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MG MGF Technical - Just a new head needed after HGF?

I was just flicking through the HGF 'hall of shame' and I noticed that the extra work done on other F's after replacing a failed HG can be

1. nothing
2. skim head
3. replace entire engine

Now I have been told that my engine needs a repair somewhere between 2 and 3 - new head, but not whole new engine. Do any of you techie wizards out there think this makes sense? Why am I the first person in MGFdom to be left with a knackered head, but a usable block?

Or am I just becoming overly suspicious because of the excruciating wait for parts?

All advice gratefully received!
David Bainbridge

By th eway, i should add that the explanation given was that the head was 'too warped to skim' and remain within recommended tolerances.
David Bainbridge

you are not the first - this has been experienced by several others previously.
David

Sorry to hear that mate, a warped head is usualy caused by excessive heat. Some folks get away with driving the car with a knackered HG others don't.

I hope it doesn't cost you too much!

RGDS RichieR
RichieR

David
This may have been asked before, if it has, please excuse the question!
Are you the only (as far as we know) sufferer of HGF on a MY2000 F? Was your car fitted with the revised HG?
I have a 2002 Trophy 160, and want to convince myself that the HGF problem has been cured!
Cheers
Paul
Paul

So - not a new thing, then.

I'm not paying - it was just within my one year warranty!

Oh, and it was one of the last to get the old HG, according to Dieter's VIN list.
David Bainbridge

Paul, HGF is a possibility on ALL engines: the gasket is inevitably the weakest part of the construction (and probably a good thing too). I would suggest that failure of it is/has been too common on K-series engines, but there'll never be a 100% survival rate. Thus the only improvement we'll see (if the uprated gasket works) is in the prevalence of failure: and we have enough difficulty discovering what that is at the moment anyway.

My impression is, so far, that things are better - the original gaskets were failing on cars as soonas the mid-10000 mile mark, and there seem to be few if any reports of such early failures from 2000MY cars and later, which should be well into those distances by now.

Just myimpression, of course.

E
Ed Clarke

Ed, whilst HGF can happen to any engine the K series engine - especially the 1.8 litre model - does seem to have an ongoing failure problem and seems to be more afflicted than other alloy block/alloy head engine designs, a construction that's now very common across many automotive OEMs.
What are the changes in this uprated gasket that you describe? Do you know if there are any other features of the K series unit that make it prone to HGF ?
Adrian

David,
Sorry to hear your troubles. Been nearly there, done that....

Many HGF's result in a skim being required - due to warping of the head by a greater or lesser degree.
Mine was 4 thou warped - just within tolerance for a skim.

In the old days, one could machine quite a bit off a head, and insert a special "gasket" or just use 2 head gaskets during the rebuild (to maintain valve to piston crown clearance). This does not seem to be an option these days, and on the K series engine, there is precious little material around the bores and cooling/lube passages to support one head gasket material already (due to the "over bored" nature of this lump).

Therefore if your head becomes warped due to local overheating (and that doesn't mean the temp gauge shot up, or you were doing 100mph when it happened!) and would require too much machining away of material to achieve a "flat" face - ie the valves would contact the piston crowns - then the head must be rejected.

Engine rejection can be for a variety of reasons - severe overheating (partial seizure) liner distortion or dislocation etc etc - often it is cheaper to find a "salvaged" engine than the manhours/parts required to recover ones own.

Paul.
Paul Lane

David,
I've just flicked through the HG hall of shame, and its dire. I'll never let anyone take the piss out of my Triumph Stag's original (remember the Stags overheating HG problems?) V8 ever again. Just hope the KV6 engine doesn't have the same failure mode, my Rover 75's just out of warranty.

Cheers
Adrian
Adrian

This thread was discussed on 24/05/2002

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