Two (or more?) Bent Pushrods

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dibbons

dibbons

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This motor was running (idled rough) when I removed the rocker arms/shafts and sent them to rocker arms unlimited. Vehicle has been parked for over a year. Now I have a used set of rocker arms/shafts I was preparing to install today when I noticed the pushrods from intake valves #6 and #7 are both bent (#7 a lot and #6 a little). I haven't pulled out the other pushrods yet. I hope I can just replace the pushrods and go from there. I just want to get the engine running enough so I don't have to push the car ('65 Valiant Signet Convertible) around the yard (needs complete restoration).

bent pushrod.JPG


Signet motor 273.JPG
 
Let me know what the length is on the push rods, I have a bunch of incomplete sets & I'll sell you however many you need.
 
Thanks for the offer, let me check with the local "Mr. Mopar" first (he has a Charger, Cuda, Road Runner, and Satellite). Shipping to Mexico right now is kind of a nightmare (three months USPS).
 
Just let me know, I have plenty to choose from & since they are incomplete sets, they will be cheeeeep.
 
I would really want to know why those bent if it was my car. The typical cause is a piston strike which generally leads to bent valves as well as bent push rods. If you have the rocker shaft off, are all of the valve stems sitting at the same height or are some shorter than others? If a valve is bent it won’t sit flat against the seat causing the stem to be a tad shorter. I suppose another possibility is a seized valve. You can rule that out by compressing them to see how freely they move. Please keep us posted. Even if it turns out that I’m completely full of beans I’d really like to know what you find.
 
I had a 65 Valiant years ago with a slant. When I got it, it had a dead cylinder. Pulled the valve cover and it had a bent pushrod. I stuck it on a vise and hammered it back out straight and drive the car for like a year before I put the 360 in it. It ran great.

Course yours is bent so bad I'd never try to do "that".
 
For all I now, it was still running like that! Number one and three spark plugs look bad, but those from the suspect cylinders (#5 & #6) look normal.

Spark Plugs.JPG
 
Stuck valve, tight guide. something preventing the valve from closing.
 
RustyRatRod said:
I had a 65 Valiant years ago with a slant. When I got it, it had a dead cylinder. Pulled the valve cover and it had a bent pushrod. I stuck it on a vise and hammered it back out straight and drive the car for like a year before I put the 360 in it. It ran great.

Course yours is bent so bad I'd never try to do "that".
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That’s even better than that story(ies) of the guy who drained the coolant (or oil) and drove it and still couldn’t kill one!
 
you can run a leak down test to check for valve damage
 
12many said:
That’s even better than that story(ies) of the guy who drained the coolant (or oil) and drove it and still couldn’t kill one!
Click to expand...

I ran my slant with no oil in it for an entire week and it never blew. This was back in high school days. Had another fresh slant ready to go in it. Man those engines are tough.

I would start by checking the valves. Could very well be a stuck valve, especially if it sat for a long time.
 
I checked all the pushrods, they are fine except for the two already found.

I brought out a big rubber hammer and bumped all of the valves, seemed all sixteen moved at tad at impact, each making a different tone sound when seating. I haven't done this before, so I hope my impressions are correct.

I brought out a 24 inch carpenters square, put a dab of toothpaste on each valve stem tip, and placed the flat of the square over all of the valve tips at once. Moved the square up and down over the valve tips, the paste was rubbed off some valves more than others, but all of them were close enough to hardly tell the difference.

Nothing way out of wack, so a slid a .015" and .020" under the space where the two bent pushrod valves were located (respectively), but could do the same on a couple of the other valves as well. Granted, the carpenters square is not as accurate as a straightedge. Going to town today to search for a couple of pushrods, hoping it will run OK after simply replacing the damaged parts.

I have yet to bolt down the rocker shafts, photo just shows one shaft/rockers sitting in place:

convertible valve train.JPG
 
now that is bent ! i've bent a few but never like that
 
I just measured the pushrods (overall) in this 1965 273 which are exactly 7.5" (191 mm) and .3149" (8 mm) in diameter. The chart I found on the internet doesn't show that combination, but shows the '65 pushrods as slightly shorter. Measuring end to end (ball to end of cup) they are definitely 7.5", not the shorter 7.344 in the chart. The diameter agrees pretty close to my measurements .3149" (me) and .312" (chart).

pushrod specs.png
 
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looking at your adjusting screws I believe they are too high / you might have hydraulic pushrods on mech lifters /
 
teringer said:
looking at your adjusting screws I believe they are too high / you might have hydraulic pushrods on mech lifters
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Except all hydraulic pushrods are listed as the smaller .28" diameter and I measure .313"-.315". Or the chart is wrong, would not be the first time.

And the rocker arms pictured (above and below) are not the rocker arms that were on the engine. I sent the original rocker arms to "Rocker Arms Unlimited" in Oregon. The rocker arms I have presently (in the photos) I picked up second-hand from a forum member or internet advertisement (forget where exactly). They are not adjusted, in fact, never have been bolted down (just sitting on top of the rocker stands for a photo shoot)

rocker arm hole 1.JPG
 
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Looking at a Clevite engine parts book, the 64-67 273 pushrod is listed as being 7.490 oal(which would put the effective length at about .156” shorter).

The 68/69 273 is listed as using the same part number pushrod as the 68-88 318(w/o roller lifter).
7.500” oal, ball/ball.
 
you have aftermarket pushrods made for a adjustable rocker arms to use with hydraulic lifters I have some of them left over from racing /the hydraulic lifter push rod looks the same only shorter also the 1970 340 ta exhaust push rod is also used on hyd. lifter. and is adjustable like the 273 just shorter
 
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