irishminis.ie

I changed the Head gasket on the Se7en today (2000 MPI). When I lifted the head off I saw a lot of carbonisation on Cylinders 4 , 3 and 2. Number 1 was perfect. Can anyone tell me what might have caused this?

that's one blown gasket

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A fully carbon fiber Mini Marcos shell weighs just 7.25kg.

Oil??

That looks like the engine has massively over heated, this could lead to the gasket blowing where it is, the carbon deposit has been cause by poorly seating valves causing misfire and carbon,

have the valve seats re-cut in the head have the head skimmed to make it flat, change the head gasket for the BK450 and change the thermostat to a 80deg one all your problems should go away and the power will return,
regards,
Paul.

I know a bit odd, but could this manifest itself in a cold engine? then go when warmed up adn everything has expaned?

Was the car smokey before the head gasket went ? that ammount of carbon could suggest rings . It would be wise to get a compression test done when you rebuild it .

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i *love* this forum.....

I have swapped the head for another, this is temporary to get back on the road. In the meantime I have already planned to get my original head skimmed and cleaned up ( valves reseated ) . The overheating might have happened whilst my MPI expansion bottle developed a pinhole leak ( replacements weren't available at the time). I have a new Temperature sensor to fit.
Thanks lads.

Still in trouble , I did some test on the car the other day , low compression on cyl no 1 and a leak down test shows it leaking into the crankcase so it looks like rings.
Merlin says rings for these pistons are no longer available.
I've serched the net and I can't find a part number for these pistons, I have found sites claiming to have the right rings but I think they may be rings from an earlier engine ( ring no R41570).
Anybody help?

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TECHNICAL MODERATOR

Have you spoken to an engineer about rings what is special about these rings ? Talk to a good piston supplier dont
get to hung up on part numbers. The head of the piston will be stamped std or 20 ,40 being standard bore or first
oversize and so on if you are useing the same bore you will need a set of ridge dodgers the top ring has a small step
in it to avoid the ware ridge

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Lads I'm not going to Go into it as I just don't have the hours in my day to wright long winded post explaining why, you cant get standard size rings, etc, It quite complex and it suffices to say they cant be got other than a company in the states Total Seal who will supply you with a set of gap-less rings to suite the later type piston fitted to MPI for the grand price or £100 + vat + postages,

Why would people even thing of doing such a thing the reason there is bad leak down is because the bore is worn and the piston is most likely in the same state why would anyone even consider striping an engine completely to fit a set of rings to a worn bore and piston when for an extra few hundred quid you could have a freshly re bored engine running a nice set of +0.020" pistons and have piece of mind you have a new engine,

Kill Ill send you that quote in the morning My internet went down today so Im on Iphone at the moment hopfully it will be back in the morning,
Best regards,
Paul.

Yep that would be the way to go on this one ok!

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It looks like rings but Kill did change the head for one he bought in good faith and didn't check it for any faults so if the head doesn't cheak out when removed we still may be looking at bores that are ok for new rings (80,000 mls). Kill says he didn't notice any scoring on the cylinders so it doesn't look like a broken ring, so is it common for one set of rings to ware so badly when the other 3 are showing very little leak down.

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TECHNICAL MODERATOR

*could* The issue be something up with the cylinder liners? I vaguley remember reading that they are a bit suspect?

If I got 80,000 out of a set of rings I would be well happy Only ever seen one cylinder on any mini block with a sleve in it . Wet liners are whole other set-up

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Oh right, I remember reading that the late minis had cylinder liners, where?, I have no idea.

Off I go to try and read up more

Dont know much about the late cars but still fifty year design?

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i very much doubt that *any* mini can be fitted with wet liners: from the little i know about it, there isn't enough space between the bores to fit thick walled wet liners. consider that large overbores have to be offset bored (drilled out in a slightly different position) to make them fit.
Here is a pretty picture and a link:http://www.atomos-engg.com/liner.htm

(credit:http://en.wikipedia.org/wiki/Cylinder_%28engine%29)

The MPI is defo a different Block to the SPI and the Carbs, there is no Dizzy hole or drive, also the oil filter mount straight into the block.

I have no Idea where I read that it had Liners, but I do remember reading about it!, although Id take it as not having them until I find out off a good source, could have been read on the Internet.

Could the Rings have failed because of the overheating? Cant be a coincidence that the Head Gasket Blew Between 1 and 2, and the issue is with 1?

Also if it is leaking pressure down, it must be leaking oil up, would a run on a Gas analyser give anymore light on it? if its not burning oil then, could you rule out the rings? Or does it not always work this way?

***Wild stab in the dark***

Knowing Rover , perhaps by Liner they mean some sort of wear resistant coating on the cylinder walls?

Some motors came out of the factory with a sleeve in an odd cylinder . If it was bored wrong
it would be overbored on that cylinder a sleeve inserted and rebored to the correct size i heard this but have only ever seen one . In theory you could sleeve a block and rebore it
but in reality its not that simple . Size of the bore , availability of the liners , expence ,ect ect.

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It Could be cheaper if they changed the material the block was made of, like if it wasnt as hard. That way It would need liners as the bore would be redered unuseable in a short mileage.

Im sure theres somebody (Merlin ) who will know exatley what the story is with the Liners.


When BMW took over rover they basically destroyed it and took what was good(Mini) and pissed off. They also changed alot of the engine and body parts to cheaper alternatives to reduce production costs and keep the mini going until they had developed the Bini.
Example:The later shells rust more, the metal was obviously crap and full of impurities.

did BMC/BL/ROVER *ever* make a profit on Mini? and if they had would they have gone bust anyway? BMW bought a name and an icon.

TBH i dont begrudge BMW their MINI. its a fine car, well built and fast. (the JCW one i drove was, anyway.)

What i find remarkable is that their designers managed to so neatly mimic the styling cues of the original model.

While mildly irritating, it could be taken as a compliment!

Its interesting to see prices of second hand ones getting closer and closer...

The Bini is actually a Rover Design. Hence the model being called a R-XX.

I dont begrudge them either, but I have to say that MG Rover died just as it was getting good, they had a great range when they went. Much better than the crap around nowadays.

Essentially BMW operated likea venture Capital company, they bought rover, raped it of anything profitable, and let the rest die.

The A series block is made from better material, if you deck an A series block the material comes off in chards . If you
deck an A+ block it comes off like powder . Thats one reason why the A+ has strenghten ribs down the front of the block .

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Could be one reason they decided to use liners. Perhaps the A+ blocks were known to be soft, and when introducing the MPI and the required changes to the block they took the opertunity to adress the issue?