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Discussion Starter #1
I have a new ZZ383 with a 770 Street Avenger in my 68 that's very close to being started. I am wanting to use a mechanical fuel pump and would like to have a suggestion. I have read several threads but still can't really make up my mind. It's all a little confusing. Some say you need a bronze tip pump rod with your roller and some say you don't. I would just really like to know which it is. From what I been reading Carter seems like it would be a good choice maybe a little more dependable than Holley. Surely GM would make something suitable for this application too. I think it's supposed to run around 7 psi. Any comments would be deeply appreciated.
 

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I would vote for a Carter pump. I went through two Holley pumps before switching to the Carter. I would also remommend the bonze tipped fuel pump rod. What does GM recommend for the pump rod on the ZZ383? May want to check with them also
 

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Discussion Starter #3
I talked with a guy at Chevrolet and he said he didn't know anything about the bronze tip pump rod but did have an application for the pump rod. I ended up going with a GM street performance pump. 110 GPH at 7psi. Sallee was using them on their 385 fast burn motors so I hope it will be ok for me. Plus my wife works as a parts consultant so I can get some pretty good deals with GMPP.
 

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My take on these GM rollers as well as most cast roller cams is that they are being made of the cheaper casting process and you need the brass tip push rod.
I switched to comp hydra roller and used the brass tip rod, over time I still lost my fuel pump lobe. Unpon finding this , I have gone to Carter electric as I will not pull this cam now but later as I do want to run mechanical in my new stroker which Comp recommended that I stay with same XE 282HR , providing rods will clear lobes. I have selected Compstar H beam rods and may get lucky in keeping the cam.
 

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Guys,

While you are on the subject of pushrods and mechanical fuel pumps I have two questions:

1. Does the fuel pump lobe on the cam require the same break in period as the rest of the cam? (The cam had a 30 minute break in on a run up stand with an electric fuel pump and block off plate and will have a mechanical installed before going into the car)
2. Is there a calculator for required fuel pump flow?

Thanks,
Bill.B
 

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Bill, my guess is that you need some type of moly lube or any lube on that pushrod at both ends at breakin, especially the cam side.

As for supply volume, I believe anything in the 72-100 gph range at 7psi should be enough for street. I would not go over 7 psi with a mechanical pump due to excessive load on the cam lobe.
I based that volume upon normal factory hipo cars which was in the 30-40 gph ranges but that depends on lots of things.

If you really want to get into fuel pump push rods,, Comp is making a roller tipped "guided" pushrod . I will be looking at one of these on my next roller for sure as I lost a fuel pump lobe on a hydra roller.
 

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Don,

Thanks. Remember this is the "Wrong Pistons" engine we discussed last month. As I posted previously, it is now 460 CIR at 7000 rpm. I am wondering if you have seen any "tricks" such as increased fuel hose diameters or lengths that will help a mechanical fuel keep up. I was planning on running a 110 gph mechanical with the facory big block 3/8 fuel line from tank to pump.

I will research an updated fuel pump pushrod as you have suggested and upon installation I will be sure to moly everything.

Thanks,
Bill
 

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Light weight bronze tipped push rod is cheap insurance and it'll get you more RPM's before the pump starts to float.
I found this very true in my application. A light weight rod stopped my fuel pump float at high rpms.
 

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Bill, I too will go with the roller tip push rod when time comes, after all the trouble i had with even the brass tip on "austratempered" hydra roller. Not too many tricks with fuel hoses but it prolly would not hurt to have the volume there using 8 or 10 AN lines and fittings. If I recall correctly ,yours was a race motor? Go larger lines , you could prolly even use some 1/2 from the back to front with some shear protection covering. I am working with a guy that is plumbing a 540 together and was trying to go with the BG 400 pump so I guess you need plenty of volume with carbs feeding larger motors.
 

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Discussion Starter #12
If you need a bronze tip pump rod on the roller motor why wouldn't GM put one in a turn key motor or at least recommend one for their crate motors if you are going mechanical?
 
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