Since this is the best mopar forum i ask this question here about my 400cui

[bobfist]

Hi!

I got this 71 RR yesterday and the prev owner didnt manage to have it run smooth at low rpm.
We have been checking the timing but cant get anywhere close to the factory timing spec if we did the engine wouldnt run.
The engine runs like crap at low rpm when i trying to get away with the 4 speed trans.
Could they installed a way to rough camshaft?

Also does anyone know what camshaft the 300hp 383 came with from factory? bec i guess that cam works in the 400?
And where can i get it?


Tony

[Kern Dog]

Please don't take this wrong, but you ARE a musclecar restoration shop, right?
If the plugs are firing, the distributor is firing and the carb is mixing, the problem is internal. If it isn't misfiring, maybe it has an aftermarket high performance camshaft in it. Factory timing settings are for factory assembled engines that came with mild factory camshafts. High performance camshafts need MORE initial timing to idle right, and they still may idle pretty rough. In some cases, the harmonic dampener slips on its rubber ring and the timing marks move with it. When that happens, the dampener must be replaced.

[Hemidog]

Does the timing mark move around? I it does, the timing chain has some serious slack, and should be replaced.

[bobfist]

Hi thanks for answer!

Ha ha , i wouldnt say a shop, just producing some parts me and my dad, so we dont know everything

[tan top]

whats the initial timing at  ?  whats the idle speed ?  have you got a vacume gauge to hook up ?whats the reading at idle ?

[ws23rt]

Now this guy knows how to start a thread.

[Cooter]

Sometimes, it can be as simple as a vacuum hose off due to a backfire. Check around the intake with carb cleaner. BE CAREFUL as if you have a bad ignition wire, WOOOF! Flames. Not good. just spray a little round the carb base, intake where it meets heads, and see if the engine smooths out.

This problem may be why the Owner before you sold it. I have gotten some good deals due to vacuum leaks, loose converter bolts, etc.

Something like a balancer has moved or something like that may be why you cannot get factory specs on Ignition timing. I have seen weird distributor issues cause this as well. Are you unhooking the Vacuum advance when trying to set base timing?

What kind of carb is on it?
If the engine is original, what kind of compression does every cylinder have?
What kind of condition are the plug wires in? Are they on correctly in the firing order?