1970 Ginetta G15

I guess thats not an engine set, 2 long 2 short 1 with a diagonal split

Drop this in here as this is the diversions thread. And this is a reasonably large diversion from the norm although there is a loose connection in that we are playing with engines and carbs on the 875 of KBW.

This is a little different as its a carb rebuild from what I believe to be from a Rolls Royce Phantom III - 7. something litre V12 from around 1938.

Arrived in a flimsy box with some new parts - new parts with a price tag of £3K ! - yet to get that confirmed but as I need to speak with the supplier about some other parts I will do a double check. My lad brought it home from work as none of the guys in his main dealership workshop want to go near it - It's only a carb for goodness sake.......

Things were a bit ominous when I gave it the once over as the only bolt that had been removed was the one sheared off and in a separate bag - hmmmmmm. So what if it's the carb from a £200K Roller - Strato's are £500K and have the same carbs from one of those sitting in my shed. And a GTO uses similar Webers. What can go wrong. Oh its not a Weber - let's get that straight its a Zenith - I think.

As you need to be in a particular frame of mind to tackle these tasks it has sat in its box for the past week until a time where the stress levels had subsided from the day job and I was in a generally calm and mildly happy place.Comfy chair at the table in place - let's begin.

Some shots to assist in putting it back together.














As its from 1938 its not particularly complicated - Made for Rolls Royce there is a decent feel of quality about it - Its a simple twin choke downdraft and although I have not seen the manifold in detail I expect that it's one choke for each bank of 6 cylinders. Its a simple venturi principle with a single main jet and an adjustable idle jet. An enrichment pump for acceleration and really that's about it.

The reason for the rebuild is that the centre body of the carb and the float bowl are damaged - Something when looking into these thing that appears to happen.






Break out the Whitworths and get stuck in - slowly and gently. Taking ones time and taking a good number of pictures along the way does help and within a couple of hours I had the first part of the body removed and identified problem #1 the enrichment plunger seal is goosed. - It will not be going back together this week.








Carried on with the tear down gently easing each of the fasteners out. Splitting the lower butterfly assembly from the float bowl section was a test as two are held together by bolts on three ears. Ears on casting have a nasty habit of fracturing unless great care is taken and There was plenty of evidence that someone had been here before. Who knows how many time in the past but the last time was when some sort of epoxy had been invented. Prior to that in the last 80 odd years who knows if it was ever apart. Anyway, it split down without any ears being separated!









Remove the float assembly and ...






That's a bit nasty - but looking at the enrichment plunger not altogether unexpected.

That £3K part is a newly manufactured centre casting and thankfully it comes mostly assembled because there would be very little chance in removing many of the blanks and screws from the existing one.







There are 4 that need to be removed and its a bit of a twitchy time when you get down to the last 4. Still, as they are available and the casting you are removing them from is scrap anyway its not that much of a worry.




One bank may have had the odd running issue - PTFE tape and crud in the jet seat.



Probably also see if the needle assembly fro the float is available as this one has a bit of wear - Its odd that the new assembly did not come with one as it did come with a new seat.



Back in the box - owner needs to get some new parts on order.

I still can't believe that people still make parts like this. What's going to happen when they all die off?
Not cheap though, but it's a stunning piece of workmanship.

Except for the petrol in your case... But, point taken. You are quite right.

Then I came to thinking... The big time and skill for this sort of thing is making the plug. So could you 3D print the plug and use it in a 'lost wax' sort of process?

I hate it when I have a good idea and the rest of the world got there first!

As mentioned, yes! And this is the most DIY friendly approach, as plastic 3D printers are getting cheap and a standard that is useful



I wonder how cost effective it would be for a carb body... I suppose in terms of keeping 3D data for one-off obsolete parts it must be a good option



I didn't know about this, awesome!

They can be a lot of fun.

Never been a fan of those ferrous kits. I would love to be one of those environmentally friendly sorts but I just cannot get on with biodegradable body/chassis units.

Is leather that uncommon as a plunger seal?
From memory the seal on my aisin carb is leather as well..