Pushrod V10

[Nathen Paisley]

SoI was getting the car ready for the upcoming autox/de season. Pulled the valvecovers because I wanted to remove the show-n-shiney covers for the stock ones. The pics show the rest of the story. Not sure why this happened or exactly what I should do to fix it. I've asked two friends that I know what they are doing (more than I do) around engine related stuff -- one says replace the bent pushrod, ,check remainder of valvetrain for similar problems, readjust valves, check compression and move on. The other says do a total teardown/replace bearings because there has to be metal everywhere.

As far as causes.... Hmmm.. Adjusted rocker arms without the lifter being fully extended? If that is the case, I would take the head off. Check the valves for that cylinder (I had one make slight contact with a piston and was bent BUT it still sealed). Check the top of the piston in that cylinder.

The second pic looks like that rocker was adjusted lower than the ones surrounding it. That will cause binding/bending. I would replace that pushrod with a new one, and adjust correctly (slowly tighten until you can't spin the pushrod, turn 90*).

That wouldn't be as much of an issue on the stock cam. There's plenty of room in the springs for the stockers to be tightened even a little over. But once you bump the lift up it gets really serious. I know when I put together the 88 TPI even with new springs matched to the cam, I bent several pushrods by over tightening them just a little too much. I bent mine turning it over by hand on the engine stand.

Possible causes - improper adjustment can do it. If you have too much preload with the plunger near the bottom, it could run well for years and then one time when it is hotter than normal it runs out of lash. A good intake backfire can do it. A spring/retainer package that is close to max lift can do it. Same as the lash/heat scenario above. If you have a spring/retainer combo that hits interference at .550" lift and your cam/rocker combo gives you .540" lift, high RPM/high heat, tight lash, and bent pushrod. I've also seen just poor pushrod craftsmanship and it just decided to fail. There is another story that I can't prove or disprove. Some old-school guys swear that its possible for a spec of something to get jammed in the orifice of the lifter in effect making it a solid lifter for a second. I don't buy it, but I guess it is technically possible.

Replace all pushrods with stronger ones, or replace that one only, doesn't matter. Recheck your lift clearance. Revisit your valvespring selection. If you have stock type retainers and springs, they are heavy. Asking a stock pushrod to control them is asking a lot. Is your seat pressure too high? Often times cam manufacturers (especially with rollers) spec spring rates that are too high. They want their cam to perform well and pushrods are your problem. I would then do a good flush with a few oil changes and filters, but don't worry about it.

Was that one rocker arm off the top of the valve when you opened it up? Looks to me like the pushrod guide plate has a notch worn in one side, that could have allowed the rocker to rotate to the side, which would let it pop off the pushrod, which could have bent the pushrod.

If the guide plate is worn replace it, along with the pushrod itself. Check the top of the valve stem to make sure it's not rounded off from the rocker sliding sideways, also check the face of the rocker for wear.

Curtis -- thanks -- will check springs. That is one thing I was accepting as not a problem. The ZZ409 does have more lift than the stock cam and the guy that did the heads is very good at what he does....still bears a peek "while I am in there"

You did bring up what is in the pan -- only thing I have ever found is a little metallic sludge stuck to the magnet in the drain plug. That sludge (if I can even call it that) isn't even enough to cover my pinkie fingernail and it's not gritty at all.....it's smooth. Oil always comes out honey colored in this motor. Granted I change it more often than needed (usually changing it every 6-12 months/ An overhead valve (OHV) engine, sometimes called a pushrod engine, is a piston engine whose valves are located in the cylinder head above the combustion chamber. This contrasts with flathead engines, where the valves were located below the combustion chamber in the engine block.

Although an overhead camshaft (OHC) engine also has overhead valves, the common usage of the term "overhead valve engine" is limited to engines where the camshaft is located in the engine block. In these traditional OHV engines, the motion of the camshaft is transferred using pushrods (hence the term "pushrod engine") and rocker arms to operate the valves at the top of the engine. However, some designs have the camshaft in the cylinder head but still sit below or alongside the valves (the Ford CVH and Opel CIH are good examples), so they can essentially be considered overhead valve designs.

The first internal combustion engines were based on steam engines and therefore used slide valves.[2] This was the case for the first Otto engine, which was first successfully run in 1876. As internal combustion engines began to develop separately to steam engines, poppet valves became increasingly common.

Beginning with the 1885 Daimler Reitwagen, several cars and motorcycles used inlet valve(s) located in the cylinder head, however these valves were vacuum-actuated ("atmospheric") rather than driven by a camshaft as with typical OHV engines. The exhaust valve(s) were driven by a camshaft, but were located in the engine block as with side-valve engines.

The 1894 Diesel prototype engine used overhead poppet valves actuated by a camshaft, pushrods and rocker arms,[3][4] therefore becoming the first OHV engines. In 1896, U.S. patent 563,140 was taken out by William F. Davis for an OHV engine with liquid coolant used to cool the cylinder head,[5][6] but no working model was built.

The first overhead camshaft (OHC) engine dates back to 1902, in the Marr;[13] however, use of this design was mostly limited to high-performance cars for many decades. OHC engines slowly became more common from the 1950s to the 1990s, and by the start of the 21st century, the majority of automotive engines (except for some North American V8 engines) used an OHC design.[14]

At the 1994 Indianapolis 500 motor race, Team Penske entered a car powered by the custom-built Mercedes-Benz 500I pushrod engine. Due to a loophole in the rules, the pushrod engine was allowed to use a larger displacement and higher boost pressure, significantly increasing its power output compared to the OHC engines used by other teams. Team Penske qualified in pole position and won the race by a large margin.

In the early 21st century, several pushrod V8 engines from General Motors and Chrysler used variable displacement to reduce fuel consumption and exhaust emissions. In 2008, the first production pushrod engine to use variable valve timing was introduced in the Dodge Viper (fourth generation).[15]

Shine a light through the openings in the head that the pushrods go through, you should see the ends of all 4 lifters. As you put the push rods in, just have a light handy so you can see where you are putting the end of the rod. Once they are in the right spot, it just "feels right". Hope that helps.

Edit: Just realized you are talking about in-car. Start from one side and "feel" with the end of the pushrod for the first lifter. It should slip into the recess end of the lifter, and then not slide around anymore inside. Then just work your way over.

They should stay in place while the rocker arms go in. When I have the rocker arm "body/cradle" thing in place, ready to be tightened down, I like to turn the little valve adjuster arms down so that the outside ends of the pushrods are supported and will line up in the end. I'm not adjusting the valve screws, just pushing the arms because they rotate freely on the cradle.

Okay I did this today and thanks for the advice. I found installing the rocker arms to be a complete PITA. The pushrods did not want to stay in the lifters and it just plain sucked. Would be a breeze with the engine on a workbench. the lift kit doesn't help, less room to work with and the holes in the frame for the long bolts don't line up. A good mirror on a long handle and a little bendy light made it possible, but not fun.

I would say even if the valves aren't stuck now. I would have the head run though and tell them the ones that have had a problem. They may have a clearance problem in the guides when they heat up. The balancer check the rubber between inter and outer sections for slippage, generally their would be large section missing. The sleeves get their hotest at the top of the bores and the damage would be on the outside of the sleeve. It's not easy but perhaps someone else has some good ideas.

With the engine running the oil will enter the cooling system from a leaking oil cooler because the oil pressure is greater than than the pressure in the cooling system. When the engine is shut off, the pressure is now greater in the cooling system than in the lube system so the coolant if forced through the leaking cooler in the opposite direction.

LIKE I SAID BEFORE U SHOULD PULL THE SLEEVES AND PICTONS. CHECK FOR ELECTROLIUS ON THE OUTSIDE OF THE SLEEVE. DOES IT HAVE A WATER FILTER ON IT? WHY SPEND ALL THE MONEY AND HAVE TO OPEN IT UP AGAIN. MIGHT AS WELL THROUGH IN A SET OF RINGS ALSO AT THAT TIME.

aar - I found 4 broken off pushrod cups laying under the valve cover. All were the same style you describe. So if I have 2 mushroomed pushrods, but I found 4 top cups...tells me this happened before. Just want to put her back together to prevent it from happening again.

yes i would say it happened before and that's why u have a mismatched set of push rods. If u look at the remaining cup style you'll probably find they are cracked just below the cup. I'd replace them with the newer cone style.

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