Tap, Tick, Knock... Whatever it is, it sounds bad.

[n33k0]

Greetings,

My truck has recently (within the last few months) developed a tap/tick/knocking noise on cold starts. I don't know what is causing it, and I would appreciate any input from you more knowledgeable folks. I have included a link to a video where you can hear the noise, hopefully it works: http://tinypic.com/r/1z2j34k/9

It ticks for a few minutes after a cold start, then the noise goes away and stays away till I let the truck sit for a few hours. It will start quiet and get louder until it reaches the volume heard in the video, then stop abruptly after the engine has been running for 4-5 minutes.

My suspicion is a problem with a lifter (or multiple lifters), but I don't have enough experience with these motors to know for sure. The engine is a 350 with a cam, don't know the specs, I am pretty sure the lifters are not rollers.

Thanks in advance!

[bronze 72 super]

Noticed you have headers. Check to see if one of the gaskets are blown out. That ticking happens on my El Camino with headers. That sometimes gives the impression of a lifter ticking. If that doesn't cure the problem, try using something like Marvel Mystery Oil, should be able to buy that at any good parts store. Put a quart in with your next oil change. I've use this product for years with good results. Is this a newer engine or a old one? What weight oil are you using?

[n33k0]

Thanks for replying, Super.

It's a new engine, according to the previous owner. It had about 30k miles when I bought it, and I put about 9k more in the past 1.5 years. I have been meaning to check the headers, like you mentioned. Since the noise disappears after a few minutes, I thought maybe there was a leak that plugs itself when the parts heat up and expand.

I have used Marvel Mystery Oil twice on this engine so far: once, a few months ago when I first noticed the noise, and I put another quart in last week (it's still in the oil when I recorded the video this morning). I'm due for an oil change this weekend, using 10w-30 Mobil Synthetic. I changed the oil after running the MMO for a few laps around town last time, and will do the same this weekend with the current MMO in the oil.

[geezer#99]

Sounds like a lifter.
Pop the valve covers off and check all the rockers are moving equally.
Also look at the rocker studs. One could be pulling out.
And check the rockers themselves. They crack sometimes.

Hopefully it's not a cam going flat!

[67 chevelle]

Check your header bolts , check the collector bolts , if it still knocks , take your valve covers off and see if a rocker is really lose , hows your oil pressure ?

[bronze 72 super]

Usually running Marvel Mystery Oil will free up a sticky lifter. I've rebuilt numerious small blocks in the past, using the old rockers, and have never had a problem. High R.P.M. and heat sometimes causes problems, stress cracks, fatigue, etc. Most newer cams are heat treated for strength to prevent a flat lobe. Imported engine parts, I try to stay away from, bad metal. How's your oil pressure? At idle, and high speeds?

[cleszkie]

Has this engine always been run on synthetic oil? Or did you make the switch from regular to synthetic when you bought the truck? The flat tappet lifters and cam may not like the change.

[bronze 72 super]

I also should say, with that mileage it just might need the rockers re-adjusted. Some people only adjust them cold, not hot. Some thing else to think about.

[n33k0]

Oil pressure is very close to the max on cold starts, but when the engine is up to normal operating temp the idle oil pressure hovers just above the first line on the gauge. When driving down the highway the pressure is constant at just above the third line. The gauge doesn't have any numbers, so I'm not sure what the exact pressures are.

[bronze 72 super]

Is this a older re-built engine or a newer one? If it was me living were you do, I would use a straight 30wt. oil, doesn't thin out as fast as a multi weight. I live in Eastern Oregon, and with the 402 in my '71 Cheyenne and 350 in my El Camino I run only 30wt. oil. Haven't had any problems with this combination. I also use a product called Power Punch, produced in Bremerton Washington, been using it for over 35 years with very good results. It more that likely isn't available on the East coast. Lucus works just as good, I prefer Power Punch over here.
Anyways just some more tips and advise. Good luck with your engine.

[n33k0]

Originally Posted by cleszkie

Has this engine always been run on synthetic oil? Or did you make the switch from regular to synthetic when you bought the truck? The flat tappet lifters and cam may not like the change.

I'm not sure what the previous owner used, but I have always used synthetic since I got the truck. It never occurred to me to try a conventional oil. Has synthetic oil been known to cause problems like this?

Originally Posted by 67 chevelle

Check your header bolts , check the collector bolts , if it still knocks , take your valve covers off and see if a rocker is really lose , hows your oil pressure ?

I'll check the exhaust bolts, and replace the gaskets while I'm at it. Might as well start with the easy fixes first, right?

Originally Posted by geezer#99

Sounds like a lifter.
Pop the valve covers off and check all the rockers are moving equally.
Also look at the rocker studs. One could be pulling out.
And check the rockers themselves. They crack sometimes.

Hopefully it's not a cam going flat!

I had checked the rockers before, but only by wiggling them around to find a loose one. I'll pull the valve covers and watch them while the engines running to see if I can spot any problems.

Originally Posted by bronze 72 super

Is this a older re-built engine or a newer one? If it was me living were you do, I would use a straight 30wt. oil, doesn't thin out as fast as a multi weight. I live in Eastern Oregon, and with the 402 in my '71 Cheyenne and 350 in my El Camino I run only 30wt. oil. Haven't had any problems with this combination. I also use a product called Power Punch, produced in Bremerton Washington, been using it for over 35 years with very good results. It more that likely isn't available on the East coast. Lucus works just as good, I prefer Power Punch over here.
Anyways just some more tips and advise. Good luck with your engine.

Thanks for the tip. The straight weight oils aren't easy to find on the shelf around me, maybe it'll be worth it to order the next batch online and have it shipped to me.

I appreciate all the input, fellas. I'll report back after trying these suggestions this weekend.

[toolboxchev]

Originally Posted by bronze 72 super

Noticed you have headers. Check to see if one of the gaskets are blown out. That ticking happens on my El Camino with headers. That sometimes gives the impression of a lifter ticking. If that doesn't cure the problem, try using something like Marvel Mystery Oil, should be able to buy that at any good parts store. Put a quart in with your next oil change. I've use this product for years with good results. Is this a newer engine or a old one? What weight oil are you using?

X2 on that, I had the same issue on a top end rebuild. Pretty common.

[mike16]

use a 3/4 inch diameter 4 foot long length of heater hose as a stethiscope to very specificly locate the noise. make sure you dont put the greasy end in your ear by putting some coloured tape on one end.

[geezer#99]

Originally Posted by mike16

use a 3/4 inch diameter 4 foot long length of heater hose as a stethiscope to very specificly locate the noise. make sure you dont put the greasy end in your ear by putting some coloured tape on one end.

If you put a funnel on one end, there's no fear of accidental greasy ear!! LOL!!

[engineer_gregh]

I just watched the video, sounds like a lifter to me. I've had good luck with Hyperlube stopping lifter noise in the past. You can buy it at Walmart. If you post pictures of your engine and any engine stampings it would help in identifying what engine you have in your truck. I agree with some of the other advise about going away from Synthetic oil. I would recommend 10W-40 in FL, but keep in mind oil recommendations are plentiful and can lead to arguments.

[snipescastle2]

I guess I'm just old school, but I always added a quart of ATF to my oil change when I suspected a sticking lifter.the ATF is mostly detergent, and does a pretty good job of freeing up a stuck lifter.
of course, you would change the oil after the noise subsided.
The header gasket/collector gasket leaks have fooled me before as well, so +1 on checking/replacing the gaskets/header bolts.
good luck, and hopefully it's something simple.
Ben

[GASoline71]

That sounds like a bad exhaust leak or a cracked flexplate to me.

Also noticed that the headers are welded directly to the exhaust pipe. That can create a lot of stress on the header flange at the head.

Gary

[n33k0]

Originally Posted by GASoline71

That sounds like a bad exhaust leak or a cracked flexplate to me.

Also noticed that the headers are welded directly to the exhaust pipe. That can create a lot of stress on the header flange at the head.

Gary

Could a cracked flexplate cause a temporary knocking noise? Honest question; the flexplate is always spinning, right? So it would always be knocking if it was damaged? This knocking only lasts a few minutes after a cold start, then it goes away.

[geunther]

I throw this out there only because it happened to me. I had one rod that would ever so barely hit the side of the block. It was so slight, that expansion of waring up would stop it. It was close to the sound of a lifter tick, and certainly not what you would think from something in the lower end.

It would do it on cold starts for a couple of minutes. After warming up a bit, it would disappear. It was a big block and was from the area where the connecting rod bolts were. I would only consider this after proving its not lifter related.

[n33k0]

I change the oil today, took the advice of going back to conventional oil, and I added the oil supplement suggested by engineer_gregh. Started her up and still had the noise. I have the header gaskets, but didn't have time to change those yet. I'll hopefull have time this week to do that, but I could use some help figuring out what tool I will need to remove the bolts.



Removing the valve covers and looking for problems there is next after the header gaskets.

[bronze 72 super]

use a 12 point wrench. Also if you have the money, go back to stock exhaust manifolds. In a truck you will gain little, if any performance benefits from headers. A cracked flex plate would give your starter problems. Those bolts look like 3/8 or 7/16 in size.

[toolboxchev]

Originally Posted by n33k0

Could a cracked flexplate cause a temporary knocking noise? Honest question; the flexplate is always spinning, right? So it would always be knocking if it was damaged? This knocking only lasts a few minutes after a cold start, then it goes away.

I have seen a loose flex plate bolt knocking its way around. Tightened it up, problem fixed.

[toolboxchev]

I say it again, this stuff is the correct chemical composition for out hydraulic flat tappet cams.

http://www.compperformancegroupstore...Category_Code=

http://www.valvoline.com/our-product...vr1-racing-oil

If you look deeper you will see the vr1 is formulated for todays alcohol based fuels.

[NoNeck]

I searched for days for a similar tick I had with an El Camino with a 350. Believe it or not, it turned out to be the fuel pump push rod. The pump rod had worn down after many miles of use and would tick exactly like a lifter noise. Turned out the ticking sound was being transmitted into the camshaft lobe that drives it. Then into the valve train/lifter area.

I purchased a new fuel pump push rod at my local auto parts store, replaced the rod and the tick disappeared. Just a thought...

POP

[67 chevelle]

get copper gaskets and stage 8 locking fasteners