86 intake whistle
Thread Starter
Instructor
Joined: Aug 2012
Posts: 234
Likes: 1
From: St. Louis, Missouri
86 intake whistle
Got a bad whistle somewhere in the intake.
I pulled the intake to put in Greg Browns oil baffle.
When I put everything back together i have this whistle.
Took it apart again, pressure tested the TB.
The throttle body O-rings were leaking, I replaced them.
Put it back together.....still whistling.
Sounds like it is coming from my ISV.
It is new.....anyone have this problem?
Solution?......Ideas?
I pulled the intake to put in Greg Browns oil baffle.
When I put everything back together i have this whistle.
Took it apart again, pressure tested the TB.
The throttle body O-rings were leaking, I replaced them.
Put it back together.....still whistling.
Sounds like it is coming from my ISV.
It is new.....anyone have this problem?
Solution?......Ideas?
Last edited by Dadddio; Feb 10, 2015 at 09:52 PM.
Racer
Joined: May 2011
Posts: 262
Likes: 0
From: West Chester Ohio
There are so many places that that intake could suck air it's not possible to list them all!
I would however try squirting a touch of starting fluid around the hoses and clamps for starters... just enough to see if you get a response from engine? Should eventually find it!
I would however try squirting a touch of starting fluid around the hoses and clamps for starters... just enough to see if you get a response from engine? Should eventually find it!
Nordschleife Master
Joined: May 2012
Posts: 5,222
Likes: 432
From: Thousand Oaks California
Try puffing a cigar's smoke into the intake while the engine is off to find leaks. It's a fair bit safer than using ether on a running engine.
But geez, I have never heard a squealing leak that bad before.
But geez, I have never heard a squealing leak that bad before.
Race Car
Joined: Jul 2005
Posts: 4,793
Likes: 92
From: Mechanochondriacism
flappy no adapty
You don't have a flappy [valve] in the [S4] way that term is usually applied. I think you mean the throttle body?
Frequent fliers for the intake whistle are the Idle stabilizer valve/associated hose. Given the service, the vent tube on the water neck is a good prospect.
https://rennlist.com/forums/928-foru...e-whistle.html
Mechanics stethascope may help you isolate, and/or the smoke.
EDIT: Ok, now that I've heard the vid...wow, that sounds almost like a reed valve, I'm a little concerned that something may have been left in the intake track? Maybe a collapsed hose....What came off for the baffle R&R?
Frequent fliers for the intake whistle are the Idle stabilizer valve/associated hose. Given the service, the vent tube on the water neck is a good prospect.
https://rennlist.com/forums/928-foru...e-whistle.html
Mechanics stethascope may help you isolate, and/or the smoke.
EDIT: Ok, now that I've heard the vid...wow, that sounds almost like a reed valve, I'm a little concerned that something may have been left in the intake track? Maybe a collapsed hose....What came off for the baffle R&R?
Last edited by SMTCapeCod; Feb 10, 2015 at 10:49 PM.
Addict
Rennlist Member
Rennlist Member
Joined: Mar 2005
Posts: 2,301
Likes: 4
From: Austin, Texas
I recently had a very bad whistle after rebuilding a motor with a powdercoated intake: one of the runner flanges was no longer flat (was a donor intake) and had to be placed on a flat surface with lighting to see how non-flat it was. A few passes on a belt sander fixed it just fine. 
Yes, use a firework punk, incense stick, or cigar to find the source of air infiltration.
Yes, use a firework punk, incense stick, or cigar to find the source of air infiltration.
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Thread Starter
Instructor
Joined: Aug 2012
Posts: 234
Likes: 1
From: St. Louis, Missouri
Capecod,
Stripped the entire intake plus water bridge.
So, pretty much everything.
Gonna have some better ears listen tonight.
Gonna see if it changes with idle adjustment also.
Stripped the entire intake plus water bridge.
So, pretty much everything.
Gonna have some better ears listen tonight.
Gonna see if it changes with idle adjustment also.
Thread Starter
Instructor
Joined: Aug 2012
Posts: 234
Likes: 1
From: St. Louis, Missouri
Crap.
Now that you mention that, it does.
Like blowing across a piece if plastic or rubber or silicone.
I have silicone intake gaskets.....not sure that's what it is, but it sure does sound like it.
I guess I need to put paper gaskets on trim the silicone ones.
What do you guys think?
Now that you mention that, it does.
Like blowing across a piece if plastic or rubber or silicone.
I have silicone intake gaskets.....not sure that's what it is, but it sure does sound like it.
I guess I need to put paper gaskets on trim the silicone ones.
What do you guys think?
Last edited by Dadddio; Feb 14, 2015 at 01:57 PM.
Pro
Joined: Oct 2010
Posts: 678
Likes: 2
From: Indianapolis, In
Thread Starter
Instructor
Joined: Aug 2012
Posts: 234
Likes: 1
From: St. Louis, Missouri
Okay.
Removed the intake and throttle body.
Removed all hoses, re-installed.
Trimmed a few edges on the silicone gaskets.(don't think that was the problem)
Put it back together.....still whistling.
Never did this before.
The only thing different is the oil baffle.
Listened with a piece of hose, sounds like it's
coming from the front of the throttle body.
Guess i need to do a smoke test next.
Removed the intake and throttle body.
Removed all hoses, re-installed.
Trimmed a few edges on the silicone gaskets.(don't think that was the problem)
Put it back together.....still whistling.
Never did this before.
The only thing different is the oil baffle.
Listened with a piece of hose, sounds like it's
coming from the front of the throttle body.
Guess i need to do a smoke test next.
Rennlist Member
Joined: Apr 2005
Posts: 1,698
Likes: 9
From: Plano, Texas
I had the exact same thing happen when I redid the top end of my 87. I dissasembled and reassembled and the whistle continued. Once I went through a few heat cycles, the whistle stopped. The only thing I could figure was that some of the the paper gaskets had a glue bead that did not go all the way around. Once the engine heated and the glue melted the gasket sealed better. It has been a few years. Let me see if I can find the thread.