Re: M151a2 The proper way(s) to seal exhaust manifold

Date: Fri Feb 28 2003 - 01:16:09 PST

Dear Listers,

there are two methods of installing the exhaust manifold on an M151-series,
both of which were authorised at the same time by the Mil. The choice was
left to the user.
One method used the gasket kit, the other (original method) was w/o kit.

TB38-0108-03 decribed how to install the manifold without the kit. It also
showed how to straighten the ports on a damaged/crushed manifold using a
"home-made" die-form.

Document 12302579 showed how to install the manifold using the gasket kit.
This document should accompany the kit.

The biggest cause of manifold leaks is overtightening / uneven tightening of
the manifold securing bolts. That extra "half-a-turn" does much more harm
than good. The tubular exhaust manifold usually ends up being distorted,
hence the leaks. Then if the bolts are tightened further to stop the leak, it
gets worse, not better.

If you don't normally use a torque wrench on your Mutt, this is one time that
you should !

The spec for tightening W/o kit is 12-16 lb-ft
The spec for tightening WITH the gasket kit is 18-23 lb-ft.
And if you use copper-grease or other anti-seize compound on the bolt
threads, you will find life much easier when you come to remove that manifold
once again in a few years time.

Kind regards....

This archive was generated by hypermail 2.1.4 : Wed Apr 23 2003 - 13:25:35 PDT