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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - mg tf cylinder heads

as most of us know, the mg tf cylinder head is prone to blowing the gasket, basic design fault but with a new gasket and a quick skim all is fixed.
however, how does one know that this has been done? i ask as i considering buying one as an everyday run around for uni, but the salesmen at the car place isnt sure that the particular mg has been done.

any visable signs such as different colour gasket or head markings? or should i consult my tealeaves and/or crystal balls?
c mccallion

Probably less risk on the TF as they stopped using the plastic locating dowels a long time before that. It's a risk we take, but look after the cooling system and you're hopefully be alright.

Good luck ;)
Russ68

nuts, i meant it was an mg f. not the tf. does that make any difference?
c mccallion

chances are it will have been done hard to tell if it has been done right again check water level if there is any oil in water or water in oil if you are unsure take a mechanic with you or look for mg car clubs in your area we are all pretty helpful lot maybe one of these guys would come with you regards richard
tg hardwick

Unless done badly, there is no real tell-tale way of knowing whether a gasket's been replaced or not.
Rob Bell

Sorry, but have to take issue with your comment that it's a basic design fault and that it can all be fixed with a quick skim and new gasket.

The vast majority of HGF failures are attributable to some other coolant issue not being detected early enough, eg weeping joint or water pump, underbody pipes leaking or expansion bottle cap etc, resulting in HGF.

A skim is usually required to eliminate any warping that may have occurred during the inevitable HGF overheating, but the fitting of the new style gasket, modified oil rail (and steel dowels - if there are any cars still around where the original plastic dowels haven't been replaced!) should sort the problem - provided that the coolant system is duly maintained in future.

Prevention is better than cure, and this is one reason why the low coolant level alarm kits are very popular.

As Rob mentioned above - short of removing the head, there's no way of telling whether any work has been done.
Mike Hall

My other one still has the original gasket and plastic dowels and runs very sweetly.
Disgracefully it is just showing signs of starting to go after only fifteen years, so couldn't come to MGF15.
Charless

There are a number of contributory factors to HGF.

Poor head location - plastic dowels
Design flaws in early head gaskets
Porosity on the head surface, specifically under the fire ring
Head annealing/softening due to deficiencies in the cooling/cooling system
Low liner heights

If these are not addressed when the HG is fixed then the failure is likely to repeat itself.

Just blindly skimming the head does not provide a guaranteed fix, it is necessary to condition the material of the head where the fire ring of the gasket sits prior to skimming or a skim is likely to expose inter-dendritic porosity which may wel, cause a repeat failure.

Liner heights too must be corrected if they are low.

The head should also be hardness tested, if it is less than 95 brinell then it should be scrapped.

Dave
Dave Andrews

This thread was discussed between 01/08/2010 and 03/08/2010

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