Pusher Pump
 

I'm thinking about a pusher pump for better start ups after a long rest, and maybe a little boost to my old fashioned mechanical pump (RobbMc 550). There are lots of options but I would want something that would not cause any additional flow restriction and in the event of failure would still flow. I'm running stock 3/8 fuel lines.

After a long rest so to speak why don’t you just prime the primary side of whatever carb you have thru the fuel bowl vent until the accelerator pump works some.?

It’s a lot cheaper way to go and besides your mechanical pump is already over kill volume wise.

Takes some effort to remove the air cleaner to prime the bowl vent, not very fun to do that every time the car sits for awhile to cause hard starting related to fuel evap or drain back.

A 550 mech pump is not overkill for a 500+ hp stroked pontiac...

jhein- Theres some threads on here about what pusher pumps will still flow when turned off or how to make a bypass set up that flows fuel around the pump when its off or failed. Do a search on here if you dont get the answers youre looking for.

For priming purposes only a diaphram style electric pump has more suction to self prime the fuel system versus most vane style pumps. A vane style pump back at the tank in series with the mechanical pump both primes and increase performance with the smaller fuel line. But after the car sits often you have to crank over the engine some for the mechanical to prime the electric pump in the back. It varies depending on where you locate the pump at the back of the tank. A Robbmc 550 with 3/8” lines is about a 450HP setup, for cars that are able to hook up off the line they don’t keep up really well, the 550 Robbmc even with 1/2” lines is really not overkill if your making much power.

Effort, like removing the air cleaner lid?

The vents always stick up thru the air cleaner base.

Yes effort... like popping the hood, removing the shaker on a TA, then the air cleaner/lid... then putting it all back together just to fill the carb bowl takes some effort that can be avoided by adding a pusher pump & flipping a switch when needed.

Doing that every time after the car sits for 4-6 days gets old real fast, I know because Im in the same boat as jhein & many others with a Q-jet that goes dry or fuel drains back for whatever reason in a relatively short time.

I find it easier to just use the starter to crank for a few seconds a couple times to fill the carb when needed, but an in tank elect pump is in the near future for me to remedy that as well as provide better fuel supply on hard launches at the track where mech umps have a hard time keeping a q-jet full. A pusher pump is a good option for this situation, plus can add a little extra flow.

I didn't like all that cranking to fill my tripower after a couple weeks between cruise nights I wanted to go to. I put in a low pressure pusher pump with a parallel check valve to use for priming, But it looked like the check valve was itself a restriction when it was running on just the mechanical pump.

So I got a switch over valve like gets used on truck saddle tanks. Then running through a momentary toggle switch I can change the valve from direct through to a bypass flow through the primer pump and run it for about 20 seconds. When I release the toggle it changes back to straight through flow and shuts off the primer. Pump the throttle once and it fires right up and uses only the mechanical pump.

With the availability of parts these days and options for electric pumps, if you're at the point where you need or want a helper, isn't it simply time to go to an electric setup completely?

Tanks Inc tank with a TI Automotive 255 lph pump and a bypass regulator to keep your pressure where it needs to be.

Yes, it's initially more expensive and a bit more work, but you'll never regret it afterwards.

Thanks for the replies. Doing a search I found that a few people have had good long term results using a Holley red or Blue pumps back near the tank so that's probably what I'll do. Simple, inexpensive and easy.

Yes, it's not the worst thing ever to have to crank for 10 seconds or so. And yes, on a car with the shaker it's too much of a PITA (to me) to prime the carb. This will solve the priming issue and provide a little support for the mechanical pump to overcome the 3/8 line restriction.

Just go Holley Terminator EFI... you'll end up there eventually anyway... just kidding :D

As JLMounce suggested, the Tanks Inc setup with the small internal pump is a nice set-up. You could actually eliminate the RobbMc pump entirely if you wanted.

I have the Tanks Inc 20.5 Gallon tank in my TA with dual Walbro 450lph pumps and a floatless fuel sending unit. It is super quiet. I have no complaints.

https://www.tanksinc.com/index.cfm/p...rod/prd411.htm

Those pumps are pretty noisy. If you go that route I'd suggest something quieter like a Mallory (or something similar)

Check out this carter pump, quite a bit less $$ than the holley pumps and Ive read it allows fuel to flow through it when off. Holey blue pumps are 14psi, the carter is more q-jet friendly at 4-6psi.

https://www.summitracing.com/parts/crt-p4070

10 seconds.

A couple 5 second cranking sessions and you’re there.

I personally don’t see an issue worth spending time and money on.

Carry on.

Great timing since I’m considering a new tank & sender to fix my fuel smell and inop gas gauge. So I could use a Tanks Inc tank with an electric in tank pump for my Quadrajet, I assume I’ll need a regulator and fuel pump block off?

The Mallory 110 looks nice. Thanks.

I don't mind a 10 second crank at all. Let's me see the oil pressure come up on the gauge first.

I've run a Holley black pump (vane type) in my race car and it was very loud. I run a Mallory 140 (gearotor) now and it's much quieter.

My Mallory 140 would not let the mechanical suck through it well-eventually pulled the mechanical and dead head the Mallory. It is even with the tank and sucks fine to prime.
I do believe the Carter will allow a mechanical. That is what I used in the 70s on my dual quad 409. Mechanical unless racing then used the Carter as a pusher.

This is meant as a joke obviously, but this is actually how it starts.

OP has already changed the wheel and tire setup for better handling and traction. He's stated that he's going to be doing some suspension upgrades next.

Everything he's doing is in service of actually driving the car more. Some sort of EFI system would be the next iteration of what he's trying to accomplish with a pusher pump.

By going to an in-tank pump with a bypass regulator and proper feed/return lines, that system would grow into an EFI system if he wanted it to. The pusher pump into a mechanical pump won't.

Here's my issue with the pusher + mechanical deal. If you're using the pusher only to help fill the bowls at start-up, then shutting it off, you degrade performance of the mechanical pump you are using, now that it has to suck through both hose and a pump. Now you have the possibility of fuel starvation at WOT, unless you turn the pusher back on. For the type of motor the OP is running, that's a real possibility.

Okay, so run the pusher at all times now. At that point, why have the mechanical pump at all? Now that you don't have a mechanical pump, you want your electric pump to be as reliable as possible. Well, the way to do that is to put it inside the tank with a proper sump.

The pusher pump may be "cheaper" and "easier" at first, but when you get to the point of having to deal with the limitation of that set up, you're going to end up doing the in-tank pump anyhow. Now you just added time and expense over doing it that way in the first place.

If it was me, I'd deal with the mechanical only setup while I saved for the in-tank setup, then go right to that. Bandaid fixes always cost more in the long run.

OK, both Mallory and Holey tech support say that their pumps (Mallory 110 and Holley red) will not allow the mechanical pump to pull fuel through them if they are off or if they fail. That seems to contradict what people have said here, at least for the Holley. I don't know which is correct but if they won't allow the mechanical pump to pull fuel through in the event of a failure then that's a no go. My intention would be to run it at all times, not just start up.

So now I'm back to either living with the limitations of the mechanical pump, which are not terrible, or going in-tank electric. I was on the verge of doing that a couple years ago but I soured on the idea. One of the reasons was because people advised that you should have the low oil pressure safety switch. I agree that seems like an important part of the system. But people said that the currently available switches were poor quality and not reliable. That really turned me off. But, when the fail, do they fail open or closed?

I have a Holley red pump mounted at the tank on the GTO (tripower) and the Chevelle (Holley Dominator or 950HP).

I use them for priming and for periods of high demand. Otherwise I tool around on the mechanical pump.

The Holley pump has been on the GTO for over 60 years and on the Chevelle for nearly 50, with no issues.

GTO has been 12.20 in the quarter, Chevelle has been 9.56 @ 139mph with this set up.

K

Hi Keith. I read that in an older thread about this. What Holley just told me is different. I wonder if the pump has changed?

Regarding the oil pressure safety switch, it's something that is smart to have, but isn't absolutely necessary. Your own risk assessment would need to be done there.

If your intention was to run the pusher pump all the time, you'd need that same switch in that type of environment. I would actually say if you're risk averse, you'd want that safety switch regardless of whether or not you had the pusher pump functioning all the time. What happens when you turn it on at the drag strip, or on the street to have some fun, and you wreck? Same issue.

So if you feel that is a necessary part for an in-tank system, it's also a necessary part for your external pusher pump system.

As far as the quality of those pieces, I have no idea. I do know most of them are designed to activate at pressure below 15 psi, which for some pontiac engine owners is basically any time the engine is at hot idle.

The Tanks inc version says it cuts off at 5psi. The Holley one says 3 psi. I have 20+ psi at hot idle. So that's a pretty good margin there. I just don't want a failed switch to shut off my fuel pump. I don't now if most people run these or not. Seems like with a low pressure system it would be less important than a high pressure system. I'm thinking of it more as a fire prevention system in the event of an accident rather than saving the motor from loss of oil pressure.

Wow - didn’t realize you have a 3/8” line with that power plant - should definitely be 1/2” supply and return in tank with 255 or 340lph and never have to worry again.

Yeah that's typically why they are run, for the accident based issues.

I'd talk with Tanks Inc about it. I don't know much about them, but it seems like a basic hobs switch, these are commonly run in various applications. Is it possible that the people having issues have them installed in such a way that the issue is presenting itself?

My question is how far do you want to go with this? If the only thing you're worried about is a bit of cranking if the car sits for a while, but otherwise you don't have any fuel starvation issues with your mechanical pump, is the juice worth the squeeze here?

My personal preference, but if my car has sat for a couple weeks and there's no risidual oil on the bearings, I don't mind a bit of cranking to get some oil flowing through the engine.

Man, I can literally feel my self-esteem plummeting.

But I know you didn't mean it that way. :)

I don't know but people have suggested that even if I don't have any obvious starvation, it's still happening. I don't know if that only matters for someone who is racing or if would have any noticeable effect in a street only car like mine. So you are running a mechanical pump? I had you pegged for a in-tank guy.

No, I run a FiTech system with an in-tank pump. The EFI controls everything having to do with the fuel system. If the engine stalls, the fuel pump is shut down.

And yes, while you may not "notice" fuel starvation, that doesn't mean it's not happening. There are rich and lean thresholds that the engine will run under. It's possible that your system provides enough fuel that the engine doesn't nose over, but without a wideband, you can't really tell if the engine is singing WOT at 5000rpm while having a 14-15:1 AFR either.

But my point is that if it's not broke, why fix it? If you wanted to move to EFI, you'd pretty much be forced in this direction. If your intention is to keep the carburetor, there's less of a need here, especially if you aren't having any fuel starvation issues.

I think the Red Holley street pumps are quieter than they use to be. The higher pressure Blue and Black pumps are still noisier though. I would not put a Carter pump to feed a Robbmc, the Carter is a little smaller pump than a Holley. The Holley Red matches up better to the Robbmc.

I have check valves to bypass the Carter pump, which is a kit you can buy. The Carter pumps seem to have the vanes not draw in as easily as the Holley’s for running on just the Mechanical pump.

I just helped a friend put on a Holley Red in series with Carter strip/street Mechanical pump. His electric pump is just on when he arms the NOS system. Otherwise it runs on the mechanical pump all the time, it has 3/8 line, 550+ HP.

My Ta unfortunately sits way too long between starts.

When starting my car. I tap the throttle once to set the choke, then spin the engine (while NOT tapping the throttle) for about 5 seconds.

If no cylinders hit, I tap the throttle twice so that the accelerator pump will maybe squirt.

If the accelerator pump squirts, at least a couple of cylinders will hit. It may run then. If not I tap the throttle once and spin engine again. That's usually ALL it takes.

And that's the thing. With no O2 sensor I have no idea. Plus you guys all correctly predicted the future with the 18' wheels and suspension. As you now have said, maybe soon I'll have a sniper TBI sitting on top of a Torker II or something like that.

If you’re likely/eventually installing efi, do it right. Install the in-tank pump with a universal bypass regulator like the Aeromotive 13301. It comes with a spring for low psi carb application and a heavy spring for efi. Once you convert to efi, simply install the heavy spring.

Agree, this subject has come up before and I've said the same thing.
We have to ask ourselves what constitutes a crank time that's too long? I see this as pretty normal and just part of old car life. Everyone has gotten used to there new EFI cars I guess.

I figure if you crank 3-4 seconds, stop, pump the throttle a couple times, crank another 3-4 seconds you should be there. That's just not a big deal.

If youre really set on an electric pump, just go all the way and do a tanks inc setup, put it in the tank and be done with it. With a car that has the HP you've mentioned in the past it should honestly already have a solid fuel system like that. A mechanical with 3/8 line isnt going to get it done.

This is the solution to the Hobbs switch issue. I've got 58k miles on mine. Works great.

https://www.revolutionelectronics.co...Fuel_Pump.html

Well, so the main reason I changed my mind on the Tanks inc in-tank pump system last time was the fact that the oil pressure cut off switches were said to be of questionable quality and prone to failure. I didn't like that. Then someone mention NOS units but those are harder to come by and getting worse. So that kind of soured me on the whole deal. Maybe I overreacted to that a bit. So I'm reconsidering it now. First I need to know if the switch fails open or closed. That's important. But also, one could easily wire in a bypass switch so that if it fails open, you could literally restore power with the flip of a switch. So unless someone here knows the answer about how they fail, I'll be calling tech support tomorrow to find out. But, if I can wire a bypass switch, then it doesn't really matter. Also, I don't know how important everyone thinks that is. It seems like a good safety feature but also seems like it would be extremely rarely needed. I guess that's just a personal decision.

Oh, that regulator looks nice but Tanks inc also makes a carb pressure regulator for half the price that can be upgraded for EFI pressures for $21. I don't know if the Aeromotive is that much better. Maybe it is?

Now that looks like a great solution. Thanks.

Thinking about either of these safety switches, either tach based or oil pressure based, when do the come into play? Basically, when the motor stops running. No tach signal means it's not running, no oil pressure means it's either not running or it will be stopping very soon. But how often in an accident does the engine stop running? Probably not if it's a rear or side impact. Maybe not even if it's a front impact, at least not immediately. And if you're running soft lines, then what is the likelihood they're going to fail in any case? So just how important are these devices?

I recently did the same as Keith Seymore with a Holley Red in line. 3/8 braided line with under 400 HP. In n out at the bottom of the tank. If my car sits for 3 or for days the QJ fuel bowl dries up and the pusher for priming makes for a quicker start. The mechanical has no problem drawing through it. Typically I only need it when I'm winding it up to 5500 rpm or so. I'll hear it when I'm priming. When driving I won't probably because of the loud exhaust. (my 461 with close to 500 hp has 1/2 line, 550 Robb pump, no pusher, no problems)

Modifying your car to the way you want it is the fun part of this hobby! I think a Holley sniper would be great. I’d choose a northwind over a Torker II though. You can still use the shaker with the northwind btw. You just need that drop base deal.

I do not do safety switches on the mechanical and electric pusher combinations, just the full electrics. With the engine shut off an electric 7 psi pump usually won’t pump much fuel thru most mechanical pumps. The full electrics have full flow to the carb all the time.

I usually start the car as soon as the electric pusher pump is under a load after the fuel line fills up to the mechanical pump. I don’t wait for the electric to fully fill the carb, once the mechanical pump has fuel to it, the engine does not have to crank over very much to start (about 3 seconds)

So with the oil pressure safety switch, I assume cranking will give you enough oil pressure to activate the pump so it will start right up.

If you don't have any kind of shut off system and you have the ignition on, the pump turns on, then what? The pump just runs and floods the carb?

Longk ago i enjoyed the notion of using the oil idiot switch to enable the Dizzy & Bright Oil alarm light. Add pusher pump enable, and it's all good. Cube relays to do it right.

Also has "Speedo-Alert" to crowwbar such stuff, but that became a nuisance.

Was typical for my car to have Carter pusher pump into stock mech pump. Was good even with return tap plugged..

I don’t care for the Hobb’s oil pressure switch’s on a car, there is to much delay. It is ok on something industrial where you can hold the bypass button down until it starts, PITA on a car that you start frequently. The Revolution switch that uses the tach out put is a lot better deal. That is a well thought out safely feature on an electric pump. The only down side is after the car sits very long, on an intank electric feeding a carb with 1/2” lines, the 3 second prime feature isn’t long enough. You have to cycle the key switch on an off several times. It works best with higher pressure fuel injection setup that retain line pressure better.

If the carb’s needle/seat are working correctly and the fuel pressure is set correctly the electric pumps should not flood the engine. You can pull the site plug out of a holley carb and walk off and forget the pump is running, come back an hour later and the engine will start right up. Years ago I had a Predator carb on one of my cars and the needle and seat didn’t hold and if filled a cylinder full of fuel and bent a connecting rod. I am not sure the oil safety would have caught it because you have to bypass most of them until the engine starts. That would be far less likely to have happened with the Revolution safety or a mechanical pump with the pusher pump. The electric pusher pumps I have done do not blast much fuel thru a non operating mechanical pump.

It doesn't quite work that way.
Cranking to get oil pressure to activate the pump will take just as long to start as a mechanical pump deal filling the carb.
What the idea of those switches assume is that there is already fuel in the carb, as there should be, don't know why you guys are going dry but that's a different problem. Anyway with fuel in the carb and in the squirter circuit, the car will fire off on that, it doesn't need fuel pressure, and once it fires off, oil pressure builds and turns on the pump. That's how they typically work.

As far as the pump running when you turn the key on, it doesn't flood the carb. If it is you have a needle and seat problem, again a different issue.

My TA I cut out the mechanical and just have the electric. Mechanical was a restriction as well as a source for heat.

The starvation issue usually only happens at the dragstrip with good traction/hard launch, with a better robbmc mech pump it usually takes low 12's or into 11's & faster to show the starvation... on the street the tires break free and you lose that highj G force that causes problems with a mech pump sucking fuel through almost 20ft of curved & bent lines. If all you ever do is run the car on the street with no drag strip time, you most likely wont see the starvation problems and your 3/8 line will be ok.

Did you see the link to the carter pump I posted? Should allow fuel flow even when off or failed according to what Ive read over the years from people that have used it as a primer/pusher pump... and its a lot cheaper piced that the others mentioned that may or may not flow when failed as their techs explained.

If you want to go the pusher pump route, the carter elect pump is probably the best bet for what you want... but going with the tanks inc set up allows for future upgrades to EFI and will supply the q-jet much better than a mech. But again for a pure street car, all that may be overkill if all you want is to fix a hard start issue after sitting awhile and dont have any drag racing or auto crossing plans. A primer/pusher pump fixes that for under $100 vs well over $1000 for intank set up.

https://www.summitracing.com/parts/crt-p4070

Yeah, I looked at the Carter pump. I was just a little worried about the 1/4" size. I'm sure it would work. I know I started the thread with quicker starting in mind, but that's not the only consideration. Yes the Robb pump works with the 3/8 line, but it's not optimal. With a 1/2 line it would be better but that still means dropping the tank and replacing the pickup and running a new line. $1000 isn't chump change but, I spent $20000 on the motor so spending another 1000 to feed it properly doesn't seem out of line. Plus it will allow for future options. I just need to decide what I want to do about the safety switch business.

Thanks FJ. When you set these up what you do for the safety switch, sounds like you may use the oil pressure type?

As for starting up, my car right now starts instantly if it has been run in the last 72 hrs. I like it so much I even posted a video about it, LOL. After 3 days though, it gets dry. I think that's probably normal for a Qjet. If it was a DD, it would always fire up instantly. If I went with the oil pressure switch, then putting a bypass switch in the car would take care of priming after a 3 day rest and also if the oil pressure switch fails. BTW, do you know if they fail open or closed? Or is the failure thing even realistic or overblown?

Yeah, I was wondering if the 3 second deal would be enough.