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Author Topic:   cam life?
dirtbuster
Member
posted November 22, 2002 12:12 PM
For those of you running flat tappets. How many races can you get out of your cam before having to change it. I hear guys at out local track complain about having to change them every 12-13 nights because they wear them out. We have run our current cam for 3 years now and have had no problems. WE know we have to change it this season but I cant beleive we got 70 nights on it and some guys only get 13.


Flatlander
Member
posted November 22, 2002 12:26 PM
Do you think maybe oil might play a part in it. An engine builder once told me that with high spring pressures and flat tappets you need to run a heavy 20W50 or even 50 to lube the lifters right otherwise they wipe the lighter oil right off the cam. Maybe these guys are running lighter oil to squeeze out more HP but it is tearing up their cams.



Flatlander
Member
posted November 23, 2002 03:44 AM
The lower the level of stress on a part, the longer it will last. If you run off the shelf cams with 20 year old lobe designs(smooth), they will last a long time. But once you start running cams with new, highly aggressive lobes, higher rocker arm ratios, with spring pressure to match, things can go bad in a hurry. SBCs are notorious for misaligned lifter bores, and the more aggressive the setup, the more critical lifter location becomes. Most blocks have at least one lifter bore that will not completely clean up when taken to .875". They are that bad. Some cams will move the point of lifter contact to within .015" of the lifter edge. See what happens? You may have the rare block with a good set of lifter bores, or your competitors may be running the super aggressive stuff without proper preparation. Before I bought a BHJ Lifter-Tru, I had a local shop do it for $250 a pop. Our cam life was horrible. The first block I did on my own, I found several bores off the proper location over 1/16", even after already being corrected!! Our cam life is much better now.


66jj
Member
posted November 23, 2002 05:26 PM
IVE RAN CHEAP MIDWEST MOTORSORTS CAMS FOR 3 YEARS, ABOUT 90 NIGHTS ID SAY.. STILL GOING. I SPRING THEM NO MORE THAN NECSSARY, STOCK DIA. 115-130LBS CLOSED AND 330-350 OPEN AND STAY AROUNF 6500RPM SBC.

TRIED SEVERAL BULLET SPEEDWAY CAMS THIS YEAR AND LOST ONE LOBE EACH TIME, BROKE IN WITH 1.35 ROCKERS EVEN, MAYBE NOT LONG ENOUGH, BUT BOTH HAD LIFTERS NOT ROTATING. THEY MADE A LOT OF POWER.

I NEVER RUN MORE THAN 40WT OIL, USUALLY 30WT.

dirtbuster
Member
posted November 25, 2002 09:21 AM
Well we are running a ISKY tight lash solid, which i think is pretty agressive, but we are using the EDM special oiling lifters, maybe that is what is helping us out. For only about 50$ more than regular solids i would say they are defintely worth it. We are also using sythetic oil, mobilw 15w50. Like I said never had any problems.


Racer X
Member
posted November 28, 2002 08:12 AM
I'd always heard that you were not supposed to run synthetic oil with solid lift cams.Of course this was about twenty years ago when I read this.


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