K Series Rover rubbish

[Soton Pug]

Hi Guys, the GF's Rover 25 has finally given up I've talked her into getting rid now but she's asked me to try and repair the head gasket so it can be flogged. Other than the obvious don't bother trying remarks is there anything other than the fact that it's a rubbish Rover that I need to know about before I start surgery? I've rebuilt my 205 engine so i've got moderate mechanical ability.

I've heard lots about getting a Land Rover HG but I really can't be bother, anything else that is an absolute must? (Other than the scrap yard).

Ta in advance

Mike

[paintman]

Get the head checked. They usually warp at the same time. My neighbours just had one go & they had to take around 15 thou off it.

[fatjon]

If you really can't be bothered, and let's face it who could be bothered, there are some blokes on ebay who do a fixed price, come to you K series head gasket replacement service. It may be a cheap and cheerful way of seeing the back of it. Of course if they don't skim it don't sell it to a mate.

[Soton Pug]

It's very tempting to put a brick on the loud (obviously not really loud as it's a rover) pedal and let it seize up, maybe leave the drain plug off by accident or something...

I'll take the head off and get it checked, can get a skim cheap from my local engine shop so not a massive issue, i'm starting to think i really shouldn't have agreed to sort this out...

Never mind.

Cheers all

[Mr2Mike]

Soton Pug said:

Other than the obvious don't bother trying remarks is there anything other than the fact that it's a rubbish Rover that I need to know about before I start surgery?

Yes, with that attitude it's definitely not worth you repairing it. Give it to someone who would appreciate the chance to get a useful car back on the road with a small amount of work.

paintman said:

Get the head checked. They usually warp at the same time. My neighbours just had one go & they had to take around 15 thou off it.

They warp if brain dead drivers carry on driving after all the coolant has drained into the oil. With drivers of moderate intelligence that stop before serious overheating occurs than the heads are usually ok. Don't skim them unless they need it.

Edited by Mr2Mike on Monday 12th April 16:35

[paintman]

Why so arsy?

Assuming a head is true can result in getting to do the job all over again under warranty. Usually not long after the engine has got back to normal usage after the rebuild.
Does wonders for customer relations and profits so I guess we'll just keep checking they're true. Which doesn't mean skimming.

Edited by paintman on Monday 12th April 21:08

[Mr2Mike]

paintman said:

Why so arsy?

Assuming a head is true can result in getting to do the job all over again under warranty. Usually not long after the engine has got back to normal usage after the rebuild.
Does wonders for customer relations and profits so I guess we'll just keep checking they're true. Which doesn't mean skimming.

If you could point out where I suggested you ASSUME a head to be flat I'd appreciate it, as I can't seem to find it.

Many people seem to think it's a good idea to get a head skimmed irrespective of whether it's flat or not after HGF. All I'm saying is this is not a good idea to do this on the K series if it's not necessary as it removes the harder, heat treated gasket surface.

[paintman]

Mr2Mike said:

With drivers of moderate intelligence that stop before serious overheating occurs than the heads are usually ok.

Edited by Mr2Mike on Monday 12th April 16:35

I totally agree that you only skim if necessary but as you say, many just get it done as a matter of course.

Same as those that think it better to follow the Haynes manual instructions rather than the manufacturers instructions that come with a new head gasket & then wonder why one of the stretch bolts snaps Sometimes its very difficult to keep a straight face.

Edited by paintman on Tuesday 13th April 20:57

[Yuxi]

Mr2Mike said:

All I'm saying is this is not a good idea to do this on the K series if it's not necessary as it removes the harder, heat treated gasket surface.

Are you sure? How do they heat treat the surface of the head.

[Mr2Mike]

Yuxi said:

Mr2Mike said:

All I'm saying is this is not a good idea to do this on the K series if it's not necessary as it removes the harder, heat treated gasket surface.

Are you sure? How do they heat treat the surface of the head.

I don't know the exact process, but the heat treatment forms a harder "skin" on the head. There;s lot of evidence to show that a skimmed head is more likely to recess around the fire ring, and a badly overheated head won't hold a gasket for long at all as they get very soft. This is why the "head saver" shim was produced to rescue otherwise scrap heads.

[Yuxi]

Mr2Mike said:

Yuxi said:

Mr2Mike said:

All I'm saying is this is not a good idea to do this on the K series if it's not necessary as it removes the harder, heat treated gasket surface.

Are you sure? How do they heat treat the surface of the head.

I don't know the exact process, but the heat treatment forms a harder "skin" on the head. There;s lot of evidence to show that a skimmed head is more likely to recess around the fire ring, and a badly overheated head won't hold a gasket for long at all as they get very soft. This is why the "head saver" shim was produced to rescue otherwise scrap heads.

I am a Manufacturing Engineer for a company who design car engines, I have installed petrol and diesel aluminium head and block machining lines in India, China, Malaysia and the Philipenes and have visited most engine plants in Europe, I have never heard of this. Fancy milling cutters for covering up porosity yes, heat treating one face of a machined casting no.

[Simon says]

Mr2Mike said:

Yuxi said:

Mr2Mike said:

All I'm saying is this is not a good idea to do this on the K series if it's not necessary as it removes the harder, heat treated gasket surface.

Are you sure? How do they heat treat the surface of the head.

I don't know the exact process, but the heat treatment forms a harder "skin" on the head. There;s lot of evidence to show that a skimmed head is more likely to recess around the fire ring, and a badly overheated head won't hold a gasket for long at all as they get very soft. This is why the "head saver" shim was produced to rescue otherwise scrap heads.

The head saver shim was designed to stop the constantly moving fire ring gouging into the headface which in turn eventually scraps the head due to to much material removal from constant facing/skiming,nine times out of ten this is the reason why i get the head re-faced pre modifications because of fire ring gouging,i have never heard of this heat treating on the head face you speak of i am not a K lover but i have yet to see a cracked head either that they are supposed to be prone to seen a few broken liner's due to heat damage though although i dislike the engine if the jobs done correctly then you should be OK for some time,certainly kept me busy over the years

Edited by Simon says on Wednesday 14th April 11:31

[Pumaracing]

Mr2Mike said:

Many people seem to think it's a good idea to get a head skimmed irrespective of whether it's flat or not after HGF. All I'm saying is this is not a good idea to do this on the K series if it's not necessary as it removes the harder, heat treated gasket surface.

bks. There's no "harder,heat treated gasket surface" on any head - period.

[Meldonte]

Just to attempt to clarify some of the issues here.. ( I cant get help but get stuck in on a "K-Series is **** thread)

It is not just the machined surface that is heat treated, the whole head is.. it is held at around 500-600 degrees for several hours and then rapidly quenched in hot water then held at 250 degrees for a few more hours..

This is a necessary process for the particular alloy used to attain the required strength and hardness given the large % reduction in material which gives the massive weight saving that you get with a K over other 4-pots. This can also become its downfall as when the temperatures become elevated above normal operating temperatures, the microstructure becomes "un-frozen" and over periods long periods of time the head becomes well, soggy.

In order to combat this the gasket is designed "wet" so there is a cooling film of water accross the whole head face that obviously cant get into the firerings or the oil wells, this helps reduce temperatures around the fire rings at prolonged high load and allows the head face to retain its quenched properties and not go soft.

The problem is unfortunately more complicated than this, because of the location of the thermostat on the inlet side for quick warm up and emissions reasons, the engine can see very strong thermal gradients length wise along the head (as much as 60 degrees difference between 1 and 2.) the relative thermal expansions gradually rub off the elastomer beading on the gasket and twist and warp the head ever so slightly , allowing this small amount of cooling film of water to drain down into the church window oil drain between 1 and 2 and it boils of in the oil unnoticed. This causes air pockets around the fire rings, the head face sits at elevated temperatures for extended periods and gradually loses its enhanced strength.

The nail is finally buried all the way in when the fire rings on the gasket bite into the head after it has gone soft, the clamping strength is vastly reduced and the fire rings leak, pressurising the cooling system, water goes into the oil and vice versa and the game is up. So in reality, the gasket is probably already doomed to failure long before the first signs of HGF.

Contrary to popular belief, there IS a cure. Assuming the head has not over heated and the correct gasket is fitted (it depends on the liner heights whether a MLS or an uprated castellated elastomer gasket should be fitted.) Although a long way away from the problem, the uprated oil ladder which the stretch bolts clamp is substantially stiffere and helps to reduce the thermal expansion problem that occurs at the head face. The fitting of a PRT thermostat or a remote thermostat on the outlet side also reduces temperature fluctuations during the warm up period and effectively removes "thermal shock" problem of cold coolant coming into a hot engine in the mid engined K-Series variants.

In reality it is just like any other engineering problem, it requires careful thought, analysis and testing before throwing a solution at it or simply writing the whole engine off as a useful piece of rubbish.

People are so very quick to jump on the "Hurr Durr Rovers HG dey rubbish" bandwagon without ever attempting to understand why it happens or solve the problem at its root, throwing a new standard gasket on after the engine has been run without any coolant for an hour by some cretin is as good as useless. it is literally like changing the air filter after someone poured iron filings down your bores. the horse has bolted and is halfway to France.


And before you ask, yes I bought a tomcat with a HG on its way out 2 and a bit years ago, I did the job myself for 100 quid and have done 35 thousand miles since without ever looking back, and if it does go again? I'll swear for an hour or two, fix it again in a day or two and get on with driving it.

http://www.mgf.ultimatemg.com/group2/common_proble...
http://www.uk-racing-castings.co.uk/lm25data.htm

/Rant

Edited by Meldonte on Wednesday 14th April 13:07

[Yuxi]

Meldonte said:

It is not just the machined surface that is heat treated, the whole head is.. it is held at around 500-600 degrees for several hours and then rapidly quenched in hot water then held at 250 degrees for a few more hours..

You should make it clear that the heat treatment is done before any machining, the fire face does not exist when the heat treatment is done.

[Tony427]

Just had a relative's Rover 25 head gasket let go.

How much would be a reasonable charge by a small garage to get it fixed( skim and new uprated HG). She's been quoted £500 which feel is a bit excessive.

Cheers,

Tony

[Simon says]

Tony427 said:

Just had a relative's Rover 25 head gasket let go.

How much would be a reasonable charge by a small garage to get it fixed( skim and new uprated HG). She's been quoted £500 which feel is a bit excessive.

Cheers,

Tony

Well it should be done along with a cambelt change also,no it's not excessive ridding the cooling system of oil contamination is not always that easy

[Soton Pug]

Mr2Mike said:

Soton Pug said:

Other than the obvious don't bother trying remarks is there anything other than the fact that it's a rubbish Rover that I need to know about before I start surgery?

Yes, with that attitude it's definitely not worth you repairing it. Give it to someone who would appreciate the chance to get a useful car back on the road with a small amount of work.

paintman said:

Get the head checked. They usually warp at the same time. My neighbours just had one go & they had to take around 15 thou off it.

They warp if brain dead drivers carry on driving after all the coolant has drained into the oil. With drivers of moderate intelligence that stop before serious overheating occurs than the heads are usually ok. Don't skim them unless they need it.

Edited by Mr2Mike on Monday 12th April 16:35

Mr2Mike, a little message for you sir.

1. It's a sh*t car, mainly because of the build quality (sh*t), reliability (sh*tier) and service costs (disgusting) which have been attached to it so no, i'm not over the moon about repairing something which is actually, no use at all.

2. The brain dead driver as you put it is on her way to becoming a fu**ing professor in Clinical Psychology, the fact that she knows nothing about cars is completely irrelevent to intelligence.

Thanks for your input, you make PH such a wonderful place to play.

Edited by Soton Pug on Friday 30th April 13:44

[Mr2Mike]

Soton Pug said:

2. The brain dead driver as you put it is on her way to becoming a fu**ing professor in Clinical Psychology, the fact that she knows nothing about cars is completely irrelevent to intelligence.

Perhaps complete and utter lack of common sense would be a better description, certainly not an uncommon trait amongst academics.

A fu**ing professor you say? Some kind of dual role?

[Del 203]

Mr2Mike said:

A fu**ing professor

I think i've seen that DVD