why is the fuel pump eccentric so large on TA roller cams

interesting, when my cam arrived I called Rob and sent him a pic of the eccentric and he was in disbelief, he said he didn't think his pump would handle that. are you running a spacer between cover and pump?

 

It works fine, I used my cut away timing cover with the first RobMC pump to insure we had sufficient arm stroke. That pump does not come with the wear pad, which is what gets the stock Stage 1 pump in trouble. The only pump that can use that hardened steel wear pad is my CV Billet pump.

JW

 

does it need to be spaced out or can it be used as is?

 

Bolt it right on, no issues.

JW

 

Interesting, reading all the reasons as to maybe why. Jim had been told but he must be getting OLD Lol. The photo of the 2 cam cores towards the top doesn't really show well, but the stock eccentric is much smaller as you all have stated. Problem was machining it from billet became very challenging, the stock one is cast. There is a bit of a dog leg in the cast core if you look on the other side. There was no easy way to machine that. The base of the lobe (eccentric) is at the OD of the core behind the gear, trying to machine that angled dog leg between the gear and eccentric was the game changer. So I ask them if they would consider making the eccentric larger, yes. Problem then became the amount of lobe
(eccentric) lift, they first had a smaller lobe, less lift. I checked the lobe lift on a stock core and on the GM print, they were short so I had them match the lobe lift of the factory core. This made it look as it does, it is the same stroke as stock just large diameter to by pass that dog leg. I checked everything once I received a core the way it's been pictured above. The info in the catalog is what is needed to make this work. Even that we have got this to work they have been unwilling to put the eccentric on the 54mm core for the aluminum block. The lobe lift on the Buick fuel pump eccentric is one the highest on engines according to Jerry a Schneider Cams. I had them make a master so when they grind a TA roller they grind some off the eccentric to make it smaller. It does get close to running out of travel with some pumps. Never run a pump with a cam pad on it, and stacking a few gaskets won't hurt. Mike Modena, Modena Motor Sports made some spacers that he sells to space the pump out a bit.

 

Never heard that story Mike.. we never got that far, because when you told me during development that they were not going to put a fuel pump lobe on it, I told you to not bother making it.. you figured it out with them after that.

Now when I get to your age, I might be able to use it as an excuse.. ... I just turned 50, and can still remember where I put most of the tools, and my glasses.. most of the time..

JW

 

Getting to be my age is painful, forgot my new Pixel phone was in my bathing suit, ya I jumped in then wondered what the hecks in my pocket. Yes, I lost my glasses for part of a day last week. Lol.