Thread: 454 finished wont start help!!!

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Just finished tear down rebuild of my 454 gen vi. Installed new comp cams hydraulic roller cam and lifters, new springs, seals, retainers, roller rockers, timing set, head work, and my old msd 6a box that test good, new blaster 3 coil that sparks, and 8555 distributor with new mag pickup, rotor, and cap. Spark out of coil, still wont fire engine even with new cap and rotor. Mag pickup gapped to specs. Maybe i need an outside opinion, did i overlook something simple cause im tired? Haha need help got fuel no spark out of ideas!

Call one of your buddies to come over. Remove #1 spark plug. Bump the starter one click at a time, slowly, while your buddy holds his thumb over the spark plug hole. As soon as he feels compression on his thumb, stop and use a breaker bar to turn the motor on over slowly until you get the slot on the inertia ring of the damper to line up with zero on your front cover timing tab. Now, you are at TDC on the firing stroke. Pull the cap on the dizzy and check where the rotor is pointing. If it ain't pointing to the #1 plug wire, pull the dizzy and reposition it. Fire the motor.
http://www.boxwrench.net/specs/chevy_bb.htm

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Ill give it a shot. I did set tdc of compression stroke before installing distributor and installed cap with number 1 wire facing rotor contact. But its worth a shot going backwards and seeing if something is off. Also pulled a spark plug and stuck it in wire while turning over engine and plug wouldnt spark.

If you're getting a strong spark from the coil into the center pin on the distributor cap, but no spark at the plugs your problem would have to be in the rotor to cap interface, seems to me. MSD has a bunch of different rotors and caps, so I'd be checking to be sure that I got the right rotor for the distributor & cap, and the right cap for the distributor. Doesn't take much of a mis-match to block the spark, and it's easy for a parts guy to grab the wrong part, especially if it's a kid thinking that all MSD parts are the same.

When i was troubleshooting distributor i thought maybe rotor or cap so i ordered msd 84335 replacement cap and rotor set that msd support line told me was for my particular distributor. Still same problem as with old ones so im assuming not the culprit however is there a way i can test and see if spark is going from coil to rotor? Or another way to troubleshoot spark out of coil but not to spark plugs. Also thanks again for the input guys i appreciate it. I have hit a serious roadblock at the end of a build. Getting frustrated.

Assuming this was a working install, if not recheck that. I have a suggestion and think is the problem. The part you may need is the magnetic pickup # 84661. Here are the ways to check firing, information supplied is directly from the MSD install instructions. Good luck I think your answer is here

Cheers,
Greg

I wish it were the problem. I suspected that and replaced magnetic pickup already. Did spark test with purple and green wire and sparks just fine. I literally am getting spark going into center of dist cap just not out wires to spark plugs.

Originally Posted by FearMy442

I wish it were the problem. I suspected that and replaced magnetic pickup already. Did spark test with purple and green wire and sparks just fine. I literally am getting spark going into center of dist cap just not out wires to spark plugs.

Given that I'd probably pull the distributor and using a good VOM meter check continuity between the center coil terminal on the cap to each of the plug terminals on the distributor, and then check continuity of your plug wires. If you have continuity, look at the possibility that you've perhaps severely fouled the plugs? Maybe it's worth buying a good set of plugs (I like NGK's), confirm TDC on compression for #1 and re-install the distributor. I'd be frustrated, too.

I would check continuity from the spring clip on top of the rotor to the whisker on the side and is the whisker coming into close contact with the plug terminals inside the cap. If neither one you either have a bad rotor or the wrong one for your application.

Originally Posted by NTFDAY

I would check continuity from the spring clip on top of the rotor to the whisker on the side and is the whisker coming into close contact with the plug terminals inside the cap. If neither one you either have a bad rotor or the wrong one for your application.

According to MSD the numbers are right, but with today's QA/QC Ken is right - verify continuity across the rotor first.

Originally Posted by FearMy442

I literally am getting spark going into center of dist cap just not out wires to spark plugs.

Not sure of what you mean you have spark in the center?

Reading this spark/voltage at the tower of the coil ..?

What about a bad coil wire as the bad actor for no a spark condition?


Electrically speaking: you should be able to stick a plug wire in the top (tower) of the coil, plug hanging on the end, and grounded.

This isolates the cap & rotor, removes it from the circuit.

In a well ventilated area, no fuel fumes. Turn over the motor and it will spark, as the magnetic pickup turns the coil off and on.

Fouled plugs are starting to sound good but 8 at once, that's rich .........PUN intended.

Have you tried without the MSD?

You should be able to get a spark just by turning the ignition on and off-on-off-on
the collapse of the field should cause a spark--

Gonna try all of the suggestions, but in the end im so sick of the reliability issue with msd im going to switch to pertronix hei distributor instead. Ill update after i get some cash together and order one. I also have a sneaking suspicion that my old msd 6a box may have finally crapped out. Im gonna go throw a brick through a window haha jk. Thanks for the help guys.

Beg, borrow or steal a stock distributor from a running BBC and stick it in your engine.