I’ve made a discovery and it has cheered me up. Long time readers will know that the current engine has developed a habit of destroying bottom end bearings. After several rebuilds the gap between running big ends has got smaller and smaller and I got so fed-up that I put the car on eBay.
Before I put it on the ‘bay I had done a lot of research. So much so that I had lost track slightly of the class I compete in. I was planning on building as tough a bottom end as I could and we reading and absorbing the terrible tales of the engine’s weak bottom end. At the same time I was ignoring all of the advice from other people, professional rebuilders and owners of these engines who said that the bottom end is not anywhere near as bad as its reputation suggests and if mine kept going wrong then there must be something wrong with my particular engine. I was even ignoring my own expiriece of this engine in several hard-driven cars in the past.
My sister had a Spitfire 1500 (same engine). My dad (an engineer) rebuilt the engine when it got tired. He didn’t have the bottom end balanced to reduce strain on the bearings or use competition spec bearings. He didn’t modify any of the oil ways to increase flow or use Escort Cosworth big end bolts and ARP bolts for the main bearing caps.
I drove that car several thousand miles following its rebuild. Quite often in long stints. Some of the miles were quite fast. All were on cheap oil. And that car was good. As good fortune would have it, this car was unused in a garage and had not been on the roads for the best part of a decade, though it had been regularly carefully started and warmed up / driven about by my Dad. So I know of a second hand engine that is of a known and tested quality. You know where I’m going with this…
At the same time I spoke to an engine builder what wanted to build me a full-on bottom end. For 5 grand! I declined his offer, even though he pointed out that some people spend 15 grand. Interestingly, he said that blocks can warp. I also read in a book on competition engines that an overheating bearing can throw the crank out of true. I think that one of these happed in the past and this is why my engine is so unreliable. This is my big discovery that has cheered me up – its not the engine design, its my particular engine.
So I’m going to start again. After a bit of coaxing, a new set of plugs, a new condenser and a new set of points the engine from my sister’s car sprang to life and sounded good. Not bad considering it spent the last 10 years unused in a garage. So it going to have a new home and we’ll see how it gets on.
To celebrate I’ve made a little composite video of Gurston Down last year.