------------
FLUCK A SPELL CHECK<I CAN SPELL REALLY GOOD< IT'S JUST THE TYPEING THAT STINK AT!
http://phillyfabanddesign.tripod.com/parts4sale/
http://phillyfabanddesign.tripod.com/phillyfabricationanddesign/
http://phillyfabanddesign.tripod.com/PhillyFabsLT1RX7/id1.html
88 RX7 GTU, 97 Lt1/700R4,10" 3K stall, 4.30 gears,285CFM heads,12.4-1 compression, custom cam and 2700lbs...Daily driven!
08-28-2002, 03:10 PM
#5
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Join Date: Jun 1999
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Posts: 329
Well I just figured that was the nature of low tension rings. I thought that was the whole point was to run a low tension ring with a vacuum pump for less friction and so the motor could rev quicker. This is my first motor with low tension rings so I really don't know what the deal is or how it should act.
It didn't really start blowing oil til I put the blower on it....and then I also got the oil in the intake system as well. Hence why I think the blower sucking thru the PCV system might also be a problem.
I really don't want to go in and swap out rings for the simple fact that I really don't like pulling that motor in and out of the car.
It didn't really start blowing oil til I put the blower on it....and then I also got the oil in the intake system as well. Hence why I think the blower sucking thru the PCV system might also be a problem.
I really don't want to go in and swap out rings for the simple fact that I really don't like pulling that motor in and out of the car.
08-28-2002, 10:14 PM
#6
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Join Date: Mar 2000
Location: 51°N 114°W, 3500' elevation
Posts: 2,037
There are a few other advantages and disadvantages about using a vacuum pump.
Pro:
Will build HP by letting the piston push down into a vacuum.
Eliminates pesky gasket leaks.
Will pull moisture out of the crankcase especially on cold running alcohol engines.
Will keep any oil blowby out of the exhaust compared to using an exhaust evac system.
Con:
If too much vacuum is created in the crankcase it can actually suck oil out of the wrist pins. Not a good thing to happen.
The rear main seal usually has to be install backwards since the pressure is now trying to come in instead of being pushed out.
Having to completey seal the engine.
When I was trying a smog pump and vacuum pump I could hear 3 leaks. One came from the fuel pump block off plate. One came from the dipstick mount on the oil pan (BBC), the third was coming from the dipstick at the top. Some silicone fixed the first 2 leaks. A spark plug boot over the dipstick tube fixed the last. I don't use a vacuum pump right now but at least my engine doesn't have any oil leaks any more.
Most vacuum pump systems are designed for a dry sump system. It just eliminates the amount of oil that might get pulled out with the vacuum.
Pro:
Will build HP by letting the piston push down into a vacuum.
Eliminates pesky gasket leaks.
Will pull moisture out of the crankcase especially on cold running alcohol engines.
Will keep any oil blowby out of the exhaust compared to using an exhaust evac system.
Con:
If too much vacuum is created in the crankcase it can actually suck oil out of the wrist pins. Not a good thing to happen.
The rear main seal usually has to be install backwards since the pressure is now trying to come in instead of being pushed out.
Having to completey seal the engine.
When I was trying a smog pump and vacuum pump I could hear 3 leaks. One came from the fuel pump block off plate. One came from the dipstick mount on the oil pan (BBC), the third was coming from the dipstick at the top. Some silicone fixed the first 2 leaks. A spark plug boot over the dipstick tube fixed the last. I don't use a vacuum pump right now but at least my engine doesn't have any oil leaks any more.
Most vacuum pump systems are designed for a dry sump system. It just eliminates the amount of oil that might get pulled out with the vacuum.
08-28-2002, 11:54 PM
#7
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Join Date: Jan 1999
Location: I reached back like a pimp and smacked that LS1....
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Just so you know, you shouldn't have any excessive blowby or oil consumption with low tension rings.
If you have a problem with ring seal, a vacuum pump is not likely to help you now.
What was your break-in procedure on your engine?
If you have a problem with ring seal, a vacuum pump is not likely to help you now.
What was your break-in procedure on your engine?
08-29-2002, 12:00 AM
#8
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Join Date: Jun 1999
Location: TEXAS
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Well I did the same thing Kellermeyer (www.djrace.com) does on his endurance race motors. I put the motor thru 3 heat cycles, changed the oil then did a few medium throttle runs on the car to get the rings in....drove it for about 100 miles and changed the oil again. Then I pretty much just drove it. I didn't really drive it hard that first summer when it was NA, the only hard runs on it were the dyno runs last Friday. Friday was the first time I really saw any kind of smoke out of it. When it was NA it would smoke for a little bit til the temps came up then it would stop. When it was on the dyno it pretty much smoked as soon as it got a load on it.
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