Crankcase Evacuation with the LT1 smog pump. How To:

[Rodney87GN]

How are they designed to work on the GM cars that they come standard on?
What activates them if they are not running all the time?

KS

If i remember correct....its to heat up the cat converter quicker. So it only comes on at startup, at a certain temp (usually when it's cold). It'll run for about a minute or two then shut off once a certain temp is reached for the cat.

 

[KEVINS]

If i remember correct....its to heat up the cat converter quicker. So it only comes on at startup, at a certain temp (usually when it's cold). It'll run for about a minute or two then shut off once a certain temp is reached for the cat.

OK.. Thanks

ks

 

[Pronto]

Has anyone ever logged the pressure that the crank case would see under boost? I know it would be a function of how tight the rings are sealing but I'm curious how a vacuum pump that draws only a few psi would work well enough. Is the initial vacuum in the crank case when at low boost enough to seal up the rings so it holds back the blowby better when boost gets 20+? It just seems that more draw would be needed to clear out the block.
I want to try this and a catch can too. To reduce the plumbing could just one v/c feed the evacuation pump?

 

[KEVINS]

I think these pumps do suck a lot of volume but not enough vacuume to seal rings. I think it draws just enough to eliminate the pressure in the block so oil doesn't get pushed out between the gaskets but I've found this to be determined by how much boost I run. If I keep boost pressures below 26psi I get no oil leaks. Once I started pushing 29-30psi that's when I noticed a few drips from somewhere towards the front of the motor. When I lowered the boost back down to 26 they disappeard. I plan on installing a second pump next spring to hopefully cure the higher boost leaks I get.

From what most people say you won't need a catch can. I was always checking the output hose on mine and it was never wet with any oil whatsoever.

Yes, one valve cover will be enough to vent the crankcase. I still need to work on my system tho b/c the DS valve cover is not vented and I run no PCV so driving around town I'm probably getting some pressure built up in the crankcase and I need to vent this out. This is also why I may run a second one. I may just run the second one all the time and see how long it does last.

ks

 

[Pronto]

The catch can I want to run will be in the PCV line. Looking to help stop oil being pushed out of the gaskets as well. Guess it's time to hit the bone yards. Next question- where to put the unit? It's not tiny...

 

[KEVINS]

I welded some tabs to the DS frame right behind the bumper and mounted it there so it can't be seen unless you crawl under the car.

I still use the stock valve covers and breathers so I ran the hose from the pump along the bottom of the radiator, under the turbo and up to the passenger valve cover. I bought a steel hose adapter from the hardware store and stuck it into the stock rubber breather elbow and I stuck the hose onto the hose adapter. The whole setup is pretty stealthy and uncluttered.

This pump was too large to mount on the PS along with the alchy pump but maybe the smaller pump will give me more room to fit it next to the alchy pump when I put the second one on.

ks

 

[Pronto]

Which pump style do you have, the one with the hose nipples on the face of it or the style with them on the side? I've searched all over the internet to see if there are any smaller ones but they all are pretty much the same sizes from all the car manufacturers.

 

[KEVINS]

Which pump style do you have, the one with the hose nipples on the face of it or the style with them on the side? I've searched all over the internet to see if there are any smaller ones but they all are pretty much the same sizes from all the car manufacturers.

The same one as the OP uses in this thread, page 1.

ks

 

[CS99]

bringing back old thread......What are the options when installing the vent tube from the lt1 pump ??? Can I just have the tube blow on the ground or do I have to plumb it back into the air intake?

 

[KEVINS]

bringing back old thread......What are the options when installing the vent tube from the lt1 pump ??? Can I just have the tube blow on the ground or do I have to plumb it back into the air intake?

Just leave it open venting into the air. I actually put an elbow on it so it points backwards to keep things from getting inside it.

I'm in the process of installing a second pump on my car. Anything over 27psi of boost a single pump can't quite keep the leaks away so a second one should do it.

ks

 

[ttypewhite]

Just leave it open venting into the air. I actually put an elbow on it so it points backwards to keep things from getting inside it.

I'm in the process of installing a second pump on my car. Anything over 27psi of boost a single pump can't quite keep the leaks away so a second one should do it.

ks

If you have leaks and need a second one at your level, that would just be masking a problem with your motor. I have run 30+ on mine for years and no leaks what so ever. I run a line off of my pump and vent it inside the frame.

 

[KEVINS]

If you have leaks and need a second one at your level, that would just be masking a problem with your motor. I have run 30+ on mine for years and no leaks what so ever. I run a line off of my pump and vent it inside the frame.

Mine is still the bone stock, factory engine with 87K miles on it (with RJC head gaskets and studs) and I'm pushing 35psi of boost through it. I know what the problem is..lol

ks

 

[CS99]

If you have leaks and need a second one at your level, that would just be masking a problem with your motor. I have run 30+ on mine for years and no leaks what so ever. I run a line off of my pump and vent it inside the frame.

Are you running your vac pump off just one valve cover? Does the other valve cover just have a breather that is open to atmosphere?

 

[dpasadena]

Are you running your vac pump off just one valve cover? Does the other valve cover just have a breather that is open to atmosphere?

I run my pump from one valve cover and a breather on the other cover. Seems to work ok

 

[Pronto]

To create good vacuum wouldn't the system need to be sealed or at least restricted during boost?

 

[CS99]

To create good vacuum wouldn't the system need to be sealed or at least restricted during boost?

That is what is was thinking, but I hooked mine up like dpasadena said and everything works great. Maybe would work better with a sealed system...just don't know how I would go about installing a check valve on the drivers side valve cover vent.

 

[larry33kc]

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[Pronto]

Skip one side and use an oil filler plug?

 

[ttypewhite]

I run both Moroso breathers under the intake to a T then to the evac pump. I run no breathers on my valve covers. Can't stand the smell of oil vapors inside the car. I still run the factory PCV valve with the RJC check valve inline.

 

[CS99]

I run both Moroso breathers under the intake to a T then to the evac pump. I run no breathers on my valve covers. Can't stand the smell of oil vapors inside the car. I still run the factory PCV valve with the RJC check valve inline.

I think I'll try that when I get a chance...thanks