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Thread: 350 SBC Engine Problems

  1. #1

    350 SBC Engine Problems

    OK,

    Built a .030 350 for dirt track racing. Scat crank, new scat rods, clevite bearings, summit racing 510/533 lift, 254/264 duration cam, 291 heads w/ 2.02/1.60 valves. After getting all the parts back from the machine shop and putting together, we had the correct .002 clearance according to plasti guage. Now we raced Saturday night and the engine would not turn up like we wanted. Could only get 5000 RPM out of it, but still running with them, just in the back where I don't want to be. After I finished the race, still on the track I lost power to my tach and guages, and the car died. OK, I lost power from the battery, got to the pits and fixed that problem and now it won't turn over. You guessed it. Sorry this is so lengthy buy I want to give a good description. We loaded it on the trailer and went home. Got up Sunday morning and put it in the shop. Pulled the plugs and the motor would turn over. Did a compression test and 150 lbs on each cylinder. OK, put the plugs in and started the engine. Runs but poorly. no knocks rattles, etc just clicking lifters. Gut feeling told me to pull the engine and tear down. I did. Top end looked good until I pulled the cam...... 14 of the 16 lobes wore out. I only have 25 laps on this motor...... Felt the from cam bearing and it felt like sandpaper. Pulled the oil pan to find metal in pan. #7 bearing spun and thin as paper. It actually sliced my finger while trying to pull off crank. All the bearings looked bad but only that one spun. The aluminum coating was peeled off all but the front 2. Cyl 1&2 looked as they had never been run. Now to the main bearings. They all looked like they had been very hot. The rods on the crank where cyl 7&8 go are discolored black and blue. and the crank is not silver anymore, it looks kind of goldish color. What do ya'll think. Could that much metal from the cam caused all that or did I have something else wrong. Any help is much appreciated, as I can't afford to build another for the same thing to happen.........

  2. #2
    Senior Member RACING JUNKIE curtisreed's Avatar
    Join Date
    Feb 2004
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    KIEFER, OK.
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    1,309
    First thing is .002 is not enough main bearing clearance in my opinion. Don't use plastigage on a race engine buy or borrow the right measuring tools. What kind of spring pressure? Did you break in the cam before you went racing? Why keep racing when the motor isn't running right? Sorry it happened I hate that sick feeling when this happens.

    Curtis

  3. #3
    Senior Member SENIOR BUILDER
    Join Date
    Nov 2008
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    Phoenix AZ
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    Were you running a break in additive in the oil? Most shelf oils have had the zinc and phosphorous removed and are no longer flat tappet compatible.

  4. #4
    Senior Member DYNO OPERATOR
    Join Date
    Aug 2007
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    Lost Creek, WV
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    533
    Quote Originally Posted by ccperf721p
    Were you running a break in additive in the oil? Most shelf oils have had the zinc and phosphorous removed and are no longer flat tappet compatible.
    X2 on the zinc...Lucas break in additive #10063 is what I sell.

    TS1955

  5. #5
    Senior Member MASTER BUILDER
    Join Date
    Apr 2009
    Location
    B.C. Canada
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    145
    How much oil pressure did it have?


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