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  • #1

    rebuilt engine will not start only backfire

    I rebuilt my 1968 400 engine over the winter with new rings, bearing, valve job etc. I also upgraded the distributor to a no point Mallory distributor and coil. My problem is the car will not start and will backfire throw the exhaust (loud). I made sure the marks on the crank and cam were line up before putting the timing chain on. The # 1 cylinder is at TDC on the compression stroke and the rotor is at the # 1 terminal on the cap. The valve lash should be close until it starts and then I could adjust them. The 600 holley carb. was a used one that I pick up at a swap meet so I not to sure how good it is but, I don’t think its the problem. I not sure what else to check or to look for. Has anyone else ever had this same problem. If so what else could I try?

    Thank you
    Brian
    2 firebirds are better the 1.
    Tags: None
  • #2
    What is the firing order on that 400? what kind of 400 is it? Chevy? Pontiac?
    Tracy
    2002 C5 M6 Convertible
    1994 Z28 M6 Convertible
    Current Mods:
    SLP Ultra-Z functional ramair, SS Spoiler, STB, SFCs, Headers, Clutch, Bilstein Shocks, and TB Airfoil. 17x9 SS rims with Goodyear tires, 160F T-Stat, MSD Blaster Coil, Taylor wires, Hurst billet shifter, Borla catback with QTP e-cutout, Tuned PCM, 1LE Swaybars, 1LE driveshaft, ES bushings, White gauges, C5 front brakes, !CAGS, Bose/Soundstream audio, CST leather interior, synthetic fluids

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    • #3
      The distributor could just be off or you could be 180 degrees out.
      LS15 Power! Another LSx engine coming soon.

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      • #4
        I experienced the same problem with my buddy when he dropped in a new sbc motor in his bird. It wound up being 180 degrees off, just like norm said.
        black 95 t/a, a4, beefed up tranny w/ higher stall converter, transgo shift kit, trans temp gauge, trans cooler, richmond 3.73's, loudmouth, hypertech programmer, 160 thermo, descreened maf, TB bypass and airfoil, trick flow intake elbow, underdrive pulleys, moroso cai, edelbrock panhard rod, bmr stb, slp sfc's, fiberglass firehawk hood, hawk pads, taylor wires, ngk plugs, royal purple fluids,...and hopefully more to come

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        • #5
          I know you say that you are on the compression stroke but it really sounds like it is on the exhaust stroke and 180 degrees out. Double check it.
          2002 Electron Blue Vette, 1SC, FE3/Z51, G92 3.15 gears, 308.9 RWHP 321.7 RWTQ (before any mods), SLP headers, Z06 exhaust, MSD Ignition Wires, AC Delco Iridium Spark Plugs, 160 t-stat, lots of ECM tuning

          1995 Z28, many mods, SOLD

          A proud member of the "F-Body Dirty Dozen"

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          • #6
            We did the engine in my friends '79 T/A and the same thing happened. that one was 180 out too.
            LOUD2000T/A
            '00 Trans Am M6, K&N filter, Airbox Lid, F.A.S.T. LS-X Intake, Stainlessworks offroad y-pipe, Loudmouth catback, Pro 5.0 shifter, Hypertech programming, 17" Torque Thrust II wheels, 12.97@113; '87 Monte Carlo SS; '91 Sonoma V6 4x4.

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            • #7
              Be glad you weren't looking over the carb and it belchs a flame 3 feet out the top. It sounds like it could be 180º out.

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              • #8
                That's my bet that's its 180 out. Been there done that.....
                2005 GTO (mine) K&N CAI and Magnaflow exhaust, drilled and slotted rotors, and other minor mods.
                1994 Formula (mine) SOLD 6-23-08 Still miss it
                2002 V6 Firebird (wifes)
                2013 GMC Sierra (mine)
                2011 Cadillac CTS4 (wifes)

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                • #9
                  Originally posted by Joe 1320
                  Be glad you weren't looking over the carb and it belchs a flame 3 feet out the top. It sounds like it could be 180º out.
                  That is why I didnt mention it being 180 out... he didnt say he had 3 foot flames shooting out the carb

                  The first time I ever timed a brand new engine that happenned to me. It was a 350 in a 86 Camaro.

                  The best way I found to get TDC on #1 was to remove the spark plug and put my thumb in the hole. Have a buddy crank it over until the compression stroke pushes air past your thumb. Next turn the motor by hand to line up the timing line on the balancer to 0.
                  Tracy
                  2002 C5 M6 Convertible
                  1994 Z28 M6 Convertible
                  Current Mods:
                  SLP Ultra-Z functional ramair, SS Spoiler, STB, SFCs, Headers, Clutch, Bilstein Shocks, and TB Airfoil. 17x9 SS rims with Goodyear tires, 160F T-Stat, MSD Blaster Coil, Taylor wires, Hurst billet shifter, Borla catback with QTP e-cutout, Tuned PCM, 1LE Swaybars, 1LE driveshaft, ES bushings, White gauges, C5 front brakes, !CAGS, Bose/Soundstream audio, CST leather interior, synthetic fluids

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                  • #10
                    Ditto.... 180 out. Been there, done that too!
                    1999 Black TA Ram Air M6 with lots of Mods and many coats of Zaino!
                    http://community.webshots.com/user/runbikejrb1

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                    • #11
                      I guess everyone agrees I better pull the dist. and do a 180 degrees. I'll let you know what happens.

                      Tracy it's a 400 pontiac motor firing order 1-8-4-3-6-5-7-2

                      Brian
                      2 firebirds are better the 1.

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                      • #12
                        It does sound like the timing is out, either dist. or timing gears "but you said they did line up."

                        If your dist. is right, then I would suggest you check your valve lash... You may have some too tight, and some of the valves are hanging open.
                        John Wagner "Owner"
                        D.E. Engine Performance & Fabrication
                        1995 Formula

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                        • #13
                          Actually, there was an '85 firebird near my hometown that was for sale for $500 the previous owner was a teenage boy who took out the distributor and when he reinstalled it, the car when stated would do nothing but backfire. That was the only thing wrong with it! it was in pretty good shape
                          1982 Trans am w/ t-tops
                          V8 5.0L 305 H out of an '86 Caprice
                          previous owners abused it!!!

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                          • #14
                            may as well jump on the bandwagon....i did it to my Mustang a few years back...installed a new distributor and was 180 degrees out
                            1998 TA M6 SLP Lid, Cold Air and Bellow, Flowmaster 3", Centerforce DF, Fast Toys MAF ends, JET skip shift eliminator 312rwhp/366rwtq

                            92 Lincoln Mark VII LSC For Sale

                            Visit Central Jersey Mustangs & Fords

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