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Tick in engine

1121 Views 6 Replies 2 Participants Last post by  scottyz
I just recently rebuilt my engine. It is a 383 small block. It has a comp XE274 flat tappet cam. After initial break in I noticed a slight tick or knock. It sounded most noticeable from the fuel pump. When you removed the pump you could not hear it. I put on a new pump. Tick was still there. I dont believe it is from a crank or rod bearing as I have good oil pressure and my specs during assembly are all good. The tick seems to be with every revolution of the cam. Today I pulled the valve covers to watch the valvetrain operation. I marked all the pushrods. One does not appear to be rotating. A few are slow like a full revolution is about every 25 seconds. I would imagine that the one pushrod that is not rotating means the lifter is also not rotating? The rest rotate at a good pace and rotate consistently. The one slow rotater happens to be closest to the fuel pump eccentric on the cam. Would this tick go down the fuel pump pushrod to the pump and make the noise greater? I have driven the vehicle about 200 miles so far and it runs great and strong but this noise cant be good so I am back to not driving it. What are your recommendations at this point?
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SWHEATON. THanks for the reply. My 2 friends and I built the engine. My one friend builds high performance engines for a living very successfully. This is another reason why we are pretty sure it has nothing to do with crank/rods or clearances with bearings or rod to cam or rod to block. We have adjusted the valves twice and still not much diff at all. I have listened with the stethoscope and this is the reason why i first condemned the fuel pump. So I replaced the pump and pushrod and still same thing. We are going a half a turn on the valve adjustment by the way. We also removed the belt to make sure it had nothing to do with the water pump or alternator. I find it coincidental that the sound is much louder with the pump in place than if we run it without the pump. The cam does run the pump so this is another thing that makes me think its the cam going for a dump but I also want to know what others think. Its a shame that the car runs so well but has this noise. I dont know how long it takes to kill a lobe but I would have figured with the few beatings I laid on the engine when I drove it I thought it should have been done by now. I may be wrong though. Another thought was if a lifter is not pumping up? Wouldnt this cause a running condition though?
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If I do have a bad lifter what can I do to avoid this next time? WHen we assembled this engine we spun every lifter in its bore. The breakin of the engine went smooth and its not like we havent done this a ton of times before. Weird to me. Also, when I remove the lifters for inspection will I be able to see the cam well enough to determine if the cam is ok? I would imagine but want second opinions. Thanks again. I am a little bummed.
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