crackling noise on throttle lift? normal?

rdc767 · #1 (**permalink**) 11-07-2008, 05:52 PM

I have 10 miles and a short break-in on my stroked 351. I bailed on the Holley and went with a edelbrock 750cfm. After getting the timing , idle mixture set and idle rpm set.

On my short test hops. I notice it crackles or short backfire sounding noise. I think it sound great.

My buddy thinks its running rich? so the excess fuel is making the cracking noise on throttle lifts. It has ton of power and accelerate very strong. I haven't check the spark plug color yet. What does your sound like after running hard through two gear shifts and lifting off the accelerator? Should I be concerned?
Ron

patrickt · #2 (**permalink**) 11-07-2008, 06:06 PM

and check the connection from the primaries to the sidepipes. What your describing is not uncommon for exhaust related issues.

Ron61 · #3 (**permalink**) 11-08-2008, 01:03 AM

What Patrickt said. When I ran hard through a corner and lifted mine just came out as a roar. But after every run I would check the exhaust bolts and everything as I heard a lot of them popping and crackling as they lifted from thee gas.

Ron

727pilot@usa.co · #4 (**permalink**) 11-08-2008, 04:33 AM

Hey RDC what kind of kit is that you are putting together. Ours is a CMC that was put out about 1992. Here is a picture

Tom

rdc767 · #5 (**permalink**) 11-08-2008, 04:45 AM

Thanks
I have notice the header bolts loosening on there own. I need to get some of those locking header bolts. The header to sidepipe joint is a slip joint with spiring retainers.
rdc

727pilot@usa.co · #6 (**permalink**) 11-08-2008, 04:51 AM

I tried to upload a picture but apparently did not do it right. Here is a link to some pics of the kit

Cobra pix

Tom

Ron61 · #7 (**permalink**) 11-08-2008, 05:09 AM

Tom,

Both are very nice cars. Looks as if yours is about ready to go. I will see if I can put the picture in this post for you. That is one nice, big garage. Wish I had one that large.

Ron

rdc767 · #8 (**permalink**) 11-08-2008, 10:58 PM

nice lift and cobra!. Love the color. Antique & Collectibles out of Buffulo NY. Nothing fancy but very nice fiberglass and Gel coat is awesome no painting. This is my first engine build and I am proud it runs and no piece flew out!!
I check around the headers and number 5 was leaking bad. The header bolt was very loose. I was using copper gaskets and stainless header bolts. I am getting ready to put it away for the winter and I am going to send the headers and pipes off for cermamic coatings. So I can put better bolts and seal the sidepipe joint with some exhaust rtv.
rdc

patrickt · #9 (**permalink**) 11-09-2008, 05:29 AM

Quote:

Originally Posted by rdc767

... I am getting ready to put it away for the winter and I am going to send the headers and pipes off for cermamic coatings.

Keep in mind your slip-fit when coating -- you want everything to fit back together when you get it back.

DAVID GAGNARD · #10 (**permalink**) 11-09-2008, 07:48 AM

Quote:

Originally Posted by rdc767

nice lift and cobra!. Love the color. Antique & Collectibles out of Buffulo NY. Nothing fancy but very nice fiberglass and Gel coat is awesome no painting. This is my first engine build and I am proud it runs and no piece flew out!!
I check around the headers and number 5 was leaking bad. The header bolt was very loose. I was using copper gaskets and stainless header bolts. I am getting ready to put it away for the winter and I am going to send the headers and pipes off for cermamic coatings. So I can put better bolts and seal the sidepipe joint with some exhaust rtv.
rdc

Leaking headers/pipes will cause your "crackling" noise when getting off the gas,almost sounds like a back fire......as for your headerrs bolts, I use ARP bolts and after you run it a few times re-tighten them down, after 3 or 4 times, they stay put........

David