I wouldn't say head gasket fail would be the obvious one as a gasket can fail without any, or only a very small lose of compression. Worn bores/ stuck or broken rings and burnt valves contribute to uneven cylinder pressures.

 

Absolutely correct.

 

Yes, apart from the obvious, it can give a clue as to what area the problem is which can be helpful.

On any car, a cylinder head gasket can be damaged and still show perfect compression.

On a few occasions I've used my compression tester on engines as different as A-O-S-T and K-series, a single individual low compression reading is more likely to be a warped head, valve, bore, piston and/or rings problems.

If you get identical low readings on adjacent cylinders, that can suggest gasket damage in the area immediately between the two adjacent bores. Last year my son's third of a century old MG Metro [ :yikes: ... .] started to run rough and compression testing showed very low identical readings on cylinder two and three and healthy ones on one and four. Here's why.

We do not think that gasket actually failed, prolonged lack of use ( years of storage ) in both current and previous ownership probably caused corrosion to set in and then using the car for longer runs blew the weakened fire rings away there in that very narrow area.

Got near identical low readings on cylinders 2 and 3 on Rover's T series turbo a few years back. The unfortunate previous owner, lovely lady, spent a small fortune on her nice 620ti which still seriously overheated. She gave up and cut losses. I investigated the car and despite a hefty bill which included having the cylinder head, skimmed and dressed, the head was fitted without checking the work. On removal and checking with my straight edge, the head was in a bowed condition ... Using my trusty straight edge on both block and head :~



Revealed this :~



Here is evidence ( Bowed head face ) of exhaust gasses passing the fire rings on middle two cylinders over-pressurising the cooling system once the engine reaches full operating temperature leading to coolant boiling over. :~



Fitted a known good used head and that 620ti became a delightful car to run and own.

 

Thanks for the replies men. I'm suspecting a warped or cracked head to be the cause of my problems.. Ever since I changed the gasket the car has been loosing coolant while sat on the drive. (quite a bit actually, almost a header tank full a week)Becausw of the coolant loss I haven't driven her and was planning on running her with some uv dye. When firing her up this afternoon ahe ran a little rough, burped and started to produce a great amount of white smoke from the exhaust. Dipstick was covered with frappuccino so quite a lot of coolant in the oil. (should have check before stating, I know stupid of me).
So it could be HGF again, or otherwise the coolant is being dumped into the oil elsewhere... But I'm not to sure where.
For the sake of € 30 I'll get a compression tester and see if that shows any clues as to where the problem might have originated.

Other cause could of course be that I bodged the repair myself, but although it was my first time replacing the head gasket, I believe I was quite careful and did everything as per the manual.. Only thing that comes to mind is I might not have cleaned the surfaces well enough..

 

9 time out of 10 a compression test will NOT detect HGF on a K series engine. Normally an HGF on a K series is a failure of the join between the water and the oil, not the combustion chamber and coolant . A more reliable test (I think) is a coolant pressure test. Or the obvious milk shake on the dipstick.

 

I'm 100% sure the gasket has failed(oil looks like coffe with a lot of milk in it), but wanted to know what sort of tests I can do to find out what caused the hgf.
Last time I din't get the head checked so that is something I'll most certainly do this time.
So apart from a compression test kit another good investment would be a coolant pressure kit..
Any other suggestions are more than welcome!

 

Positive evidence of oil-coolant mix is a sure indicator of cylinder head gasket damage. Off with its head ..

Finding the cause of the so called "failure" can be very difficult. It takes time and that costs in a professional environment. If the cause is not identified and a repair is completed without eliminating the original cause of the problem, this can lead to a so called "repeat failure" soon after or much later following any repair. Easy to blame the much maligned K-Series when that happens.

In my limited amateur experience of about twenty K-Series, O and T series cars professionally diagnosed as a "they all do that" HGF with the widespread "It's a Rover" mindset, six of the cars did NOT have a damaged CHG. These were three K, one O and two T-Series. They all had worn out water pumps. That's where the coolant was being lost. A worrying high percentage of the other "failures" were on cars where much expense was involved for the previous owners with pro-repairs which did not end in a satisfactory outcome.

A worn water pump or other coolant loss reason leading to overheating, sometimes severe overheating when car users foolishly drive on knowing something is not right, can damage engine components. The first component to be damaged, not fail, is guess what. I "John can you help with your car transporter trailer" recovered TWO work colleagues' cars. Both were admitted having been driven on knowing something was not right and guess what happened shortly after. One was a Rover, the other a Toyota. Both cars needed far more than a Cylinder Head Gasket.

Human Nature being what it is, it is so convenient to blame the "They all do that" ... trouble is, they do not all do that, only some. More often than not, the real cause and blame lay elsewhere.

Just my opinions of course. Now retired with time available, working on "failed" K-Series engines has been a challenge which I've enjoyed with a number of these cars. My latest, a MKII MG ZT-T 1.8t is a challenge I am currently enjoying.

 

My suggestion would be to strip the head off and inspect. John's given some good info on what to look for, also check the liner heights ok. If the head and block are reusable, do the job again with new HG and IMG. It will be easier second time

 

thanks guys

The liner on cylinder one appeared to be flush with the block when I did the HG in september. Also the piston in that cylinder was clean as a whistle compared to the other three, where there were obvious signs of combustion residue. I checked the liner to see if it might have been cracked with special dye, but all looked well.
Would a sunken liner be clearly visible or would 0.01mm do the trick

Due to the flush liner on cylinder one I opted for a payen gasket at the time as this is supposed to be the best option.

My other theory is that the head isn't straight so first thing I'll do is send that off to get checked and pressure tested (might be a crack)

Hopefully the bottom half is allright as I wouldn't want to take out the engine and try and source a new one here in NL

The Liners are a job I don't fear too much but the most important and difficult thing is to Identify what the underlying cause is.

With any luck it's just the head that needs skimming and I won't have to buy a ton of other parts.

As I've only driven about 100 miles since october and changed belts, pump and headbolts am I right in assuming I'd only need the gaskets if it turns out it's the head?

 

Different people will say different things, but on an old Rover I'd reuse all those bits, less the hg (but inspect and replace if any look damaged or out of spec). If you mean 0.01mm protrusion for the liner, that's about a thou so pretty flush. How different from the other liners is that as uneven is probably worse than simply low? Anyway, I'd say the elastomer gasket was the right choice if you are going to use the block it as it is. Of course, other more pricey alternatives would be to lift another engine in if you could get a better looking one, or do the liners which is a big job. Have a good look at the stripped engine before you decide.

 

I did a sort of 'fingernail' test. I could feel the otherliners protude a bit but the liner on cylinder 1 felt flush. At least i couldnt feel any ridge (down nor up if that makes sense).

 

Hallo Michiel,

Het beste is om even een setje voelermaatjes te kopen (€5 bij de gamma) en een stevige rechte liniaal te regelen.
Mijn blok zat tussen de 0.00 en 0.005 mm en met behulp van een Payen koppakking zit deze weer dicht (ik heb wel de kop laten vlakken).
Mocht je toch een nieuw blok nodig zijn, Weusthof in NL heeft vaak goede exemplaren voor rond de €800,-.

Translation:
Best thing is to get a feelergauge and a straight edge to check the liners.
Mine had between 0.00 and 0.005 mm protrusion.

 

Hallo Michiel,

Het beste is om even een setje voelermaatjes te kopen (?5 bij de gamma) en een stevige rechte liniaal te regelen.
Mijn blok zat tussen de 0.00 en 0.005 mm en met behulp van een Payen koppakking zit deze weer dicht (ik heb wel de kop laten vlakken).
Mocht je toch een nieuw blok nodig zijn, Weusthof in NL heeft vaak goede exemplaren voor rond de ?800,-.

Translation:
Best thing is to get a feelergauge and a straight edge to check the liners.
Mine had between 0.00 and 0.005 mm protrusion.

Thanks/ dankjewel for that. I was planning on measuring the differences in height once I've taken the head off. Need to find a decent straight edge to check though. I have a decent set of feeler gauges at home which I normally use for my guitars.
I'll get the head examined as well whilst I'm at it..

Hopefully I wont need a new engine but If it's just the liners I think I might even try to just replace them..

Would any other damage in the lower block cause these symptoms? Or would I notice other things as well?

 

Just stumbled across this great video on youtube:

 

Feeler gauges and "finger test" for cylinder liners.

My son and I have renewed the Cylinder Head Gaskets ( CHG ) on about 20 K-Series engines over the past ten years. These include 1.4; 1.8; 1.8VVC and 1.8 Turbocharged. Only in three cases did we decide a head skim was necessary ... I actually thought two need not be done but, better safer than sorry. I have only ever had one done. By the way, I prefer to use a local engineering firm between Stroud and Stonehouse in Glos who impressed me with some examples of K-Series Heads they had worked on and who recommend "Grinding" rather than "Skimming". I have since had a 1.8 Head "Ground" on their machine which I plan to fit to the engine removed from the MG ZT-T 1.8t project car I am currently working on when I rebuild that motor. The original cylinder head has been heavily skimmed more than once and I consider scrap.

Have never actually measured how proud are cylinder liners. I usually check with a simple finger test ~ by running my finger across the block-liner interfaces ~ there are several, usually four around each liner ~


When my "finger test" is not conclusive, I use a feeler gauge by sliding it on the block against the liner. If the liner is proud, the feeler blade will come to a stop. That has so far been good enough for me. :~



The latest CHG renewal was on my MG ZT 1.8t which is now my daily driver. I used the feeler gauge blade as a second check as my finger test left me with some doubts. I have always used the MLS ( Multi-Layer-Steel ) CHGs and head saver shim and so far, all results have been very good. Not used as a measure, used to confirm the liner is proud of the block. Like this :~

 

I know the thread has progressed beyond this but I have to make my smart-ass (but true) comment. "If your compression guage fills up with dirty water it is likely you have HGF!"
I have been impressed by the latest "Chinese" head gasket BTW.

 

There again, a perished INLET Manifold Gasket can allow coolant directly into usually Cylinder No. 4 ( nearest Gearbox ) or No. 1. After hot engine switch off the heat still in the engine continues to transfer to the near static coolant super heating it well above normal operating pressures and temperatures. That's why it is wise to allow an engine to cool after switching off before undoing the Expansion Bottle Cap. Those are the higher pressure conditions in the recently switched off hot engine which will force coolant past any gasket weakness be it the Inlet manifold or the Head Gasket allowing coolant to enter the combustion chamber. If the Inlet valve on No. 4 Cylinder happens to be open when the switched off engine stops, that escaping coolant past the gasket will go straight into the cylinder past the valve then or later when it opens up next engine start.

Folks frequently report slow to start and rough idle or stalling on a cold engine when started up. This usually clears after a while and engine runs fine. Running the engine expels any escaped coolant which can quench sparks until it is cleared out of the engine.

Worth checking the Inlet Manifold Gasket before head removal ... just in case. It's usual for the Inlet manifold to be removed from the head before removing cylinder head anyway ... so check that manifold gasket first ... just in case. Could be all that's wrong in some cases.