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Discussion Starter · #1 ·
I have this RV that i got for free. it has a 78 dodge 440 in it and when it runs it pulls that 12k sucker easily. But since I got it started it kept bending pushrods. Supposedly it had been sitting for X amount of years and that the valvles are gummed up and that is the reason for the bent pushrods. Everytime I replace a rod it drives perfect for about 1-3hrs and then clack,clack,clack a pushrod bends. Eventually Im going to knuckle down and take the heads off and have them only cleaned with a small valve job, but is there any suggestion for this motor so i can drive it without having to carry a set of pushrods with me. Thanks for the advice, and I came here first cuz yall practically helped build my torino and figured yall could do the same with the RV
 

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Befor it bends the next ones pull the valve covers and roll it throu a cycle by hand and mesaure the lifts and see if one of the lifters is stuck full of gunk.. and maybe tape the valves as well with a hammer and see if there sticking (you might have to pull the rockers first..) are they Adjustable???? It might be worth the time to pull the intake and pull and clean the lifters and see whats in the valley. Mitht be able to see if things are getting oil....
tim
 

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Sounds like the valve springs are binding. Take the cover off, and crank by hand and check the clearence between the spring coils when that spring is being compressed. Can be caused by too many shims under the spring, or just the wrong springs for the cam.
 

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Probably has 906 heads on it.....may have 452s....not that it makes any difference. But I'd suspect varnish buildup on the valve stem. Is it an intake or exhaust valve pushrod that is bending? I'll bet it's an intake valve or two. My advice....go find a Yamaha dealer that sells ATVs, motorcycles or waverunners...and ask them for a couple bottles of "ring free". That stuff works wonders! It takes the carbon right off of intake valve stems, chambers, piston tops, etc. Its not cheap but it's quite possible that it can fix the problem permanently. I don't know how many gallons the tank holds, but with a full tank, I'd dump about 4 bottles of ring free in there....run it, even idling in the driveway will do it...then change the oil. All that carbon usually ends up in the oil.
 

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I had a lot of old engines doing exactly the same thing.You have to take watcha get,when it comes to american V8s over here..
In my case it was always sludge in the lifters.If you dont want to open it up add 1quart of ATF or synthteic motor oil,let it run hot and change oil+filter.If that wont work,i'd say time for new lifters.
Olli
 

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Discussion Starter · #8 ·
Im going to try that ring free, I have taken the intake off and everything looked more or less in order. I will try and crank it over and see if anything is binding. Finally the cam and springs are original so it shouldnt be mix matched springs. I also put new lifters in it without a new cam but i broke them in like i was supposed to. thanks for the help guys

<font size=-1>[ This Message was edited by: torinoracer on 11/4/06 10:53am ]</font>
 

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I just spray wd-40 in the intake ports while working the valves up and down, works great.
 

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I'd change the oil. And on the refill I'd make it, 5 qts, 3 qts motor oil and 2 qts ATF. Run it around. It will loosen up what ever is gummed up.

I'd also check for a broken valve spring...just in case.
 

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Your problem is due to old gas residue in thed fuel tank(s). When gasoline evaporates as a vehicle sits over the years, what is left in the tank is a nasty goo. When you come along and add fresh gas and fire the old girl up, the new gas dissolves this old crud which mixes in with the new and ends up in the combustion chambers. But it doesn't burn and deposits itself on the exhaust valve stems to the point that it causes the valve to seize. You will keep having the problem until you get the fuel tank flushed out. While you have the intake off, remove the rocker arms, use air pressure to hold up the valves and take off the springs (do one valve at a time). Release the air pressure while holding onto the valve and work the valve up and down while spraying with a good carb cleaner. Add a few drops of oil on the stem and reassemble. Then use the "Ring Free".
 

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Torinoracer....

Does it bend WHILE driving or only after a startup?

Gummed engines will only bend the pushrod after sticking the valve closed, which means that you have to get the car warm so the varnish will heat up and run down the valve to the seat.
When shut off the seat and valve cools and the varnish/old fuel build up GLUES the valve closed, then next tiem you crank it up the push rod bends.
WHILE running the valves will NOT stick closed.

If this happened while it was running you may have debris in that hole like maybe a broken piece of spark plug or some other foreign object..

FE
 

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Discussion Starter · #13 ·
good question, come to think of it, it does to tick right after it we turn it off and then restart it. although after a while the truck will start to run bad and we turn it off and clack clack clack. I think im just going to take the heads off and have them redone.
 

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Do that and be secure with it but do this as well for a better piece of mind.

EMPTY THE FUEL TANK.... That old fuel is causing the sticking valves!

Get it empty then fill it up with new fuel and toss in a can of sea-foam and that will prevent any future sticking.


FE
 

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Lots of good suggestions. But to argue with one post, it is usually the intake valves that stick...if there is old fuel involved. Seen this thousands of times over the years with small engines. Most notably the Kawasaki FD620D 20 HP liquid cooled V-twin. They use that engine on many utility vehicles. In the fall, farmers & ranchers tend around here tend to fill their 500 gal tanks with fuel for the coming season. In early spring, they will bring their equipment to us with no compression....the gas sitting in those tanks gets old/stale and they will pump it into their utility vehicles....that gas gets on the back of the valve stems and gums up, causes the valve to get STUCK in the guide, hung open, pushrods bend....etc. Its always the intake valve, not the exhaust. Sometimes they'll run on one hole, in that case I'll put fresh fuel in, pour in a bottle of ring free and let it run. As SOON as the stuff hits the carburetor you can tell....it starts running MUCH better (even on that one hole)....let it idle for a few minutes, shut it off....put a pushrod in the other hole that wasn't running and it will eventually run fine.

also had a Yamaha 1700 Road Warrior (neat bike!) in the shop the other day...guy complaining of missing under cruise and a "lopey" idle (they lope anyway...but this one was worse). I poured in a bottle of the stuff and again, as soon as it hit the carb, it started running great. Odors out of the pipes STUNK but the stuff works wonders!

For $6 a bottle, its worth a try. Even then, the 440 is a very easy engine to pull the heads....drain the water, pull the intake off...then the heads. Leave the distributor in the block. Interestingly enough, the motor homes usually have the best iron heads available for the RB engines...aside from the HEMI heads and six-pack heads. They're pretty good engines and quite easily modified to make serious power.
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"it is better to appear ignorant than to open your mouth and remove all doubt"--Mark Twain

<font size=-1>[ This Message was edited by: mavman on 11/7/06 3:24am ]</font>
 

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Get a set of fresh new lifters while you have all this off.

Did it with my '63 Marauder and it was like night and day. The old ones were so broken down and collapsed, I wasn't getting half of a tiny cam. New ones and a fresh tune = 100 ft of rubber in a 4200 lb one legger 2.80 axle car!

Sounds like you might have a stuck check ball in one or two of them, they're cheap. You can do it when the heads are off.

Doing the heads is good anyway, cleaning carefully, fresh valvesprings (check for bind) fresh seals, maybe even take a few thou off the deck for good seal. A good valve job and good new springs will really put the snap back in it for you.

Mark Donahue found back in the '60s the best way to win races was to break the race engine in for several hours to let all the running parts get friendly with each other, then put new heads on -- he saw a repeatable 30-40 hp on a 450+ hp 302 V8.

If you ever get a chance, look for the high speed video of a typical valvetrain and watch the close up of the valves bouncing like super balls even under normal operation and the rockers flexing all the time. Can't believe the thing even runs!
 
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