383 ENGINE TAP!!!

[shane67gtx]

So I recently bought a 67 Belvedere with a 383. The motor has a pretty beefy cam, im not sure the exact cam it has in it but it’s big enough to pull most of the vacuum out of the brake booster. It had a slight tap when you would first start it and when it was up to temp. But wouldn’t do it all the time. I wanted to bite the bullet and see if I could get away with replacing, lifters (flat tappet) pushrods, and rocker arms. Looking threw the lifter valley the cam appeared fine, and none of the old lifters and any obvious wear. Seemed to run pretty quite for about a week. But started it up for the first time in a couple days and sounded like this. What could this be? If anybody is willing to send me their phone number, I do have a video of the noise. It will not let me post the video on this thread.

 

[440Coronet500]

You sure it's not an exhaust leak? They can sound like a noisy lifter. 440'

 

[shane67gtx]

Yeah, it seems like a pretty violent tap. Didn’t start out that way, slowly progressed. And like I said it doesn’t do it all the time

 

[Jerry Hall]

1967 left side exhaust manifolds are notorious for an exhaust leak at the connection to the exhaust pipe. It usually goes away as the engine warms up. I have replaced about 5 of them on a 67 GTX. Finally I decided to leave it alone until the noise doesn't go away with warm up. I replaced the last one at about 80 thousand miles. Now with 91 thousand miles, it's no worse.

 

[Rebelrouser]

So I recently bought a 67 Belvedere with a 383. The motor has a pretty beefy cam, im not sure the exact cam it has in it but it’s big enough to pull most of the vacuum out of the brake booster. It had a slight tap when you would first start it and when it was up to temp. But wouldn’t do it all the time. I wanted to bite the bullet and see if I could get away with replacing, lifters (flat tappet) pushrods, and rocker arms. Looking threw the lifter valley the cam appeared fine, and none of the old lifters and any obvious wear. Seemed to run pretty quite for about a week. But started it up for the first time in a couple days and sounded like this. What could this be? If anybody is willing to send me their phone number, I do have a video of the noise. It will not let me post the video on this thread.

Depends on the cam they purchased but a lot of the cheaper cams they take a stock blank and reduce the base circle to gain the extra duration, so the stock push rods then are a little short. When you assemble one you have to look and see how deep the plunger is depressed to see if it needs longer push rods. Just fixed one last week, two lifters would peck when it got warm. .020 longer pushrods fixed it up. When the lifter in on the base circle you should have about .035 depression of the lifter piston, i look art the snap ring that holds the piston to gauge the depression.

 

[shane67gtx]

1967 left side exhaust manifolds are notorious for an exhaust leak at the connection to the exhaust pipe. It usually goes away as the engine warms up. I have replaced about 5 of them on a 67 GTX. Finally I decided to leave it alone until the noise doesn't go away with warm up. I replaced the last one at about 80 thousand miles. Now with 91 thousand miles, it's no worse.

Yeah I thought the same thing, but the tapping is just so violent now. Almost as if a rocker arm is hitting the valve cover, but i know that’s not the case. Because it isn’t consistent and doesn’t do it all the time

 

[shane67gtx]

Depends on the cam they purchased but a lot of the cheaper cams they take a stock blank and reduce the base circle to gain the extra duration, so the stock push rods then are a little short. When you assemble one you have to look and see how deep the plunger is depressed to see if it needs longer push rods. Just fixed one last week, two lifters would peck when it got warm. .020 longer pushrods fixed it up. When the lifter in on the base circle you should have about .035 depression of the lifter piston, i look art the snap ring that holds the piston to gauge the depression.

Well a little background. My grandfather actually owned the car 14 years ago. Someone bought it and actually had it ever since. I was Able to track it down and find it via Facebook. The guy didn’t touch anything. He basically just performed general maintenance. But when my grandfather owned it, never made any sort of noise what’s so ever, ran perfect. So I replaced everything with basically identical parts that came out of it, same length pushrods, rocker arms, and lifters.

 

[QuickBpBp]

Pull the valve covers. Check the valve lash. Maybe a loose rocker and it's ready to spit the pushrod out...

 

[PlymCrazy]

Do you have a mechanical fuel pump? Similar noise as you describe on my 383 wound up being the mechanical fuel pump was coming apart. Found it using a cheap mechanic stethoscope from Harbor Freight. Was very happy I found it before tearing too far into the top end.

 

[Lefty71]

Post your video to Youtube.com first, then copy and paste a link to it here.
Still may be very tough to tell for us from a video.
Before you start tearing things apart, cut off a broomstick or find a fat dowel rod and listen around the engine at various locations while its idling, including the bottom end. This will go miles towards learning what is (and what isn't) happening.
Post up what you hear.

 

[eldubb440]

But when my grandfather owned it, never made any sort of noise what’s so ever, ran perfect. So I replaced everything with basically identical parts that came out of it, same length pushrods, rocker arms, and lifters.

this makes no sense to me.....why?

 

[Lefty71]

this makes no sense to me.....why?

Wondering if he wiped a lobe or ruined a lifter???..... it should have gotten a total new break-in treatment.

 

[shane67gtx]

Post your video to Youtube.com first, then copy and paste a link to it here.
Still may be very tough to tell for us from a video.
Before you start tearing things apart, cut off a broomstick or find a fat dowel rod and listen around the engine at various locations while its idling, including the bottom end. This will go miles towards learning what is (and what isn't) happening.
Post up what you hear.

figured it out. Here’s a video. Sound is coming from the passenger side. And does eventually quite down a little. Doesn’t stay that loud.

 

[shane67gtx]

this makes no sense to me.....why?

I meant that, over 10 years ago when my gpa owned the exact car. The motor had no noise what’s so ever. The guy who purchased the car off my gpa didn’t touch anything in the motor therefore everything’s the same. The motor developed that noise. But since it ran fine with the parts it had originally back when my gpa owned it I just replaced the parts with identical stuff. And didn’t change pushrod lengths or anything

 

[Jerry Hall]

Now, I don't understand either. If it's not broke, why fix it? You can replace everything you mentioned, but as mentioned above, if you didn't do a proper break-in with a high zinc oil, you are asking for trouble.

 

[shane67gtx]

this makes no sense to me.....why?

I meant that, over 10 years ago when my gpa owned the exact car. The motor had no noise what’s so ever. The guy who purchased the car off my gpa didn’t touch anything in the motor therefore everything’s the same. The motor developed that noise. But since it ran fine with the parts it had originally back when my gpa owned it I just replaced the parts with identical stuff. And didn’t change pushrod lengths or anything

Now, I don't understand either. If it's not broke, why fix it? You can replace everything you mentioned, but as mentioned above, if you didn't do a proper break-in with a high zinc oil, you are asking for trouble.

i did, I used brad penn, 20w50, high zinc partial synthetic oil, and used cam and lifter assembly lube, as well as filling the lifter plunger with the lube. Ran it up to 1500 RPM for about 10-15 minutes on initial start up. Ran extremely quiet for a few days then sat for about a week. That video was the start up after sitting for a week and probably 50 miles after replacing all those parts

 

[Lefty71]

figured it out.

Where's it coming from??

 

[QuickBpBp]

I meant that, over 10 years ago when my gpa owned the exact car. The motor had no noise what’s so ever. The guy who purchased the car off my gpa didn’t touch anything in the motor therefore everything’s the same. The motor developed that noise. But since it ran fine with the parts it had originally back when my gpa owned it I just replaced the parts with identical stuff. And didn’t change pushrod lengths or anything

i did, I used brad penn, 20w50, high zinc partial synthetic oil, and used cam and lifter assembly lube, as well as filling the lifter plunger with the lube. Ran it up to 1500 RPM for about 10-15 minutes on initial start up. Ran extremely quiet for a few days then sat for about a week. That video was the start up after sitting for a week and probably 50 miles after replacing all those parts

PULL the Valve Cover. It's a simple task. Why you are still running it like that wondering what it is when you can find out by removing a hose and 6 bolts...

 

[QuickBpBp]

Where's it coming from??

I think he means he figured out how to post a video..

 

[Lefty71]

I think he means he figured out how to post a video..

Oh, lol.
Progress......