Well, I've got a situation I'm hoping that I can get some help with.

I've got an L69, right now, all stock except for the HEI vac advance distributor and the entire computer system is removed.

Timing is set at 10*, and I haven't heard any pinging, I think...I'll explain.

The removal of the emissions and computer system and the timing have done me wonders.

I drove around for a week without any trouble, but never REALLY got on it. So the other day some BMW was trying not to let me on the freeway, so I down shifted to 3rd and roasted him.

My car took off, but I heard something that sounded like valve chatter, only once I get to about 4500 rpm aggressively. If I just rev it up to 4500 rpm more slowly, no noise.

The car has done it 3 times now. I am going to change out the springs anyhow, but was just curious what your take on my noise might be.

I'm very new to SBC's, and am not familiar with some of their idiosyncracies.

Please advise.

 

sounds to me like the preignition that you say you've not heard. try changing the timing or going to 93 gas

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ICON Motorsports

1st & 3rd

 

Turns out it was valve chatter, and it became more frequent despite the timing changes. The intake rocker on the #8 cylinder was a little loose. Of course I didn't find this out until I did a cam change, but just a good point of reference for everybody.

 

yeah- preignitoon could also make that problem surface to an audible level... glad you found the problem....

Steve