When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I'm wondering if it is possible to modify a thirdgen smog pump to function as a vacuum pump.
Looking at the design of a thirdgen smog pump, it appears that the air intake is done at the front through the "vane wheel" and flows air through the hose outlet at the rear (Normally routed to the manifolds). I would have to somehow modify the pump to reverse this flow and if this can be accomplished of course use a puke can.
The second question is would the thirdgen smog pump even be capable of flowing enough air?
The reason I want to use a thirdgen pump is due to ease of mounting. I'm still running the factory belt system so it would be as simple as mounting the pump back to the engine in its original location and re-installing the belt.
Last edited by FireDemonSiC; 06-18-2015 at 10:50 AM.
Are you wanting to use this for brake vacuum assist and other? I f it worked, I think you will also need a check valve and of course the vacuum ball/orb.
Are you wanting to use this for brake vacuum assist and other? I f it worked, I think you will also need a check valve and of course the vacuum ball/orb.
I like your think'n!
That may not be a bad idea since the engine I just built is running a 110LSA cam.
However, I was wanting to use it as crankcase vac pump.
I was just reading that thread. The one problem I have is that my belt system uses the hyrib 5 rib serpentine + v-belt drive. Other than reverse mounting the pump (Which would defeat the ease of installation since I would need a different mounting solution), there is no way I can get the pump to spin opposite of the crank rotation.
Awesome idea FD. If u have the right pistons u can pull some more power with a good vac system. I recall most conversions used the '90s FORD smog pumps from like big cars and trucks to convert to vac pmp - for the drag strip. U have to be careful and regulate the vac as to much can hurt your engine seals. U can buy them from Summit - just search vacuum pump for racing. But some are over a thousand bucks so not for a tight budget.
Good luck and let us know what u find - id like to run one also.
You can always add a vacuum relief valve and set it at your desired pressure/vacuum; not to exceed value. I listed one type that we used in the past for space applications.
Control Devices VR Series Brass Vacuum Relief Valve, 0-30" Hg Vacuum Range, 1/4" Male NPT for about 8 bucks on Amazon.
You can always add a vacuum relief valve and set it at your desired pressure/vacuum; not to exceed value. I listed one type that we used in the past for space applications.
Control Devices VR Series Brass Vacuum Relief Valve, 0-30" Hg Vacuum Range, 1/4" Male NPT for about 8 bucks on Amazon.
I was thinking of getting a vac relief valve and setting it to 10".
I am using total seal moly ringset with tops gapped to .020" and second rings set to .022"
I stripped the bottom hex bolt out of mine but when I get the patience to go at it again and get it removed you can have the thing.
Shoot me a PM and let me know. I would definitely be glad to take it off your hands. I've got an empty v belt groove at the end of my water pump pulley waiting to be fulfilled. I will need the bracket that goes with it aswell.
I believe the differential pressure of an air injection pump is quite low. The vanes are designed to "relieve" if the pressure differential gets too high, much like a hydraulic vane pump. It is not a true positive displacement pump as a result.
Still, it might be just enough pressure (and flow) to alleviate excess CC pressure under peak conditions. Keeping the oil vapor out of it might be a different problem altogether, however. I'm not certain the carbon vanes will like oil and HCs for very long.
The feedback from this experiment should be interesting.
Vader made an interesting point about the carbon vanes not liking oil and HCs for very long.
We use oil/mist separators in our vacuum pumps and chambers. It keeps oil and mist from reaching the pumps themselves. Might be able to find something along the lines of that.
I believe the differential pressure of an air injection pump is quite low. The vanes are designed to "relieve" if the pressure differential gets too high, much like a hydraulic vane pump. It is not a true positive displacement pump as a result.
Still, it might be just enough pressure (and flow) to alleviate excess CC pressure under peak conditions. Keeping the oil vapor out of it might be a different problem altogether, however. I'm not certain the carbon vanes will like oil and HCs for very long.
The feedback from this experiment should be interesting.
Are the vanes inside the same style as say, a power steering pump? If so, can't the pump be oepned up, vanes removed and new vanes cut to size but of a different material? Say I got some metal stock from the hardware store, then made good use of a cutoff wheel and sanding drums?
While I'm in there, I'm sure something could be done about the mechanics of the unit as well. Just a few ideas.
Are the vanes inside the same style as say, a power steering pump? If so, can't the pump be oepned up, vanes removed and new vanes cut to size but of a different material? Say I got some metal stock from the hardware store, then made good use of a cutoff wheel and sanding drums?
While I'm in there, I'm sure something could be done about the mechanics of the unit as well. Just a few ideas.
If you're going to do all that, why not just cut the vanes in reverse of the originals? Wouldn't that reverse the airflow creating a vacuum pump?
For that matter, what about modifying the vacuum motor fan from an old household vacuum cleaner? Or, better yet, use a small 12v car vacuum to create the necessary vacuum. The advantages here are that you could mount it anywhere in the engine bay, and you would eliminate the (admittedly small) parasitic losses of the belt-driven vacuum/smog pump.
For oil/HC separation, what about a small separator designed for air compressor tools? For draining the separator, you could replace the drain valve with a check valve that closes while the pump is running, then opens when it's off(no vacuum).
Just throwing out the first couple thoughts that popped into my head while reading this thread.
If you're going to do all that, why not just cut the vanes in reverse of the originals? Wouldn't that reverse the airflow creating a vacuum pump?
For that matter, what about modifying the vacuum motor fan from an old household vacuum cleaner? Or, better yet, use a small 12v car vacuum to create the necessary vacuum. The advantages here are that you could mount it anywhere in the engine bay, and you would eliminate the (admittedly small) parasitic losses of the belt-driven vacuum/smog pump.
For oil/HC separation, what about a small separator designed for air compressor tools? For draining the separator, you could replace the drain valve with a check valve that closes while the pump is running, then opens when it's off(no vacuum).
Just throwing out the first couple thoughts that popped into my head while reading this thread.
All great ideas. I would however, like to attempt the smog pump idea first. I need one to open up and see how I would be able to modify the design.
All great ideas. I would however, like to attempt the smog pump idea first. I need one to open up and see how I would be able to modify the design.
I may still have the pump from my old V6 engine if you're interested. I can't remember if it was locked up or not, but I don't think so. I'll try and look for it later tonight.
I may still have the pump from my old V6 engine if you're interested. I can't remember if it was locked up or not, but I don't think so. I'll try and look for it later tonight.
Yeah shoot me a message and let me know if you turn up anything. Definitely interested.
Not yet. I did receive the pump but haven't done anything with it yet. I'm putting all my focus into getting the new engine in the car and running. Once that's done I'll move onto the smog project.
I know it's been a year since this was last updated, and I don't know if you ever got a chance to look at the smog pump I sent you. But I wanted to pass along something interesting I found out recently. My wife has a 2012 Dodge Avenger, and last week it threw a code for the smog pump relay. While troubleshooting the code, I discovered that it has an electric smog pump, not a belt-driven one. It might be easier to convert it to a vacuum pump since all you would have to in theory is reverse the polarity of the wires to the motor. Plus,you wouldn't have to deal with belt routing and such.
There are lots of vehicles with similar electric pumps designed for emissions purposes.
To my knowledge I have not seen one implemented as a crankcase vacuum source successfully. I believe "true" crankcase vacuum pumps are generally belt driven, and notorious for requiring "rebuilds" and not being very street friendly.
There is power to gain from utilizing such a device, however, the engines that take full advantage of true vacuum pumps for racing are also using very tightly sealed engines with high quality oil seals and extra careful attention to the robustness of the seals themselves, because too much pressure/vacuum can push/pull an oil seal right out of the engine.
The cheapest "free" ways to get a slight PCV action at WOT without using an actual PUMP device, there are two I know of successful implementations:
1. Exhaust driven PCV with check valves. I have used this on my blower 355 and you can actually feel it work even at idle. I was told that if I had a muffler it would ruin the the checkvalve feature (backpressure is not "good" for them) but didn't seem to have trouble, although I only ran it for 5k~ miles before getting bored with the blower and moving on to something else.
2. Venturi style PCV duct, just after the air filter, connected to the crank case. Basically you weld an angle pipe to create a pressure drop just after the air filter, which routes to the crankcase such that at WOT it will pull a slight PCV action. The Factory already has this installed on many engines, especially every 4-cylinder turbo ever made has one of these. Its very common, it "works" but it isn't powerful of course.
And finally one more word. In #2 above, pay special attention to the pressure drop after the air filter. Think of this- what you removed the air filter and put your hand over the pipe, and crank the engine? It will create ALOT of suction/vacuum against your hand right? Much more than 1" of vacuum, it could be 15" or 20" if you could really seal your hand up good. The point here is, the more restriction the air filter presents, the more vacuum signal you will have just after the filter. The Factory turbo vehicles I spoke of in #2 traditionally use an OEM paper element (like most cars do from the factory) which becomes filthy fast, and that increases the vacuum signal just after the filter thus improving PCV action at WOT. Although the engine will LOSE power (more restrictive filter = less power usually) the fact that it simultaneously improves PCV action at WOT means an even cleaner engine/crankcase, because more of the crankcase vapors are being routed back to the intake pipe for "double digest". It helps keep the oil cleaner at the cost of power, which is really the point of PCV on a factory engine to begin with.
I know it's been a year since this was last updated, and I don't know if you ever got a chance to look at the smog pump I sent you. But I wanted to pass along something interesting I found out recently. My wife has a 2012 Dodge Avenger, and last week it threw a code for the smog pump relay. While troubleshooting the code, I discovered that it has an electric smog pump, not a belt-driven one. It might be easier to convert it to a vacuum pump since all you would have to in theory is reverse the polarity of the wires to the motor. Plus,you wouldn't have to deal with belt routing and such.
I did get the pump, but it didn't occur to me to check the belt style first. I need a V-Belt pump.
So I started this thread over a year ago and left alot of people hanging. Other issues arose and cars sadly took a back burner for awhile.
Anyways, I am back and with results!!! I was finally able to get my hands on a v-belt thirdgen smog pump. FWIW, the v-belt pump is physically larger by a small margin than the serpentine version and also uses different mounting brackets. These pumps are only 2 vane units vs 3 vane for the ford pumps, which are always a popular choice, so they need all the help they can get.
While the size difference between the v-belt and serpentine versions isn't astronomical, the vanes in the serpentine are also physically smaller which translates to less airflow potential. Because of this, I decided not to use the serpentine version.
So anyways, about those results. Attached are some photos of the pump. It was dis-assembled, cleaned throughout, needle bearings all re-greased and the front bearing replaced (Serious PITA). The case was painted, the original front inlet "welded" up and the case drilled/tapped for a 1/2NPT fitting. For these pumps, 10AN diameter is the minimum you'll need with 12AN being recommended.
Also, check out the below video. I mounted the pump to the car and plumbed it directly to a vacuum gauge to see exactly what it was pulling. 22" of vac is the highest reading I got just free-revving the motor to about 4500rpm. 5.5" at idle.
Now keep in mind, these readings will not be as high once the pump is actually plumbed to the crankcase. I am hoping it will pull 8-10" of vac and where I'm placing the goal at. I will report back with additional documentation after I get all the necessary hose, fittings and a good oil separator so this thing will hopefully live for awhile. Until then, enjoy the following:
I believe the differential pressure of an air injection pump is quite low. The vanes are designed to "relieve" if the pressure differential gets too high, much like a hydraulic vane pump. It is not a true positive displacement pump as a result.
Still, it might be just enough pressure (and flow) to alleviate excess CC pressure under peak conditions. Keeping the oil vapor out of it might be a different problem altogether, however. I'm not certain the carbon vanes will like oil and HCs for very long.
The feedback from this experiment should be interesting.
Vader, I believe you are correct. However, I do not believe it is the vanes themselves that relieve.
Look at the back cover of the pump in the above photos. Those two small holes are the relief holes. I plan on testing the vac both with them open and with them blocked.
Yes was emailing GZ on getting a pump for my car. They were really limited in their response. Basically all my info and use factory serpentine belt system ineither smog pump location or ac location. Response? You will overspeed the pump. 7.15 crank. No workarounds or other avenues. Found this thread and it's got the wheels in my head spinning now.
Lots of talk about this at LS1tech where the 4th gen guys have tried the electric smog pump. It seems to be unsuccessful for the most part. The explanations I've seen are the pumps don't move enough volume to do the job, aren't made for continuous operation, and fail frequently when exposed to oil and crankcase vapors.
That said, I have a friend that uses one with an 8000 rpm LS1 engine that will run for hours a day on a road course. He plumbs it on the PCV valve and controls the motor with some kind of automated switch (can't remember the details right now). And there is an oil catch can in front of the motor. But he also changes the PCV layout on race day with extra breathers, and then puts it back to stock on the street.
Interesting. The factory smog pump modified on paper looks like the best option. The problem with the gz is it needs to stay under 6000. So a bigger pump pulley vs crank. My max rpm is 6200. So I would need a 8 inch pump pulley. But I like the smog pump idea alot better.
Interesting. The factory smog pump modified on paper looks like the best option. The problem with the gz is it needs to stay under 6000. So a bigger pump pulley vs crank. My max rpm is 6200. So I would need a 8 inch pump pulley. But I like the smog pump idea alot better.
How 'bout attach a propeller to the pump and hang it out in the windstream? Steal a prop from a drone or RC model and mount the pump right on the front of the car. Hey it won't cost a thousand bucks to do that and should last forever. Easy to maintain if needed. For looks you could put a cowling around it and give it the radial engine look! Bet you would have to answer questions every time you stopped the car.
I use a Moroso 3-vane vacuum pump with pressure regulator, it pulls 11.6 to 13.59 psi from 4500 to 6900 RPM.
These are not made for continuous street use because the catch can only holds 16 oz.
I drain mine after every track outing, the only maintenance is flushing the vanes with some brake or carb cleaner when the pump stops pulling vacuum. ( maybe once a season I have to flush it, depends on run time)
Keep in mind for the pump to work properly the oil pan & valve covers have to be sealed and you cannot use the OEM dipstick, you have seal off the dipstick or use an aftermarket model with o-ring seal.
I have fel-pro silicone valve cover gaskets so I can inspect the valve trains, check and adjust valve lash (solid roller lifters) every season.
These gaskets are re-usable have steel inserts at the bolt holes so you cannot overtighten the valve cover bolts.
I use a Moroso 3-vane vacuum pump with pressure regulator, it pulls 11.6 to 13.59 psi from 4500 to 6900 RPM.
These are not made for continuous street use because the catch can only holds 16 oz.
I drain mine after every track outing, the only maintenance is flushing the vanes with some brake or carb cleaner when the pump stops pulling vacuum. ( maybe once a season I have to flush it, depends on run time)
Keep in mind for the pump to work properly the oil pan & valve covers have to be sealed and you cannot use the OEM dipstick, you have seal off the dipstick or use an aftermarket model with o-ring seal.
I have fel-pro silicone valve cover gaskets so I can inspect the valve trains, check and adjust valve lash (solid roller lifters) every season.
These gaskets are re-usable have steel inserts at the bolt holes so you cannot overtighten the valve cover bolts.
Something that gets overlooked is installing a drain back line from the bottom of the catch can to the oil pan. It should have a check valve in the drain back line but I believe it would work without the check valve as there is nothing wrong with pulling the vacuum from the oil pan but you would have to ensure the pump suction tube is shielded in the catch can. Saves you from having to drain the catch can yourself. Oh the catch can has to located higher than the oil pan too.
Something that gets overlooked is installing a drain back line from the bottom of the catch can to the oil pan. It should have a check valve in the drain back line but I believe it would work without the check valve as there is nothing wrong with pulling the vacuum from the oil pan but you would have to ensure the pump suction tube is shielded in the catch can. Saves you from having to drain the catch can yourself. Oh the catch can has to located higher than the oil pan too.
The problem is you cannot run these vacume pumps on the street without extreme pully combos. Using the factory smog pump eliminates the need to run a 3 inch crank pully.It's not ideal.
How 'bout attach a propeller to the pump and hang it out in the windstream? Steal a prop from a drone or RC model and mount the pump right on the front of the car. Hey it won't cost a thousand bucks to do that and should last forever. Easy to maintain if needed. For looks you could put a cowling around it and give it the radial engine look! Bet you would have to answer questions every time you stopped the car.
I take it Santa didnt bring you the brains you asked for for Christmas? Better luck next year.
Last edited by ShiftyCapone; 12-28-2019 at 11:39 AM.
Something that gets overlooked is installing a drain back line from the bottom of the catch can to the oil pan. It should have a check valve in the drain back line but I believe it would work without the check valve as there is nothing wrong with pulling the vacuum from the oil pan but you would have to ensure the pump suction tube is shielded in the catch can. Saves you from having to drain the catch can yourself. Oh the catch can has to located higher than the oil pan too.
I have never seen a catch can that drains back to the pan. The crap that get picked up in the can isnt something you want back in the pan. Condensation, trace amounts of fuel little bit of oil mixed in.
A properly running vacuum pump on a sealed engine will remove all the condensate/moisture during engine warm up. I have seen steam come out of the catch can breather during warm up.
A production car has a pcv system to purge the condensation and other crankcase vapors into the carb or throttle body to be burned.
Production cars prior to 1967 (before pvc systems were mandatory) vented to the atmosphere with a breather on the valve cover(s)
The moisture and other vapors are not recycled into the crankcase oil.
Moisture forms every time a hot engine is shut down and cools off, so the process repeats every time a cold engine is started. if the moisture was not allowed the exit the system engine oil could never last 3,000 to 15,000 miles .
If you see what comes out of vacuum pump catch can (which is a pcv system that vents to the atmosphere) you would not want this draining back to the clean engine oil on a race engine.
The main job of the pump is to remove crankcase air pressure during a run (by creating vacuum) The vacuum helps the piston rings seal better which means you can also run thinner piston rings to reduce frictional loss.
Better sealing rings with less friction means you can make more TQ & HP.
My pump is mounted on the RH head (where the A/C compressor would be on a production model) it pulls air from the LH valve cover, the catch can is mounted to the fan shroud, all I need is a water bottle or cup to drain it.
Nice setup. I only asked about the smog pump because it seems most vacume pump designs are based off the same vane system. I have taken apart smog pumps and compared to vacume pumps they are simaler in design. Just was trying to get a system mounted in the factory routing. I read somewhere about the GZ motorsports vacume pump, the owner said his design is based off the factory smog type vane pumps. Thanks for the info.
GZ motorsports did do that.. they modified the internal parts to handle contact with oil.
The OEM smog pumps were "dry pumps" that moved air only. If you like to tinker then have at it or just buy one already modified that someone else learned on.
I used a smog pump for a 78 toyata corola fit factory brackets on a 92 3.1 camaro plumped into crank case breather on valve cover pulled 10" at 6000rpm's, but had to remove and degunk about every5 months, also used camaro pump pulley
06-18-2015, 10:29 AM
U can buy them from Summit - just search vacuum pump for racing. But some are over a thousand bucks so not for a tight budget.
