xr 282 hr backfire

timakins · #1 (**permalink**) 08-01-2010, 12:49 AM

Backfires exaust under hard eccell. This is a new engine ran very little. Timing is 18 base and 38 at idel with vac. to man. about 42 max. Anyone help please?

amick · #2 (**permalink**) 08-02-2010, 06:02 PM

What RPM do you have full advance coming in at? Are you noticing any excessive valve train noise? Where do you have the rotor phased in at? What engine are we talking about here? At what RPM does this backfire occur? What process did you follow to adjust the valves?

timakins · #3 (**permalink**) 08-07-2010, 09:11 PM

355 Chevy in a 74 Camaro it does`nt have a tach installed yet, im not sure of rpm. I removed carb today found secondary squirter plugged , cleaned it out reinstalled, ran compression test had 180-185 on all cylinders.

amick · #4 (**permalink**) 08-09-2010, 11:19 AM

Well have you tried running since this issue was discovered? If so has this cleared up the issue?

timakins · #5 (**permalink**) 08-11-2010, 10:22 PM

Cleaned carb installed did not change still poping out exaust. I`m thinking maybe ignition problem. Checked compression had 180-185 on all cylinders. plugs look rich im thinking the Procomp HEI is a bad one.

amick · #6 (**permalink**) 08-12-2010, 05:52 PM

From looking at what you posted the inginition would be my guess for the culprit. With the cylinder pressure you posted that you are making it is unlikley a camshaft or valve train issue.