Bending push rods
#1
My 1970 428cj was setting for 20 yrs and i finly got her out and primed oil pump did everything right before firs start up etc . ran good for about 50 mils then bent push rod 3 of them to be exact !! So I replace all lifters and new rods now same thing hapend agen any sugustions on why it is doing this ? Stock motor arround 65 thousand miles 1 owner car , bad rockers ? camshaft . And cold I upgrade to roller rockers that are adjustable with original cam if it turns out to be ok ? oh yeah it has about 30 lbs oil preasure also
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#2
Nice car to have had in storage!

There are others here that will be better able to define your problems (they should be along shortly), but in the meantime I will hazard a guess.

My first inclination is to believe that you have some valves that are sticking thus causing the bent push rods. The second time around did it bend the same three?

Short of pulling the heads (if I am even close to correct on the diagnosis) what can be done to alleviate the issue.

Let's see what others have to say.
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#3
First off Thank you. I was thinking same thing but with valve covers off all valves were opening and closing good but may be sticking later on down the road. If so I wonder if possible to put new valves in without pulling head ? Like you said could be something else lets see what others have to say. Thanks agen Will
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#4
First off, I think Steven is on track with the valves sticking. Another thought is there could be carbon buildup on the pistons or heads that is braking up since having been sitting all those years, and getting between the pistons and valves. And NO! you cannot change the valves without pulling the heads. As far as the valves sticking you can put a can of "Rislone" in with the oil. It is a super thin micro lubricating oil and will creep into every space in you engine and loosen the crud from the 20 year nap. I would probably put a fresh filter on it, and run it a couple hundred miles, then change the oil again. If that doesn't cure the problem pull the heads and have them worked and checked for galled valve guides. But I really think the "Rislone" will cure you ill's. "Z max" is basically the modern version of "Rislone". Probably couldn't hurt to add a quart to the fuel also, as an upper cylinder lubricant. Good Luck JTS 71 Mach1
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#5
Thanks JTS,

I figured that you would have a possible solution that did not involve removing the heads.

Here's hoping the "Rislone" does the trick.
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#6
+1 on JTS71. After 20 years I would be inclined to have the heads off any way. There will be untold crud everywhere. If the oil was fresh (or near to) when the car was laid up the carbon and gum will be loose enough to be washed off and end up in the oil filter - clogging it.

Change the oil filter (only) again after a few hundred miles - been there - got caught. Blush
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#7
Thanks for all the reply's very helpfull . What do you guys think about adjustable roler rockers on those stock heads ?
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#8
If you have a stock Hydraulic cam, there is absolutely no reason for an adjustable valve train. In fact it would be near impossible to make an accurate adjustment as the squish in the lifter is necessary to maintain geometry and quietness, and without some preload, you would get looseness in the valve train which definitely wouldn't be any good, possible damage and a loss in performance. You can use Roller rockers, the Cleveland uses positive stop pedastels. (no adjustment) A Windsor uses the ball stud style and can be adjusted for preload. Make sure the valves are completely closed on the cylinder you want to adjust, TDC on compression stroke, tighten stud nut while turning pushrod as soon as pushrod becomes tight, won't turn or very hard to turn, tighten one half turn more, Now the preload is set. Turn each cylinder to TDC compression stroke and repeat until all 8 are done. Or you can remove the valve cover and start the engine, and tighten each ball stud until it starts missing, then back off one half turn. Continue until all have been set. This is the messy way but still effective. Hope this helps. JTS 71 Mach1
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#9
Certainly helped me with sorting her misfire. Drink_to_that
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#10
Thank you.
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