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Worse than I thought...

15K views 166 replies 34 participants last post by  FrankieThe69Kid 
#1 ·
(continued from my recent backfiring issue) Popped the valve covers and discovered what's possibly 2 collapsed lifters, one on 5, the other on 7.
Yesterday was a bad day when it started backfiring up through the carb while idling in the driveway. Today's not much better.

Anyway, I'm rebuilding a Holley 4160 I've had sitting in the shed since 2005. It should work really nicely when I get the engine back together.
 
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#3 ·
How likely would it be for cam lobes to get wiped with the car idling in the driveway? I don't know much about this kind of stuff. The engine was built quite some time ago and never run. I dropped it in my car a little over a month ago, buttoned everything up, and got it started for the first time a couple of weeks ago. Before I started it, I primed it to make sure oil was pumping everywhere, then I hooked up the ignition system, pumped the gas pedal twice, turned the key while my son adjusted the dist. It started right up about 10 seconds later. I let it idle in the driveway for about 1/2 hour. Couldn't drive it anywhere because I had to adjust the clutch. We pushed it back into the garage and I got everything adjusted. Took it out for a short, and very easy ride the next night just to make sure everything was working... and it was.
Last thing on the agenda was a front-end alignment, which I did a couple of days later. Took it out for another ride and I was the happiest man alive. Ran like a clock and I brought it back home after about 40 minutes. Around town driving, so no highway.
Was hoping to get it out for an inspection sticker yesterday. Had it warming up in the driveway for about 10 minutes. Sounded nice. Then I hit the gas to kick the idle down and it started popping... So... what did I do wrong? and how would cam lobes be wiped after only running for two hours tops since the engine's been built?
 
#4 ·
The proper procedure for breaking in a flat tappet camshaft involves starting the engine and immediately running it for 20-30 minutes at a slightly varying speed between 2,000-2,500 rpm or as instructed by the cam grinder.

The procedure establishes smooth mating surfaces between cam lobe and lifter and, if not done properly, will result in the lifter acting like a file on the cam and removing the lobe.

Proper lubricant is key as it needs to contain a sufficient amount of zinc diethyl dithiophosphate (ZDDP) and other anti wear agents while sparing the detergents found in regular "production" oils. Also key is valve spring pressure in that excessive pressures during break-in can also wipe a lobe. For builds with high lift cams special light "break-in" springs should be used.
 
#5 ·
Now you tell me :)
I wasn't aware of any of this "break-in" procedure. However, on the initial start, it did run for 1/2 hour +/- at idle, and at varying speeds because I was checking things like throttle, listening for strange and exotic noises, etc. The couple of times I did take it out, I made sure the temp gauge showed the thermostat opened and then I waited for the temp to get back to 180-190 before I put it in gear.
Everything can be fixed... right? I'm just hoping it's not the cam... unless that's easier to fix than collapsed lifters. I've never done either, and I'm "frankly" not looking forward to either adventure.
Oh... and I'm using Pennzoil 10W-40, and it doesn't have the dreaded starburst logo.
 
#9 ·
Sooo, sounds like everybody's thinking it's the cam. Should I drain all the oil, or, if there's metal in it, would it be pretty evident with a quart or two?
 
#12 ·
Drain all of the oil.

After initial break-in (which should be variable RPM oscillation for 20-30 minutes with no idling), you are supposed to change the oil almost immediately. You're then supposed to change it after the first 500 miles. You've likely killed the cam by not breaking it in properly.

You have to remove all of the lifters in order to get the cam out. Therefore, it is technically easier to remove collapsed lifters than a wiped cam. But this is not something you want to mess around with. Do it right. Pull all of the lifters and the cam to verify what is okay and what is not.
 
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#13 ·
Hmmm... School of Hard Knocks... I'm still trying to graduate. Anybody else in my class? Uggh. Well, one thing for sure: I haven't made the same mistake twice.
My issue is becoming apparent though... it appears that the people who see the car I have automatically assume that, when I buy something, I know what I'm doing. I, on the other hand, don't ask questions because I assume that what they're selling me is "plug and play"... but I don't really know what I'm doing.
This has kicked the crap out of me. Just got finished putting everything together. Now I have to take it all apart again.
Well, the Patriots won. My wife and I have just been approved to buy a cottage at the beach. I get to store my car in a climate-controlled garage... life is good, right?... I feel like s**t.
 
#15 ·
Well, I would take things one step at a time before giving up. I know cams flatten but I would be shocked if they rubbed off that quickly without a serious assembly problem. Compare the lift at the push rods and see how it compares with your cam data, but more importantly how they compare to each other. for $20 you can get a dial indicator and magnetic base at harbor freight.

Did you hook up a vacuum advance between when it ran well and when it started popping? How was the oil pressure, check to see if the lifters are correct for the block perhaps there's a reason they are not pumping up.

good luck
 
#18 ·
that's a video of metal in the oil. that's were I would start, drain it and see whats happening. from what I'm reading your oil should probably look like this. meaning you wiped out the cam and lifters.
Well, I'm getting over the initial shock. Hoping for the best, but prepared for the worst. I like the "one step at a time" approach, so I'll get the car back up on jack stands today and drain the oil.
I don't have access to the cam data... well, I don't have a paper to look at because I'm not the one who built the engine or bought the parts. I'll find the data sheet online.
The guy who built and sold me the engine is coming by. I'm not blaming him. From what I'm hearing around here, this is my fault.
Hopefully, this will be the last "live and learn".
I'd actually rather do this than track down an electrical dilemma. At least I can look at parts and see where the problem is :)
 
#19 ·
So... what did I do wrong? and how would cam lobes be wiped after only running for two hours tops since the engine's been built?
That's when they get wiped. If the cam survives the break-in, it will last for years.

How likely would it be for cam lobes to get wiped with the car idling in the driveway?
Very.

The engine was built quite some time ago and never run. I dropped it in my car a little over a month ago, buttoned everything up, and got it started for the first time a couple of weeks ago. Before I started it, I primed it to make sure oil was pumping everywhere,
Good.

then I hooked up the ignition system, pumped the gas pedal twice, turned the key while my son adjusted the dist.

It started right up about 10 seconds later. I let it idle in the driveway for about 1/2 hour.
Oops. Big mistake. Cams should be seated at 2000 rpm. Idling caused an under-oil situation, the cam lobes are lubricated by splash oil from the crankshaft. You didn't have much.

Was the cam (and lifters) installed using cam lube or STP Oil Treatment on the lobes and faces? Was there ZDDP in your oil?


You'll need to pull the valve covers and check for movement of the pushrods on the suspect, or even all, of the valve train. Lifters don't "collapse" and stay collapsed. Engine oil does not compress.
 
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#20 ·
Hydraulic lifters bleed down if the engine has been off for a while. Can you really get an accurate measurement of cam lift at the push rod if a lifter is not fully pumped up? Just asking - its always a question I've had when I was diagnosing a misfiring engine.
 
#21 ·
David, I've already pulled the valve covers. Everything's OK on the right side. On the left side (and I was mistaken at first saying 5 & 7, it's 5 & 6) exhaust valve on 5 and intake valve on 6. When I pulled the VC off the left side I saw... well... see attached photo. When I checked the rest of the train on that side, I found the same issue with the I valve on 6. Only difference was that the rocker was still positioned correctly.
 

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#25 · (Edited)
Hmm… Photo too small and distant to learn much. What type of studs do you have the rockers mounted on? I don't see a hex in your photo. If they are pressed-in, then we are done.

If not, it's time to look at the lifters.

The clearly-focused lifter on the right is normal, with the pushrod cup against the retaining clip. The one to its left is 'collapsed'. The spring inside may have been defective, and has broken, or the plunger may be jammed by debris. Pray for broken springs, if this is what you find.

 
#29 ·
The adjustment nut on the sideways rocker is higher on the stud than its neighbor. Was it loosened by the OP or did it come upmthat far by itself ?

Maybe I'm overlooking it, but I don't see info regarding the cam, is it stock or aftermarket grind. Are the valve springs regular rate or heavier ? Press in studs are not my favorite by any means, but with a stock set-up they should hold. Sometimes they don't. In this case that would be a happy finding vs. cam destruction.

Z
 
#30 · (Edited)
The adjusting nuts on both defective "sets" were higher up than the adjacent rockers when I opened the cover. I spun the nuts on both down until they bottomed out... no more threads left on the studs, but the rockers are still so loose you can still move them around.
The studs appear to all be even. Attached pic shows the two rockers in question have the push rod way too far down. They're so loose I can pull the valve-side of both rockers up off the stems.
 

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#31 ·
With the nuts cranked down all the way, spin the engine over some and see if the rockers move at all. The way that looks, I bet they won't. I don't think that lifters can collapse that much.
 
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