Engine Miss

G

giowest

Well-known member
The Grand Wizard of Nova Scotia has been offering ideas to neighbors 440 dilemma, What do you think. 70 440 standard rebuild 3 years ago then stored away. No fancy machining, wild cam, just vanilla rebuild. He's using one of those GM HEI distributor kits. Cylinders one and two are getting what appears to be good spark with the plugs getting wet but not completely firing. Using laser heat gun shows one & two 450 degrees colder than the other 6. 90psi for 1 & 2, 130 on the other six.
One idea from the great north was something wrong with the dist cap from one to two in the firing order.
My first thought today is to put the mopar dist back in and try again. Ideas?.
 
cap/wires/plugs come to mind first..my zr7 had a wicked stumble/miss then i swapped the plugs and it went away..they were NEW

after that..i wonder if the low comp in those 2 are to blame...stock intake? dual plane?..i ask cause a dual plane intake can actualy cause something similar to this if one side of teh carb is acting up
 
Wet plugs means weak/no ignition. I would start by switching wires & plugs. If that doesn't do it, then it's the cap. :huh:
 
Just a thought here, but #1 follows #2 in the firing order so they're right next to each other. Any chance the two wires somehow got reversed? Brain fart on the counter-clockwise distributor rotation? Can't help beyond that; I'm not familiar with the distributor itself so I won't hazard a guess.

That cranking compression seems low across the board. 90PSI on a recent rebuild is downright scary.
 
The thinking here is the 90 PSI is because the rings didn't seat yet from a lack of ignition?. Truck owners out of town on business this week so no updates yet. He did grind off a lot of metal from the bottom of the distributor and valve cover to get the dist to sit flat in the block. Possible shorting there?. He's going to try a regular mopar dist and module I have extra this week and see if we can't restore the original spark to 1 & 2.
 
There is no such thing as "shorting" the body of a distributor. They need to be grounded to the engine block. :huh:
 
OK, I'm with you on the rings not seating. As far as the distributor goes, you're either gonna get no spark or spark on all 8 unless the cap is warped or made wrong. It's not a wiring issue to the distributor.

I still can't figure out why anyone would downgrade from Mopar electronic to HEI. The first damned thing GM guys do is either add an MSD-6 or flip the HEI completely, probably because it sucks. Failure-prone modules, shit spark above 4,000, frail wiring... not exactly the stuff of dreams.
 
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