timing, backfiring, some damn issue.

mbalbritton

mbalbritton

#@$%!
Joined
Mar 22, 2005
Location
Lakeland, FL
So, the saga continues on the 258.

I swapped the #5 piston and Also deleted the Mechanical Fuel pump in favour of an electrical pump. Now that everything is back together and (should) be ready, I cannot get it to fire. I am getting a bunch of backfires from the Carb while trying to crank. Starting from the beginning and walking through until now:

- Disconnected manifolds and pushed to the side, pulled gaskets
- Pulled Valve Cover, Rockers, Push rods, Head, Head Gasket
- Dropped oil pan, pulled #5 rod cap and popped the piston out the top.
- Closed up bottom end
- Cleaned up carbon build up in combustion chamber, wasn't all that bad really.
- Reinstalled head with new gasket
- Reinstalled push rods making sure they were seated in lifters, Reinstalled Rockers making sure they were seated on the rods and torqued to spec.
- Closed up valve train
- Reinstalled manifolds with new Gaskets.
- Confirmed TDC on compression stroke and Confirmed firing order.
- Plated off Mech Fuel pump hole
- Plumbed and wire new electrical.

Confirmed Fuel and Spark and compression on at least #1 and #3 with my finger plugged in the spark holes.

What could I have missed or accidentally done? I swear it's acting like a timing issue. But I have been over and over the firing order. Stuck my finger in the #1 spark hole and felt compression and confirmed #1 wire aligning with Dist. Button. We didn't mess with the distributor, but I did check and confirm that it's holding tight and not loose. I'm about to remove the Valve Cover to make sure all the rods are still in place and make sure there's no apparent issues in valve train.

Thoughts?
 
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Little more info. For shits and giggles, I adjusted the timing. I advanced it a bit and got it to fire and and run really rough. the more I advanced it, the better it got until I bottomed out the Vac Adv. on the block.

With it actually "running", and by running I mean I could let go of the key and it was hitting enough to keep running on it's own, but really damn rough. It had a very rhythmic backfire through the carb. two pops from the carb and then a few proper combustion hits to keep it running. sounding like: pop-pop, stumble along, pop-pop, stumble along, pop-pop....

I'm really leaning toward some issue in the valve train. When I had it apart, all rods were nice and straight, all rockers looks good. Same for springs and valves. Unless a pushrod fell out of place on reassembly. but I had me and buddy working on putting the valve train back in and we were both watching everything. Not saying it couldn't still happen, just that I'd be surprised. I just hate pulling that damn cover....
 
I'm definitely not an expert, but this is my 2 cents. If you got it to run better by turning the distributer farther and farther until it bottomed out, I would be tempted to pull it out, rotate it one tooth so you can turn it more, and reinsert it.

Iv'e seen Jody post how to do this many times over the years. I would wait and listen to him.
 
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drkelly said:
I'm definitely not an expert, but this is my 2 cents. If you got it to run better by turning the distributer farther and farther until it bottomed out, I would be tempted to pull it out, rotate it one tooth so you can turn it more, and reinsert it.

Iv'e seen Jody post how to do this many times over the years. I would wait and listen to him.
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I was thinking that, or retard it a bit and relocate each plug wire one spot counter clock wise in order to gain a little more swing in the dizzy. but, that is a shit ton of advance it seems (he says as he waits for amazon to deliver his new timing light). My question would be, How the heck did it get that far out? I never pulled the dizzy.

So, I just pulled the valve cover. at least I'm getting efficient at that. :shaking: No slop in Push rods, they spin easy enough, all springs pass visual inspection, all rockers snug and in place... that is except for #2 Exhaust valve rocker. There was all sorts of slop in it but not enough to unseat the push rod at the rocker, yet the bolt was torqued. I removed the rocker and push rod, checked everything, even put a magnet on each lifter to make sure they were free and moving, and reinstalled and it was snug as a bug in a rug. I feel fairly certain that the valve train is good. I can't imagine that an issue with one exhaust valve is causing this.
 
Just so we're all clear... you haven't touched the dizzy, the timing chain, crank position sensor, etc?
 
shawn said:
Just so we're all clear... you haven't touched the dizzy, the timing chain, crank position sensor, etc?
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That is correct. I will throw this out there as a variable. My buddy did stand on the bumper and the passenger motor mount to lift the head out and put it back. That means there’s a chance the dizzy could have accidentally been pushed by his foot unknowingly.

Thus the only reason I played with the timing this afternoon, AFTER the issue had reared its ugly head.

Looking at the dirt/grease on the dizzy hold down flange, it didn’t look like it had been spun any. But….maybe.
 
<<< I "know" a dumbass that has pooched the firing order/wires more than once (4th time was the charm on the old Puick Oddfire and was deadnuts convinced it was perfect the first 3 times) 🤫

Not pointing fingers, but that'd be the FIRST place I looked... *again*! Maybe one of the girls can assist? 🥸
 
Caver Dave said:
<<< I "know" a dumbass that has pooched the firing order/wires more than once (4th time was the charm on the old Puick Oddfire and was deadnuts convinced it was perfect the first 3 times) 🤫

Not pointing fingers, but that'd be the FIRST place I looked... *again*! Maybe one of the girls can assist? 🥸
Click to expand...
I never pooched the firing order and I certainly didn’t put any paper towels in the intake either… this time.

Firing order reconfirmed.
 
Caver Dave said:
<<< I "know" a dumbass that has pooched the firing order/wires more than once (4th time was the charm on the old Puick Oddfire and was deadnuts convinced it was perfect the first 3 times) 🤫

Not pointing fingers, but that'd be the FIRST place I looked... *again*! Maybe one of the girls can assist? 🥸
Click to expand...
Somewhat related, the coil packs on the 4.0 Fords go 1-2-3-4-6-5

The wires for 5 and 6 are basically the same length, too. So that's nice.
 
Well… self inflicted user error wound.

Note to self and to all. Make sure those push rods are seated properly.

As mentioned, I pulled the valve cover and found #2 exhaust valve rocker was loose. Reset all of that and everything was fine. Didn’t dawn on me as to why until I had my kid crank the engine while I watched the rockers. That’s when I found that #6 exhaust valve rocker wasn’t moving at all.

Pulled that one and found that even though it was snug, it was not set in the lifter. I figure both 6 and 2 exhaust push rods were not set in their lifters, thus exhaust wasn’t opening. Then when intake opened was getting the backfire through the carb with a sequential POP POP since they follow each other in the firing order.

Set all that right and she cranked right up like she’s supposed to. This time, no detectable rod knock, piston slap wtf ever noise.

 
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