Backfiring .... after roller rocker/pushrod install - Team Camaro Tech
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post #1 of 9 (permalink) Old Aug 8th, 09, 12:59 PM Thread Starter
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Backfiring .... after roller rocker/pushrod install

I went for a first run today after installing COMP roller rockers, pushrods, and stud girdles on my motor. I have a backfire issue now when letting off the gas after a full throttle run. I do have an open Magnaflow exhaust bolt-on kit. Any ideas what this could be? I am thinking the combination of exhaust, etc. may have leaned out the tune. Thoughts?
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post #2 of 9 (permalink) Old Aug 8th, 09, 01:10 PM
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Re: Backfiring .... after roller rocker/pushrod install

That noise will disappear after you run the complete exhaust system!....It's the combination of high flowing exhaust gases and air in an open exhaust system which creates the backfiring!
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post #3 of 9 (permalink) Old Aug 8th, 09, 01:20 PM Thread Starter
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Re: Backfiring .... after roller rocker/pushrod install

It is a complete Magnaflow system with mufflers. I just ran dumps off the mufflers in front of the rear differential.
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post #4 of 9 (permalink) Old Aug 8th, 09, 08:00 PM
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Re: Backfiring .... after roller rocker/pushrod install

Did you adjust the valves/rockers properly? Could be the cause of the backfiring

John

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post #5 of 9 (permalink) Old Aug 9th, 09, 05:28 PM Thread Starter
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Re: Backfiring .... after roller rocker/pushrod install

Quote:
Originally Posted by johnny5 View Post
Did you adjust the valves/rockers properly? Could be the cause of the backfiring
It's a hydraulic set up so it was pretty straight forward. Adjusted the locknut 1/2 turn past snug like the instructions said. I don't have any noise from the valvetrain so everything seems ok.
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post #6 of 9 (permalink) Old Aug 9th, 09, 06:11 PM
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Re: Backfiring .... after roller rocker/pushrod install

Did you readadjust the timing, it could be advanced by 1-2 deg.?

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post #7 of 9 (permalink) Old Aug 10th, 09, 11:40 AM Thread Starter
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Re: Backfiring .... after roller rocker/pushrod install

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Originally Posted by Alabamcam View Post
Did you readadjust the timing, it could be advanced by 1-2 deg.?
I am going to re-adjust the pushrods to between 1/3 and 1/2 turn in case I have one valve not shutting completely. Isn't backfiring a sign of being lean on fuel or late on timing?
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post #8 of 9 (permalink) Old Aug 10th, 09, 08:26 PM Thread Starter
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Re: Backfiring .... after roller rocker/pushrod install

After checking through the forums I decided to adjust the valves and tighten them to 1/4 turn instead of the 1/2 turn that COMP recommends. That seems to have cured everything. No more backfires, and it is idling a little better as well. Lesson learned.
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post #9 of 9 (permalink) Old Aug 11th, 09, 05:16 AM
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Re: Backfiring .... after roller rocker/pushrod install

I had the same problem. It turned out to be a broken valve spring.

Lee (in Louisville, Ky)

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I specialize in Muncie 4 speeds. Rebuilding tranys for 20 years with over 50 Muncies to select from. If your looking for a certian date code I should be able to help.
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