Bent Push Rods

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mhuppertz

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So, my Dart had sat since 1989, I changed the fluids, added antifreeze, etc. Got it started yesterday, first time in 23 years. She had a miss but otherwise ran well enough for me to turn it around in the driveway. Probably ran her a total of 30 minutes or so, engine was quiet.
Then today i go to start it and she sounded like she chucked a rod! Wouldn't even start. Pulled the valve covers and found two bent pushrods. Pulled the intake and replaced the two. Turned the engine over again (no plugs installed) and it bent one of the pushrods I just put in.
What is the most likely cause? I'm thinking the lifters are pumpung up and freezing.
Thoughts?
-Mark
 
If the lifters are pumping up that hard, mark "bent valves" on your s**t list.

I'm betting the valves are seized in the guides. Only your compression and leakdown testers (it's a conspiracy operation) will know for sure.
 
OOOOHHHHH bad,....Sadness,...It don't start you say,....check your timing,...you may have disintergated the plastic around the Cam timing gear, thereby causing the timing to jump,....therby bending important things,...I hopin Its your lifters like you say
 
jos51700 said:
If the lifters are pumping up that hard, mark "bent valves" on your s**t list.
I'm betting the valves are seized in the guides. Only your compression and leakdown testers (it's a conspiracy operation) will know for sure.
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Crap!
 
I will check it out when it warms up again. Threatening to snow!

If the valves are indeed bent I'm setting the 273 aside for a future restoration and looking for a '71-'76 360....

So much darkness......
 
jaimus said:
OOOOHHHHH bad,....Sadness,...It don't start you say,....check your timing,...you may have disintergated the plastic around the Cam timing gear, thereby causing the timing to jump,....therby bending important things,...I hopin Its your lifters like you say
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Did 69's have nylon timing gears? I feel sick....
 
Let the fun begin,...Good luck Grasshopper,....

...and this is how It all starts,....BWAHAHAHAHAHAHAHA...
 
jaimus said:
Let the fun begin,...Good luck Grasshopper,....
...and this is how It all starts,....BWAHAHAHAHAHAHAHA...
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I am actually just gettign back in it after a 20 year break to raise a family. Before that I had a '68 Hemi Road Runner and a '74 Cuda 360 (I put a 383 in it because the 360 was long gone). I have probably had 40 different Mopars in my like so far!

I would love to have a Hemi Dart, but for now I will stick with the small block combo and add turbos.
 
I had the same problem with my slant 6 that had sat for several years. Unleaded gas goes bad, and ruins things. After a summer of trying to figure out what was causing my push rods to keep bending, I finally pulled out the engine. The machine shop said that the valve stem seals had dissolved, and were barely allowing the valves to move.
 
Not an expert here, but cant you take a rubber mallet to the valve springs, to see if the valves are free?? Pull the lifters and maybe give them a good cleaning??
 
4spdragtop said:
Not an expert here, but cant you take a rubber mallet to the valve springs, to see if the valves are free?? Pull the lifters and maybe give them a good cleaning??
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Good idea,...give you a chance to eyeball the cam as well...
 
If you go smacking valves with a mallet, make sure that cylinder is nowhere near TDC.
 
You don't have to smack em with a mallet, You can just apply enough pressure to the valve stem to overcome the spring tension just to see if the move. Also you can just remove the valve covers and turn it over while watching. Just a visual inspection can tell you alot. I would start with the easy checks first. To assume that it jumped timing right away without checking everything else could cause you to do alot of uneeded work. Good luck on getting it fixed.
 
That works,...start simple, pull the plugs and the cap and try to give it a few spins by hand,...see where things line up.
 
I have seen this before from sitting the valve sticks in the guide and bends the pushrod. It looks like you are in for pulling the heads and getting valve work done.
 
I think I will spray PB Blaster down the guides and let them sit a while, then carefully try to work them loose. If I go smacking the valves with a mallet I might dislodge the keepers and the valve could drop. Don't want to pull the ehads unless I have to. If I can get the valve to loosen up I will go get some new umbrella seals and fix that issue.
It froze here last night and it just too cold to go out there and work on her right now! Gotta get my son's Subaru engine back together so I cna put MY car in the garage....
 
spray them and let the PB sit, but if you are worried about the mallet knocking the keepers loose, then you have more issues. I have always given them a tap with a mallet and never had any issues both small and big block.
 
no way the lifters are pumping. they only allow oil to take up the lash, there is no pumping on start up. Im with seized valves and PB blaster/liqued wrench and sitting then tapping with brass mallet. Seals dissolving and holding valve open? That is a bionic seal! Pull plugs and rotate crank with wrench, or on a six with no damper bolt, you can usually turn that bad boy by hand off the crank pulley. jumped chain will hit and stop with no damage if youare doing it by hand. I guarantee that 273 has no valve seals left if sitting for 23 years. If you pull the rocker gear and put a straight edge across all the valve tips, youll see a bent valve as a very low one.
 
I will check that. Just made a deal to trade my "Super Six" leaning tower of power with headers and tranny for a running 360 with a 727. I may still get the 273 running just because I can't stand not to... I'm a junkie.
 
So, I sprayed PB Blaster around the valve stems and then tapped on the valve stems with a mallot. Several of the valves drove down like a nail in wood and just stuck there. Hoping the PB Blaster will do its magic this week so i can take another crack at it over the weekend.
 
mhuppertz said:
Did 69's have nylon timing gears? I feel sick....
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YES

chain.jpg
 
mhuppertz said:
THat's just wrong. I thought only Brand X (GM) used nylon timing gears.....
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Hell I pretty sure My 90 Dakota w/3.9 used the same nylon gears,...I replaced em with a double roller set-up about 180 thousand miles ago,....
 
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