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Kirkham Motorsports

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  #1 (permalink)  
Old 04-03-2015, 09:03 AM
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Default Finding Exhaust Leak

Car is popping out one pipe during deceleration, I have slip on side pipes and trying to locate the leak. I have tighten the bolts at the header flange and
The bolts that hold the headers and side pipes together. Is there a easy way to find where it is leaking??
Jon
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Old 04-03-2015, 09:40 AM
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One suggestion I received was to get something to serve as a long wand (heavy piece stiff wire for example) tape a small tuft of tissue paper to the end of it. Then move it around each connection looking for exhaust leakage to move or flap the tissue paper. Sounds good - harder to do in real life as any contact of the wand to the body or engine component will set it to vibrating and with limited space in the engine compartnment that's a big limitation.

As a one in-a-million lessons learned - I had an exhaust leak and finally discovered that the last time I slipped my header on I left the lower bolts/washers in the head for the lower bolt slot in the flange to ride down on and hold the header pipe while I threaded in the top bolt. What I didn't catch was that on one cylinder, the flange slid in between the washer and the bolt head, trapping the washer against the head/gasket. Made for a rather persistant leak until I finally discovered it.
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Old 04-03-2015, 10:12 AM
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Inspection mirror and flashlight, look for exhaust soot.
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Old 04-03-2015, 10:13 AM
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You need two people.

One to stuff a rag over the pipe outlet to "block" the pipe, while the other looks for the leak with the engine running.

This may help you find it if the exhaust note is not too loud.
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Old 04-03-2015, 10:19 AM
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Hi Jon,

Did you use a sealant for the slip-ons? I had an exhaust leak at the collectors (where they slip together) and used a liberal amount of Walker's Acoustiseal

[ame="http://www.amazon.com/Walker-35959-Hardware-Sealing-Compound/dp/B000CQDL94"]Amazon.com: Walker 35959 Hardware Sealing Compound: Automotive@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41W2dSVXfvL.@@AMEPARAM@@41W2dSVXfvL[/ame]

to seal it. If it is leaking at the slip fit, I doubt tightening those bolts will stop it - needs to be sealed.

Kevin
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Old 04-03-2015, 04:44 PM
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Quote:
Originally Posted by MOTORHEAD View Post
Inspection mirror and flashlight, look for exhaust soot.
Good suggestion for those with silver or white coating. Unfortunately mine are black ceramic coating so didn't work so good. But for silver or white you should be able to see the soot from a leak.
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Old 04-03-2015, 08:00 PM
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Default Black Pipes

Mine are also Black Cermanic
Jon
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Old 04-04-2015, 06:00 AM
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The soot should show-up grayish on the black pipes, unless you're running rich.
Most mechs have a 2" or so mirror on a telescoping handle, so it's quick and easy to use as a first quick ck .
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Old 04-04-2015, 08:52 AM
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Same as a vacuum leak.......take a spray bottle with water and spray at the leak..area....
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Old 04-04-2015, 02:06 PM
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Checked the pipes where they slide together with a white paper cloth and all the joints have no exhause residue on them. The header flange is tight with new gaskets so now I'm not sure where the leake could be ....it's only under deceleration
Jon
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Old 04-04-2015, 03:02 PM
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Jon,

What carburettor, and camshaft specs?

How loud is the popping on deceleration, and how often?
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Old 04-04-2015, 06:47 PM
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Default Poping

This is new after having some head work and replacing with all new gaskets. I didn't have this probl prior.... Headers and side pipes have a fresh creamic coating and heads were cleaned up!
Jon
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