A new Big 7

[Hugh Barnes]

Catching up - 

Your earlier post of the Patent Plate finally identified the mystery plate I had as a Big Seven variety. Excellent - that was bugging me...

Hugh

   

[Parazine]

It took an interminably long time to find the necessary spares for this engine build. A set of +20 pistons came from Scotland after a chance meeting at the centenary, Tony Betts was able to find some shells and valves, thanks Tony. The Big 7 register was able to supply some new parts but Robin has been in poor health for that last year or so the spares scheme has been operating very slowly.

However, just before Christmas, the block and crankshaft were dispatched to the machine shop and I had word today that they should be finished next week. In the meantime, I have been cleaning:

   

I also had to machine the water side branch, which the Register were able to supply but in unmachined format.

I have also made most of the gaskets, the Register has a few but not enough to rebuild an engine:

   

Lets hope the building can begin next week.

In the meantime folks, thank your lucky stars that we have all the spares that we need to keep the "Baby" Sevens on the road!

[Ivor Hawkins]

Good work, especially the gaskets, it doesn’t look like you’ve used the old tapping around the gasket paper with the toffee hammer, did you cut them by hand?

Either way, they look great.

[Austin in the Shed]

I'd never really liked big 7's until l bought a complete wreck which was past restoration,crudely fitted with an 1100 Ford engine but it made me realise  how nice a good car could be.

[Dave Mann]

Nice find, it's interesting that the gearbox had been overfilled which seems to be a common problem thanks to misleading period manuals.

[Peter Sweeney]

Great to see another being saved. In 1975 mine broke a top ring and the fragment ate through the piston to escape through the valve. This was on Hadrians wall clouds of smoke. I drove it home to Colchester topping up the oil used a gallon on the way. Since the rebuild 47 more years and best part of 100 000 miles. One of the Family

[Parazine]

A quick update on this project:

The engine was rebuilt over the winter and installed a few weeks ago. 

   

I also rebuilt the gearbox, while it was out as the bearings were showing signs of rust damage and put new UJ's in the propshaft.

Yesterday, I started and ran the engine for the first time, sounds nice and smooth. Took the car out for a few short test runs, all OK but the back axle has a horrible growl on drive, quiet on overrun. 

I suspected that I would find endfloat in the pinion shaft and I wasn't disappointed. About 3/8" 

Pulled the torque tube out and dismantled it today. Input flange was loose on taper, spacer was very worn, the nut was still tabbed up from the factory but the spacer measure 1.095" and it should be 1.125"!

   

Sadly, the car must have done a few miles in this state as the pinion has picked up at the back end where it was being wound into mesh too deeply.

   

I'm making a new spacer from a piece of scrap steel, I'll put it together and see how it sounds but it ain't gonna be quiet!

[David Cochrane]

I think that I read somewhere that the spacer is best made from 4140 high tensile steel or similar.

[Tony Press]

From my notes the Big 7 Pinion thrust was a high capacity split outer ring double row ball bearing (R&M 3 MDJT 25) which is unlikely to be available now but a standard double row ball bearing (SKF 3305A) will fit and with the later design and limited use should be alright.

[Jeff Taylor]

From my notes the Big 7 Pinion thrust was a high capacity split outer ring double row ball bearing (R&M 3 MDJT 25) which is unlikely to be available now but a standard double row ball bearing (SKF 3305A) will fit and with the later design and limited use should be alright.

Apparently R&M 3/MDJT25 is still available from Simply Bearings here in the UK - expensive though at £62 + VAT.