Special K Part 2: Up before the Head

Special K Part 2: Up before the Head

With the bottom end now sound we moved onto the head. We needed to remove the slight indentations from the liners and a skim would do that, but we were conscious of the the notorious porosity of some of the K series head castings. The Lotus guys obviously work their engines harder than the average Rover saloon and are used to investing in expert engine builders who look after their prized machines. They hold a lot of store in peening the fire ring area around the head to reduce porosity, so that's what we did. Machining a nice gentle rounded head onto a pin punch, we began the paintstaking process of hand peening around all four combustion chambers. You can see from the photo this looks like horrible vandalism and in fact, the engineering shop that skimmed the head asked what the heck had happened to it upon first glimpse, but once they had cut it back realised what a difference it made. Hopefully you can see in the photo where we've added lines to highlight it, the area of peening after machining shows no porosity whilst adjacent to it the little black specs of voids are visible.

Alfie had been busy with the dremel, doing a lovely job of matching the ports to the manifolds and lightly relieving and polishing the inlet and exhaust tracts. He also found a stuck lifter which he freed up. The cams went back in with plenty of engine assembly lube. This stuff is cheap and great. It clings to whatever you put it on so unlike oil it doesn't run off over time if you aren't running your engine immediately. Time to refit the head to the block but first we fitted the 'head saver shim' that came with the MLS gasket kit. This is aimed at further protecting the head and spacing it from the block to compensate for the material removed during the skim. We applied Gasgacinch to the head and gasket and stuck it in place. Some people use Wellseal but that is a very permanent solution. Gasgacinch has been used in America since the 1950's and is terrific stuff. If you've used it, you'll swear by it. It still allows disassembly, but we've never known it to leak when used on gaskets.

Then the exotic MLS gasket was fitted. Multi-layer, the compression rings for the cylinders can move within the top and bottom layer so its important to make sure these are positioned correctly. We again used a little Gasgacinch to hold them in place. The multi-layer 'Klinger' gasket is considered the ultimate head gasket for the K Series, but in our experience you really do need to worry about those liner heights because if these aren't right, the MLS gasket isn't going to fix it (well, not for long). There is a Payen elastomer gasket that takes up liner height variance better, but that is suitable as a fix if you can't remove your engine for a fulll strip down, getting the liners right is the best solution. Also be careful as there are elastomer copies out there that aren't up to the job.

New Engine through bolts must be used to clamp it all together as they are stretch bolts and can only be used once. If using the MLS gasket with stronger bottom rail use the slightly stronger ones and follow the revised tightening procedure.

 


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