Big Block Help

robermj1 · #1 (**permalink**) 05-20-2005, 10:28 AM

I have a 466 that after my first trip out I had to stumble home. When the car is at idle to 2000 rpm it shakes really hard. I have checked the valve lash, rechecked the timing, when I shorted out the wires I have 3 cylinders not firing, mind you this is a new set up, motor everything, I am running a digital 6 box with coil, msd dist. I am running out of ideas, so I am asking for some help. once over 2000 rpm it smooths right out. Help needed, also there are no vacuum leaks checked the intake everyting I can think of, unless I am now the owner of a flat cam, but I cannot figure out why 3 cylinders are not firing.

John Martin · #2 (**permalink**) 05-20-2005, 03:36 PM

Just a guess , timming chain location , bad wires , firing order

Clois Harlan · #3 (**permalink**) 05-20-2005, 04:02 PM

I think John may be on to something. Varify the timing chain has not jumped.

Clois

byron w · #4 (**permalink**) 05-20-2005, 04:09 PM

SOUNDS LIKE SOMETHING IN THE CENTRIFIGAL ADVANCE. SOUNDS LIKE IT IS RETARDED UNTIL THE MECHANICAL SIDE OF THE DISTRIBUTOR CATCHES UP DUE TO THE RPM'S. JUST A THOUGHT,HOPE IT HELPS
BYRON W.

cobred · #5 (**permalink**) 05-20-2005, 04:16 PM

First see if you have spark to the plugs of the dead cyls. If you do remove the plugs and swap them with the ones from known good cyls. this will eliminate the ign. system. If the same cyls. are still dead remove the plugs and do a compression test compairing the 3 bad to the 5 good cyls. If the 3 are low suspect valve timing, pushrods, cam lobes, etc.

robermj1 · #6 (**permalink**) 05-25-2005, 02:19 PM

well here we are another day same problem, did the compression check over the weekend, 235-240 on all cylinders, took the carb off drained the gas to see if I could find gold, none appeared. I also did change all the plugs, and here we are smae problem, 1-2,000 rpms the car runs like ****, after 2000 smooths right out and she keeps going, any other ideas?

byron w · #7 (**permalink**) 05-25-2005, 02:31 PM

ONLY OTHER THING I CAN THINK OF RIGHT NOW IS THE POSSIBILITY OF SUCKED INTAKE GASKETS. STILL CHECK THE DIST.
GOOD LUCK,
BYRON W.

RICK LAKE · #8 (**permalink**) 05-26-2005, 04:36 PM

robermj1 Rob First off do you have a spark tester to check the spark? That MSD system WILL KILL YOU if you are not careful. I was smart once to and it shocked my dumb A$$ over the car. I could taste it for the next 2 days. Anyway Pull both valve cover and crank the motor Make sure that all the valve are opening the same height. What is a 466, 460,30 over or a FE 427 with a stroker kit? Firing order is OK. Put a vaccum gauge on the motor and find out what the vaccum reading is and if it is steady. Swap the spark plugs with 3 cylinders that are firing and see if there is any change in the missfires. Do you have blue or black smoke coming from the tail pipes? The carb floats could be too high causing causing gas to dump into the motor. When you get above 2000 rpm the motor cat catchup and burn the extra fuel. Check your float levels and your fuel pressure to the carb. Are the plug all black and carboned out? Start with this. Give me a call after you have tryed this. tomorrow is OK the weekend is out till tuesday. after 8:00 pm est Rick Lake 732-254-3536

Pete Wolff · #9 (**permalink**) 05-26-2005, 05:29 PM

Double check your firing order to be sure that you haven't "crossed" any wires and take a good look at the inside of your dist cap for cracks or carbon tracking. Is this a fresh motor ? I had a similar problem once when I put a CJ flywheel (external balance) on a 427 (neutral balance)

Michael C Henry · #10 (**permalink**) 05-27-2005, 09:40 AM

I'd run a comaritave compression check to eliminate burnt or bent valves. Check under the distributor cap for debris.I'm sorry but I allways think the worst and hope for the best.I sheard the dowl in the camshaft last year.It can happen ,I got it out ,it wasn't fun. watch how far the valves move. Cams have lobes wear flat. But that wouldn't have been sudden.And if the lifters wore you would have had to adjust out clearence at the rockers. I had two lobes go flat and mushroom the lifters that were riding on them.One was an intake on #1 and exhaust on #7 or #8. The filter caught all debris. I removed the engine and had it gone through. No dammage to crank or bearings.Machinist polished the crank ,replaced bearings and replaced second and oil rings. I had the gapless top rings.
I had a freind (back in the day )that was accustom to buying new 427 short blocks twice a year, putting his 427 stuff on them.In 66 he tried a new 428short block with a his old used 427 flywheel. He only got to the end of his alley before backing it back to his garrage and removeing the engine.He tried to return it to dealer .They would take it back .He tried to scatter ti and collect the warrasnty.He had it on a trailer made from the front of a car frame.with radiatror and oil and it would just throw the belts. he loned ti to a guy with a stock car,it blew the clutch and broke the bellhousung. He then sold it and later bought it back from a guy that had taken it to a machine shop and had it bored .040" over.and then lost interest in it.And sold it to me when I bought a 63 1/2 Ford Gallexy that had a old police intercepter 428 with what turned out to be a stuck valve in it.428 takes a 428 flywheel.You can swap almost everything among all the other FEs but not 428 flywheels and 428 engines those go to gether.