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Discussion Starter #62

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My guess is that the top of the #8 piston separated at the piston pin bore and then the pieces of the piston crown got mulched and pieces went through the intake valve and into other cylinders. With nowhere for the valves to go the pushrods beat the cam into submission, then the broken piston skirt and debris broke the wall out of the cylinder. Wish you had a “Fast and Furious” styled video of it. Playing Taps for it tonight...big engines that are revved too high will pull the top off the piston either because of the weight or the piston crown trying to seize or the cylinder wall failing from side loading.
 

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Discussion Starter #64
Got the distributor out. I'm assuming something stopped while something else kept going. I spun the shaft and it seems straight, but I don't know for sure. Hopefully I can just replace the gear and everything else is alright. :shrug





 

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The crankshaft speed was northwards of 5K when the cam stopped turning, so yeah, the distributor was going half that speed and broke a few teeth slowing down...😬
 

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The crankshaft speed was northwards of 5K when the cam stopped turning, so yeah, the distributor was going half that speed and broke a few teeth slowing down...😬
I'm not sure I agree with this, the cam is driven from the front of the engine, the piston that failed was #8. No reason for the cam to stop turning suddenly.

I could believe that the cam failed (broke), the stub of the camshaft fell down towards the crankshaft, (the cam just sits in the rear cam bearing, nothing holds it at the rear of the engine) and beat the #8 piston from the bottom and destroyed everything around it. The lifter and the pushrod would also have then fallen toward the crank and also got beaten in that cylinder until the engine stopped rotating.
My guess on how the distributor gears were sheared was caused by some pieces if the engine getting caught in the oil pump, and jamming the pump while the engine was still rotating (the distributor gear drives the oil pump). The engine stopped very soon after that!
 

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I agree that the front part of the cam was still turning after the back parts broke off. You are probably right about pieces jamming the oil pump....knew there was a flaw in that story....🤔
 

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I'm still leaning on the cam breaking first. You'll have a better idea once you pull the bottom end apart, either way, you really don't have much you can salvage. :cry

Big blocks are nice, but they don't like RPM's, that's a lot of weight flying around in there. :goodfinge
 

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Discussion Starter #71
That orange filter is the problem, I doubt it but still
I knew someone would say that as soon as I loaded those pics. What's funny is I don't ever remember using a Fram filter. For the first few years, at the very least, I always used Mobil1 oil and filters. Makes me wonder if my older brother did that or had someone do it as it sat at his house for a year or two towards the end of its life before it came back to me and then sat some more.

Do I really have to keep tearing this thing apart? lol Man...

As far as having more gears ripped apart, it has a gear drive on it. I'm curious what kind of carnage is up there.

Oh and as far as the cam goes, from what I can see and feel so far, the very rear part of the cam is still there. It's literally missing maybe 1-2" of cam right where those missing lifters are. I can feel both ends and yes, the rear part is barely hanging on as I can wiggle it around. It's like it literally ripped out a lobe or two and that's all. Weird stuff.

I'll have to separate the tranny from the engine before I really do much more. Anyone want a C6 with a shift kit?
 

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Discussion Starter #72
I'm still leaning on the cam breaking first. You'll have a better idea once you pull the bottom end apart, either way, you really don't have much you can salvage. :cry

Big blocks are nice, but they don't like RPM's, that's a lot of weight flying around in there. :goodfinge
Yeah, I'm kinda bummed out more wasn't salvageable. Before the engine blew up I was wanting to find a decent shortbed truck around the same year as my F150 and swap the entire drivetrain into it.

Well the order of operations didn't quite work out and I found a shortbed truck, but had no drivetrain for it. Then I figured I'd salvage the top end of this engine and put it on a good bottom end and kinda continue with the plan. Well, doesn't look like that's gonna happen either.

I already have another rebuildable 460 sitting in my back room slightly torn down, but it has even less desireable heads than the D3VE's that were on my deceased 460 as it's a later engine. I just knew I needed a new block and got ahead of myself.

There's a swap meet coming up this Saturday at our city park, which is about 100 feet from my house. I'm thinking about taking whatever good I can get off this thing and seeing if I can find some good windsor parts and either rebuild the 302w in my truck or build a 351w and swap it in. Either way I think the parts are gonna go whether it's at that meet or on CL or something.

It may sound weird, but taking this thing apart is kinda getting the performance juices flowing again. At the very least I miss the sound of that engine. My younger brother said it sounded like a lion roaring at WOT.
 

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Discussion Starter #74
get the 460 pieced back together and put it in your bronco?
I've considered that with the 460 in my back room. I'd still need to finish stripping it down and verify it's good enough to rebuild. A 460 really isn't a priority for the Bronco at the moment though. I'd like to do other upgrades to it first before swapping engines.
 

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Discussion Starter #75
Forgot I had a few more pictures on my phone.

I tried to get some shots of the cam where it broke.

This one is a shot of a lifter on its side wedged between a cam lobe and the block.




Here's the very rear part of the cam. You can see the "core" of the cam. It's the lighter gray. The cam lobe has the black on it next to the "core". You can also see that busted lifter above it and one that is still in one piece and in its bore below it in the pic.





Here's a shot of the other side of the cam where it broke. It looks like it broke flush with the cam bearing journal. Again you can see the light gray of the "core" and then the darker color is the part resting in the journal.





So maybe it's missing closer to 3" of cam. The width of two rods and a crank counterweight.
 

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Driving Stuff Henry Built
-90 xlt, 351w, e4od, man 1356, 3.55, sag, warn hubs, 35s. -73, 400, np435, d20j twin, 35s
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I've been thinking about this a lot lately, (I really love engine porn, but probably should get on with my life!) at first I was wondering if the pin on the cam broke, but then again, you'd probably have a lot more damage from piston to valve contact. Then there is also the probability that the cam may have been dropped during shipping or was just plain bad.

I guess i'm just wondering if the motor failed because of the cam, or the cam failed because of the motor?

That's why I was curious as to how the bottom end was. In other words, did #8 bearing seize up because of an oil issue? You could have picked up a piece of silicone , RTV, etc in the oil pump or as said earlier, did you twist your stock oil pump drive? I used to run Cleveland in the old days and if you ran a HV pump with a stock drive, it would end up looking like licorice.
Anxiously waiting for more (for some unknown reason, I really need to get a life, sigh....) :popc1:
 

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Yes, chicken or egg.

I see two trigger clues;

1) Water jacket breaks from heat and friction, Piston top comes off, smashes open valve, bends push rod, lifter shoots out since nothing is holding it down now, rattled around down into the cam, binds and breaks the cam, other lifter drops out and push rod with it.

2)Cam breaks, lifters drop, pushers go, why would the piston go then? Valves would be closed so no compression etc.

I think things started with the piston failing.


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Back in post 17, how did metal get in the ports? With the intake manifold intact, it seems like the only open path would be piston pieces sucked backwards thru an open #8 intake valve, not cam/lifter parts. If the #8 piston is no longer creating vacuum, & it's intake opens, then vacuum in the manifold from the other 7 might suck small pieces into the manifold. It seems like for the # 8 intake to open, that missing chunk of cam would still have to be there at that moment to open that valve. So maybe the cam survived for a little after the piston began to come apart. Long enough to allow debris to flow backwards. :shrug

If that's the case, is the cam broken when #8 valves hit the piston disintegratiing parts stacked up on the rod? It seems like pushrods should have bent instead. But if those cams are known to be weak... or did something from below hit the cam?
 
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