So it has been a a while between drinks, so to speak.
A bit of a delay in proceedings - working overseas and renovating the house.
Engine
The rebuild is basically now complete.
At the end of the day the rebuild of this motor has cost around 2.5 times more than rebuilding the DFV in my prior Surtees F1 car. Now it does has 50% more components (ie 12 cylinders rather than 8) and the BRM parts are all far more expensive than ordering DFV items (off the shelf) from Cosworth plus there is a 50% increase in time to assemble the additional cylinders, however the real expense has been the extent of component replacement and the extensive amount of fettling that has had to be done on each component to make it fit correctly.
I have been very fortunate that Hall and Hall UK (thanks Dean and Rick) have had a significant number of either original unused 1973 parts in their inventory or had stock of more recently made spare parts or had drawings of parts, which they had specially made. We found however that sometimes the new or replacement old parts did not fit correctly or mate exactly to other original parts. We suspect that as BRM manufactured such a small number of engines they did not fully achieve the manufacturing accuracy and interchangeability that Cosworth achieved with the DFV. So this kept Crawford Hall our fine machinist and also Superior Automotive quite busy to ensure everything rotated and fitted to the accuracy and tolerances we require.
As Rick Hall has also advised, BRM were running out of funds in 1973 and sometimes there were rebuilds in between races using the best used components they had, as there were limited funds for new items. It is unfortunate as the engineering on the engine is clever and has clearly imported thinking from the aircraft industry and with ongoing development may have been able to keep pace with the DFV.
As Rick Hall has also advised, BRM were running out of funds in 1973 and sometimes there were rebuilds in between races using the best used components they had, as there were limited funds for new items. It is unfortunate as the engineering on the engine is clever and has clearly imported thinking from the aircraft industry and with ongoing development may have been able to keep pace with the DFV.
There are a vast number of new internal consumable items in the engine now and for many items the component materials are of a higher quality (such as pistons, connecting rods, valves and valve buckets) than would have been installed in 1973 so we are genuinely hoping that the motor will be able to complete 1,500 racing miles before the next rebuild and be able to consistently maintain the high revs up at the 10,500 RPM limit now set in the spark box without damage. The next rebuild will also hopefully be far less expensive given that many items (eg oil pumps) will hopefully not be damaged and not need replacement. All the original items have been retained.
My engine builder Rodney Gibbs has commented that all his calculations and modelling of power for the engine indicate that it is designed to be run in the high rev range and it will not have the low rev grunt that the DFV has, so I will need to adjust my driving style and gear ratio selection to keep it operating in the higher rev range during events.
My engine builder Rodney Gibbs has commented that all his calculations and modelling of power for the engine indicate that it is designed to be run in the high rev range and it will not have the low rev grunt that the DFV has, so I will need to adjust my driving style and gear ratio selection to keep it operating in the higher rev range during events.
Photo below from when Rodney was setting the timing.
Photos below of the engine being water pressure checked and being taken through a heat cycle (pumped with very hot water) to ensure there are no water leaks, particularly where the cylinder sleeves marry into the block.
Final fettling and reassembly of ancillary components, which has been a far longer process than we had imagined.
The Water Pump rotor (refer photos below) is a work of art. It is huge compared to the rotor in the Cosworth DFV so I presume this BRM engine must get pretty hot.
Fuel Injector assembly and lines in photos below. and the case over the water pump rotor. The 12 point distributor cap is also visible.
The oil pump did take a lot of time to sort, there are four separate body castings plus multiple internal rotors as seen in photos below. I needed to replace two of the castings. Thankfully Hall and Hall had some old unused stock) and also new internal rotors as the originals were fairly damaged - a bit of debris from a prior engine blow up had been through the pump and badly scored all the working faces which would have significantly impaired the performance of the pump in terms of pressure and also volume of oil circulated.
There was a considerable amount of amount of time taken to re-machine and bush the castings so that all the components lined up correctly and rotated with correct tolerances. I suspect it is now operating more efficiently than when new.
Fuel Bags
It was also rather exciting to return back and see the box of fuel bags that had been sent from Australian Fuel Cells in Qld (manufactured by ATL in USA) waiting for me.
There had been some progressive enhancement of the design of these fuel cells and I must thank AFC and ATL for what are a fabulous and very well made set of three bags. They have been manufactured to close tolerance to the measured drawings and it is a real shame that in 5 or 7 years time they will need to be replaced (under FIA rules) and thrown away as I suspect they could operate safely for a much longer period.
There are two side pod bags (right hand bag shown below) and a centre collector bag. There are a series of one way flaps and valves both in the side bags and in between the side bags and the centre bag, to ensure there is always fuel in the center bag that may be drawn from by the fuel pump, as braking and cornering would otherwise drag the fuel away from the suction point..
Centre beg below prior to and after installation.
So how does one get the bags into the access holes - well first you remove all the internal foam (which reduces sloshing and aerating of the fuel) and then I bind them up to reduce their cross section area.
Then they are 'inserted' as illustrated below.
Once they are in the cavity I then reach in through the access panels, wriggle my hand around the bags and progressively un-peel the tape wrapped around the outside keeping them bound up so that they then 'pop' back into shape within the cavity space. And if the measurements are all perfect and the manufacturing is of high quality then 'Voila' everything lines up and fits.
Well, it would have been perfect if I had just locked the wheels of the trolleys so that when I had my arm deep inside the fuel bag side pod in the tub trying to drag up the fuel bag (inserted in the small side access panel), the car did not suddenly move taking my arm with it.
Wheels
The four new magnesium front wheels have also arrived from Hall and Hall and they are really beautiful. Identical to the originals but a far higher quality casting. Although the originals tested ok in crack testing there was a lot of pitting in the castings and I am sure they had had a hard competition life so I did not hesitate to order new ones. Manufacture took some time but very worth the wait.
I now have two good sets of wheels for the car.
The 17 inch wide rear wheels in the photo below. The colour has not really come up in the photo but the inside of the wheels (ie the side facing the car) have all been painted a very faint luminescent green colour that we colour-matched from the original wheels. The outside faces (such as the front wheel in the photo above) are all polished magnesium.
Next week should see the engine delivered to my workshop and Rodney Gibbs and I will install it into the car a few days after that. Then the slow and steady installation of the gearbox and suspension components will begin.
I did not make the March 2016 Phillip Island event but attending the 2017 event is starting to look promising
