I wouldn't worry about guideplates and fancy stuff if you stay under reasonable rpms and low lift cams, not needed.....
If non stock 1.6 rockers rubbing against the head are the problem, slightly elongating the hole through the head in the direction of the rocker stud with a die grinder to reduce the chance of the pushrods not completely seating in the rocker and the lifter would be the cure (I wouldn't do it without taking the heads off the motor). The more simple solution is using the correct 1.5 ratio rockers. I'm still guessing you wiped a cam lobe, though.
I had this problem with a 327 and Crane cam. Lost a cam lobe thanks to the new formulated oils. www.zddplus.com are Aliance vendors here and have a good product for our older engines to help prevent valve train problems.
Pulled the intake manifold tonight. The insides of the lifter at the end of the broken push rod were laying in the lifter valley. I pulled the lifter out of its bore expecting to find more destruction. But, the lifter still looks brand new. There are no nasty gouges or hot spots on the lifter at all. So, it seems as though the cam may be alright. Also found a welcome surprise in all this. The heads have a really nice port and polish job on them. Kinda strange to spend extra money, port and polishing the heads but skimp on checking out the geometry of everything. After comparing the push rods and rockers with factory stuff, the push rods are stock length and the rockers 1.6 ratio long slots. Tomorrow night I'll pull the heads and see what I've got on the valve end. A bit short on cash right now, but will take the heads in to a machine shop to have some screw in studs installed. I'll take the advice someone said earlier about using the later model self-aligning 1.5 ratio rockers instead of using guide plates. I'll also replace the push rods, lifters and valve springs. Is there a way to figure out cam lift without getting a grind or part # off the end of the cam? Thanks again guys!
Nope... This motor is in a 57 Chev. I need to update my profile and avatar... Although I do still have the Plymouth, which is for sale now...
Lift can be checked at the pushrod pocket of the rocker arm with dial indicator mounted to a magnetic stand anchored to the head. By using a degree wheel and rotating the engine with breaker bar while checking the intake and exhaust valves on one cylinder you can, not only check lift, but actually map out the lift, profiles, and overlap of any cam. Go even further and verify top dead center of the number one cylinder by any one of several methods (remarking the harmonic damper for accuracy if necessary), and you can advance, retard, or at least make sure your cam is installed to the cam makers specification. With all the **** that appears to have been floating around in your motor, for piece of mind, this sounds like the time to drop the pan and clean it and the pump pickup out.
Using the above method to check lift gives you a number for net lift at the cam, don't forget to multiply by the rocker ratio of the rockers you're using to get a number for lift at the valve. Taking the extra time to measure the actual lift at the valve by jigging up and measuring at the valve retainer of each valve in addition to checking for net lift at the cam will allow you to find out the actual ratio of any individual rocker (usually found to vary considerably with stamped steel rockers, especially stock ones).
I know I could figure out the cam specs with a degree wheel. I was hoping for something more simple... The cam is not radical by any means. You can hear the cam a little bit when idling, but that's about it. I think the previous owner put the 1.6 rockers on and didn't know to watch for the push rods rubbing against the heads. Maybe the lifter was faulty? The lifter is not damaged at all. It just looks like the retainer clip popped out of its groove and the lifter came apart. I don't think any parts fell into the pan. I will of course drain the oil and filter before I get the top end back together again. I drove the car @ 200 + miles home Sunday night after I found the broken push rod. After I removed the rocker arm and broken push rod, I took the plug wire off that cylinder and drove home on 7... And really it ran fine, 65 - 70 lbs oil pressure on the freeway and no other detrimental noises from the engine.
I'd personally pull the heads and make sure the valves aren't beating the pistons to death. If the valve isn't opening all the way the pistons are hitting them, that force will propagate all the way to the lifters via everything else. Could explain a lot of things since there are so many issues. Probably somebody just dumping in a bunch of stuff without blueprinting/checking clearances.
I understand the pushrod holes are bigger on the late heads and if you use the late self aligning rocker on an early head the pushrod will gall out where it p***es thru the head. Never tried it, this is just what I've heard. The reason a guideplate works on the early heads is you can adjust them til the pushrod doesn't rub, and the rocker tracks true. With the self aligning rocker you have no adjustment and the rocker fights the pushrod hole in the head. good luck
You said the cam does not sound too racical, it can't have large lift enough to cause all these problems believe me you'd know. Are you positive they are 1.6 rockers? Are you positive The pushrods are stock length? If both answers are yes problem solved Getting alot of responses here that may be throwing you off track come on guys this is a street motor. This is not a major melt down here just a matter of the wrong push rods for the rockers. Replace broken lifter or lifters, replace gouged studs, figure what length push rod you need to correct geometry ( probably around .100 over ) & replace pushrods, re use rockers if they are not beat to death, change oil Problem solved. If you replace the rockers with 1.5's you are going to loose a little lift and performance.
doesn't really matter if it's a street motor or not. You have no idea what the last guy that built it knew or didn't know when he was building it. You can ***ume that the last person knew what they were doing..... but we all know how those ***umptions usually end up. I would not bank on the wrong length pushrods. Most rookie engine builders tend to error on the safe side with items such as that, opting for stock size cause they don't want to go through the h***le of checking geometry. If you ***ume what you should... that whoever rebuilt the motor had no clue what they were doing... which is usually the case. Then I would look at the normal "get speed quick" items. ie. rockers w/ wrong ratio, a cam with too much lift, the wrong valve springs (might be over-stressing lifter/cam), those types of things. Obviously, the head/rocker combination should be investigated as well.
I set a rocker from my motor against a stock sbc rocker I have in my garage. The push rod cup definitely sits closer to the rocker stud; 1.6 rockers I'm sure. I also set a push rod next to a known stock length push rod from a sbc. They are exactly the same length. I'll know more when I pull the heads. I think that if the valves are hitting the pistons, I would've known during the 200 + mile trip on 7 cylinders back home.
let us know what you find. You'd be surprised at how long an engine can run with the valves hitting the pistons and not know it. I've seen it before. Hopefully it isn't that. Hopefully it's just a binding issue with the geometry. Otherwise, it's gonna be big bucks in pistons and new valves. We'll cross our fingers. In the meantime, you might do some suggested reading.... you know what they say, knowledge is power... http://www.lunatipower.com/Tech/Valvetrain/HowToVerifyValvetrainGeometry.aspx
Too bad the head is damaged, otherwise you could fix the stud, put the lifter back together, use stock rockers, and be on the road. The worn alignment holes are the problem. In the past guide plates were the cure, but maybe the self aligning rockers are the answer. Enlarge the guide holes. Personally, I'd only fix what is broken, but it's no secret that everything needs looked over really close.
Thanks for the link! Checking it out now... Unclee - The head isn't damaged, though I will be replacing all the rocker studs at a minimum. Probably need at least one new valve guide, but shouldn't need to enlarge the push rod holes if I run stock ratio rocker arms. I'll know more soon. It's the unknown that's the killer.... This is what I found after pulling the intake... The face of the lifter that came apart looks good, so shouldn't be any camshaft damage...Correct?
I ran across this statement while searching the internet. I know the article is talking about Vortec Heads, but also applies here I think... http://www.chevyhiperformance.com/howto/97458/index.html "Do not use guided or self-aligning rocker arms with heads that use guideplates, since this will cause pushrod bind and excessive wear. Also be aware that 1.6 rockers move the pushrod very close to the pushrod hole. Elongating the pushrod hole should be considered essential when using 1.6 rockers."
Well, I pulled the heads of Friday night. No piston to valve interaction, which of course was a pleasant surprise. I dropped them off at a reputable local machine shop to have them checked out. "Jerry" says the heads look like they are in pretty good shape. I'll know more in a couple days. If all checks out cool, he's going to install screw in studs, without shoulders and suggested I go with the later model self aligning rocker arms. At this point, I'm also looking at putting a bigger cam in... I'm already this far into it, why not?
I had this happen to me once driving through Colorado. What happened in my case is the water in my radiator was low enough to not cause overheating but the heads got hot enough to cause the valve to stick in the guide. So pull your heads, check your valve guides and always top off your water.
He's going to check the guides for sure. He said it's possible that whoever rebuilt the heads last may not have done a very good job at replacing the guides. Thanks for the tip on the coolant issue. I checked all the fluids before I left on the trip and before I left Frisco. I did add a half quart of oil before I left to come back home, but the water was fine.
I really didn't look much into this statement by belair, until I took my heads into the machine shop. The intake valve guide on the #3 cylinder was falling out of place and no hardened seats had been installed. So with that, at least I know what I have now. Might as well start from the beginning with them. The heads are being magnafluxed. All the studs have been pulled and new screw in studs are installed. A couple valves are being replaced due to the rockers sitting off to the side and wearing the valve tips down. This is going to cost @ $300 when the shop's done with them. The block has been bored .030 and you can see the hatch marks in the cylinders, so it must have fairly low miles... I think the 2000 miles I stated earlier is a bit optimistic, but I only know what I was told when I bought the car. At any rate there is a slight ridge at the top of each cylinder, but not too bad. So, there ya go. Can't always trust everything you're told, no matter how trusting the person you don't really know seems to be...
Sorry to hear of your troubles. At least this way you know what you have going on inside your engine now. This story sounds familiar to what I just recently went through. I was told the car had been sitting 5-6 years because of a brake issue and all it needed was a brake job and a tune up. Here's what I ended up finding inside the engine: So I rebuilt the engine and found some of the intake valves froze to the heads. Now this is what I have and I know for sure what's inside there:
#1. Take Unclee's advice. Whether using guide plates or self-aligning rockers, you MUST DRILL OUT THE FACTORY SLOTTED HOLES IN THE HEAD in order to prevent pushrod binding, side loading on the rocker stud and side loading on the valve stem/guide. If the factory pushrod holes are in excellent condition, there is a special tool called a Louis Tool that is inserted into the p.r. hole to guide the drill bit to enlarge the slot CLOSER TO THE ROCKER STUD. I'm running a Comp Cams Extreme #12-242-2 with 1.6 rockers, .501" INTAKE, .512" EXHAUST. Z-28 springs, pinned rocker studs (no self- aligning rockers, no guide plates), just Louis Tooled pushrod holes in the heads. 3000+ miles on the motor; no problems. #2. Snowman, you or someone else started that engine on STALE UNLEADED GAS! 8 bent pushrods and I'll bet all intakes! Always drain the stale gas, have the tank boiled (would'nt hurt to flush the pickup [better yet repace it]), flush the fuel lines and you might have to even replace the fuel pump. Replace the fuel filter and very likely the carb will need a rebuild paying particular attention to the idle circuit ( those p***ages are tiny). Don't even think of "freshening up" the stale gas by just adding fresh gas, you just end up "flogging a dead horse". Here's what happens. On cars that sit as long as your's sat, the MMT in unleaded gas goes gummy (eventually solidifies in the pickup tube, fuel lines, filter, fuel pump valves and tiny carb p***ages). You managed to get it running on stale (gummy content) gas, probably ran half decent how-be-it with an obnoxious odor. Engine warmed up, the intake valve stems got coated with the gummy content (the exhausts receive burnt mixture and are not affected) and then shut the engine off. Engine cools down, gummy content solidifies in the valve stem-to-guide clearance and you end up with intake valve seizure!!! The next time you try to start the engine, the first two rotations will be stiff and the next rotations will free-wheel because you managed to get the intakes open a little bit before the pushrods gave out. I have encountered this phenomenon way too many times! Regular day-to-day mechanics may never encounter this problem for the simple reason that they are working on operational vehicles with a recent malfunction. Small engine throttle valves will seize up solid if let sit for too long. Usually a spray of carb cleaner or WD-40 will loosen up the "gooey". I realise this is off topic, but if it helps a few car guys, GREAT!
Von Dyck, you're right on the money. I wasn't the first person to look at the car, so I'm sure someone gave it a shot and tried to start it. After finding the bend rods, the tank got dropped, lines cleaned, new fuel pump & filters, rebuilt the carb and the engine. You've definitely shed some light on the reasoning behind why this happens. Now I'm sure we're getting a little off topic of what's going on with T-roy's setup, but some good info non the less.
I picked up my heads from the machine shop this afternoon. New valve job, hardened exh seats, screw in studs, drilled out pushrod holes, Lunati valve springs, retainers and locks. I'm going to use self-aligning rockers, replace the one broken pushrod and order a new cam/lifter set from Lunati. It was KooL to see the port work that was done on the heads when I pulled the intake off. So with a new cam in it, the motor will actually make use of the heads! It'll still be a couple weeks before it's back on the road again though. Gotta save my pennies and save my dimes...
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