Villiers 172cc brooklands engine?

[Ralf89]

Dear all,
I have this engine which looks like a mixture of different villiers parts. The cylinder is for my opinion a original brooklands. But the head also?
What is the difference to the tt head?
Furthermore the crankshaft should be also original brooklands. But the con rod is stamped with VIIA. According to the part list the brooklands engine should have a special con rod. Can someone confirm?
The crankcase is marked with T, so should be from a petrol standard sports engine. But all these parts are together for a very long time. Could it be possible, that this engine was built in this configuration? The engine number is 18xx, so it should be aprx 1925/1926?
Further photos will follow.
Many thanks in advance
Regards
Ralf

[Ralf89]

More photos

[Ralf89]

Many thanks in advance

[33d6]

What an interesting engine. As you surmise it’s not ” pure “ Brooklands but something built up with available parts. Nothing wrong with that as long as you understand what you are doing.
It’s easy enough to identify all the various parts, about the only tricky bits are the Brooklands head and piston. It’s not easy to tell them apart from their SuperSport equivalent. The head is not too hard, the obvious difference is the length of the cylinder head bolts. 4” on the Brooklands, 2&5/8” on the Super Sport.
I have no practical information on the pistons. I’ve never seen original factory Brooklands or Super Sports pistons, only aftermarket Super Sport. I have a new aftermarket Super Sport piston to hand but how accurate a replica is it? There is always a whisper of doubt.
It’s easy enough to run through a Villiers parts list to check out the rest. I have the No 22 parts list which is laid out like an Excel spreadsheet so is effortless to see what bits and pieces are interchangeable between what engines. Makes life easy. My copy came from the VMCC Library.
I’m not quite sure why you are concerned about the year of manufacture. As it’s not a factory original does it matter? It would be nice to know its provenance but is it essential?
Cheers,

[Ralf89]

Hello and many thank's for your answer.
I fear I haven't understand your explaination about the difference of the head. The different head bolts are clear, because of the aluminium part of the brooklands cylinder. But how does this effect in a difference design of the head itselve? Is the height of the head (where the head bolt nuts are in place) different?

You are absolutely right, it is not so important to know the year. I just want to investigate the history of the engine. I heard the brooklands engine was only sold to racing teams and not to private persons. Is this true?
Does anybody know, if there are any remarkable differences in the geometry between the brooklands conrod and my VIIA conrod (except the weight)? A different length would result in different timing and compression ratio. Or my piston was specialy designed for this  con rod. Many speculations....

Many thanks in advance

[cardan]

Hi Ralf,

In "The Villiers Engine" Browning makes it quite clear that the "Sports", "Super Sports TT", and "Brooklands" engines use, respectively, a one-piece cast-iron cylinder, a cast-iron cylinder + a detachable alloy head, and the shrunk-on aluminium jacket on the cylinder and a "high compression cylinder head". So your head and cylinder combo is at least "pretty much Brookands".

I notice that your head has a little more beef than some others we've seen: the bosses for the bolts are more-or-less level with the top of the fins on your head, but the bosses are a little shorter on, for example, the Excelsior Brooklands we've discussed here previously. Not sure is this is a variation between a SSTT head and a Brooklands head, or maybe an early head vs a later head.

Browning says the engine number prefix is BZ for SSTT, or Y for Brooklands.

He also says that the engine was "made specifically for racing events, the number produced being comparatively small".

Cheers

Leon

[cardan]

I should add that Browning says the Brooklands "padded crankshafts", so maybe your full-circle cranks are correct. Nothing said about the con rod, but I'd expect it to be something a little more special than the one in the engine?

Leon

[33d6]

Hi Ralf,
I think I made a complete hash of the cylinder head and the longer Brooklands holding down bolts. Just ignore it. I was writing drivel.
 I have since been going through my No 22 list and comparing it to your photos. As you say, it just raises more questions. According to the list all three 172cc engines have different conrods even though they share the same bore and stroke (57.15x67mm) but the base Sports engine shares its conrod with all the interwar years 150cc engines (Mks 6,7&8C plus the different bore and stroke Mks 12 & 15C) whilst the Super Sport shares its conrod with the interwar years 196cc engines. The Mks 1 & 2E and the 196cc Super Sport.
Of the three the Brooklands stands alone not sharing its conrod with anything. Nor does the 7A share its conrod with any other Villiers engine. It’s hard to guess the engine builders intentions. Are the transfer and exhaust ports untouched? Your photos appear to show an untouched inlet port.
Finally we come to the full circle crankshaft. What engine did it come from? What is underneath the padding? And is it plain or drilled for the Villiers automatic lube system.
Altogether an interesting but frustrating little beast.
Cheers,

[Ralf89]

Thank you for your answers!

I am pretty sure, that this is the original brookland crankshaft. I have a copy of the No.22 part list and in here you can see a picture of this crankshaft, see attached photo.

The design inlet port is also mysterious to me.
I always tought, that the inlet port with the triangular edges on bottom of the port are the standard design and the complete rectangular design is made for tuning.
As an example i have two similar standard T cylinders tith different inlet ports. Now i was surprised, that the brooklands inlet port also thas the triangular edges.
Thanks
Ralf

[33d6]

Both my “T” Sports have the standard triangular inlet port as shown on your right cylinder as does the solitary Super Sport cylinder I have.
I’ve always believed this was done to smooth out and quieten the inlet gas flow. That squaring the port as on the L/H one causes a sharp cracking sound and disrupts the gas flow. True or not I can’t bring myself to make any sort of irreversible alteration to an original cylinder so I’ll never know.
Two-stroke technology has advanced so much that no matter what is done to these old three port deflector piston engines they are not remotely competitive so I tune for sweetness and dependability.
Last question. Is the crankshaft plain or drilled for lubrication purposes?

[Ralf89]

Sorry i have forgotten to answer your question. Yes the crankshaft is drilled for lubrication.
Cheers

[33d6]

As it’s drilled and appears to be full circle behind the padding it can’t really be anything else but a Brooklands crank can it.
The padding appears to be aluminium, can you confirm?
This is my first view of a genuine Brooklands crank. Any chance of a few extra photos?
Your engine is a comfort in many ways. It shows there are still pearls to be found if you look far enough.

[Ralf89]

My crankshaft it self is not full circle. Both halves are the same as the standard sport crankshaft, but between the crank and the counter weight there is a sheet metal and on this the aluminium padding riveted.
I don't know if this is a original brooklands crankshaft or just a professional modification of a normal crankshaft.
But there are no markings like "villiers sports" as on the normal sports crankshaft stamped on it.

[Ralf89]

Hi,
here are some data about the piston of my engine:
diameter of the gudgeon pin: 14.22mm
Overall length of the piston (from bottom end to very top of the deflector): approx. 96mm
distance between center of the gudgeon pin bore and the very end of the deflector: approx. 46mm
The VIIA conrod is approximately 7mm longer than the normal VIIIC conrod used in the standard T engines.
Cheers
Ralf

[33d6]

Hi again Ralf,
I don’t think it is a Brooklands crankshaft. I can’t see Villiers making a full circle crankshaft in that fashion when they had their own forging shop in house. Forging a full circle crank would make a much sturdier foundation for what they had in mind. Parts 214/219 go down that track. That’s my thoughts anyway.
Your piston is intriguing. I don’t recognise the part number but that’s no surprise, and the 14.22mm gudgeon pin is 9/16”, a fairly common oversize repair on the standard Villiers 1/2” pin. I’ve seen that one on a few old engines.
The 96mm overall height is more or less the standard Super Sport piston dimension while the 46mm compression height is more or less the old plain Sport compression height. Perhaps it is a true Brooklands piston. How frustrating not being able to get original Brooklands data.
Last thing, what is the piston diameter?
I did have thoughts it could be a 196cc Super Sport piston but I think that’s a step too far.
Cheers,