Roller cam and mechanical fuel pump question
Thread Starter
Racer
Joined: May 2010
Posts: 448
Likes: 3
From: Olathe KS
Roller cam and mechanical fuel pump question
I have a 1988 or 1989 Chevy 350 with a roller cam (no idea what cam), and I have a stock mechanical fuel pump, with the stock replacement pushrod in the pump.
I read somewhere that I should have an aftermarket fuel pump pushrod with a roller tip, to prevent damaging the cam. The car has been setup this way for over 10 years, and has never had an aftermarket pushrod, and probably been driven 15k miles.
Am I damaging the cam? Would the cam need replaced at this point, or just changing the fuel pump pushrod would be fine?
I read somewhere that I should have an aftermarket fuel pump pushrod with a roller tip, to prevent damaging the cam. The car has been setup this way for over 10 years, and has never had an aftermarket pushrod, and probably been driven 15k miles.
Am I damaging the cam? Would the cam need replaced at this point, or just changing the fuel pump pushrod would be fine?
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I can't say for sure on your cam since we don't know what it's made of, billet or austempered iron, but on mine I got the blended polycarbonate pushrod to prevent damage to the cam lobe.
http://www.summitracing.com/parts/hrs-94475/overview/
The roller tip push rods seem a bit steep to me and potentially problematic.
Don't get a bronze tipped one. I tried that first and it immediately began to wear and eventually can mushroom making removal of the pushrod once it gets too short near impossible.
If your fuel pump is still pumping then I would say your cam is fine or at least minimally damaged and no cause for concern. The wear on the end of the push rod should tell the story when you pull it out. Should look new. If the cam did see some wear it could wear the blended polycarbonate pushrod prematurely, but that would become a real problem only when it stopped pumping fuel.
http://www.summitracing.com/parts/hrs-94475/overview/
The roller tip push rods seem a bit steep to me and potentially problematic.
Don't get a bronze tipped one. I tried that first and it immediately began to wear and eventually can mushroom making removal of the pushrod once it gets too short near impossible.
If your fuel pump is still pumping then I would say your cam is fine or at least minimally damaged and no cause for concern. The wear on the end of the push rod should tell the story when you pull it out. Should look new. If the cam did see some wear it could wear the blended polycarbonate pushrod prematurely, but that would become a real problem only when it stopped pumping fuel.
Last edited by REELAV8R; Mar 30, 2015 at 01:11 PM.
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
You can use the composite, brass tip or the roller, but for a stock pump, I think you can use the stock rod, the need for alternate push rod styles and materials comes from bigger fuel pumps that have greater rates and stronger springs. In mine I ran the roller tip, expensive, but seems to work great.
Drifting
Joined: Jul 2013
Posts: 1,299
Likes: 93
From: Tri-Cities TN
The pushrod fuel pump rod we make is 4130 Seamless Chrome Moly and we use an Ampco 45 material for the bronze alloy we use. This is same alloy used in the best bronze distributor gears.
If an bronze tip or gear fails, you tear the engine apart and flush it out. Pain in butt but you can clean it. If the composite stuff fails, you throw the engine apart as the fiber embeds itself into the cast iron.
If an bronze tip or gear fails, you tear the engine apart and flush it out. Pain in butt but you can clean it. If the composite stuff fails, you throw the engine apart as the fiber embeds itself into the cast iron.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I remember trying to find a solution to the bronze tip issue.
In my search and talking to Howard's (take that for what it is worth, obviously they have a vested interest in this) I could find no failure's of the blended polycarbonate fuel pump pushrod.
The bronze tip push rod, if you do a search, you will find many, many failures.
In my search and talking to Howard's (take that for what it is worth, obviously they have a vested interest in this) I could find no failure's of the blended polycarbonate fuel pump pushrod.
The bronze tip push rod, if you do a search, you will find many, many failures.
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Team Owner
Joined: Jul 2004
Posts: 40,412
Likes: 792
From: Redondo Beach, California
About mechanical fuel pumps. When I had a clone L-88 engine in my 69, I felt that top end performance was being limited. The mechanical fuel pump was the standard 400 Hp 3X2 fuel pump. At around 110 mph, the engine power just slumped, when it should not have. I've always suspected the mechanical fuel pump. My 68 has an Aeromotive Street and Strip electric fuel pump, and I'm planning on as least as much for the 70.
Le Mans Master
Joined: Oct 2007
Posts: 7,456
Likes: 977
From: RI, Now Franklin/Nashville TN
With my Howards Roller cam, Howards told me no need to change the stock distributor gear or fuel pump rod…no issues. I think that the incompatibility issues occurred on early roller cams.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
I've know 3 expert builders over the years who have trashed fuel pumps running a stock push rod on them. For roller cams I use the bronze tipped push rods trying to keep things simple ( check them at about 10K mile intervals.) I built a vintage Fuely Vette motor once that regularly turned 7400RPMs at the track with its stock AC fuel pump.....definitely needed the lightweight push Rod on that build.
What are stock push rods good for? They make great punches in your tool box
What are stock push rods good for? They make great punches in your tool box
Drifting
Joined: Jul 2013
Posts: 1,299
Likes: 93
From: Tri-Cities TN
Bronze tip or Roller can be used on any roller core.
OEM or Aftermarket light weight Chrome moly with hard tip on SADI or Austemper Cast cores.
An aftermarket lightweight fuel pump rod is a good idea for engines that will be street strip cars. The reduced mass of the lightweight fuel pump rod will reduce the chances of "floating" the fuel pump at the higher rpms.
If you "blast" off your OEM fuel pump rod you will find that the OEM rod has a hardened tip from the factory.
OEM or Aftermarket light weight Chrome moly with hard tip on SADI or Austemper Cast cores.
An aftermarket lightweight fuel pump rod is a good idea for engines that will be street strip cars. The reduced mass of the lightweight fuel pump rod will reduce the chances of "floating" the fuel pump at the higher rpms.
If you "blast" off your OEM fuel pump rod you will find that the OEM rod has a hardened tip from the factory.
Thread Starter
Racer
Joined: May 2010
Posts: 448
Likes: 3
From: Olathe KS
About mechanical fuel pumps. When I had a clone L-88 engine in my 69, I felt that top end performance was being limited. The mechanical fuel pump was the standard 400 Hp 3X2 fuel pump. At around 110 mph, the engine power just slumped, when it should not have. I've always suspected the mechanical fuel pump. My 68 has an Aeromotive Street and Strip electric fuel pump, and I'm planning on as least as much for the 70.
I might just go ahead and order a lighter polycarbonate push rod and throw it in. Not expensive and I would assume worth the risk (even though no damage that I know of so far).
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Mine currently builds power at 3500+ rpm, with the Torquer 2 manifold. It pulls hard to 135ish mph - 5600 rpm. Doesn't feel it is lacking fuel up there. I'm not sure what is IN my engine or what my rev limits SHOULD be.
I might just go ahead and order a lighter polycarbonate push rod and throw it in. Not expensive and I would assume worth the risk (even though no damage that I know of so far).
I might just go ahead and order a lighter polycarbonate push rod and throw it in. Not expensive and I would assume worth the risk (even though no damage that I know of so far).
If your build spends time going over 6000RPM, I think you should install the lightweight part.....not required for an Impala Station Wagon motor
Thread Starter
Racer
Joined: May 2010
Posts: 448
Likes: 3
From: Olathe KS
Think of it as installing a lightweight "Hammer" that is banging on your fuel pump lever......less damage than using a heavy weight one
If your build spends time going over 6000RPM, I think you should install the lightweight part.....not required for an Impala Station Wagon motor
If your build spends time going over 6000RPM, I think you should install the lightweight part.....not required for an Impala Station Wagon motor
Had a 1976 L-82, 4-sp
Joined: Mar 2011
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Mine currently builds power at 3500+ rpm, with the Torquer 2 manifold. It pulls hard to 135ish mph - 5600 rpm. Doesn't feel it is lacking fuel up there. I'm not sure what is IN my engine or what my rev limits SHOULD be.
I might just go ahead and order a lighter polycarbonate push rod and throw it in. Not expensive and I would assume worth the risk (even though no damage that I know of so far).
I might just go ahead and order a lighter polycarbonate push rod and throw it in. Not expensive and I would assume worth the risk (even though no damage that I know of so far).
I'm using one from Howard's. No problem so far. Also using their composite dist'r gear. Again, no problem and I'm running their HR cam.