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383 Stroker noise - Name that tune

Lunatic

Lunatic

1/2 ton status
Joined
Jul 27, 2008
Posts
439
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Location
Ft Hood, Texas
[FONT=&quot]PLEASE do not bash on the builder – It won’t accomplish anything.[/FONT]

[FONT=&quot]383 stroker built 05-03-2014 - Currently has 610 miles as of 6-29-14 to current date – It is not being driven at this time. [/FONT]



[FONT=&quot]Two road trips:[/FONT]
[FONT=&quot]*1 hr one way, 1 hour back (approx 120 miles total)[/FONT]
[FONT=&quot]*2hr30m one way, 2hr30m back (approx 330 miles total)[/FONT]
[FONT=&quot]Downtime between arrivals and departures (First was to work, second was to family residence).[/FONT]
[FONT=&quot]160 miles local travel (errands, etc)[/FONT]

[FONT=&quot]Noise began after return from second road trip[/FONT]

[FONT=&quot]Minimal oil contaminants (metal) upon initial oil drain (610 miles). Although present, the amount noted was to be expected from the break-in period. Using Royal Purple 15W40 Full Syn oil with WIX 51061R oil filter.[/FONT]



[FONT=&quot]Known info from use of mechanic stethoscope and/or other methods:[/FONT]

[FONT=&quot]*No noise from heads (per valve locations, checked from valve cover to head overlap, on head surface)[/FONT]
[FONT=&quot]*No noise sourced from headers (per cylinder locations, checked along head surface)[/FONT]
[FONT=&quot]*No noise from cylinders (under heads, external check)[/FONT]
[FONT=&quot]*No noise from cylinders (under side, external check) [/FONT]
[FONT=&quot]*No noise from rocker arms (per locations, checked from valve cover surface)[/FONT]
[FONT=&quot]*No noise from intake manifold, entire surface area[/FONT]
[FONT=&quot]*No noise from mechanical fuel pump (rod, arm, etc)[/FONT]
[FONT=&quot]*No noise from crank seal area on timing cover[/FONT]
[FONT=&quot]*No noise sourced from distributor stem[/FONT]
[FONT=&quot]*No noise from new PS pump - belt removed[/FONT]
[FONT=&quot]*No noise from alternator - belt removed[/FONT]
[FONT=&quot]*No noise from new water pump - belt removed [/FONT]
[FONT=&quot]*No noise from new oil pressure sender [/FONT]

[FONT=&quot]*Rear main crank seal has minor leak (1 drop on seal housing, 1 drop on flywheel cover – No drips to ground)[/FONT]



[FONT=&quot]Oil pressure remains above 60 psi until engine is driven at operating temp and fan-cooled (not idled in driveway). The ending noise remains regardless. Drive to the store without noise, park and shut the engine off - The ending noise is heard. Once the engine is op-temp and the oil psi drops to 40ish, the squealing noise goes away.[/FONT]

[FONT=&quot]If the engine is throttled heavily under load (steep incline, etc), the noise returns briefly, then disappears.[/FONT]

[FONT=&quot]I cannot locate the noise source, even though it sounds loudest by distributor area on top side. It is even louder below, at the rear of the engine.[/FONT]

[FONT=&quot]The ending noise leads me to believe it is pressure or vacuum related being that once the crank stops spinning, the noise remains and then bleeds off.[/FONT]

[FONT=&quot]I have been hunting this issue for about two weeks now as time allows. At this time, I am focused on the oil pump. The noise is right for it, the gauge indicates an issue, and the approx location of the noise leads me to it. So it seems. I will provide updates as discoveries are made.[/FONT]

[FONT=&quot]This vehicle is not abused in any manner. Tires have never lost traction on pavement. Oil changes are kept up and any leaks are dealt with immediately. This vehicle is kept in running condition for weekend driving and road trips.[/FONT]


[FONT=&quot]Any ideas or questions leading to a solution are appreciated.[/FONT]




[FONT=&quot]Troy B[/FONT]
[FONT=&quot]Ft Hood, TX



383 Noise YouTube video



[/FONT][youtube]nsG_SGmwjZw&feature=youtu.be[/youtube]
 
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Is it that squealing noise? That could be a vacuum leak even though a vacuum leak sounds like a high pitch squeal.
I got nothing.

Edit, BTW what is that vacuum port behind the carburetor? If I recall, that would lead to vacuum moderator on the transmission. Maybe even for the controls for the HVAC.
 
You still in Killeen? I'm over in Kempner, working my own noise issue right now. Strong possibility mine is the dampner, got to put my new one in eventually.

If it wasn't still making noise after turning it off, I'd swear it was belt related. Might just for giggles pull the belt and see how it sounds. Might even be two different sounds on top of each other. Also try disconnecting the brake booster and capping that vac line.
 
JDNobodi, that was my initial thought - Vacuum.

Actually, initial-initial thought was a pulley......Couldn't get that lucky.

All I can say, right now, is the engine is strong and smooth. This noise isn't resonating through anything I can put a stick to - Which is why I can't find it.

Currently, I have my flywheel cover down and will be checking the crank area, back of oil pan and transmis pump and transmis pan for any noise resonance when I get home tomorrow night. This noise is in the rear somewhere for sure.

Kain, The water pump is new. I know that doesn't rule it out in itself. But, I did remove all belts (WP included) and ran for few. The noise was still there.

cyclic, I am still in Killeen. I also have a stock dampner if you want it (free). All belts were removed already to take accessories and belting out of the equation. I thought about the booster, but due to the location of the noise haven't tried it yet. If nothing hits tomorrow, I will give it a shot.


Thanks for the reply

Troy B
Ft Hood, TX
 
Thank you, I already have a summit racing one sitting on the floor next to me.

By the way, it's your fault I have some windstar fans sitting in my garage also.

I can't remember, are you running 6 lug or 8 lugs? (Not that it affects the noise).
 
I thinking vacuum because the noise stays after the engine shuts off.
Start spraying carb cleaner along things that could have a vacuum source.

For things that stores vacuum, the brake booster and if the blazer has A/C, the vacuum canister right above the HVAC blower motor. (non A/C blazers only have control cables.)
 
Given the amount of noise and I assume it happens every time you shut it off...........

I almost has to be vac, of a decent amount. Try the brake booster and then if you have any of those spherical canisters. Anything that would hold a volume of vacuum.
 
Will look into the vacuum angle once I roll out from under the exposed rear. It does happen every time I shut down, yes.

But what about the mysterious noise diappearing once the oil psi finally goes down to 40 ?


I still have stock axles, 6 lug.

I do have a 14B sitting next to my house though...... For the last 2 years. Finally decided to CL it last week......

I'll hold my head high on the responsibility of blame to the Windstar accusation :whistle: But plead the fifth :haha:



Troy B
Ft Hood, TX
 
I'll throw you a quick IM on something I've got going, you just can't post about it until I get it done.
 
I don't think I can get PMs - Not a payed member anymore.

Kempner isnt too far to drive to check whatever it is out though.......

phantom_squall at yahoo works.....:rolleyes:




Troy B
Ft Hood, TX
 
If it is a non mech noise, have just the rubber hose on the stethoscope.

I have hear a very similar noise coming from the egr block off plate.
 
Guess that was a lot of PM typing wasted. When I get close I'll give you a holler to come over and check it out. You love upgrades, and this is the biggest one I've ever heard of for the 6 lug axle.
 
Just had another thought, I'm definitely going with the "two" sounds theory.
First the shut down, I strongly think it's brake related. Either a booster or line leak.
Second is a good possibility of the pressure relief valve on the oil pump.
 
Couple of comments/ideas.
First, not bashing, but you should not be running the synthetic in a new engine. Even most of the synthetic makers advise against it. You need some friction to help seat the rings.
On the other hand, if it works, then no problem.

Now, the noise:
Its hard to tell, but I really think you have two noises going on there. I have heard that afterwords noise before, but can't remember where.
Actually, I remember one cause, was the air conditioner compressor. When it shut off, it had a leaky internal valve, and would creep backwards about a half round making that noise.

Of course, yours is not hooked up, so its not that. But I have heard that noise elsewhere.
Its almost certainly vacuum related. Something that is held in one position by vacuum is being released when the vacuum goes away, and makes that noise moving.
Brake booster, heater/vent door flap......
If you had a good way to apply and release vacuum without running the motor, I bet you would find it.
Try this:
Run the engine a few seconds to build up the vacuum. Turn it off, wait about 20 seconds after the noise quits, then try the brakes.
If the booster and check valve are good, you should have power brakes for about 2 to 3 presses.
If you don't, then that needs to be addressed. In the meantime, try disconnecting the booster vacuum line, plugging it, and see it the noise goes away.

I would swear the running noise was belt or belt driven related. But, you have removed the belt.
It sounds like it is running at engine speed, so I would not suspect the timing chain or distributor.
Its barely possible that the noise is not oil pressure related. The oil pressure is dropping when things get hot, and lots of things expand when hot.
Its not uncommon for an exhaust leak, for instance, to stop when hot. This ain't no exhaust leak though.
Look really hard at the harmonic balancer area. Something there could be scrubbing.
 
Fordum said:
Couple of comments/ideas.
First, not bashing, but you should not be running the synthetic in a new engine. Even most of the synthetic makers advise against it. You need some friction to help seat the rings.
On the other hand, if it works, then no problem.
Click to expand...

Just quoting this part because I also think this another problem that need addressing. They sell special brake-in oil.
 
In the old days, they used a special thinner oil with less lubricity to help the rings seat faster.
Then, they finally decided that it was not needed, and engines have not used anything other than the regular oil for quite some time.

Although several companies still sold break-in oils or additives.

Then, the nanny stater bunch started forcing the oil makers to cut back on certain additives, such as zinc.
This caused an increase in destroyed cams and lifters due to galling during break-in.

So, the break-in oils are back. Mostly zinc rich for cam protection.

The synthetic vs regular oil during break-in is a different problem. Its actually a continuation of the distant original break-in situation where less lube was thought to be needed.
But in this case, it often is.
 
OP, are you running a flat tappet cam or roller? Standard rockers, roller tips, or full roller? The others are right about conventional oil being recommended. If you are not running a full roller valvetrain, I would recommend adding a zinc additive or using a break in oil. New vehicles have roller valve trains and are designed to work with oil that has less zinc. I used a single bottle of ZDDPlus additive when my engine had a flat tappet cam and roller tipped rockers. Now I am running full roller so I add half a bottle just for insurance. So far I am not convinced that synthetic is worth the extra money for my engine. I change the oil every 3k. It is a 406 gen I sbc that stays under 5500 rpm and is guestimated for 400hp and 525 tq. I did run it in the past, but my oil changes are frequent and I stay on top of maintenance.

I agree that that sound is like a vacuum container filling with air. It sounds a lot like the damper door for the fresh air vent in the passenger side of my cab.

Hopefully it is something simple. I am waiting to get my 406 back from the engine guy right now. With 5500 miles on the engine it was drinking oil like it was a diesel. I had the heads ported before this engine guy ever worked on it. They ground through the runners and epoxied it. The epoxy let loose. The heads were to mangled to take a chance on tig welding them. Now I have a $2400 set of paper weights that look like sbc heads and another $1500+ on a new pair of heads and mild porting and installation.

Good luck on your search for the issue.
 
That noise continues for a couple of seconds after shut down and all rotation stops?
If so I'm leaning toward a vac leak.
Does the brake pedal get hard real quick after shut off. How about a cracked vac ball.
Could be way off but that's my thought.
The oil pressure dropping when hot could be bearing clearance.
 
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