Thursday, December 28, 2006

Time on the Spitfire

Work on the GT6 has been progressing slowly, with the gearbox tunnel starting to be fitted, to complete it though I will need the cut-down gear extension, so I know where to cut the hole for it.

I have had to do some maintenance on the Spitfire, I felt that it was becoming a bit gutless, so a new condenser and points were ordered. When I came to fit these parts I had great difficulty in driving the Spitfire from its normal parking space up into the barn, where I had all my tools and better lighting. Once up in the barn the points and condenser were replaced and... no change. The car still refused to go above 2000rpm.
Removing the air box revealed that the pistons and needles in the carburetters were not rising as the throttle was opened up. When the dash-pot from the carburetter was removed, the piston came with it - not a good sign. It turned out that over the years films of muck had built up inside and was preventing the piston to move freely. A quick clean the some silver polish and it was all moving well again.


For Christmas I drove in the Spitfire from Wales to East Anglia to meet up with my parents. About five miles into the journey and the car starts missing and the stops completely, on a blind corner just before the summit of a hill. After trying to start it again but to no avail, I jumped out and popped open the bonnet and whipped off the distributor cap, nothing obvious there but connections were checked and I was soon on the go again - at least I could get off the road now.
I drove to the next layby to have a better look, it turned out that a connection on the points from the wire from the coil was intermittent as the wire end had been crimped poorly and the crimp had failed.
I was on the go again though, later while passing through I was able to pick up another condenser and points, this time Lucas made.

Friday, December 08, 2006

More space required, gearbox started & 10CR

After spending some time the previous weekend making space for the metering unit and throttle bodies, I found that I needed even more space, this time I needed to push backwards into the car. Some rough cuts were made with the engine still in place but, to finish the job and make it look a bit tidier, the engine was removed again.

As can be seen in the image, I had boxed in an area for the metering unit; this has now had one side opened out to allow for the extra space required. It's all looking quite rough and ready at the moment, a bit more welding and paint should see it good though.

I seem to have had some sort of cold hanging around me for the past three weeks or so, which makes me quite lethargic. I could really do without it when I ought to be outside of an evening working on the car. Despite this I managed to drag myself out last night and started looking at gearboxes with a view to making a stronger box to go in the GT6.


The new gearbox will use the casing of the three rail boxes along with the internals of the later (and stronger) single rail gearboxes along with a "J" type overdrive. To complicate things, the later single rail overdrive gearboxes are longer than the early three rail ones, in a more standard car this would not be much of an issue, you would just have to have the prop shaft shortened and move the mount backwards.
Because I have moved the engine back six inches in my car, to move the gearbox mount further back would require an excessive amount of re-engineering. The alternative way to work around this is to use the earlier three rail "J" type main shaft (output shaft) and have a sleeve fitted over one end to bring it up to size and mate with the late input shaft. One of the Triumph parts suppliers stock a heavy-duty version of the early main shaft, hopefully this could be a direct replacement for a sleeved shaft, shall have to make a few more enquiries.

I started off with the single rail overdrive box, this came from a Triumph Dolomite 1850 which was being broken for spares, having been couriered over to me, I assumed the oil had been drained, but it had not, so that was the first job. It was quite encouraging as the oil flowed out that there was only a minimal amount of metallic material carried in the oil of on the magnetic sump plug, although I did find a locking screw, not sure where that has come from, but all other signs look good for it though.


It appears this box has been re-built sometime as all the joining surfaces have been smothered in a mastic type jointing compound and the serial number prefix of the box was CG, meaning the case originally came from a TR7, this was stamped over when it was re-built.

The gearbox, which is going to donate its case, is a non-overdrive three-rail version. This box was originally fitted in my GT6 when I purchased it and to the best of my knowledge it is the one that was supplied with the car. When I drained the oil from this box it was a completely different story as the oil was laden with bronze from the synchromesh rings and a mass of steel shavings clinging onto the magnetic sump plug.

Jobs for the forthcoming week include finishing of the bodywork around the bulkhead and stripping and assessing the quality of the component gearbox parts.

Almost forgot to mention, my entrance into the 10CR has been accepted. To learn more about the 10CR have a look here