Cylinder Head

[robin]

If the head is not porous (pressure testing & visual inspection is used to determine this) and the liner heights are OK, why did it fail (more importantly, why will it not fail again)?

From the information we have so far I would say that it is very likely to fail again - the new gasket will fail in due course in the same way the old one did.

If there is no specific answer forthcoming I would suggest hardness testing is a must. If the head is soft the clamping force of the bolts can compress the face of the head around the fire ring, thus reducing clamping force on the fire ring and allowing exhaust gas -> coolant.

Cheers,
Robin

[roadboy]

Sound advice from Robin.

And don't sell it. Just don't take it somewhere that charges you £100 per hour to fix it.

Shouldn't cost you any more to maintain than a focus or vectra, etc.

Dan

[campbell]

If MMC will offer to warranty their work for a period, it's worth considering their charges.

If not, it's worth shopping around to see where else you might trust to diagnose and complete the (correct) work at a more palatable cost. But a quality job by someone clued up is crucial here.

I changed my head about 3 years ago, I would absolutely recommend the outfit that helped me (well, did most of the work as well as laughing at the bits I did!), however they are so expensive that you would have to sell your wife to fund it

On the upside, you are getting free advice from the head honcho of said outfit on this thread, so fear not

[m.crawford]

Cool - thanks for all the advice again. I guess maybe I should have taken it somewhere else but unfortunately I broke down fairly near Murray and was in a rush to get to work. I have learned my lesson!

Anyway the current situation is that they are waiting for parts and the car should be ready for Monday. When I go in I will ask again what the liner heights are and why it failed. If they cannot tell me why it failed - what should I do? If they have already done the work can I ask for them to warranty it before I pay? Can I demand an answer about why it failed before I pay?

If I was to get an independent specialist to check the situation out afterwards would that be worthwhile? Although really you would think that a Lotus dealership would be able to sort something like this professionally - am I wrong!!?? I feel so powerless in the face of these people - just because I lack the appropriate skills and knowledge I feel like I am constantly being taken advantage of! Except on here of course where everyone is honest and helpful!

Martin

[m.crawford]

Also I looked at AA Parts and Labour and it says that it must be serviced at an appropriate garage does that include independent specialists who are VAT registered? And would the work also be covered if taken to someone such as SLS or SPS?

Martin

[robin]

If you're unsure as to what counts for AA P&L probably worth asking them direct - the reason I say that is that different people have had different experiences with whether or not VAT registration is required, both in terms of the service history and the actual repair. Of course it might be clear cut these days - even so, it's worth asking them to confirm?

Cheers,
Robin

[tut]

From my considerable experience, the repair work has to be carried out by an MOT registered Garage, and probably the servicing as well, though both applied for me with Ricky and John Duthie.

tut

[roadboy]

From my considerable experience, the repair work has to be carried out by an MOT registered Garage, and probably the servicing as well, tut

That's not true Tut. I have no problem with AA P&L and I am not an MOT testing station. I am VAT registered and have never had a claim knocked back for any reason other than them claiming the failure was wear an tear rather than a part failure.

If your car is serviced at either myself or SLS (or any other Lotus specialist or VAT registered garage) you will have no trouble using you P&L cover to claim for the repairs. So long as you have a complete service history. They may ask for evidence of your service history when claim is made.

HTH

Dan

[tut]

Sorry guys got my wording wrong.

Twas meant to read VAT and I was too busy pouring drinks to notice. Ricky is not an MOT garage and neither was John until recently.

tut

[m.crawford]

Got the car back and have been taking it easy for the moment. It seems to be behaving itself the same as before but running a few degrees higher than before. In the past it would sit at 88 and go quickly up to 93 in traffic. Now sits 89/90 and up to 95. Could this be a consequence of a new thermostat and all the rebuilding work?

MC

P.S. I put it on Pistonheads but am secretly hoping nobody is interested!

[robin]

If the stat was changed then the operating point will no doubt be different (by a degree or two) than the old stat. Coolant change can have similar impact.

Cheers,
Robin

[KingK_series]

Just to inform there is now a revised gasket kit from xpart this was devoloped for the N series and consists of
new single mls gasket
new 10.9 ( was 9.8 ) bolts to be used with a different torque setting
new ladder rail
only available as a kit ZUA000530
this was something rover was looking into before it went bust
there is also a new BW750 payen elastomer that has revised beading coloured blue

These parts were in the pipeline when Rover collapsed. Essentially the MLS gasket is a 4cylinder version of the Kseries V6 gasket that had been trouble free for years, Ford owners of LandRover at that time were pushing really hard for a very "visable" poilitical solution to the issues and pushed it out, and into dealers hands as a service item before the part had been through testing and against many I know wishes within the design team. There was a dogfight. The new gasket came along because the MLS being made of several layers did not compress like the elastomer gasket and therefore gave less clamping load over the firering unless you had 0.125mm standproud. That standproud is so important because the ally block grows up around the iron liners at temperature, - another reason why I always fit my 74deg PRT.

The new gasket is a single layer, so you get that clamping load even if you have a tolerance on the standproud - ie 0.05-0.125mm , it's also cheaper because there are less parts. When I last spoke to the guys working on it they were trying to cost down the firering as well, which seemed a mistake to me, but they were trying a new coating on the firering. Presumably this gasket has gone through the full testing proceedure. The new bolts are 10.9 grad and were being tested 4 years ago, the old bolts are not heat treated at all and are equivalent to grade 8, they were designed to go into yield, and in my opinion should never get reused. -Try torquing a set up, mark the bolt, then torque up again, you will find the mark moves round by 45 degrees near enough. On all my 2L and 1.9L builds and most recent 1,8Ls I use a 9mm stud that I have made specially - the reason being that I need to torque up the blocks so many times to blueprint the block, and discard each set every time, it is cheaper to make bolts that do not go into yield.

Having said all that I have built so many engines with MLS OE [old] bolts and 0.125mm standproud that revved out to 9600rpm and never missed a beat - certainly no HGF.


The important thingto understand is that it is thermal distortion across the long 4 pot head face that causes "HGF" - in fact it is not gasket failure at all, the gasket only fails long after you are in trouble. The KV6 never had any of these issues despite having the same block architecture because it is one pot shorter. What happens is - cold head with closed throttle - goes to hot head with =wide open throttle - cold head closed throttle, and the head bananas. This causes coolant top leak into the oil, tiny amounts that get burnt off, so no mayonnaise, but causes local overheating, which causes the head to lose its quench - ie go soft, and eventually overheat the elastomer so it comes off the core plate, but by that time your head is usually soft.


The solution was PRT [and it really is not PRRT] which moderated the temp gradients to stop this bananaring in the head, and the lower temp you go the better for all sorts of reasons - hence my 74 deg PRTs. Add the stiffer oil rail - which is usually omitted because people [ garages dva etc etc] still do not understand what the process is, because that stiffer rail helps prevent that bananaring of the head again. The stiffer 10.9 bolts also act in the same way.


- porosity - constantly talked about. honda heads are porous, F1 heads are porous, my cast bronze sculpture is porous, everything cast is porous. Longbridge was a pace setter for a very long time reducing this as an issue. But at the factory the head skim was actually a "smear" done with a very dull edge in a very stiff jig to compress the ally rather than open it up with a sharp cut. F1 engineers always roll the ally around the firering before the final skim. It has been my practice for years to knock in the ally around the firering with a hardened punch to compress the metal before a final skim. DVA - happily has picked this up after a typically bruising encounter on seloc a year or so ago, just as he did with the need for aquiring and using a hardness tester, but the truth is the need to "peen"the head only exists if you are going to skim it - in other words by not understanding this process and skimming without first peening the head you are causing the "porosity" problem, however it has never been the issue it has been made out to be and the firering on thegasket is designed to fill small voids - how else would it fill the quite deep skimming cuts that some heads have.

Anyway, most important thing to do is fit the PRT, then go through the proceedure that Robin posted when you have a failure, but ALWAYS fit the new oil rail

[hiscot]

yep i have a photo and it is a coated fire ring , i think the cost is approx £120 as a kit

[Mikie711]

yep i have a photo and it is a coated fire ring , i think the cost is approx £120 as a kit

Just checked on Rimmer Bros site

"This is the latest version of the multi layer steel gasket set, as used in production of the new, Chinese manufactured, MGTF.

The set includes:-

Multi Layer Steel Head Gasket
10 Special Head Bolts
Strengthened Oil Rail

And is suitable for alloy sump K Series engined vehicles."

yours for the bargain price of £206.15 which is actually cheaper than the old bits from LR.