MG ZR: Cams & Maps

[Poodle]

Ah fair, not just some pikey selling job lot gaskets then, seems like bloody good prices too tbf. You're always welcome to help from me mate, i'm only around the corner.

Tbh water is great at cooling your car and bloody cheap to boot, waterless coolant sounds like any other expensive gimmick imo.

[Niall]

Get the head skimmed mate don't f*ck about do it right do it once

Yeah do it right. Don't just go and get it skimmed straight away. Check it. if its true, don't skim it. Im sure half of the people on this forum just like pissing money down the drain with pointless head skimming!

[procta]

Ah fair, not just some pikey selling job lot gaskets then, seems like bloody good prices too tbf. You're always welcome to help from me mate, i'm only around the corner.

Tbh water is great at cooling your car and bloody cheap to boot, waterless coolant sounds like any other expensive gimmick imo.

i have read a good few decent write ups on it, some of the racers run it.

[lolsteve]

Headgasket has been ordered. Used ebay seller gasketsforclassics as they had a more solid reputation, cost a couple of quid more but might pay off. In regards to the head bolts I want to see if the old ones can be reused, apparently provided the engine hasn't overheated there's a good chance they can be reused and will be better quality than the ebay ones which can snap failing that I can run to eurocarparts for a replacement set

[Poodle]

There should be tolerances kicking about the net somewhere, are fine to reuse if they're below xxx.xmm long etc. Let me know when/where dude.

[Piggy]

Autodata will tell you what maxlength the headbolts can be.

Although I always prefer to use a new decent set.

As for skimming, had my head checked with straight edge and it was bang on...yet that didnt go so well

[lolsteve]

http://forums.mg-rover.org/showpost.php?...ostcount=1
97mm or less and they're good to go. Messaged a chap on the forum who has done about 20 HG jobs and photos of a couple hes done too, says that in all but one case he's been able to reuse the bolts and used ebay gaskets without any failing yet.

Will ask dad if can use the driveway so I can get to work on it when everyone is busy, thinking might start taking apart this weekend. Gasket will arrive Tuesday so that's plenty of time to have the head off then inspect for damage, replace stuff like waterpump if need be, reseal the leaking cam carrier while it's off too and check the vvc timing

Did you find a cause piggy?

[Piggy]

Yeah...the head needed a skim!!!

[zx_volcane]

Get the head skimmed mate don't f*ck about do it right do it once

Yeah do it right. Don't just go and get it skimmed straight away. Check it. if its true, don't skim it. Im sure half of the people on this forum just like pissing money down the drain with pointless head skimming!

Agree, if you clean it up properly and check if its true in all directions with a proper straight edge (front back, diagonal ..etc) then it should be fine to go back - especially if it hasn't seen any overheating. Unbolt when the engine is cold in the same sequence that you tighten to take the load off evenly.

However if you can afford it and want peace of mind, then you could ask an engine recon place to check and resurface if necessary.

I'd also re use headbolts too if they're within spec, no reason why you shouldn't.

Have fun with it, take your time, shouldn't be too bad of a job

[Ruan]

Those heads have f*ck all material around them, they're ripe for warping and they're sensitive to it anyway!

No way I'd do it without skimming the head... Way I see it, is my time worth the same as the money spent on a head skim if it goes wrong... No... Not only do you could yourself time, you've then got a new gasket, theoretically new bolts - don't be cheap - get it pressure tested and skimmed, you'll kick yourself if you don't and it goes wrong again - half the time with a straight edge you can't see because there's deposits and crud from the old gasket stuck to the head which you'll struggle to get off without damaging the head.

And yeah, I've reused bolts, I've reused gaskets before - but not on cars that have to get me from A to B - f*ck doing it it if you have the money not to, they're an awkward job, why on earth give yourself more chance to have to do it again.

[lolsteve]

I thought the pressure testing and skimming should be done on engines that have overheated? As far as I'm aware in my ownership this has never happened due to the temp gauge never getting higher than the "normal" position.
Not trying to cheap out on it just does it need skimming and removing the protective surfaces if it doesn't need doing

[Poodle]

Not being funny, but if the mating face isn't clean how could you expect an accurate reading? Do it properly and there shouldn't be any reason to skim the head unecessarily. Easy to say you should always do it when £50 is pocket change.

[Niall]

Those heads have f*ck all material around them, they're ripe for warping and they're sensitive to it anyway!

No way I'd do it without skimming the head... Way I see it, is my time worth the same as the money spent on a head skim if it goes wrong... No... Not only do you could yourself time, you've then got a new gasket, theoretically new bolts - don't be cheap - get it pressure tested and skimmed, you'll kick yourself if you don't and it goes wrong again - half the time with a straight edge you can't see because there's deposits and crud from the old gasket stuck to the head which you'll struggle to get off without damaging the head.

And yeah, I've reused bolts, I've reused gaskets before - but not on cars that have to get me from A to B - f*ck doing it it if you have the money not to, they're an awkward job, why on earth give yourself more chance to have to do it again.

But if it checks out to be dead true still, why skim it? What possible benefit could you gain from skimming a head except ever so slightly raised compression? I'm not just talking about checking it with a bit of old scrap metal. I'm talking about using a proper straight edge.

Also yeah i would reuse head bolts if I was skint and they were in tolerances but generally you don't know how much they stretch when you re torque them so you don't know if you are pushing them past their tolerance.

[procta]

one thing I found with these engines, is people repair the head gaskets, but never really find out why its failed.
As the pressure cap on these can cause headgasket problems, the wrong coolant, there was a write up on the engine, in mechanics' monthly. that gave you a list of what causes problems.
I wouldn't re use any head bolts at all on these engines, as they can snap if you reuse them. with them been already torqued down. plus whos to say they haven't all ready been re used too.
if they snap or round off your might aswell ditch the lump and drop another one in, as that's what happened to me as you lads remember on the gta. not worth the f*ck on if that happens.

[Niall]

Procta that's why you check the length to see if they are past the maximum stretch tolerance. If they are then bin them, if they aren't, you can Crack on with them. If the snap during the rebuild, it's not exactly difficult to get them out. 99% of the time you can just lift the head off and unscrew what's left with your hand

[Curt]

Not being funny, but if the mating face isn't clean how could you expect an accurate reading? Do it properly and there shouldn't be any reason to skim the head unecessarily. Easy to say you should always do it when £50 is pocket change.

100% this.

I had the same when I did my DT... Apparently if I didn't skim it, it would obviously fail again... It was spot on.

I don't see why people are so set on skimming a head that might not even need it. If the car hasn't overheated and checks out with a straight edge... It's fine.



Anyway, it's a shitter it's gone Steve, but they're not a bad job at all really . At least you'll have some peace of mind after, too.

[lolsteve]

Cheers curt, been reading up on how to do it all day and doesn't seem the worse job in the world just some fiddly bolts here and there.
Also looked through service history and the cambelt was done in 2010 at 50k miles, now on 69k miles so still got life in it
No mention of headgasket change though..not even a receipt for the parts

[procta]

Procta that's why you check the length to see if they are past the maximum stretch tolerance. If they are then bin them, if they aren't, you can Crack on with them. If the snap during the rebuild, it's not exactly difficult to get them out. 99% of the time you can just lift the head off and unscrew what's left with your hand

id still play it safe with the kseries engine niall, plus I think you can get them with the kit too,
so there is no question marks for errors.

[Ruan]

How on earth do you know it hasn't overheated... Just because the temperature gauge says it hasn't gotten hot, does NOT mean you've had air locks inside the head - if the head gasket has gone, you can bet your bottom dollar that combustion gasses have made their way into the cooling system, soon as that happens you've got potential for hot spots - soon as you get localised overheating, that's the worst kind of overheating, you've got areas that are cool, areas that are hot, bam recipe for warping. Not to mention once you've induced stresses into the head from heat in places spots, re-torquing it and then heat cycles will often cause it to settle not true.

The whole thing that you HAVE to take off enough to cause an increase in compression - not the case at all, soon as you touch the wheel to the surface, it'll instantly show up if the head is true or not, past that there is no need, if done correctly, you should be taking off absolutely fractions of mms to just get the head back to a perfect face. Something that you simply cannot do with some emery cloth, aloxide paper and wire wool.

Meh, do whatever you want, I'm just going off my experiences and research into it, you've got an engine that is prone to head gasket failures and you're not doing everything in your power to stop it happening again - mental IMHO.. Maybe if people gave a slightly more scientific response of "Get a DTI gauge on the head and measure at multiple points" - that might be better, but jamming a straight edge on and looking by eye IMHO isn't a good enough test.

For the record I'm not just saying "£50 is pocket change to me" - it's never was and still isn't! I'm just averse to people dishing out the advice of "don't bother if you've put a ruler on it and it looks OK"...

[Seb_Ryan]

Personally I always take them to the place we use, and they decide if it needs doing, they are always pressure tested and cleaned, but not always skimmed

[Piggy]

If there is a decent place nearby, go have it checked, thats got to be the safest bet?
It cost me a new gasket and a few days and many hard hours putting it all back togetheir because I didnt have it skimmed.
I did use a straight rule though to check...and it was spot on.

On another note...you were mentioning age of the cambelt on a post...are you thinking of resuing it?

[Dum-Dum]

Skimming the head if you put it back on with the same thickness HG as before will increase compression if only by a negligible amount, this is why once its skimmed you re-measure the thickness of the head and get a thicker HG if needed to make up for the difference.

While I can see you re using the head bolts as long as they are within their stretch tolerance (they are designed to stretch when they are torqued up, stretched too far = snap) I would get the head professionally checked on an engine that is famed for its dislike of head gaskets. Yes its more money to have it done but its a whole lot less than the time effort and cost of doing it again in 6 months time if your "it'll be ok" turns out to be wrong.

Also I know its money and probably money you don't really have but if its 4 years since your cam belt was done most of us would be changing them at 5 years irregardless of mileage so you are nearly at the interval so while its apart. It's piece of mind then on a car I assume you are planning on keeping for another year or 2.

[Piggy]

I know others dont...and it was only college...but I was taught that once a cambelt has been used...thats it. Regardless of mileage. It shouldnt be reused.

I know some do risk it and get away with it though

[306Dan]

Just a few things to remember with the k series use the head saved shim if it's been skimmed, and get the proper cam ladder sealant don't use rtv or you f*ck the cams.
I'd also get new bolts regardless although their supposed to be able to used 3 times I've known them fail quite quickly.

[Tom]

Im on the "just skim it side", i asked my machine shop to check/skim it and he said it goes on the machine anyway even if its just the smallest, tiniest amount to give it a nice clean face. Theres not really a downside to it, is there? Cost is all i can think of?

[lolsteve]

I was under the understanding that "just skim it" is not worth doing unless the engine overheated or head is warped because it removes a protective layer making the head more porous .
This debate may be for nout anyway since may find it does need a skim regardless

rtv being silicone? Don't worry already know to use anaboregltic(?) sealant such as loctice 547 so it doesn't block the oil ways

I wasn't aware cambelts were a one use thing, pretty sure I've seen people push them to one side before however if they only have a 5 year lifespan I'll look into seeing if I can find a pair as there's two on these engines

[Danny2009]

For the sake of £30 I just skim them they don't make the head porus

How you can check every inch of the head being square with a straight edge is beyond me, as Ruan says unless you can do it properly with a dti gauge

If you have it skimmed there is no question about it, it will be straight and true

I'd think about it even more with how easy they like popping gaskets don't give it a excuse

Your car upto you how you go about it mate we can just offer our opinion

[Niall]

For the record I'm not just saying "£50 is pocket change to me" - it's never was and still isn't! I'm just averse to people dishing out the advice of "don't bother if you've put a ruler on it and it looks OK"...

Lol no one has said just bang a ruler on it. Theres quite a substantial difference between a straight edge and a 99p ruler as I'm sure you of all people are aware.....
But still, I'm just going off of the advice of the engine shop i used to have my work done. The guys who have been doing these things for the likes of rolls royce since before you were even swimming around in your dads testicles and very successfully i may add.

I know others dont...and it was only college...but I was taught that once a cambelt has been used...thats it. Regardless of mileage. It shouldnt be reused.

I know some do risk it and get away with it though

Yeah I've been told the same that a cam belt is basically a one use item.

Im on the "just skim it side", i asked my machine shop to check/skim it and he said it goes on the machine anyway even if its just the smallest, tiniest amount to give it a nice clean face. Theres not really a downside to it, is there? Cost is all i can think of?

One particular downside i can see with this car is that they have a right reputation for head gaskets and i don't think Steve knows if it has had one before so if it has over heated badly before to the point it has warped the head then it may have had a fair bit taken off so taking more off you don't really want to do. But then again thats why it should always be checked to make sure its still within tolerances.

[Ruan]

For the record I'm not just saying "£50 is pocket change to me" - it's never was and still isn't! I'm just averse to people dishing out the advice of "don't bother if you've put a ruler on it and it looks OK"...

Lol no one has said just bang a ruler on it. Theres quite a substantial difference between a straight edge and a 99p ruler as I'm sure you of all people are aware.....
But still, I'm just going off of the advice of the engine shop i used to have my work done. The guys who have been doing these things for the likes of rolls royce since before you were even swimming around in your dads testicles and very successfully i may add.

Always gets me that one, "Have been doing x for x company for x years, before you were even born"

Whoop-de-f*cking-doo...

That just means they've been doing things (possibly wrong...) for longer... The amount of people who have apparently been jet engineers/engine designer/highly experienced tuners/extreme diesel engineers/lorry technician/the queen/my mate down the road/any tom dick or harry who've said some outstanding stuff in the past which I now know to be bullshit.

According to "Cornwall's Leading Diesel Specialist" who've been in the Diesel business for 40 years and now make rally cars... An XUD will never possibly make more than 130hp, you *CANNOT* put an 11mm plunger element on a VE pump designed for a 9mm, no point in upgrading the turbocharger, and any adjustment of the max fuel screw will ultimately end in chronic borewash, glazing and a f*cked engine...

And I quote "You'll be running to me when you want me hone the glazed bores"...

Don't take anything anyone else says for certain, I'm just offering out my advice here, no one has to take any of it - infact I absolutely encourage you to go find out for yourself - I sure as hell had to, I just have a bit less of a social life than everyone else, have researched and have this shit on my mind all day. Hence I'm a little opinionated now, but I'm proud to be and I'm only trying to help...

[Poodle]

True dat!! ^^^

Reusing the cambelt and headbolts is fine if within tolerances, do you see the XUD boys changing the cambelt every time they swap a pump?