416 Stroker Help Identifying Noise

[Travis Mayfield]

Hello all, I need some help identifying the... dare I say... "knocking" noise in this video. To help identify what you are listening for: is louder in the first 1/3 of the video, fades out some in the middle, then comes back in the last 2/3 of the video.


(excuse the watermark, I used a free video editor to rotate the video)

The sound speeds up with RPM, but does not seem to get louder or anything on accel or decel. I have a mechanics stethoscope but I do not think I hear the noise through the stethoscope, all I hear anywhere is normal valve train noise.

I have confirmed that it is not flex plate bolts.

Engine:
416 stroker
Edelbrock 70.5cc heads
9.9:1 compression
Comp XE285HL hydraulic flat tappet 241/247 cam
Crane 1.5 roller rockers

I recently re-adjusted valves after I replaced the valve seals, noise stayed the same. It has been making this noise since I purchased the car last year and I've driven it maybe 1,000 miles around town.

What does it sound like to you?

 

[Alaskan_TA]

Automatic trans? I see more than one cable there....

If so, pull the inspection cover on the bell to see if the bolt heads for the flex plate have been rubbing on the webbing at the back of the block.

A loose harmonic balancer can also cause a very similar noise.

 

[Travis Mayfield]

Automatic trans? I see more than one cable there....

If so, pull the inspection cover on the bell to see if the bolt heads for the flex plate have been rubbing on the webbing at the back of the block.

A loose harmonic balancer can also cause a very similar noise.

Thanks for the reply. As I stated in the original post, it is not the flex plate bolts.
The car has an ATI Super Damper, I just gave it a good wiggle in all directions and I do not feel any play, but I will remove the belts and look into it further tomorrow.

 

[MOPAROFFICIAL]

Its hollow sounding...

Hmmm

How about you pull the valve covers and you see how much side play the rocker arms have and then you inspect the tops of The Rocker covers for any kind of contact witness marks.
The next thing you do is you put your stethoscope down at the pan rail to see if you have rods hitting the lower portion of the boars or any Rod knocking.
Then you go to the exhaust pipes and you listen for that knock to align with any sound as in valve timing, tic tic tic.
Then along the head near the plugs.

 

[Travis Mayfield]

Its hollow sounding...

Hmmm

How about you pull the valve covers and you see how much side play the rocker arms have and then you inspect the tops of The Rocker covers for any kind of contact witness marks.
The next thing you do is you put your stethoscope down at the pan rail to see if you have rods hitting the lower portion of the boars or any Rod knocking.
Then you go to the exhaust pipes and you listen for that knock to align with any sound as in valve timing, tic tic tic.
Then along the head near the plugs.

Thanks! There is a little side to side play in the rocker arms, but from what I've researched, it seems to be a normal amount. I also ran the engine for a few seconds without the valve covers on and put side-to-side pressure on the rockers, the noise did not change.

Pan rail is a good idea. I did place the stetho on the pan itself briefly but didnt hear anything, but the rail makes more sense. Along the heads/near plugs, I can not hear the noise, but I will try again tomorrow.

 

[MOPAROFFICIAL]

Thanks! There is a little side to side play in the rocker arms, but from what I've researched, it seems to be a normal amount. I also ran the engine for a few seconds without the valve covers on and put side-to-side pressure on the rockers, the noise did not change.

Pan rail is a good idea. I did place the stetho on the pan itself briefly but didnt hear anything, but the rail makes more sense. Along the heads/near plugs, I can not hear the noise, but I will try again tomorrow.

That's good to know. In the future you should tighten up all your rocker side play with shims. .010-.015 side play makes for a quieter engine 'being we're on the topic' less wear too...annnnd more consistent loading on the valve guide.
Do you happen to know what Pistons are in this engine? Because I noticed you have 70cc Edelbrock heads and that means they've been opened up to make room for something

 

[Travis Mayfield]

That's good to know. In the future you should tighten up all your rocker side play with shims. .010-.015 side play makes for a quieter engine 'being we're on the topic' less wear too...annnnd more consistent loading on the valve guide.
Do you happen to know what Pistons are in this engine? Because I noticed you have 70cc Edelbrock heads and that means they've been opened up to make room for something

Very helpful! I'll look into the shims and measure the play.
I believe the pistons are SRP forged 8.75cc dome.
EDIT: I can not seem to find +8.75cc SRP pistons anywhere on the web, but that's what the build sheet says...

 

[furrystump]

I assume you double checked the firing order and timing. Where any of the rockers loose before you adjusted them? Oh, check the under side of the valve cover is a rocker hitting the cover or baffle.

 

[NC Engine Builder]

Doesn't sound terminal, I'd be looking at rocker to valve cover clearance, and I have seen the rods barely hit the oil pump pickup tube with the 4" crank, and sound just like your noise.

 

[Travis Mayfield]

I assume you double checked the firing order and timing. Where any of the rockers loose before you adjusted them? Oh, check the under side of the valve cover is a rocker hitting the cover or baffle.

Firing order is correct, timing is 25-26 with 10 degree limiter bushing in the dist (+vac advance to ported vacuum). Rocker adjustment was good before I pulled them for the valve seal replacement. I do not think it is the valve covers, since I ran the engine with one valve cover off, but I should try with both covers off or at least tilted for clearance... I already have Moroso valve cover gaskets which are pretty thick, and should provide extra clearance.

Doesn't sound terminal, I'd be looking at rocker to valve cover clearance, and I have seen the rods barely hit the oil pump pickup tube with the 4" crank, and sound just like your noise.

I have heard of the crank hitting the oil pickup, and I have been hoping that is it. However, this engine was built by a reputable shop and I would think they would have resolved that when they were doing all of the other clearancing and assembly, but maybe not...

OK so my to-do list today:
More investigation with the stethoscope (oil pan rail specifically, and front of engine)
Run engine with valve covers loosened/lifted to check for rocker clearance.
Worst case, I will drop the oil pan next oil change and take a peek.

Thanks for the help everyone! Will report back...

 

[Travis Mayfield]

I was able to isolate the noise this morning. I hear the noise quite clearly through the stethoscope when I place it on the driver-side middle valve cover bolt, which is right between cylinders 3 and 5. The noise is not nearly as pronounced when I place the stethoscope on other valve cover bolts, on the valve cover itself, or anywhere else. Since this bolt goes into the head, this leads me to believe its something do to with cyl. 3 or 5 or their respective components. Piston slap? Loose wrist pin? Here is a quote from another thread:
"A wrist pin noise will be a double knock most evident at idle..." which sounds like exactly what I have...
When I pull plug wire for cyl. 5, I believe the noise reduces quite a bit, but it is hard to say for certain since the whole mood of the engine changes when I pull a plug wire.
My next step once the engine cools some is to put my cheap-o borescope down cyl. 5 and see if there's anything to see...

 

[furrystump]

I’m not saying it’s likely, but I have seen it happen even with a good person putting it together. Pistons in the wrong hole so the valve relief is reversed is too small and the intake valve just kisses the piston. Can you put bore scope in plug hole and see the valve reliefs?

 

[MOPAROFFICIAL]

I was able to isolate the noise this morning. I hear the noise quite clearly through the stethoscope when I place it on the driver-side middle valve cover bolt, which is right between cylinders 3 and 5. The noise is not nearly as pronounced when I place the stethoscope on other valve cover bolts, on the valve cover itself, or anywhere else. Since this bolt goes into the head, this leads me to believe its something do to with cyl. 3 or 5 or their respective components. Piston slap? Loose wrist pin? Here is a quote from another thread:
"A wrist pin noise will be a double knock most evident at idle..." which sounds like exactly what I have...
When I pull plug wire for cyl. 5, I believe the noise reduces quite a bit, but it is hard to say for certain since the whole mood of the engine changes when I pull a plug wire.
My next step once the engine cools some is to put my cheap-o borescope down cyl. 5 and see if there's anything to see...

I'm having an issue with notifications I didn't know you replied with any findings. Number five I've had problems with number five but it was because I had this Mopar distributor or replacement distributor from Mopar and it was rotor phased wrong. It scattered to no.5 and lit it abdc causing it to scuff the skirt. Did that **** twice before I figured it out. No.5 .
I come to find there was a bad run of mallory replacement style for mopar distributors in the late 90's.

But maybe it is a wrist pin. Glad you could pinpoint it to a specific cyl.

 

[mopardude318]

I'm having an issue with notifications I didn't know you replied with any findings. Number five I've had problems with number five but it was because I had this Mopar distributor or replacement distributor from Mopar and it was rotor phased wrong. It scattered to no.5 and lit it abdc causing it to scuff the skirt. Did that **** twice before I figured it out. No.5 .
I come to find there was a bad run of mallory replacement style for mopar distributors in the late 90's.

But maybe it is a wrist pin. Glad you could pinpoint it to a specific cyl.

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