When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I originally thought it was carb or ignition related. So I reset the timing, didn't help, got new plugs and wires, didn't help, pulled the carb and cleaned it. Didn't help. New distributor... slightly improved. Then, I started pulling plug wires while it was idling. (probably should have started with that... duh). And the number 3 and 5 didn't change the idle speed. All others did. So I was suspecting something wrong with 3 or 5 valves.
Pulled the valve cover and was looking at the rockers when I noticed that when I pushed on the pushrod end of the rocker it was spongy. So it was not holding pressure and probably not opening the valve all the way. So I looked down into the lifter valley and could see that the lifter was broken. The little clip was missing. So something happened to that lifter.
So tonight I will pull the manifold and check all of them and also check the condition of the cam. I installed the cam and lifters this spring. So probably something I did wrong...
Oh, and I also did a compression test and all the cylinders were between 155 and 170 psi.
When you stop a HOT engine all of the lifters of the open valves will slowly bleed down most or all of the way as the oil that was trapped in the bottom of the lifter will migrate out. When the engine is started those lifters will fill again and open their valves all the way. The missing lifter plunger retainer would have no effect on the lifter as its just there to keep the plunger from falling out when handling it. Are you absolutely that retainer is missing?
When you stop a HOT engine all of the lifters of the open valves will slowly bleed down most or all of the way as the oil that was trapped in the bottom of the lifter will migrate out. When the engine is started those lifters will fill again and open their valves all the way. The missing lifter plunger retainer would have no effect on the lifter as its just there to keep the plunger from falling out when handling it. Are you absolutely that retainer is missing?
OK.
Yes, when I looked down in there, I could see it was gone.
And looking at the cam, there are some worn lobes. They don't look REAL bad, I have seen a lot worse. But they were going bad. Good thing is Summit/Comp has warranted the lifters, cam and pushrods.
I have never seen a push rod do that but I have always bought OEM push rods or push rods sold by the major American manufacturers. Its likely your push rods were made in China like so many other things are now days.
Buy the one piece pushrods, better quality.
How fast are you spinning the engine?
If preload is light and you springs loose control you can get pump up on the lifters and that can push the retainer out. Loss of spring control could also explain your pushrod failure.
I think these things may be symptoms of a larger issue. How old are the springs and are they correct for the cam?
Last edited by REELAV8R; Nov 16, 2015 at 04:56 PM.
Buy the one piece pushrods, better quality.
How fast are you spinning the engine?
If preload is light and you springs loose control you can get pump up on the lifters and that can push the retainer out. Loss of spring control could also explain your pushrod failure.
I think these things may be symptoms of a larger issue. How old are the springs and are they correct for the cam?
I don't rev it up past about 4500 rpm. The springs are new with the new (Summit) Vortec heads as of this spring. I talked to a guy at Comp and he said those springs are ok.
Got the engine all put back together last night. Ready to fire her up tonight or tomorrow.
I don't rev it up past about 4500 rpm. The springs are new with the new (Summit) Vortec heads as of this spring. I talked to a guy at Comp and he said those springs are ok.
Got the engine all put back together last night. Ready to fire her up tonight or tomorrow.
I have seen a few OEM push rods break back in the 1960's but I have never seen the pressed-in and induction welded ball push in like yours did. Just a freak failure but I would definitely use another brand in case there is a manufacturing problem at that manufacturer (China?).
Sorry you had to tear down your engine. The best way to diagnose a valve train issue, without tearing down the engine is with a vacuum gauge. Once you put the engine back together, use the gauge to determine if everything is OK. Depending upon the cam, the readings should be high and steady. You Tube has some great videos on the subject. Good luck. Jerry
I don't rev it up past about 4500 rpm. The springs are new with the new (Summit) Vortec heads as of this spring. I talked to a guy at Comp and he said those springs are ok.
Got the engine all put back together last night. Ready to fire her up tonight or tomorrow.
Well, maybe just a coincidental failure. doesn't sound like you are spinning it fast enough to have a spring problem.
At least you found the problem and fixed it.
The main thing I noticed in your photos was the LOUSY polish job done on that camshaft. It doesn't look like it had "worn" lobes....just poorly finished quality on them. They appear to have been induction hardened on the lobes, OK; but they should have been cleaned-up and polished after that process. It appears that was done in a half-@ssed way, at best.
Can't say what caused the lifter problem. It doesn't look like the 'odd' pushrod was damaged or broken...it just appears to be 'different'. Maybe they sent 15 correct rods and one that was just wrong.
In any respect, you should get proper replacements from the vendor who sold them to you. And you should NOT have to pay any shipping costs for that replacement. It was THEIR error.
Good luck.
Last edited by 7T1vette; Nov 17, 2015 at 12:24 PM.
I don't know yet if any of the cam lobes are wiped. Will take a look at that tonight.
I didn't see whether you had pulled the engine, removed the pan or found the pieces of missing retainer...
FWIW, I had the retaining wire pop out of a lifter or two on my 70 LS5 many years ago. It made its way into my oil pump, jammed the pump, snapped the shaft. Since the crank had already been turned by the previous owner, I had to buy a new crankshaft and bearings. Ended up turning into a total rebuild.
If the retainer was there originally, better find out where it went if you haven't already. You may need to pull the oil pan unless you can fish around with a magnet, see if you can fish it out.
My only comment is about something similar with my engine I put in 18 years ago....'89 350 truck block, roller cam ZZ9 from TPIS in Chaska Minn......NEVER DO BUSINESS WITH THEM AGAIN!!!!! anyway, that cam went in, and after a year or so the engine developed a rough idle, and above say 2k rpm it seemed fine....but every once in a while it went rough idle, then the thing would smooth out and be fine for a week, then rough again for quite a while.....drove me nutz for YEARS....did it ALL, injectors, induction, heads, you name it....even went Jacobs ceramic plug boots, went through how many HEI's....AND computers, and chips, and sensors....
but then gasoline went up so high, I put in a stock L98 cam for fuel economy reasons......
upon pulling that damn CAM out, I found the surface was grossly botched up on 6 lobes.... examined the lifters, and they were fine.... put in the stock used cam I got....and it was FINE since...been about 8 years now.....so go figger....how IN HELL can a CAM give INTERMITTENT rough idle??? HOW??? but it did.....
Follow up to 'Intermittent missing' thread
