johny

trouble is you wont know if theyre out of round as well until youve put em on the car and then its a bit difficult to ask for your money back......

Ive wondered if the drum cant be bolted the reverse way onto the hub flange (it should still centre correctly) and then rig up an electric hand drill with grind stone (possibly on a pillar assembly mounted horizontally?) so that while an assistance spins the halfshaft steadily by hand the drill can be moved in slowly to surface grind the braking surface..... Got to be worth a go😎

Perhaps we'll get some other feedback from someone..... I believe back in the day there were lots of places capable of doing this machining but now its cheaper to replace than repair so if theres any left theyre difficult to find and probably not close by.....

Fraid the fact that a new set have gone out of round seems to back up my theory Mark. I cant believe theres many manufacturers of the replacement drums now so all available are likely to come from the same source and be prone to distortion. I went to a local machine shop who had a big lathe and they did the pair for a very reasonable 20quid (reckon they underestimated the work). However they couldnt guarantee the results as they had to use the centre hole in the drum as the datum for centering the drum in the chuck. Apparently they didnt have to skim a lot of metal off but it had been enough to cause the intermittent rubbing.....

I had this on my Vitesse and the replacement drums for it are much more expensive. However I believe cast iron can distort after being cast so should be left for sometime before machining but in many cases this isnt done so after installing your new drums they can later become oval again. In the end I got my original items turned in a lathe which has brought about a great improvement even though the machine shop found it difficult to do without the correct mandrel. Probably something suitable could be made using part of an old halfshaft so that the drum could be reverse mounted and then machined perfectly concentric......

yes it looks like on the original brass radiator the inlet pipe was formed into a curve which hasnt been matched by the welded aluminium chinese version. Perhaps the aluminium pipe could be re-welded at the same location but directly angled towards the thermostat outlet?

I would have thought that your Spitfire 1500 has the 'swing spring' back axle set up in which case you can only use 4 studs to fix the spring to the differential casing. Anyway 4 studs is enough to keep everything in place and as you say the other holes should be sealed up....

well Ive never tried turning my engine over with the dizzy cap off but maybe it too would track across the inside. However with a good rotor theres a much easier path to take so this never occurs in normal operation which why I suggested the possibility of a duff rotor....

Delboy, assuming this is a filter for a spin on adaptor dont forget to try to get it hanging down near vertical (the length of the filter chosen might affect this) so that it stays full of oil which then helps to get the oil round the engine quicker on start up.....

Have another look at Paddock site as its not very clear but they do stock both engine types bearings (not sure about there being different widths of main bearings used for the same crank though.....). You can tell the difference because unfortunately the earlier bearings are all loads more expensive than the later ones☹️ I take it youve really assessed the state of your engine as, unless its had a catastrophic failure, Im surprised any of these cars have lasted enough miles to need a rebore!

Well I think Nick has already tried a new cap so theres only really the rotor and coil left to change. In theory shorted turns in the low voltage side of the coil could change the transformer ratio so giving a higher voltage on the spark side but those resistance readings seem to indicate that its healthy.....

I wonder if theres a problem with the rotor arm? You dont say its been replaced and if it had a very high resistance the spark may well take another route and track across the inside of the cap.....

I believe the problem is that the original hose is corrugated to absorb movement between the engine and radiator and if its replaced with a straight item this forward-backward flexibility will be lost so possibly putting stress on the rad pipe or even the rad mountings. Dont think its going to be easy to find a corrugated hose of exactly the right length.....

As I understand it the problem occurs 'when the starter is engaged' so its almost as if the voltage isnt dropping enough during starting! Hence 12v+ are still being applied to the 6v coil even while the starter motor is operating. Have we got a 24v battery installed😵

Hi, I cant quite get my head round what youre explaining. Turning over on the starter motor with strobe connected to no1 spark plug you see the timing mark in 3 positions on the front pulley at 120º to each other and then once running theres only one mark showing at the correct position? Then you say you 'took the distributor cap off and could see sparking from the central rotor contact to the #1 ignition contact' without the cap in place???? First check is to measure the resistance of the coil both low and high voltage sides and let us know the results....

In the end I found going to a 0.75 master cylinder was the only way to get the pedal feel I wanted....

Could a stop bolt (doesnt seem to be the one in the photo) have been in constant hard contact with the plate either through being too long or held hard over by the driver so that its gradually destroyed the plate through vibration? Maybe the plate isnt original but something made out of mild steel....

surprisingly Ive heard that the difference in cost of insurance for a saloon or convertible is negligible and they do look so cool with the roof off, until it rains😭

yes I believe they even used to sell kits to do it!

some people like to unbolt the roof on their saloon (its easily done and as theres a separate chassis has little effect on the cars rigidity) which of course could affect their insurance so they insure it as a convertible to ensure they are covered in the event of a claim....

well with a maintenance free battery its effectively sealed as the gases produced recombine so topping up is never required. However if over charged or discharged rapidly the gases are produced too rapidly so there are valve(s) built in to the casing to release the excess pressure. Its possible this didnt happen and the pressure rose however I would still expect those plugs to push out before the casing ruptures so think it must have been caused by something more 'explosive'.....

yes those diff bearings are tapered so with the nut undone they are loose and its normal to have lots of movement. Now comes the problem as they are preloaded bearings so its recommended to count the number of turns required to undo the nut so that it can be returned to exactly the same place thus ensuring the correct tension on the bearings. Perhaps you can retrace your steps after replacing the seal to get back to the original position..... Also make sure the casing vent is clear by moving the jiggle pin (at the rear of the diff on top) as if this is blocked oil can be forced out of the seals by the increasing internal pressure when the diff warms up.

The holes in the gearbox mounting plate where the bracket is bolted are slotted so allowing a little adjustment but I think thats all thats available. I have seen gearbox mounts before distorted as youve described and think its where the engine and gearbox tend to move forward under braking so over time the rubbers end up misshapen. I reckon you'll find that the replacements will fit with no difficulty although you might have to lever the engine back a little as the forward mounts will probably have also become distorted. Note that sometimes rubber components can look perished but its superficial and theyre in fact still serviceable. This applies particularly to original components which although possibly more than 50yrs old are often far better quality than the new replacements available......

yes its difficult to see how a modern sealed battery can have an internal gas explosion ignited by an external source like a connection spark....

modern sealed batteries dont contain free acid as its all held in a gel or a glass mat which offers both disadvantages and advantages (eg. no spillage). One failure mode is that the lead connections between the plates inside the battery are gradually eaten away and when that reaches a certain point cant carry the high starting current without overheating which can then start a rapid downward spiral....