Fuel pump lobe modification.

Hamilton Cams said:
I know a lot of people here are wanting to use their stock fuel pump with a pretty hot setup p-pump. I have not messed with it much in the past, but with all of the talk of making big power on a stock fuel system. is anybody interested in a modified fuel pump lobe with more lift or multiple events? I believe we are at a .250" lift lobe.

I know we could get a little bit more out of it. Just gauging the interest.

Zach
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Is this what you mean by multiple events, Sorry for my quick drawing
 

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DEZLFREK said:
some is good and more is better jim.. right
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True, I remember there being talk about bigger lift pump some time ago, this might more good with something like that, people still laugh when they see I still run a stock lift pump on a day to day basis, I do have an aux system tied into it for high hp runs or pulls.

Jim
 
I sent a lift pump to a company that makes pumps a few years back, If anyone were to make a aftermaket replacement they would have the best plunger style pump on the market. It would have been so bad ass but it never worked out. Here is a pic....

MADLiftPump.jpg
 
The easiest thing to do would be to increase duration and add .100 of lift, then make the lobe come back to fill as quickly as possible. I will get with our designer and see what we can get away with on that little follower the lift pump has. I will make sure we get as much as is possible with the tiny foot. Two pump events will probably work well if we lower the stroke of each event so that there is not a crazy amount of return, which might be too much at higher rpm.

I will do the math on the flow and see if the longer stroke over more duration or the two events with less lift will be better.

disturbed- that is it, except it would not be as cool as your drawing
timebomb- that is pretty cool. There are so many things that could be designed better in an engine, and I only have so much time and money, I will start with the cam lobe and Airdog or someone else can do the rest. Torktech should take this one on!

Jim, get that thing out of mothballs! let's do some current mods

Zach
 
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This sounds great to me if it could let the stock pump support abit more power. I like the lift better than two events I'm not sure there would be enough fill time for the pump not to caviate at high rpm with two
 
bwdt said:
would it be possible to do this for a second gen truck with a VP pump and install a pressure regulator with a return line and a check valve before the pump to prevent drain back for start up. would it flow enough to cool the vp and retain enough fuel for start up?

I would love to get rid of the electric pumps on the VP trucks. What do you think?
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I know of a couple of guys that have run this set up with a helix cam and one with hamilton and have not had a single problem. Although they where just running the pump straight off the cam with no return.
 
The more I think about it, a longer stroke over a longer duration is going to be the way to go, After peak lift we will get back down to basecircle faster, so we don't lose fill time. My goal is to make a fuel pump lobe that will keep up with our new injection pump cams;)
 
Hamilton Cams said:
The more I think about it, a longer stroke over a longer duration is going to be the way to go, After peak lift we will get back down to basecircle faster, so we don't lose fill time. My goal is to make a fuel pump lobe that will keep up with our new injection pump cams;)
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You must enjoy making things that I enjoy spending money on. You sir are a bad man.
 
I agree that any firstgen running a cam from you will probably have a 2ndgen lift pump in the works.

Zach any idea where my cam is? I called a couple times over break but you guys wernt in the shop, just looking for a tracking number or something, no rush. seems like UPS took a turkey nap last week lol
 
After talking to the designer, instead of having an asymetrical lobe shape, it looks like we are going to stick with the round basic shape. The limiting factor is the foot of the lift pump. Too aggressive and we will side load the follower and bend it.

What we will do is go for a .300"-.350" lobe instead of a .250" lobe. We are looking to see if a better spring in the lift pump is needed to take advantage of the longer stroke at higher rpm.

In my mind the best setup would be a .350" stroke with a better return spring in the lift pump and an external accumulator to smooth out the pulses of the lift pump pand make it a more steady pressure.

I originally wanted to make the lift pump have the higher lift but make the pressure pumped over a longer period by having a longer duration lift lobe. This would have smoothed out the pressure pules and made them much more steady. Due to the small foot of the pump this could not be done.

If I get bored, I will tackle the pump issue and make one with a larger plunger and wider foot, until then, I will leave that to one of you.

By the way, Tork Tek is working on some of these issues.He might have something in the near future. Stay posted.

Zach
 
Zach, the stock mechanical lift pump does not get it's pumping power from the cam lobe, the "return spring" is actually what pumps the fuel and determines flow capacity and pressure. A short duration on the lobe will actually produce more flow because it allows more "return spring" pumping time.

I'm not great at explained it, but the pumping plunger is powered by the return spring and reset by the pushrod that rides on the cam lobe. The quicker the pumping plunger is reset (short duration lift lobe) the more time the return spring has to pump fuel.

This is a picture of the backside of the inlet into the lift pump. The spring seats against this inlet and pushes the plunger which also has a similar one-way diaphram. And finally, the outlet of the lift pump has an identical one-way diaphram. The best way I can see to get more pressure and flow at high RPM is to develop an upgraded behive return/pumping spring.
LiftPump010.jpg


LiftPump014.jpg



This is the outlet of the stock lift pump. A one-way diaphram screws in with a threaded fitting to accept the fuel line.

LiftPump011.jpg
 
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Big Blue24

I talked with the owner of Tork Tech today and he is working on a spring to go with Zachs cam.

Sounds very promising after reading all the articles on the Tork Tech site I had a lot thoughts about stock setups and aftermarket ones as well. Some things done by fuel pump companies did not seem like the correct way.
 
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