A K-Series is Reborn – Part 2
In part 1 the engine was stripped and I was at Rog Fabry’s getting the block reworked. I was also dropping off the head with him so he could work his magic in the porting department and making sure the head is “up to the job”.
Well they say you never know an engine until you’ve had it apart and inspected it. The block as we know wasn’t perfect but the head takes this to a new level. On the outset the head looked fine, well in my eyes it was. However Rog wasn’t quite so complementary about it. The first problem he found was someone had put a helicoil into one of the spark plug holes, this job must have been done on the cheap as the head hadn’t been removed to do it. This was apparent by the helicoil wire still in place and be bent out of the way by the spark plug
This was resolved quite quickly but I am not starting think what else could be wrong with this engine. Shouldn’t have asked that one! Next issue seemed to be that Rover had a off day when putting my head together and one of the valve seats was put in at one can only be described as a “jaunty angle”. Then to add insult to misery the last thing on the list corrosion on the inlet face of the block and more worryingly on the head face near the firing ring , ok the head is over ten years old so I guess it’s ok to expect some wear and tear. Rog is confident that he can fix all this and sets about working on it.
The corrosion on the inlet face is repaired by basically peening the area around it then adding aluminium weld to the area and finally machining it all flat again. Clever process and it produces a as new face on the head.
The head face is also peened and then skimmed, this will remove any porosity of the head which the K series head is known for. In fact this was the only good news I got from Rog was the head was a good’un and had no porosity.
Rog then reassembled the valves into the head and it was ready for fitting…and how good it looked as well.
The block was also returned from the engineering shop and Rog completed the decking and the liners were loose fitted. So I now have a shiny head and block for my engine….but it still doesn’t look like an engine.
Carrying on the “must make it reliable” theme I set about fitting a baffle to the sump. Oil surge isn’t really a problem on track with the K in the Elise but better safe than sorry is what I say. The baffle is designed to sit in the sump and then clamped in place when you bolt the sump to the block. Me being a fussy bugger found a local aluminium welder and permanently fixed it to the sump.
Carrying on with the bottom end I decided to get clever with the Plastigauge and measure the clearances on the crank mains and big end. Well this is where my lack of experience starts to show with the K series engine. As you are probably aware the K series is a bunch of aluminium blocks (for want of a better word) bolted together with 10 long bolts. What this means is that the main bearings aren’t “round” until the entire engine is bolted together and torqued up. I didn’t know this, in fact you can image I was a tad confused when the Plastigauge was suggesting my clearance on the mains was 0.100mm…..I could drive a bus through that gap!
So a change of plan for the measuring I purchased a digital Micrometer and used it to measure the crank journals, at the same time checking they are still round. Once the measuring was complete, which took a few hours more than I expecting. On the crank and crank ladder are a bunch of numbers that cross reference to give the right bearing sizes. With the measurements I had taken I was able to double check the bearings recommended in the table were the correct sizes. I then trundled down to my local Land Rover dealer and ordered up the bearings. The advantage of buying them from Land Rover is they are still British made. The standard MG bearings are actually good quality and should be up for the job of this engine. High RPM is what generally kills the K and because I am super charging I can cap the rpm to a safe 7000rpm. As you’ve probably realised I am also keeping the standard crank for the same reason that it will be more than man enough for the job.
With everything measured it was time to send off the entire bottom end for balancing, after a lot of ringing around a company called Rob Walker Engineering came to my attention. He had a good reputation and unlike some places didn’t charge the earth. I dropped off the crank, pulley, rods, pistons, flywheel and clutch cover with him and collected a week later. Everything was marked up ready to be bolted back onto the car.
Next on the list was to build up the pistons and rods, unlike the OEM items in which the gudgeon pins are pressed in the aftermarket pistons use circlips which makes assembling them a lot easier. The pistons I am using are forged items from Accralite, these pistons have a large dish design to enable me to run a lower compression. Because there is more meat needed in the top of the piston to create this dish the rods have been shortened by 3mm. The rods themselves are Carillo steel H pattern for increased strength.
What should have been a straight forward job was not going to be as the piston wasn’t rotating around the gudgeon pin. Odd I thought, so I took them apart again to see if I could work out what was going on. On inspection of the pistons I noticed that on the roof of them was what can only be described as a pin. This I am guessing it’s there to guide oil into the small end on the con-rod. However this “pin” fitted perfectly into said small end bearing hole which of course stopped the piston rotating around the gudgeon pin.
“Pin on the piston”
Small end bearing hole
I gave Accralite a call the following day and I spoke to a very apologetic engineer who explained to me that these “pins” should have been removed as part of the finishing process. As it turned out I was right that they are designed to drop oil into the small ends on some cars, but the supercharged K isn’t one of them. They kindly offered to take them back and machine them properly. However ss I now know they can be removed I got the dremel out and whipped them off. So we are now ready to start assembling the bottom end….