My SOHC really KNOCKS!

[dareo]

After much drifting, my red 240sx developed a knocking noise. Its quite loud. Maybe my motor wants to blow up or something. I think its running too lean or the timing needs to be retarded.

But i've tried to get it to run richer to stop the knocks, and i've added lots of octane booster, doesnt work though. I've seafoamed and tons of smoke came out, but it still knocks.

I've tried a few MAF hacks, but i cant get rid of the knock. After ****in around all day on it i've reduced the knock a little, but its still there.

I need to fix this car, a friend really wants to buy it and drift with us.

What can cause a 240sx to run overly lean? I replaced the fuel filter, that didnt help. knocking goes away with a really low gear and a lot of gas.

Thanks for reading/answering

[Nismo_Freak]

Is is a misfire, ping, or a loud sound in tune with the RPMs?

[Thecollector]

Check all the fluids?

[dareo]

Consistent loud sound in tune with the RPMs. It makes the noise unless its getting seriously flooded, like going less than 25 in 5th gear and flooring it. Situations where it would normally have way too much fuel, is where it runs fine.

Oh and the oil is freshly changed, transmission fluids i dont know about but those wouldnt knock the motor.

I think its timing or possibly a fuel pump, but i have zero experience working on those yet, so im hesitant to just bust stuff open and tinker.

[scuba_sean]

are you absolutely positively sure it's knock and not a valve tick? i had that, it makes the engine sound like a diesel jetta. i bought a can of wynns engine tune up and it worked perfectly

[dareo]

My grey one ticks, my red one fudgin KNOCKS! i mean its loud. Like it could blow up and you need to seek shelter loud.

[dareo]

Interesting, scuba, you've got 131db with 1 10" sub? What 10 do you run? I have a JBL GTO and its sounds good but doesnt really thump unless i put in my second 10 and run a bridged mono.