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Bent pushrods and a 5 cylinder journey?
https://slantsix.org/forum/viewtopic.php?t=29491		 Page 1 of 2
Author:  60 Plymouth [ Fri Jun 13, 2008 8:46 am ]
Post subject:  Bent pushrods and a 5 cylinder journey?
Hi Guys,

Bad day today, a loud clanging noise meant a very slow crawl the last few miles to my destination. I pulled the valve cover and I have a bent pushrod (Number three cylinder). I'm guessing it must be a stuck valve. I'd like to try and free it up but I will be a few weeks away from a replacement pushrod (Slant 6 parts aren't dotted around dealers in the UK like they are in the US).

Trouble is, most of my tools/mauals etc are 40 miles away.
I was wondering, would I do ANY damage if I was to remove the pushrods from #3 (ok, that's been done already) and remove the spark plug and carefully bring her back on 5 cylinders? I refuse to do anything like that without you guys offering some advice. My gut instinct tells me a whopping great big NOOOOOOOOO, get a bloody tow!!!!! So unless I get some positive "that's ok" info then a tow it will be.

Lastly, are there any simple checks I can do to try and see what caused my bent pushrod? I am concerned that there may have been a valve/piston collision (my pushrod is REALLY bent, has gouges in it also from colliding). The rockers look beautifully lubricated, and the engine sounds fine with #3 out of action (well, apart from the obvious cylinder down).

If it makes a difference, my cyclinder head has been treated to run on unleaded. Not entirely sure how (previous owner's modification), presumably hardened/deep chromed seats and alternative valves.

Any advice or other well known threads that I may have missed regarding this would be greatly appreciated.

Thanks alot,
60Ply
Author:  Joshie225 [ Fri Jun 13, 2008 9:02 am ]
Post subject: 
You can pull the pushrods from that cylinder, but leave the spark plug in place. You can drive a long way like this. The biggest danger/trouble I see is if those two lifters pop out you may not be able to tell which hole they came from. Not having pressure fed lifters is a blessing here as you won't loose oil pressure with a lifter out like the V8s. Chances are good that the lifters will stay where they belong.

It's really tough to get valves to hit pistons on a stock 225 as there is a relatively huge clearance there.

I had a 225 with a bent pushrod that I strongly believe was due to engine overspeed. 4-speed car and ham fisted driver. I put in a straight pushrod and it was fine. Also had a 170 with a few bent pushrods due to old fuel gumming up the intake valves. If you thing 5 cylinders is slow try three!

Did you bend an intake or exhaust pushrod? We had a fellow on here not long ago that was sticking one exhaust valve when he'd pull hills in low gear. Turns out the stainless exhaust valves didn't have enough clearance in the guides and that one valve would expand and stick when hot. He also had positive valve stems seals which limit lubrication.
Author:  60 Plymouth [ Fri Jun 13, 2008 9:40 am ]
Post subject: 
Hey Joshie,

Thanks for the reply. I may remove the lifters and label them if that is likely to be a problem. It is the inlet rod that's bunched, but the exhaust was knocked out of position somehow. It doesn't look bent but it was out of the rocker (still in the lifter). Hope that doesn't mean anything too drastic?
I have just been outside for another fiddle. Lack of tools means a few 'innovative' tests. I used a few pieces of steel and a claw hammer to help easy up the rocker arms. Both valves seem to depress fine from what I can tell. I think a compression check may be in order, just for peace of mind that her valves are ok.

Also, just incase by some miracle I can get some pushrods this weekend, what should the valve lash be? Again, manuals and anything useful are out of range . . .

Thanks alot,
60Ply
Author:  Backtobasics [ Fri Jun 13, 2008 10:25 am ]
Post subject: 
I would be leary for a couple reasons.

--Vibrations from a non function cylinder, and whatever potential damage might come from this.

--More importantly, fuel washdown. Unless the intake valve is stuck closed (allowing no air / fuel entry or exit) through cylinder into exhaust) , there is potential of engine drawing in air fuel mixture, and washing down cylinders, potentially damaging rings and block.

This is my input based on my basic knowledge. Some of the PRO people here might be able to give better input or blow my theories out of the water. I would tow it.
Author:  Joshie225 [ Fri Jun 13, 2008 10:33 am ]
Post subject: 
The car hasn't been in storage a long time and then recently put back into service has it? Old fuel can completely gum up the valves and guides causing it to stick hard enough to bend the pushrod. It's usually a problem on the inlet valves. This happened on my '64 Valiant. The previous owner thought he was helping the car out by starting it every few months, but it just gummed everything up with stale fuel and varnish. After putting in fresh fuel and getting it hot and well oiled it was fine. Just needed the 3 intake pushrods. Later I put in new valve stem seals as most of the old ones were MIA.

If I were stuck in a similar position I'd pull the pushrods and lifters and drive it home. It won't run as smooth of course, but it won't hurt anything. You won't pull any fuel into the cylinder as it's that cylinder will be nearly sealed and will just compress and expand the same gases over and over.
Author:  SlantSixDan [ Fri Jun 13, 2008 10:45 am ]
Post subject:  Re: Bent pushrods and a 5 cylinder journey?
Quote:
I have a bent pushrod (Number three cylinder). I'm guessing it must be a stuck valve
Quite possible. Some of the '60 (first year) engines had insufficient oiling to the top end, but this usually manifested as bent pushrods at the rear (#5 or #6), not in the middle. So if your engine was sitting for a long time, then yes, a stuck valve is a likely culprit.
Quote:
I'd like to try and free it up
See the procedure I gave another '60 owner with similar problem here .
Quote:
I was wondering, would I do ANY damage if I was to remove the pushrods from #3 (ok, that's been done already) and remove the spark plug and carefully bring her back on 5 cylinders?
Remove the pushrods, but leave the spark plug in place. You'll be running on 5 cylinders, but you won't be doing any damage.
Quote:
Lastly, are there any simple checks I can do to try and see what caused my bent pushrod?
Sure...with the pushrods removed, look at the spring height. If it's not quite as tall as the other valves that aren't lifted off their seats, and/or if when you give a good, healthy rap atop the #3 valves with a hammer they don't immediately spring all the way back, you've got (a) stuck valve(s).
Quote:
I am concerned that there may have been a valve/piston collision
Don't worry, there hasn't been.
Quote:
What should the valve lash be?
See the valve adjustment procedure.
Author:  SlantSixDan [ Fri Jun 13, 2008 10:47 am ]
Post subject: 
Quote:
Vibrations from a non function cylinder, and whatever potential damage might come from this.
There'll be no problematic vibration of this sort.
Quote:
More importantly, fuel washdown
...won't happen to any significant degree.
Author:  60 Plymouth [ Fri Jun 13, 2008 11:01 am ]
Post subject: 
Hi Guys,

Thanks for the help! The valve springs look good, I already laid a straight edge over the top and they seem fine. They can also be moved by carefully prying under the rocker, and they depress neatly.
Dan, the car hasn't been sat, I have run her once a week at the very least since she was brought back after the winter. I did notice a strange bogging when pulling earlier on during the week, however, I put that down to pitted points, though maybe it is possible that a valve was sticking slightly. Points need replacing anyhow, but maybe they weren't the problem.
It is good to know that a Slant 5 will get her home ok though. I was a little concerned that she may vibrate in a slightly worrying fashion.

Does anyone know where I can obtain suitable push rods? RockAuto were a favourite of mine but for the past 6 months or so they have done somthing to their shipping prices, and even a grommet seems to cost $35 to ship to the UK now :roll: .

Once again, thanks for all your help!
60Ply
Author:  SlantSixDan [ Fri Jun 13, 2008 1:10 pm ]
Post subject: 
Back to this thread; ring Bob Hodgson and see if he's got any smart ideas (or pushrods).
Author:  Backtobasics [ Sat Jun 14, 2008 9:26 am ]
Post subject: 
Quote:
Quote:
More importantly, fuel washdown
...won't happen to any significant degree.
You are the expert, but I fail to see how the still existing pumping action of the piston is not going to draw in the intake charge if the intake valve is open. If it is the intake, and he pulls the pushrod to both valves this leaves the exhaust valve closed, held closed by the spring pressure. I would expect that on each down stroke, the piston is going to draw in air fuel mixure, and on the way up it is going to press it back into the intake manifold. All this time, the plug is not firing, so there is consistantly air and fuel rushing in and out of the cylinder. I see a helluva clean intake valve, and intake tract, but cylinder walls that are constantly being hit with atomized (as best atomized /6 gets) fuel, that is not being ignited.

Instead of Suck Squeeze Bang Blow, it becomes Suck Blow Suck Blow... :lol:
Author:  SlantSixDan [ Sat Jun 14, 2008 10:00 am ]
Post subject: 
The slant-6 is not a delicate hothouse flower that wilts if you sneeze at it. Slant-6 engines have survived extended operation with considerably worse problems than an inactive cylinder without suffering. And from the OP's description, it sounds like the intake valve is closed, not open.
Author:  Backtobasics [ Sat Jun 14, 2008 11:31 am ]
Post subject: 
I agree on the the strength and durability of these legendary engines.

Hopefully he gets it fixed
Author:  Bren67Cuda904 [ Sat Jun 14, 2008 12:12 pm ]
Post subject: 
And to add... the spark plug is still firing. So if by so chance a little fuel gets it it will burn.
Author:  67DartGT [ Sat Jun 14, 2008 6:50 pm ]
Post subject: 
I had a 225 blow the rings and spin the rod bearing on #6 cylinder. All I did was unplug the spark plug from the distributor and it ran for over 3 months while I got the money and parts together to build a replacement. I have to agree, these engines are not delicate. Other then a loss of power from running on 5 cylinders, the only other thing I noticed was it sounded like a Subaru (horizontally opposed engine) taking off from a stop... which led to people trying to race me in a crippled A Body.
Author:  60 Plymouth [ Sun Jun 15, 2008 5:54 am ]
Post subject: 
Hi Everyone,

Well removing the rods let me get the car back home safely. Sounds like a dog at low speeds and pulling away but once we reached highway speeds she seemed to run fine, just the rhythmic sound of a cylinder not firing. Incidentally, when I pulled the cover again, she had knocked the exhaust lifter out and the intake lifter was half out, so if anyone else ends up doing this it might not be a bad idea to remove and label them, just so you know where to put them.

I am still scouting around for pushrods, few people have replied to emails over the weekend. There was a set on eBay that somone beat me to before I got a reply about international shipping. Will have to wait till tomorrow and do some phoning around the UK. I'm anxious to get her engine running nicely again, after all, she's the only car big enough to start hauling sheet steel to do her bodywork.

Once again, thanks for all your help,
60Ply
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