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Discussion Starter · #1 ·
Hi I just had a discussion with a mechanic regarding mini/ Peugeot cylinder heads. He tells me that they can be problematic when changing a head gasket as they can crack when torquing them back down and you will know nothing about it until the car is running again.
Is there a work around so to speak to minimise the likelihood of cracking it?
One garage who constantly does these repairs thinks there is an issue with the heads made by Peugeot,and you have to sign a disclaimer if they do the work as head cracking is a chance even after all the costs involved.
Be interested to hear any others thoughts,best practice to replacing one.
I'm in the process of the same job now and timing chain while it's all apart. Mine is a gen 2 r56 N12 engine.👍
 

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Hi I just had a discussion with a mechanic regarding mini/ Peugeot cylinder heads. He tells me that they can be problematic when changing a head gasket as they can crack when torquing them back down and you will know nothing about it until the car is running again.
Is there a work around so to speak to minimise the likelihood of cracking it?
One garage who constantly does these repairs thinks there is an issue with the heads made by Peugeot,and you have to sign a disclaimer if they do the work as head cracking is a chance even after all the costs involved.
Be interested to hear any others thoughts,best practice to replacing one.
I'm in the process of the same job now and timing chain while it's all apart. Mine is a gen 2 r56 N12 engine.👍
that so called mechanic speaks poo .. i have done hundreds of them never had that happen , have had cars that have been boiled and then owner ads cold water and crack a head ,, no worse than any head,,
Is there a work around so to speak to minimise the likelihood of cracking it? DONT USE THAT MECHANIC ,
only crack when been boiled lack of coolant, also lack of oil destroys the camshaft journals,,
no one in the trade likes working on these engines to be honest i get sent loads from garages who just dont understand them,,,
best bit of advice i can give you is this,, always replace thermo housing cat and both 02 sensors around 100k as well as do a engine refresh, also timing chains at 60k never let oil get below 3/4 mark on dip stick,, and by 80k and 10 years old they are in realms of needing engine refresh as i feel they are designed around a throw away car design,,
i also do a lot of vag tfsi and fsi engines these go same way 100k if that need same as mini do,,
i've lost count the amount of engine refresh jobs i have done, ie head off pistons out hone bores and new better 3 piece oil rings sets reduces the oil using a lot , cant remember the last head i have had skimmed as dont warp fairly strong new timing chain kit and must do valve stem seals and reseat the valves etc,, link below shows coupe i done with picks also there is a vag 3.2 v6 engine that went same way as mini do,,
 

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Discussion Starter · #3 ·
Hi Mike,These were his words and only going by what was said. The garage will not touch the minis due to the amount of stress they cause,they direct them to some BMW mini specialist in west Midlands on the Portway,sure someone on here probably knows the name?
I have never heard of the head problems tbh,he mention they can crack easily around the head bolt holes!
Anyway I'm doing all the work myself,head is being pressure tested atm and probably a skim too. I'm replacing head gasket,bolts, timing chain,valve stem seals,lapping valves in by hand,,painful on the hands last time i did some.
Can you recommend a replacement head gasket kit and timing chain kit,any pointers to note with reassemble. Thermostat was last changed in 2016? Also the aircon condenser is literally flaking apart on the fins,so will need a replacement too.
Rear brake seized,just cannot turn the piston either way to free it,so might have to get it off and into the vice.
Thanks for the advice
 

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i would while head off pop sump off and put set of rings and big ends is ,, i use ring sets as per below best ones 23 piece oil control rings better than the factory rubbish single piece ,, i use elring on head gaskets febi best for chain kits king best for big ends
honestly its best to go all the way with these engines extra days work and extra £100 ish,, can reuse the conrod bolts but get some red full strength thread lock and clean the treads with brake cleaner before doing up,, but ensure oil on the bearings etc,, then crack engine with coils umplugged before first start a must gets oil up and around ,
if need any advice just ask i'm doing them like this all the time it gets the beat results for sure,
 

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Discussion Starter · #5 ·
Hi Mike, the head gasket,timing chain kit you linked to on that other thread,is that perfectly ok to use. About £150 from eBay seller Shirley?
Also is it just a case of dropping sump cover and undo the Conrod bolts and pull out,or is there more labour involved to get them out. I have never gone as far as piston removal on any car,so just curious about doing so.
Pistons out,just a case of changing rings and new big ends and bearings. Are the big ends and bearings a standard size when replacing.
Cheers
 

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you will need to hone the bores with special tool, will also need piston ring compressor tool , will also need a valve compresser tool as well as valve grinding dolly as well list of parts tools needed below that i know work well got them myself
ring compressor
hone tool
valve spring tool
valve lapping tool for the drill by far easy way to do 16 valves
valve paste
strong thread lock
scotchbrite pads great for cleaning everything can put valves in drill spin them up while holding pad on them
video on honing
 

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Discussion Starter · #7 ·
Hi,Apart from the above tools for the job,is it a case of removing the sump and oil pump and I then have access to the conrods/pistons from underneath with engine in situ. Are the shells one size to renew for the mini.
Was greeted to this on removing head
Thanks Mike
PXL_20210219_165913647.jpg

PXL_20210228_151009253.jpg
 

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head cracks can't be detected easily, one can pay for a test showing negative and the head still have a crack open up at a certain temp, not the garages fault, I guess where an upfront conversation with a customer can be a sensible idea for that 'what if' scenario, very unlikely occurrence nonetheless, but possible.

skimming heads can be totally unnecessary, rough handling is as much to blame for the need as anything else, corrosion maybe, I wouldn't unless a last resort but that's just me, hate that it reduces longevity, one day it might actually need doing only to find it has no scope....

the hardest part of getting the pistons out is the lack of room, so you need to poke the rod up with something as you won't get your hand in far enough, don't use anything hard that can mark the cracked rod surface as it can hinder 'mating' in reassembly, bearings should take standard size and on the back of the shell might be marked to say 'std'. Bear in mind this cracked rod joint which must go together the same way, so note the cap order etc. You'll see why with the rod out if you offer it up the wrong way. Personally I would never reuse rod bolts especially these puny little things, for the sake of £20 or whatever, the consequences aren't worth facing whether ever actually faced by anyone or not, that doesn't matter, if there's one bolt not to reuse, or two, it's head bolts and rod bolts imo, but people do. I have a spare set here if you can't get any from BMW, I just did one where ARP were used instead so have an extra set, or two actually maybe.

some emulsification in the rocker cover isn't unusual especially in Cooper/One with lower use
 

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Discussion Starter · #9 ·
Hi ExclusiveWorkshops, Thanks for your input.If it's not to much of a problem I might give the rings a change of all goes smoothly.
So unless the head is not level,do not bother skimming,just give it a good clean instead.
Head gaskets, can one brand be a lot better than others,or generally any correct fitment gasket should do and last the time?
BMW head/rod bolts , what is the price for them,I don't imagine BMW being cheap compared to ARP
Thanks for the advice.
 

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the new stretch bolts for conrods from bmw are £1.09p each need 8, i've done loads with engine sayt in car and can use a rubber hammer handle to push the pistons out from under the car, worth pulling exhaust down at front helps with room,, i've been doing these for years on the floor no work ramp or lift just axle stands,,
i personally use brake cleaner to clean both the head and block just before putting them together,, i also use well seal on both sides of gasket been using this for years never had one bad for gasket failure so read what ever you like in to that,, some that have never used it dont like using it and stick to what they know ,,
also before putting head bolts in must clean out the holes in the block and must lightly oil the bolts i always rung the new bolts in and out the holes a few times it helps to take off the burr on the threads so bolts will clamp better
wellseal
can only skim these heads a very limited amount in 5 years of doing them i've not skimmed one yet , and like said they are strong heads in my view
 

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Discussion Starter · #11 ·
Hi Mike is the head and timing chain kit you linked to,one you use yourself? @£160.
I take a look at the wellseal link aswell.
Going to give the piston rings a go I think,seems best as you mentioned while its apart.
Do I need to measure anything for replacement conrod shells.
Cheers again
 

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will add would need to ask them to confirm fitment with n12 1.4 engines pretty sure are same off top of my head, except the big end bearings the 1.4 the crank is smaller than turbo cars
 

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Discussion Starter · #16 ·
Just had the head checked it is 5 thou out,but it's the opposite way to a normal warped head,so I have to check the block with a straight edge now as it's possible the head may have pulled on the bolts distorting the block.
Fingers crossed it's not🙄
 

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5 thou is nothing the gasket would take that up,, or as i do use wellseal as a insurance and dry run it for 5 minutes on idle ie n coolant that will heat the the surfaces up before adding coolant,, all engine rebuilder's are there to make money remember that every skim they do its profit every check they do more money
 

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Discussion Starter · #18 ·
Just had the head checked it is 5 thou out,but it's the opposite way to a normal warped head,so I have to check the block with a straight edge now as it's possible the head may have pulled on the bolts distorting the block.
Fingers crossed it's not🙄
5 thou is nothing the gasket would take that up,, or as i do use wellseal as a insurance and dry run it for 5 minutes on idle ie n coolant that will heat the the surfaces up before adding coolant,, all engine rebuilder's are there to make money remember that every skim they do its profit every check they do more money
Took a straight edge to the block and I also have around 5 thou gap where the machine shop said he thought it was,through the middle of the piston bores. Basically the jacket area around pistons
Will skimming the 5 thou off the head help or hinder the 5 tho-ish also on the block. Can I get away with using this block and head again!!
Mike, the machine shop is a friend of family and he told me to check block so not to waste money on having head work if the blocks knackered.His not trying to do me over 😬
Cheers
 

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or does the 5 thou in block sit with the 5 thou on head at same points ,, ie where block is dipped dose the head match the other way perhaps ie both settled in to each other ,, if so by removing the 5 thou off head that could effect it when not matched when put back together,, guess your at a cross roads where new engine or not ,,
 

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Discussion Starter · #20 ·
I think it has morphed to the head shape so maybe do not skim it and hopefully gasket will take up the clearances.
Like you say I am a bit sceptical on buying new gasket,timing chain etc if it's going to blow still.
 
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