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302 Gives Way - Update...Issue Finally Found

Re: 302 Gives Way

"65fast" said:
Well I got the heads off last night and there were definitely piston to valve contact on all the cylinders. Luckily none of the valve broke off into the cylinder though.

I have not taken the timing chain off yet, but I am guessing this is the culprit. This was on my other motor that blew so I am wondering if it was weakened from the previous event on that motor.

I am happy that the bottom end did not come apart!



I think I might go for some aluminum heads putting it back together and maybe a new cam.


Thanks for the offer Tim, I will let you know!
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DeJaVu... :scar
 
Re: 302 Gives Way

I have not taken the timing chain off yet, but I am guessing this is the culprit. This was on my other motor that blew so I am wondering if it was weakened from the previous event on that motor.
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Timing gears/chains are inexpensive enough that they shouldn't be re-used from one engine to the next.
 
Re: 302 Gives Way

"65fast" said:
It was a gear drive that went on yours right? Did you pistons meet the valves as well?
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Yes sir. If'in my memory serves me correctly - every exhaust valve was hit and either 2 or 3 intakes were hit.
 
Re: 302 Gives Way

"daveSanborn" said:
Timing gears/chains are inexpensive enough that they shouldn't be re-used from one engine to the next.
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:wstup

Truer words were never spoken!

65fast, what you found sucks, but I guess it could have been a lot worse!
 
Re: 302 Gives Way

Agreed and I have certainly learned my lesson.

I am glad I had forged pistons in the motor this time instead of hypers. like I did the last time. I am pretty sure I would have ended up with another oil pan full of metal.


I was thinking about getting some aluminum heads anyway, so now should be a good time to do it.
 
"65fast" said:
UPDATE - 7/18

I got the timing cover off and spun the motor over to TDC and the dots lined up on like they should do I went to take the cam bolt and and the cam spun, but the cam gear did not. Somehow the pin that keeps the cam and cam gear spining together worked its way out of them cam allowing it to spin separate from the timing gear...Ughhh It's always the little stuff!
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Ok, after reading that 7 times, I think finally figured out what you're saying ... you snapped the cam. Well, could be a lot worse! You're just out a cam/lifter set and some gaskets, right?
 
I read it as the dowel pin that lines up the timing gear on the cam is missing/broke.....not a broken cam.
 
It's kind of hard to explain without pictures LOL.

What I meant was the dowel pin that goes through the timing gear and into the front of the cam worked it's way out of the cam and was only engaging the timing gear.


I am out a set of heads too since it bent every valve.
 
If it were me, I would be contacting the cam manufacturer. That kind of thing should never happen. It's not the type of thing that can be blamed on anything other than a manufacturing defect. I would expect them to comp (pun intended) you a new cam at the very least.
 
I'm not sure about everyone else, but I had to install the pin into my cam...and actually had to buy a longer one due to the thicker dual roller timing set. If the pin does not fit tight then it has a chance of backing out, but there should still be a washer beneath the timing sprocket bolt that holds the cam pin in. Was this washer present and if so, was it more like the bolt loosened up enough to allow the washer to rotate out of the way, allowing the pin to work its way out?
 
I did have the washer installed, but mine has a semi-circle shaped groove in it. I always thought this was normal, is it supposed to be a complete circle?
 
My take on this is the cam gear to camshaft bolt was under torqued. The pin is not supposed to take the load of the valvetrain. If the bolt was torqued correctly, the gear was not in contact with the camshaft face. Could be a burr in the camshaft snub or inside the gear. Torqued down it was OK till vibration got ahold of it.

I'd also think strongly about pulling the pisons all out if you have not done so. There is a change one or more skirts could have been cracked by the piston to valve contact. The sudden hit not only bends the valve but forces the piston sideways in the bore. If the piston deflects much, a skirt can be cracked. If you leave them alone and one is cracked, a skirt falling off during engine operation will mean death to the block shortly after.

If you clean the bore of carbon and the engine is low miles, you should be able to reuse the rings and simply reinstall the same piston/ring into the same hole. If a piston is damaged, you will need to replace the rings on that piston when replacing the piston.
 
Re: 302 Gives Way - Update...Issue Finally Found....Back on the Road 11/21

After six months and a good bit of work I am finally back on the road!

The furthest I had to strip it down was enough to take it to the machine shop and have them install cam bearings.

I ended up getting a set of brand new AFR 185's, pushrods (ended up being the right length), and a set of Crane Full Roller rocker arms for $1,000 locally off Craigslist. I went ahead and converted to a roller cam while I was at it and had Ed Curtis (Flowtech Induction) spec one out for me. I also upgraded to a Duraspark ignition while I was at it too. I still have my Edelbrock 600 and Weiand Stealth on the car.

I had a hell of a time trying to get the car started, I had no idea Ford swapped firing orders in the mid 80's. I guess this is when the swapped to roller cams, so after figuring out what cylinders were not firing, I switched the wires around which ended up being a 351 firing order LOL.


Just putting around yesterday for a few miles the car feels great and much stronger than before. I am going to put a wideband on the car in hopefully a couple weekends and get the carb sorted out as it is stumbling at WOT.


Glad to be back on the road!
 
Nice!!! Sounds like you gave it a bit of "upgrade" with those heads :) So eh.....when does that trans go in? :thu
 
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