Diff-icult Customer

 

Well I have made some progress with the build, but unfortunately in order to do so I have had to completely rebuild the back end. It’s my own stupid fault really as I presumed that because the differential wasn’t loosing oil before it was removed from the donor car that it wouldn’t when reinstalled….. I was wrong. 

When removed from the donor car the diff was dry (not loosing fluid) the breather was clean and the output and inputs all felt really smooth…. So a quick cosmetic refresh and ready to go….. not! I filled the diff with oil a few weeks ago and within hours it had started to weep past the input seal and start covering the floor with EP90 oil. I am however one of those weird people that loves the smell of this thick sticky oil, so not all bad. 

I decided to rip the diff out again so I could replace all the seals, input and output. Despite it only leaking from the input which “could” have had the seal replaced in situe by just removing the prop shaft and input flange, however i now may as well replace the output seals and bearings also, so out it comes.

The removal of the diff is also a total removal of all suspension and leaf spring along with pretty much everything on the back end… so I have been a tad miffed having to do it. It would have been so much easier to have done this months ago before the body was fitted. But with the diff eventually out and on the bench I soon discovered that it is definitely not the diff from the original car… as the input flange nut is castellated, and on the late 1500 Spitfires it should be a solid nut with a dust cap cover… learning and discovery time. I continued to strip all the bearings and oil seals out of the diff housing and clean everything up. The issue now is ordering the correct replacement parts… many scenarios could be present for this diff, for example it could be an earlier housing (round input flange and castellated nut) with later 1500 internals so a mongrel as such. It’s definitely a 3.63:1 ratio (later mk4/1500) as I calculated that before stripping the input and output shafts. But it’s important to know exactly the ID as the mid production mk4 spitfires changed the diff slightly using different oil seals and bearings. 

Another lesson learned from this escapade is that I will not be using Rimmer Bros again for anything. Whilst they have a very comprehensive parts availability and platform for sales, the customer service and order processing is nothing short of shocking…. whilst not particularly on this order specifically the quality of some parts supplied is way short of acceptable. I won’t bore you with details but in a nutshell I placed an order on a Monday mid morning, all parts in stock, and payment made. Nothing delivered by Wednesday so a courtesy call on Thursday morning to check status. They apologised and said their had been an issue with the dispatch and they promised next day priority upgraded delivery so delivery now Friday….. and guess what it wasn’t delivered until the following Monday…. Tossers. 

I am however skeptical with anything I’m told over the telephone from someone clocking on and off for minimum wage, so I had on the Thursday (after chasing the order) placed a duplicate order through Moss which was about £8 overall more expensive (general price against Rimmers supposed trade price) and on the Friday the Moss order was delivered…. Great stuff! Rimmer Bross can just fuck off now with all future business from me they are a shower of shit, and for you chaps over in America that use Rimmers for all your British car parts, you should definitely use a different supplier… Moss, Canley Classics or even EBay… pay more get what you want/need. Don’t use Rimmer Bross. 

So with my contingency supplier out performing a market leader I was able to spend a weekend rebuilding my diff. I had taken the output shafts to work and used the press to push the new bearings on…. So easy to do with the right tool. The oil seals are a fairly low friction push and seat nicely with just a little hammer tap. Then I started to fit the output shafts back into the diff housing. I used a thin smear of RTV to seal the flange plate 100%. It’s rare for the output shafts to leak, but prevention is better than cure this time around. Once these were done I moved onto the input shaft. The oil seals here when removed was a metal circumference unit which is now superseded by a fully rubber unit. Still it’s the correct seal for the diff as the earlier diffs had a slightly smaller diameter seal. 

I refitted the input shaft and nut, which was torque up to the same paint marks I made on it just before it was removed then a new split pin… and after filling with more smelly sticky oil it was left to sit at an angle for a day or so on the bench.  Happily by the next weekend there was no signed of any oil getting past the seals and it was all rotating smooth and cleanly so start to rebuild the back end…. Again! 

I also since my last update received an email from Mick at Fiorano to say that he got his project car registered and mot’d with a quick home inspection from a DVLA representative. That is fantastic new so massive congratulations to Mick for that!… but it made me check further my own car…. And I’m glad i did. Mick said the DVLA only really wanted to check the chassis number and engine number. So I also checked mine….bugger. The frigging engine which was in the donor car and is 100% a 1500 engine which has been fully rebuilt, is not the engine number on my V5….fuck. 

When rebuilding the engine you can see from this photo that after the engine number the machine shop have stamped a 6 digit number that refers to the warranty with the head skim etc… that I paid for. So now I have written to the DVLA and sent them my V5 requesting a change of engine number. This could be an interesting avenue to go down, because normally they will want to know absolutely everything about the engine and its origin and have this verified through official channels. However I have pleaded with them to utilise all the information with the public domain to confirm the engines specifics. 

The engine number dates it from a 1979 MG Midget as opposed to a 1981 Triumph Spitfire. They both used exactly the same engine and gearbox setup and the engine parameters are identical, same compression ratio, same cubic capacity, same carburettors and most importantly for nowadays the same CO2 output…. Let’s cross my fingers and hope that all this information which is available online is sufficient for them to amend the V5 to the actual engine I physically have in the car…. And to be fair “was” in the car when I bought it. I feel this is potential going to escalate slightly but I’m sure we can work something out, after all I’m trying to do things correctly and keep everything above board. I could have just flattened off the engine number and re-stamp the block to match the V5, but I would have lost my warranty stamps for the machine work done. 

Fingers crossed for the next update.