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BBC fuel pump cam lobe wear

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BBC fuel pump cam lobe wear

Postby 1kwik72 » Wed Apr 21, 2010 1:08 pm

Cast core BBC hydrolic roller stock fuel pump pushrod. Had this BBc apart for a freshen up due to some other issues we had. It is a mild 9.5:1 dart block 540 in a street car with a generic mechanical fuel pump the kind that has a bunch of allen screws holding the bottom of it together so it can be clocked to whatever position you need. We ran a stock fuel pump pushrod.

As I was getting ready to put it back together I noticed the fuel pump lobe had about .020" worn off over the nose and for lack of a better term "chatter" marks on the ramp area of the lobe. We sent it back to Comp to have it checked/fixed. The question is what caused it?

We did have a slight internal coolant seep from a head gasket that we fixed prevously and put a couple hundred miles on. The owner wanted to be sure there wasn't any lasting damage after we fixed the leaking head (found a head bolt bottomed out) That was the reason for this freshen up as it only had about 2000 miles on it since we installed the cam. There was very little coolant that actually got into the oil. it never "milked" it, just a little snot in the PCV valve and on the top of the dipstick. We wondered if that was the cause or if it was because we were running a low zinc/moly oil (Mobil1). Honestly I really didnt think about needing anything special for oil as we put a roller cam in it. But I guess the fuel pump pushrod is still a sliding interface.

The other question is was it just a soft core or some incompatabillty with the stock pushrod? Any Ideas?

Thanks
Craig
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Re: BBC fuel pump cam lobe wear

Postby dfree383 » Wed Apr 21, 2010 1:36 pm

wore out stock pushrod?
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Re: BBC fuel pump cam lobe wear

Postby Ron Golden » Wed Apr 21, 2010 8:06 pm

Check with Comp Cams....they may require a different fuel pump pushrod with that cam. We've ran into that before.

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Re: BBC fuel pump cam lobe wear

Postby 1kwik72 » Thu Apr 22, 2010 7:09 am

Yeah thats what my machine shop guy said they (Comp) would probably say. Use a lightweight pushrod just in case. I remember asking about a bronze tip when we first put it in and they said no because supposedly it is on a cast core. There must be something weird about it or the heat treat or something because I know they wanted us to use the melonized GM distributor gear. FWIW the distributor gear looks great no wear at all.
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Re: BBC fuel pump cam lobe wear

Postby revolutionary » Thu Apr 22, 2010 7:24 am

I ran into the same exact problem a couple years ago with a comp cast hyd roller. I won't use a cast hyd roller anymore, no reason not to order a steel core for a couple dollars more. I'd use a lightweight pushrod with the bronze tip but now that there is wear you still need to replace it.
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