Mini Spares Articles - 16.07.07 - Silverstone Report by Keith Calver
After a monumentally busy start to the year work-wise, I made a concerted effort to get the car sorted to get back out there and have some fun. My plans for stripping the car back to the shell and re-checking all the suspension alignment starting from the shell and subframes went to hell in a hand cart, so it was a case of building an engine and doing my best to re-sort the suspension geometry to try and suss this weird and inconsistent handling ....
13/11/2007

After a monumentally busy start to the year work-wise, I made a concerted effort to get the car sorted to get back out there and have some fun. My plans for stripping the car back to the shell and re-checking all the suspension alignment starting from the shell and subframes went to hell in a hand cart, so it was a case of building an engine and doing my best to re-sort the suspension geometry to try and suss this weird and inconsistent handling thing. I picked Silverstone as my début race.

I set a plan of action to make sure I covered the most needy stuff. First was a trip to my local tyre and exhaust joint (Ian Brown Tyres – 01653 690300 – excellent folk). They have an interesting radio-signal kind of alignment set-up that the boss said he'd do me a measurement check for nowt on. This I had to do before plucking the motor out. I slid down there early one morning and popped it on the ramps to get a set of readings. Interestingly, according to the machine, the wheels were arranged around the car centreline OK, but the left side had almost half the camber it should have had. So that would have been most of the problem I was having then – bad under-steer in right turns.

Sort of pleased to have found something concrete at which to point the finger, out came the motor. Removing the head showed the damage the dropped valve at Croix en Ternois in France last year had down – basically destroyed the head and number one piston. The bore was scored to hell too – so no surprises, a new engine and head would be needed. I had already decided not to spend a fortune of a mega-whizz-bang unit for this year. I wanted to sort the handling, so that meant maximising time on the circuit. Consequently the engine was to be a 'what's under the bench' special with a new cylinder head. Not something I was especially looking forward to doing as I had already spent way too much time in my grinding 'pit' so far this year. Still – it had to be done.

The 'under the bench' parts store was a little limited. Largely because I have been trying to maximise space use for useful stuff and binning anything that wasn't particularly useful. I ended up with a block re-bored to +0.060”, a set of used pistons with new rings, a Piper STR930 'Miglia' spec 649 type cam, a set of welded up pressed steel rockers (I personally find that 1.5 ratio rockers and the 649 type profile do not make a very happy combination), an reasonable EN16T crank (wedged and heat treated), a set of my mates excellently lightened A+ rods and of course a new head. I didn't flow test the head – but the way the motor goes, I'm thinking it id pretty darned good. 'Nowt flash' as they say round these parts but basically a good, strong, reliable performer. A quick run up by genial Pete on my local rolling road (Alwyn Kershaw, Gate Helmsley, 01759 373399) to check fuelling and ignition as best we could since the engine was brand new bar 20 minutes fast idling to bed the cam in showed everything in order, and a pretty decent performance considering the spec. Oh – the only concession to costly parts I made was a set of Total Seal Gapless top ring piston ring set. I'll talk more about this at some other point, but it is something I've started looking in to and using.

Back to the tyre & exhaust folk to set the suspension up. Sorted the front geometry, moved to the rear, checked out the readings, hoiked the back up to make some alterations – to find the near side bracket was broken. Excellent. So, back on the trailer with it, ordered up some new brackets and made plans to get back down there before leaving for the race on the Friday. I decide to try out KADs machined from billet brackets as I has going away from the big negative camber I had been running. I needed to make the car turn faster/sharper so planned on halving rear camber at least. The new brackets arrived as promised, fitted excellently, back down the tyre & exhaust spot. Actually – that sounds way too easy. What actually happened was the brackets fitted perfectly – so in the morning I went to load the Clubby on to the trailer – and it rained. No – it didn't rain – it monsooned. I got absolutely soaked through. This rain continued all morning – so I got drowned unloading the car at the tyre place, then drowned re-loading it, then drowned unloading it again at home. And I mean drowned – that's four changes of clothing. I kid you not. Anyway – sorted the rear geo and we were ready for action.

I don't like Silverstone. It's like Stalag 12. In fact we call it 'Stalag Silverstone' (not original I know but to the point). And the club circuit is not good for Minis against big engined cars. I was not looking for glory, just getting time in the car and to see how it was handling now. The plan was to do 3 laps keeping to a maximum rpm of 6,500 to bed the engine in a bit more and make sure the handling wasn't doing anything not in the script. Then push the rpm up to 7,200 and start pushing the handling more to see where we were at for a few laps, then banzai the last few laps. All was going well – the car was predictable and consistent in the handling department (not fast – but solid) and the engine was feeling pretty good. Got the first 6 laps done as planned and was getting in to the 'all out' phase when, coming out of the Becketts hairpin, dipped the clutch to change up to top, and the engine immediately went on to three cylinders. Hmph. This turned out to be a pinched in the guide number two exhaust valve! This is the first time I have ever had this happen. I have heard other suffering this problem – but never me and not on any of the heads I have done over the years. The valve head got bent, so that was that. I hadn't had time to do a spare head to take along to race meetings.

Still - the good news was that the car was handling consistently and predictably – a huge improvement on last year. It would seem that the supposedly 'flat bed' commercial lift I was using to set the car up last year wasn't all that flat. But then this got me to thinking about setting cars up on lifts anyway. I wonder just how many lifts are absolutely flat and level... there must be some change made by the raising and lowering of them at the very least. So now I am looking for a perfectly flat and level floor to check the car out on!

Next race planned is Croft – my 'local' circuit and one I like despite it being again not much of a Mini circuit in the face of big BHP motored opposition. It has enough different types of corner to test the suspension and handling. Just the small matter of a bent valve to sort – please don't let it have trashed the head, please don't let it have trashed the head, please don't let it have trashed the head, please don't let it have trashed the head.....

www.calverst.com

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