hckymstr21

I'm new to this forum and thought I'd give you guys a shot at diagnosing my engine noise...

Several weeks ago my 302 started making a clicking noise that sounded like lifters. I replaced the lifters and the noise is still there. However, the noise used to be there both in park and in drive. Now the noise goes away when the car is idling in gear. Once I get above 1200 rpm or so it clicks again. Below is a link to a video of it. Hopefully it works. Here is a little background on the past few weeks of troubleshooting...


It's a '68 302 I installed several years back. It has less than 10k on the rebuilt 302. It has a 2bbl carb and '72 heads. The oil pump seized a few weeks back and I drove it about a mile before I realized what was going on. I replaced the pump, primed it, and started it back up. That's when the ticking noise started. I checked for collapsed lifters and found one. I went ahead and replaced all of the lifters, but left the cam in since it had such low mileage.

The noise appears to be coming from the passenger side lifters, but even using the screwdriver to ear method it's hard to tell. I rechecked the rockers to see if another lifter was collapsed, but they were all good. I even loosened a rocker to compare the clacking of a loose rocker to the noise I have. The noise sounds deeper than a clacking rocker or lifter.

I tried removing the spark plug wires one by one to see if the noise went away. It didn't. The oil pressure reads a tad low, but all I have is the OEM gauge. I can't afford a decent gauge right now. I'm running 10W-40.

I'm thinking it may have soemthing to do with the oil pressure being a tad low, but it doesn't seem to be low enough to cause any noise. When the valve covers were off the oil was flowing better than ever. I thought about replacing the bottom main bearings and getting a high volume pump to see if it helps the pressure as a temp fix. But like I said, the oil was flowing so well on the heads I don't know if that would make a difference.

Also, I've only driven it around the block since replacing the lifters. Nothing above 3500rpm. I've heard of some guys getting rid of a little noise after putting a few miles on new lifters, but I didn't want to take a chance on driving it too far without asking.


100% 100%

hckymstr21

Also, the noise increases with rpms. And it is defenitely not an exhaust leak.

fastbackford351

Bet you scored one or more of your cylinder walls when the oil pump seized.

MonsterBilly

still sounds like a lifter to me. Have adjusted the rockers with the engine running.

Remove valve cover, place a towel at the bottom of the head to catch the oil, start the engine paying close attantion to the towel (avoid the fan). Then loosen one lifter hold down until the lifter stats to clack then slowly tighten it until the clacking goes away then go another 1/4 turn. Do this one by one until all the lifters have been adjusted. quickly not to let the engine get too hot with the oily towel next to the exhaust manifold.

If it is a rocker or lifter chances are you will find it. If the sound doesn't go away it may be a rod. Its too hard to tell from the video whether it is a rod or a lifter.

jlg2002

If its a rod, pulling the spark plug wire off of the offending cylinder will isolate to a specific location. Listening to your video it seems like a lifter lash issue and I agree with monster billy, pull the valve cove off and look for obvious looseness. Before you start the engine without a cover, go to an auto parts store and get a set of rocker clips to keep the oil from getting all over the place.

http://www.jegs.com/i/JEGS/555/80517/10002/-1

Gun Jam

Try this:

1) Get one of those fancy mechanics stethoscopes from NAPA

2) Place it on top of the valve cover starting at the front and move back 2" at a time make sure you press the stem of the stethoscope hard against the valve cover.

Keep moving the stethoscope back a little at a time when you place it above the offending valve you will hear the click through the stethoscope. Move slow and listen carefully.

3) Now that you have isolated the approximate location of the click remove the valve cover (could be intake or exhaust for that cylinder)

4) Rotate the engine by hand until that cylinder's exhaust valve or intake valve is at zero lift then rock the rocker arm back and forth and look for excessive looseness as you rotate the engine feel all the rocker arms as they enter zero lift they should all feel the same except for the bad one that is clicking. The one that is clicking will be noticeably loose compared to all the rest.

5) Once you find that one rocker arm that is loose press on the back of it right above the pushrod. Can you depress the pushrod? Does it make a squish sound? If yes then collapsed lifter.

IF NO THEN:

6) Remove the rocker arm and extract the push rod is the pushrod bent? Roll it on a piece of glass is there move than .001 wobble? IF yes then bent pushrod.

IF No THEN:

7) Check the rocker stud is it loose has it back out?

IF NO THEN:

8) Check cam lift has that lobe worn off compare that pushrods lift to that of the next closest pushrod on the same cylinder does one pushrod have less lift than the other?

IF No THEN:

9) Maybe it simply needs that one rocker arm set to zero lash and then preloaded to spec which is typically .75 to 1 turn past zero. (Zero is defined typically as no up and down movement of the pushrod when lifter is on base circle of cam (Zero lift) and is usually determined by rolling the pushrod between your fingers while tightening the rocker bolt until the pushrod cant be easily rolled between your fingers now its at zero)

-Gun

hckymstr21

Thanks for the input so far guys. I haven't been able to try everything suggested yet due to the rain, but here is what I've looked at so far. I pulled the valve covers and loosened all of the rocker bolts. Then I tightened them a little at a time. I could get the noise to go away temporarily while doing this. But as soon as the idle adjusted itself the noise would come back. All I can do is torque the bolts down properly because they are 72 heads and are non-adjustable. I noticed upon start-up the oil pressure was perfect and I couldn't hear the noise. Once it warms up it tends to drop a bit and the noise comes back. It's supposed to rain the next two days, but once it stops I'll get out there and try everything suggested. I'm leaning towrads another bad lifter like some of you suggested. I'll keep yall updated.

68dustin

have you over reved it? check to make sure all the pushrods are straight and not bent.

jlg2002

yep, you have an oiling problem, the cam is worn out or the lifters are leaking down. I hope it's the last one as it's the easiest thing to fix. You did make sure your rocker nuts are staying tight/torqued - right?

hckymstr21

I pulled the intake and checked the push-rods. None of them are bent. I also pulled each wire to check the rods and the noise didn't go away.

I've already ran it with the valve covers off and re-adjusted the rockers. The noise would go away when the idle dropped after tightening some of the rockers...only to return a few seconds later when the idle leveled out.

I've got the lifters back out and going through them one by one. There was one lifter I pulled from the area the noise was coming from that was a little stubborn to disassemble. The others would come right apart. I'm thinking this might be the culprit. However, I checked for collapsed lifters like Gun Jam suggested prior to pulling everything out and didn't find any. Is it possible for lifters to not be collapsed and still be bad? When I replaced the lifters last week there were 5 I left in because they seemed to be fine after inspecting them. This stubborn one is one of the 5. I probably should have just replaced them all in the first place. I pulled this stubborn lifter apart, soaked it, and put it back together. I'm thinking I'll just replace all 5 older lifters just to be safe.

I did notice that there is a slight difference in some of the lifters I got from autozone. I had to make to trips to the store because money was tight. There are two types. Some are like the original and some are slightly different. The different ones don't seem to come completely apart. I can't get the spring out of them. I can't even get a set of needle nose pliors around the lip to pull it out. I'm thinking they're a different brand and won't cause any issues. I've already ran them in the motor and the only issue was the noise which was there with the original lifters.

I'm hoping when I replace the last 5, to include the stubborn lifter, it will fix my problem. But I wish there was a way to tell for certain which lifter was bad...if any.