e35 cam and backfire

[ddog437]

I have owned my 78 280z for just over two years now, it passes smog and runs well. Before I bought the car, the previous owner (who I have found out to be somewhat of a liar), told me the car had a mild cam instead of the stock cam, car passed smog in California anyway, (why I think its stock). Recently I had a loud ticking noise from my car, and a friend mechanic took a look for me, told me it was my exhaust manifold, and proceeded to take a look at my valves. they were too loose according to factory specs, so he changed the valvelash to 10 and 12 I believe (whatever is factory stock). Yet after I left his place my car started backfiring! My car now backfires at 2600-2900 rpms but only when I let out the gas and I am in gear. I checked the cam, it says e35 on it. Just wondering if anyone knows if this is stock or if this is aftermarket, I think the backfiring is due to my exhaust leak at the manifold, yet I am not sure because I had the leak before the valvelash was adjusted. thanks.

[jevmaster5]

alright, i cant claim to be an expert, as i dont YET have enough experience. BUT, i,too, have an exhaust leak at the header, and have backfiring at that same rpm, so my vote is that it IS due to the leak

[ddog437]

seems we have the same problem, my car is a 78 what is yours? im pretty sure you are right about this, hopefully i can put in my exhuast manifold this coming weekend and find out for sure, thanks!

[m4xwellmurd3r]

Sounds about right. at around that RPM the injectors kick back on. if I don't run a muffler on my car, i can get some big backfires (technically, afterfire) at times.

 

our Z's kick off the injectors on deacceleration till around 2600+ rpm, and will make a pop when they come on sometimes. with the exhaust leak, it won't filter out those pops that the muffler normally would, probably are escaping out of your leak.