VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Bent Push Rods

I drove a 216 1951 engined car over 160 miles last Friday. Saturday morning it would not start. After checking all the obvious I discovered three bent push rods on #1, 3 and 5 cylinders. I have not had time to remove the head to check valve stem sticking but intend to do so. Lifters are free and look ok. A manual rotation of the engine did not indicate any timing gear failure.
Is there any other area that needs looking at?
Broke down now---

LooseRocker, hello.

I have a dozen questions about your situation, but to just check if valves are sticking in guides, what I do on old tractors and cars is to remove the rocker arm assy, make sure piston on offending clinder is not at TDC, then rap valve with hammer to duplicate movement of valve action and see if valve goes down easily and returns immediately. It doesn't take a great big hit to move the valve.

Was the eng just overhauled? When was the last time eng was run before you took your trip? Was it running poorly on trip? Could use more details for a better answer, especially from the experts on this site, as I certainly am no guru.
More qualified people will be able to help you in your situation.

Best of luck with solving your problem.

Jim.

I will bet all were intake valve push rods. Common and usually caused by a formation of a stickey carbon like formation on the lower portion of the valve stem. Old gas can form a varnish in this area. For starters lubricate the valve stems with a thin solvent like Marvel Mystery Oil. going between the coils of the valve springs. Then with the engine running at a fast idle pour the MMO through the carburetor throat.

Other posibility. Auto machine shops today often fit the valves too tight in the guides and when they get good and hot the valves hang up in the guides.

Other posibility. Auto machine shops today often fit the valves too tight in the guides and when they get good and hot the valves hang up in the guides. [/quote]

One of our machine shops is over 50% on sticking several valves on his rebuilt heads for 216 and 235 engines. He asked why (He reams the new valve guides as shown for the current era heads.) This happens after a normal break in period and a good drive. I wouldn't replace the valves or valve guides just grind the valves. (lapping compound like we did back in the 50s). machine shops here want to replace all valves, new hard seats and guides, springs and seals. It is a snap with their new machinery, once they get set up for the straight six OVH engines. I had to do a complete overhaul job to an extra head found in a junk pile, most of the valve stems are rusted almost away on some of them. The rockers and shafts were ok after I PB Blasted them and worked the rockers around the shaft and loosened them up, a carbon like residue was everywhere.

Engine history not fully known. No work for last eight years and several thousand tour miles. Always ran well. Used locally several times in past month ok. Was hard stating brfore trip but seemed fine once warmed up. Ran at Interstate speeds with several stops and restarts. Yes, the bent rods are #1, 3, and 5 intake. Plugs were all clear with no fouling or differences one to another. My plan is to remove the head and inspect all parts, clean the guides especially, checking size. I have seen web sites that say that sticky valves are more likely with modern ethanol containing fuel which ages more quickly. I must say that I started the trip with about 1/4 tank of old fuel.
My major reason for the post was to ask if I am missing something.

As Gene suggested the problem is most likely oxidation products (gum and varnish) from the modern fuels. Ethanol gets the blame and it does contribute to the process but it is the unsaturates in the hydrocarbon fuel blend (gasoline) that combine to form the gunk that sticks the valves. A secondary lubricant added to the fuel (a glug or two of MMO or ATF to each fillup) will help to keep the gunk from sticking the valves. ATF is less expensive so that I what I use when I remember to add it.

While I am writing, if the valves that stick are the exhausts it is most often due to rust accumulation from lack of running and water getting between the parts. Good penetrating oil followed by ATF or MMO and then running the engine frequently will prevent the exhaust valves from sticking.

When disassembled I found 4 bent push rods and two questionable. All intake valves were solidly stuck and required brute force to remove. The valves and seats did not need grinding but a good cleaning and I started on reassembly. It fought me all the way since I was by myself and since I could not lift out the head I used an engine lift and in reassenbly got hung up on a 1/4-20 screw in the middle of the firewall. However all should be compete tomorrow. The moral here is watch out for old gas. I think the long run just melted the tar so that everything froze after an overnight cool down.

Chipper,

My '54 will also get a glug or two of ATF with each fill up from here on.

Engine started and ran fine. Final tuneup delayed for a week. When tried to start had a tap like a "loose rocker". One was visually too wide. When the 5/8ths wrench was applied to the lock nut the rocker arm broke. This was #5 intake. This saga is continuing.

The arm may have already been cracked from the first episode.

When I overhauled my 49 Chevy 4400, I had no help either. Putting the head back on the engine with the engine in the engine compartment is difficult when doing it without help. I also used my engine hoist to maneuver the head under the hood - it was too heavy for me to maneuver alone. Until the new rings seated so the compression tests were all 110-120 psi, I worried about whether or not the head gasket was leaking. It had all the signs... overheating (eventually due to gunk in the radiator), low compression (which eventually went away after a couple hundred miles)...

Lee

I did the same thing with old gas, and bent pushrods, lesson learned!

Continuing the saga: I replaced the broken rocker and begorra the valve was stuck again. Probably I was not thorough enough in my cleaning. However when I removed the side pan I noticed coolant weepage at the block to head seam. I am sure I tightened and torqued the head bolts to spec. I borrowed a newer torque wrench and checked all bolts before disassembling. They were tight. I then noted that a prior mechanic had machined the head leaving coarse tooling marks. I believe this, together with the FS copper head gasket, would not seal. Head is even now being ground. I'm getting too old for this!!!

Some of us that also run overhead valved Kawasaki Mules, John Deere Gators and various other OHV gas engines have discovered that a proper mix of Seafoam gasoline additive, in addition of the Marvel Mystery Oil manual treatment, will help correct the buildup of crappy varnish on the intake valve stems and guides sticking the valves. I have freed sticky valves by pulling the rocker shafts and without removing the head. be careful that you don't unstick a valve (springs and keepers removed) and drop it into a cylinder that the piston is at the bottom of the stroke.

Your copper head gasket is probably not the problem with the seepage. The rough surface could be the cause and if you didn't use any Copper Kote that could also contribute to the seeping problem.

The saga continues! Head ground, reinstalled with new copper koted copper gasket. All head bolts seated with only finger pressure then torqued with good borrowed wrench in 4 increments to 80 ft lbs. Lifters removed and cleaned and found two with small pencil eraser sized chips. Replaced with other used lifters. Then discovered that a rocker shaft had been bent in the prior assembly. The parts engine again donated. Assembly complete before thanksgiving dinner. Primed carb and she fired right up but would not run except on primer gas into carb. Thought tank was empty and put $10 worth in. Still no run. Have now identified the problem as a fuel pump failure. What is next? Oh yes, I bought a magnetic oil pan plug and can not use it since the one in the pan turns out to be oversized.

Or is the fuel line plugged up?

Trust me, I checked all fuel lines, carb float valve and removed and reinstalled pump before reaching conclusion. TODAY, Friday installed NAPA replacement pump, started checked timing adjusted all valves and drove about 10 miles. Tomorrow morning I'll start her again and determine if I have won!