Mopar Muscle Association UK

Hi guys, I've recently rebuilt a 383 v8 for my 1970 charger, I tried to fire it up but when I try to start it, it just backfires and spits though the carb, I haven't got and exhaust fitted yet, just open headers, would this be the problem? I have set the timing and checked it a few times to find its dead on and I've got plenty of compression. Any info would be appreciated, thanks.

Sounds like the distributor might be 180° out, are you sure that it's on the compression stroke when pointing to no 1 cyl? Is the fuel fresh?

How do you check the timing without the engine running Kyle?

Is it a new Hydraulic / flat tappet camshaft or one that has run previously?

If new, then you really need to get everything ready and double checked before you attempt to start the motor - timing, spark, fuel, etc; spot on or you are in real danger of wiping a cam lobe and trashing the motor.

Sorry if you already know this, but you have to break the cam in by running for 20 - 30 mins without a stop.

If you do not break the cam in correctly you will end up with an engine full of grinding paste.

its hydraulic and I've checked the rotor lines up with the leads as I turn the engine over by hand, I also pulled number 1 plug out and got a friend to turn it over by key whilst my finger was over the plug hole and it sparks dead on at TDC. Ive checked a few times to make sure its not 180 out but it seems to be dead on Thanks for replys

..also there not new lifters, there the ones that came with the engine, I've made sure to not mix them👍

Needs more timing, TDC will be be retarded on today's fuels, you'll need at least 10 degrees, probably more.

Blue wrote:Needs more timing, TDC will be be retarded on today's fuels, you'll need at least 10 degrees, probably more.

This. As the wise man says, probably more.

You might want to plug the vac advance too (if running) - mine will bang and pop something awful on vac - cant run it. Block off carb feed and dizzy pipe. You will then be sure what you have set stays set !!

I assume you timed the crank and cam with the dots facing each other with number 1 at tdc and not accidentally timed it up on one of the advanced or retarded keyways on the crank gear? (if multi position gear)

When you are checking the crank timing are both valves closed on number 1 you want both valves closed? Thats compression stroke. If it is 180 out the engine would be on exhaust stroke as it comes up and the exhaust valve will be open, this is because there are 2 crank revolutions for 1 cam revolution so the pistons will be at tdc twice in 1 cam revolution, both tdc's will line up via the dots, if you have timed it up on the wrong tdc you are 180 out, pull the dizzy and turn the rotor 180 degrees.

Also check HT leads easy to get wrong.

Also as Pete says cam will need breaking in for at least 20-30 min but ran at 3000 rpm but keep an eye on it they get hot.

Ahhhh, that sounds something I've gotta check, I made sure I aligned the crank an cam dots but I'm not sure if number 1 was at TDC, so would make sense if 180 via cam timing. I'll pull the timing cover tonight and check number 1. Cheers

First thing I would do is pull the rocker cover, turn over engine so number 1 is at tdc and both valves closed, timing mark on pulley at 0, then check rotor arm is pointing to number 1 if its pointing the opposite way your 180 out, you can either take dizzy out and spin the rotor arm round or swap leads so that becomes number 1 but mark it as 1 otherwise it could cause someone a headache.

Found the problem!! The book I bought "How to rebuild the bigblock mopar" made out that the rotor spins clockwise but mine spins anti clockwise so following the book I wired up the leads backwards lol, it's running now, open headers so it sounds awesome! Thanks for your help guys, hopefully see u at the shows this year!

Best feeling in the world right?

Nice one usually is something simple.

Carl wrote:
Also check HT leads easy to get wrong.