Triumph Repair: 1974 TR-6 Exhaust Manifold Gasket

Question
QUESTION: I believe the exhaust manifold gasket is leaking.  Other than the sound it makes, how can I be sure that is the problem before I begin removing the Carbs and Manifolds and risk a broken bolt?  If I do need to replace the gasket, what advice can you offer?

ANSWER: Hi Bob,

It is difficult sometimes to pinpoint a manifold leak. One thing that I used in the dealerships I worked in to help locate an exhaust leak is to take a 2 or 3 foot length of small hose (like a piece of vacuum hose) and listen at one end while probing tight places with the other end, while the engine is running. Works very well.

Manifold studs and nuts do get rusted so badly that breaking a stud off is a danger. I have broken many over the years but saved many more badly rusted ones with the use of a Oxygen/Acetylene torch by heating the rusted nut to a red color then quickly loosen the nut.

Care must be taken because you are in an area of fuel, hoses and wires. So even though I was experienced at it, I still kept fire fighting equipment near by and used small pieces of sheet metal at times as well placed heat shields.

When I did find an exhaust manifold leak I tried to leave the pipe to manifold alone as that is the most likely place to brake bolts and studs on all cars. But also a common place for a leak too.

Howard

---------- FOLLOW-UP ----------

QUESTION: Thank you for your timely reply and helpful tip on utilizing a length of hose to pinpoint the leak.  I'm not sure what you mean in the last sentence where you say "pipe to manifold".  By "pipe", are you referring to the front double down exhaust pipe?

This is the first time I've used "allexperts" and I'm impressed.  Thanks again.

Bob

Answer
Yes, That double exhaust pipe to manifold joint is a common rust point for studs and nuts. But do probe that joint with the hose as it can be a point of leakage that can sound like a manifold to head leak.

Also use "Never Seize" (available as most auto parts stores) on all the studs before putting the nuts back on. This will help stop the nuts from rusting solid to the studs for later on.

Howard