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MG MGF Technical - HGF new

Sorry if this opens old wounds but I am wanting info.
There is no doubt at sometime, being that I am an MG enthusiast of almost 40 years, that I will purchase an MGF or TF. However I have already being doing some research on HGF. I am fortunate to live in a town of a number of engine builders and remanufacturers. It is Staggering though the amount of K series failures these people are dealing with and I must say the majority of them are NOT engines from MGF or TFs so that definately rules out any notion of this being caused by the water and cooling installation of these cars.

So at the moment what I would like to know is why did MGR change the dowel pegs from plastic to metal? (Did they do this because they believed the head was "floating" about?)
Bob (robert) yes I own an MG Dwarf!

Bob,
Even if you could ask 'them' you wouldn't get the factual answer. I suspect nobody really knows, I am not going to take the top off mine to tell you for certain if it still has the plastics. Just buy the oldest F you can find and love it. Or wait for a bit and buy a 'MinG'! Lol
Charles
PS WTF is a dwarf or even a wasp??
C.R.B. Simeon

Bob,

I was once told that the change from plastic to metal dowls was to stop the head moving around which apparantly it does, particuarly when cold. My 2000 MGF had metal dowls already when I removed the head, however, I removed the head due to bent valves rather than gasket failure (camshaft siezed due to blocked oil way!)

In my humble opinion and being someone who is not a mechanic but an enthusiastic amateur, replacing the head gasket on an MGF is not a particuarly difficult job (non VVC as I think the VVC can be more difficult), just time consuming. As far as cost go, a firm on ebay sell the gasket sets with bolts(which were the same make as my local motor factor when I last checked)for about £45, add to that a head skim, £30 at my local machine shop, a cam belt for around £20, a tensioner around £30-40 and if you want to go the whole hog a new water pump for around £25. I even bought a new cylinder head for mine from a local breakers from an X ref car with a damaged bottom end for £40 (although I have been told that this was extremely cheap by the machine shop that skimmed it). If you are prepared to do the work yourself then I think that they are cheap cars to run and if every couple of years I have to spend £100-200 doing the headgasket it doesn't worry me. The only tool I needed that I don't have was a suitable socket for the headbolts which are a star (torx?) drive.



A D Smith

Bob. If your 2000MGF had metal dowels, then the head had been off before as they were only fitted from May 2001. My November 2000 build still had plastic.
Geoff F.
G. Farthing

Agree if you feel up to DIY then go for it including a head skim but I would recommend using the official MG Rover Head bolts + the latest MGF or Payen head gasket. Not sure the cost saving on an eBay alternative is worth it. Break one head bolt and no saving at all!
Derrick Rowe

Some seem to have misunderstood my question. I do not have an MGF or TF. I also have not got the problem of HGF. I am merely for my own benefit investigating all the claims of the causes and remedies of HGF for when I do buy one. Having inspected 16 HGF engines I simply asked the question "why did MGR change from plastic to metal dowels?" I suspected that it was to stop the head moving as many of the failures I have seen appear to be as a result of this. Unfortunately the failures look the same even with metal dowels so therefore they were unsuccessful.

OK the next question

The headgasket is very strange and has rings around the cylinders that are raised. In the engines I have seen these raised areas have eroded the head around the cylinders! with disasterous effects. Looking at the erosion (if that is the correct word) it seems like it is caused by movement of the head although this can not be the case because the exhaust side is worse than the inlet suggesting it is heat related. Perhaps the head becomes plastic at higher temperatures and suffers from the gasket "digging in".

Anyway what is the idea of this strange gasket design?
Bob (robert) yes I own an MG Dwarf!

There were a number of mods to improve reliability. The steel dowels do stop head movement, there was a new manifold gasket/bolts plus a number of refinements to the head gasket. The idea is that the liners are a few mm above the head to ensure a good seal when all is tightened down.

At high temperature the Head can become soft allowing the liners to dig in.

Land-Rover has introduced a radical change to a multi-layer gasket plus higher torque settings involving a stronger bottom rail and head bolts.

Time will tell on this gasket although it is said that it is less tolerant of liner height variation.

Land-Rover has also introduced a thermostat that operates on pressure as well as temperature (PRT. This is thought to be useful on an "F" as well. Certainly it is said that Ford was not happy about the K series legacy it inherited although the "K" series is generally much more reliable in the less heavy models to the Freelander.

Search the archives for more info on this well aired subject.
Derrick Rowe

Bob,
It is not the head gasket that has dug into the heads, it is the liners. When the K series overheats it is not uncommon for the head to go soft and the liners to move, hence the contact between heda and liner. Also, as I have said before, around about 80% of the time that supposed HGF has occured, it is not the gasket that has failed initially, it is merely a sympotom of some other problem (often air locks in the cooling system or thermostat).
As regards the palstic dowels, as I understand it they plastic dowels go rather soft when warm and allow the head to move when the car starts to overheat.
In any case, if you notice the car is overheating stop driving and investigate the problem. The big repair bills come when people ignore hte steam pouring from the back of the car and keep driving.

As a footnote, remember the K series has been produced in quite large numbers for a huge range of cars (the actual number escapes me at the moment), and the actual incidence rate of HGF is lower than a lot of comparable and contemporary engines.
Andy

Not where I come from Andy, those who believe it not to be a basic design fault are in for a shock. I could not believe how many heads from k series engines were in the machine shop, certainly far more than all other engines put together.

However Andy answer this if you can. The head gasket is unusal to say the least! why does it appear to have raised areas around the cylinders?
Bob (robert) yes I own an MG Dwarf!

Bob, this may be the case but as I say this is mainly due to the large produciton volumes of the K series - lots more engiens means there will be more cases of problem engines.

Not having worked much with other alloy block/head engines, but from what I understand this is a fairly common thing with damp/wet liner engines, as the raised bits are the sealing rings around the liners.
Andy

I think we will have to beg to differ, although outside our circles the K series is looked upon by the second hand car dealers as a joke!.

Anyway I need to look more carefully at this gasket and its relationship to the liners to see if I can understand it better. Will get back to you Andy thanks.
Bob (robert) yes I own an MG Dwarf!


> the K series is looked upon by the second hand car dealers as a joke!.

I look on second hand car dealers as a joke... ;)
Andy

Bob (robert)

There is an article called 'King K' in which Simon Erland looks at the design of the K series and ways of addressing its high incidence of HGF.

Have a look at http://www.sandsmuseum.com/cars/elise/thecar/engine/kingk.html

James
James Reinhardt

Good reading,....
m
m e johnson

An interesting read if a bit over long and flawed.
If the major cause of failure is caused by race engineers overstressing the K series, why does the domestic engine have such a poor reputation as well?

Chris
Chris

I don't buy the idea that the 1.1 and 1.4k series were immune from HGF my old 1.1 metro suffered it after 5 years and a local garage gets a rover 25 a week in with HGF.
Jon Baker

This thread was discussed between 16/02/2007 and 01/03/2007

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