Jim,
I was amazed too when I found that the factory GT V-8 used no exhaust
manifold gaskets as stock. When I visited Beer of Houghton (one of the
foremost MG V-8 shops in the UK) Syd and Malcolm confirmed the lack of
gaskets, and they always retrofit the later gaskets, part number GEG 692.
These were used on the SD1s, but not the earlier cars.
It is my feeling that the very low torque (13 ft-lb.) that was specified for
the GT V-8 manifolds was to allow a bit of "wiggle room" because of the
expected differential expansion of the parts as they heat up. Most early
Rover installations also used lock tabs on the manifold bolts, but although
these were shown in some of the MG factory manual photos, they were not used
on the GT V-8 (probably due to the tight quarters and the need to install
the manifolds with the engine suspended and part-way installed in the car).
Instead of lock tabs, the GT V-8 manual specifies the use of one drop of
"Locktite 40" on each bolt prior to installation. I believe the photos
showing the lock tabs in the GT V-8 manual supplement were cadged from other
Rover workshop manuals.
The other caveat that the Beers mentioned is that when installing the A-pipe
on the factory GT V-8 manifolds, you must be careful that the ends of the
A-pipe slip into the manifold flanges with no side loads. You have to
adjust the distance between the two A-pipe ends using jacks, clamps or
hammers, so that the A-pipe slips easily into both manifolds. Otherwise,
you run the risk of cracking the manifolds, and at $800/pair for the factory
manifolds you need to protect them!
I will use the gaskets and torque the bolts to 16 ft/lb as specified for the
later cars. I am using 3/8-UNC Allen head cap screws with nice thick
washers (the washers are the same as used on early Chevy smallblocks). I
plan also to use Fel-Pro grey bolt prep (a combination anti seize and
threadlocker) on the bolts, but am open to suggestions.
Thanks for everyone's input
Paul Kile
-----Original Message-----
From: Jim Stuart [mailto:jimbb88@erols.com]
Sent: Tuesday, October 17, 2000 4:49 PM
To: KILE, PAUL D
Cc: buick-rover-v8@autox.team.net
Subject: Re: Torque settings for Rover exhaust manifolds
Paul-
While there are no illustrations of an exhaust manifold gasket in the MGB GT
V8
Workshop Manual Supplement, I can't believe that these engines were built
(by
the factory) without them. It is almost impossible to get a seal between a
cast
iron block & cast iron exhaust manifolds because of the different rates of
expansion, and at least 4 times as hard when one part is aluminum.
I have a 1980 Rover Workshop Manual, 2300, 2600, 3500, & a Rover 3500NAS
Parts
Catalogue, also 1980. The manual goes into great detail about removing &
replacing the exhaust manifolds, but is silent about gaskets except within
the
exhaust system itself, Same for the 6 cylinder engines. The parts catalogue,
however, clearly shows manifold to block gaskets with a part number, & a
notation that they are part of a manifold set with a part number.
My own opinion is that there were always gaskets, that it was so obvious
that
it was not mentioned. There were certainly gaskets in the 1980 versions, as
I
have removed them when discarding the 3500 iron manifolds.
I further believe that 13 lbs. is safe with a gasket. My own practice has
been
to snug the bolts enough to compress the lock washers, run the engine a few
minutes, let it cool, then retighten the nuts until the washers compressed.
Jim Stuart
"KILE, PAUL D" wrote:
> Hi guys,
> I'm getting ready to bolt the exhaust manifolds onto my 3.5 for my factory
> MGB-GT V-8. The factory recommends 13 foot-pounds for the bolt torque,
but
> that is for the original specification without manifold gaskets (the cast
> iron manifolds bolt right up to the aluminum ports). I am retrofitting
the
> manifold gaskets, as recommended in an MG V-8 Workshop Note from the MGCC.
>
> Does anyone know if a US-spec Land Rover or Range Rover which uses the
> exhaust manifold gaskets takes a different torque on the bolts? I don't
> have any Rover workshop manuals, only the original MGB-GT V-8 supplement.
>
> Thanks in advance,
> Paul Kile
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