75ZT Community

A K-Series head gasket caught my eye on eBay so I bought it out of curiosity. It had the appearance of being mls but it had no shim and no compression limiters, hence my interest. It came sealed in original factory packaging from Ultra-Parts but the part number on the packaging was no longer listed in UP's catalogue when I tried to look it up. Link to gasket pic: Click

So I sent off a query not really expecting a response to be honest, maybe I'm just an old cynic but these days a response to this type of query is not summit I've experienced very often. Imagine my surprise when I not only received a reply but a very informative one informing me that the gasket I had bought was actually a discontinued COMPOSITE gasket. Apparently it was used when the K-Series engine 1st came out, presumably only suitable for the early closed-deck blocks, and was then superceded by the sls and mls gaskets which can be used on both closed and the newer open-decked blocks.

I've never heard mention of a composite gasket before, not even in Des Hammill's book on the K-Series engine, and I wonder if it played a part in the better reputation that the closed-block engines have for resisting HGF (Head Gasket Failure).

hmmmm....... not sure if I would use any gasket other than the genuine MLS (Multi Layer Steel Gasket) gasket from an XPart dealer. There are so many on EBay and 99% of them are cheap copies, some are made from inferior materials, some don't have a shim........This issue has been widely speculated upon for many years, there are lots of curve balls out there created by companies who "do a cheap job" and try to justify themselves. We see lots of people who have had a HGF job done using poor quality gaskets in the past yet have called upon our services to rectify yet another HGF.
We have had possibly 2 back that we have done at our spot in the last 4 or 5 years, and we do 3 to 5 per month. These 2 that did come back had other issues crop up which caused HGF such as poor servicing of the coolant system and a blocked radiator. Had this been taken care of then they wouldnt have suffered with HGF again.

Quote: 'We don't just look after Mini's'

One can't help but wonder what else you do to them ?

The mls as originally made consists of 6 layers, 5 integrated into the gasket and 1 separate shim, and I have read of cases where this was found to be too thick for purpose in the absence of any head skimming. An unskimmed head can apparently sit too high on the extra thickness of the original mls gasket resulting in the cam belt not fitting and its rear cover bolts not lining up. Some people also have concerns about engine performance and any adverse effect with the head sitting higher. There is also the low-liner issue and mls maybe not being reliable/suitable when this issue is present.

If faced with one of those situations, what would you do?

Well, what some have done and maybe still do is to fit the 5-layer gasket on its own WITHOUT the shim when thickness is a problem or concern. This is not acceptable to many pro mechanics because it voids any warranty with the gasket and experience of the problem is not without cost in time and labour. Hence one of the reasons why some prefer to use the "LATEST" sls gasket shown on the right in this link. Click

As shown in the link the sealing beads on the latest sls are less likely to part company with the metal base because they are bonded together via a number of holes through the base, unlike the earlier type where the sealing beads are only bonded to the surface. Also, note how the beading on the latest sls is spread a bit wider and that it is reinforced in places with extra sealant.