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MG MGA - cylinder head torque

The Haynes manual lists the head torque at 70 ft lbs but mine has a handwritten amendment at 50 ft lbs. I can't remember why. Can anyone shed any light ?
I am using a copper gasket - have taken the Payen compo off.
Roger Walker

roger
haynes got it mixed up, it's supposed to be--

70ft/lb---twincam engines
50ft/lb---pushrod engines

if your new copper gasket doesn't have a coating on it i'd recommend that you get yourself a spray pack of vht- or similar, copper based gasket spray and give the gasket a light spray on both sides, this helps to prevent oil/coolant from weeping from the gasket. the vht can is called coppercote, it needs to be a metal based sealant
William Revit

Roger

I thought the Payen gasket was the tops, why did you decide to replace it?
Bolney Coupe

"Bolney",

I also think that the Payen gasket is the better option, particularly if you suspect that head and deck surface are not perfectly flat.

The copper gasket is perfectly fine though for a standard MGA engine, particularly if the surfaces are flat.

I used a Payen composite gasket on my 1950cc engine a few years ago after the Cometic composite gasket failed.

Cheers
Colyn
Colyn Firth

Welcome back Willy.

The Spridget/Mini Payen gaskets* have been (were?) hard to get for a while, there was a problem with them previously, I fitted one last year and it had a small label on it, I forget the wording but basically not to fill the engine with coolant until the engine was to be (immediately?) run.

I was disappointed to find the gasket that had blown was the same Payen gasket I'd been recommended to fit, it lasted under 12 years and 50,000-miles which I thought was disappointing for a mildly tuned road only use car.

Both times the head was skimmed.

ETA: *BK 450 (I even remember the number which is very unusual for me)
Nigel Atkins

cheers nigel
William Revit

Willi - thanks - good advice as always. Yes, I have been looking on Peter Burgess' advice ( 5 years back) for a Payen gasket but they don't seem to make them anymore.
Roger Walker

Owners have enough problems refurbishing their car without the repair manuals double-crossing them.

An Autobook manual told everyone with an MG engine to install the distributor 180 deg. out.....

BTW, you shouldn't need any sealant on a head gasket if the surfaces are level. Using any usually results in a clean up mess next time you take it apart.
Bill Spohn

Bill, You are so right;Peter Burgess (of all people) recommended I fit the 1622 head he had just modified, with a Payen gasket and messy sealant. It was in perfect shape when I removed the head now five years later, in order to replace piston rings. Cleaning up the
legacy of the messy sealant is taking ages.I am disappointed to have to use a copper gasket but NTG ( the major parts supplier in UK) say they have supplied lots and never had complaints about them. I am mindful now of Willi's advice - Do I use Coppercote or Peter B's messy sealant ?
Roger Walker

I have never used any sealant on my heads and I've run upon to 12:1 compression with no leaks.

A normal copper gasket should accommodate 2-3 thou out of dead flat, and they are usually sprayed with a shiny lacquer coat anyway that helps seal.
Bill Spohn

One solution that I have never seen used on B series engines, but was at least sometimes used on T series race engines, was to carefully lap the head and block together using valve grinding paste, then clean it all up and assemble it dry. Apparently that works.....
Bill Spohn

Bill, that was done on the Works Sebring Deluxe cars. They also had an external connection at the rear of the block going to the cylinder head for cooling. Our local Senring owner still has this engine as a spare but elects to run an enhine with a head gasket- a lot less mucking around and more forgiving.
Mike
Mike Ellsmore

This thread was discussed between 16/09/2021 and 28/09/2021

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