Hi Comp Cylinder Heads for 2T and 3T engines

[dave higgins]

This is a burette, very accurate...in fact a lot more accurate than my spelling..., http://www.ebay.co.uk/itm/Glass-Bure...item19fc2cecf2
Can`t find that porn channel though......

[IanCordes]

Well, what will they sell on ebay next? The one-stop shop.

Thanks gents.

[John Wakefield]

John. My books are Villiers ones, so the spec. shown is not to a specific bike manufacturer, which probably explains the difference. I don't know what my engine came from originally. It was with a basket case 25DC which I bought a few years back. It included 2 1/2 2T engines. I sold the kit' with one, and kept the remaining 1 1/2. It has a strange engine number, which I can't identify - PRO 369 58...any ideas?

Gary, you may have found the high compression head parts numbers, maybe?

Ian Just revisited this thread. The engine number PRO 369 58 is a 'prototype' number used by Villiers, I have since come across several, some with just 'P' numbers and one, a 2T with the number PRO1570S1038 fitted to a 25DB. From what I have gathered they were issued to bike manufacturers for evaluation prior to production.

[IanCordes]

Interesting, John. That engine has long left my stewardship. Thanks for turning up this thread. I had quite forgotten it, although a quick scan through doesn't answer the question as to whether HC heads work on the 3T, or not. Hopefully I will get an idea of an answer tomorrow, as this evening I switched a pair of HC heads with standard ones. A test run tomorrow should be revealing; or not.....

[IanCordes]

I have deleted the other thread I started, as no point in 2 on the same subject. BTW, I did try a couple of search options in the search box at the top before starting the other thread, but nothing came up. This site needs serious attention....

Anyway, fitting the lower comp heads to my 3T made barely any difference, maybe not quite as crisp on acceleration, but as the bike is in trials trim, lowering the CR a touch might give a bit more torque low down.

Out of interest, I unearthed some photos of that 2T/3T engine I rebuilt a few years back, with the odd number, which turns out means prototype. You can just about make out the number.

[John Wakefield]

A query solved. The cylinder heads ARE the same on the 2T and 3T engine. The extra capacity required in the 3T (324cc) engine is allowed for by shorter pistons with which dont go to top of bore. (see pic). Obviously the higher compression 2T ones will have the effect of increasing the compression on the 3T.

[Stuart Baskill]

A query solved. The cylinder heads ARE the same on the 2T and 3T engine. The extra capacity required in the 3T (324cc) engine is allowed for by shorter pistons with which dont go to top of bore. (see pic). Obviously the higher compression 2T ones will have the effect of increasing the compression on the 3T.

Has anybody noticed how similar the 2T is to the earlier Excelsior Talisman Twin engine

[John Wakefield]

Stuart, whilst I would agree that to some extent the barrels and heads of the Excelsior are similar to the Villiers 2T, but the rest of the engine /gearbox unit are more in the style of the Villiers 8E. The crankshaft is were the main difference is, whilst the Villiers has a pressed together crank shaft the Excelsior is in effect two single cylinder cranks bolted together, this results in a wider engine and more space between the cylinders. Here is a copy of the Excelsior manual showing the bolted up crankshaft assembly https://www.pearsy.co.uk/Manual/Exce...gineManual.pdf