Parts

I hope it's OK if I expose my parts here

This is for the new build 1360cc Prince Vincent motor that is going in the bike in the background.

Glen




Valve Springs are R&D race from Terry Prince. Cams are Terry's MK5 full race ,440 lift. Pushrods are Tuftrided Stainless, also from Terry. Crankcases are from Andy Molnar, the Manx builder.

Holy guacamole, batman...

Nice stuff right there.

The cam profiles came from the Mercedes Formula one Team's cam development program. Fritz Egli Jr (son of Egli the frame builder) is Terry's Godson. He is also the lead Engineer on the Mercedes F1 team. Terry gave Fritz all of the Valve Data for the Vincent valve train and Fritz plugged this into the F1 cam develoment program. The power band is 3 k to 6500.
Supposedly this is the optimum shape. When Terry exchanged these cams with his old Mk 4 race cams, his engine showed another 16 HP on the dyno.

They look at bit lumpy tho!




10.5 to one lightweight forged CP pistons



Used Primary cover , gear cover and G50 plate given to me by a friend. He also provided me with much of the gear change mechanism. After buying the Quiafe, I thought that part was pretty much done until I had a good look at the parts book. The gear change mechanism is partly supplied by Quaife, but there must be close to 50 small pieces that are not. Fortunately my friend dan had about forty of those pieces.
In return I'll build the gas tank for his current project, a replica of Velocette's one off Supercharged 1939 Roarer.






Terry Prince Head- Bathtub combustion Chamber with Squish band and two plugs. 38 MM inlet ports



Quaife/Surtees 5 speed gear cluster



Belt drive from Bob Newby racing. Bob made this up as a one off for this engine. He suggested using thinner plates and adding two to the standard pack he would normally use with a standard capacity Vincent.




D shaped exhaust ports. Pontiac came up with this idea in the 1950s for their 6 cylinder engine used in stock car racing.
With a standard round port there is a tendency for some of the exhaust gasses to roll back into the combustion chamber. This reverse flow of exhaust has a considerable negative effect on the intake of the combustion mixture.
By raising the floor of the port the engine breaths better and makes more power.

" I hope its o.k. if I expose my parts here " .

SORRY , totally unacceptable .

Penalty CONFISCATION .

Send all to Matt Spencer , Address . . . . .



Hymph . A 5 - Speed Vincent . notta bad idea . Is this Terry Prince still in Australia ??

Id like you to polish all those untill we can see our face in them . please , thankyou .

P.S.

Loking for a ' Pilote ' . :lol:

Hi Matt

Yes, Terry is still in OZ. That seems to be the land of the hotrod, be it motorcycle or auto. For example, I believe GMs high performance LS engine range came from an Australian hotrodder's mods to a standard old 350 GM V8.

The crank, cams and top ends Terry sent me are the same as he used in his 142RWHP 1360cc Vincent sidecar rig.

Glen

So what you are saying, Glen, is that YOU ARE NOT SCREWING AROUND!

Ye gads, man.

Paul, this all started with an ebay bargain gixxer front end and the desire to build a frame in stainless.
It has now gotten totally out of control and cannot be stopped!

Glen

worntorn said:

It has now gotten totally out of control and cannot be stopped!

Click to expand...

Keep the posts and pics coming then - we want to hear how it goes !!
(Sounds a lot for a street bike though ?)

F1 cam development program ?
Lucky he didn't send you the 19,000 rpm cams then.
They would be interesting to see but.....

In the past Vincent hotorod cams have always been trial and error, grind a bit off here, add some there then see how it goes. Some extra power has been found, but always at the expense of power somewhere else in the range.
These mk fives of Terry's have to be the first time that some science was added to the trial and error. Terry was reluctant to sell them for road use at first, then with further testing realized they work fine at lower rpm as well.

Terry is not one for self promotion. I had to drag the F1 cam development story from him, even though it is information that could really help sales. Most of the Vincent club members in England are only dimly aware of his high performance designs for the Vincent.

Glen

Hello Glenn
You have to be in awe of the old fellows (I am) who did development by trial and error!
The D in the exhaust port, does it suddenly change to round at the header pipe joint or is it blended to the round header?
Graeme

Hi Graeme

The exhaust header will be full round right away, but the diameter should be large enough that a little flat is created at the header to exhaust port connection. This little flat, maybe 1/8 wide around the circle, also helps to prevent the exhaust back flow.

Terry has done a lot of trial and error as well, hence the number Mk5 on the cams. In reality they are more like MK 20 because there are many other profiles that he tried but did not bother naming.
Same with the port design and the combustion chamber design. He thought he had those down pat, then Steve Hamel modified one of Terrys big port heads for even more power. Terry then incorporated some of Steves changes into the later designs, plus added the D shaped exhaust port.
Of interest, te latest GM LS engine uses D shaped exhaust ports.

Glen

nice porn ;^)


JD

I believe this cam development program is designed to work with any engine type, just plug in the information and let it do the math.

Not sure the Mercedes F1 team would let us have access to it tho!


Glen

Thanks for keep the posts and pictures comming on this outstanding project. The exhaust port shape fits right it with what Jim (AKA ... comnoz) had said about his own efforts tuning the commando head back when he was racing. There is a thread on it here. He raised the floor on the intake port to stop the turbulance. Again, thanks for the photos and info. Cj

Any update on the engine build?

I just pick up a basket case Black Shadow engine myself and am looking at getting Terry Princes top end
Im building a Vincati with an 860GT frame

The engine is still unassembled, I plan to assemble it over the winter. Finally have all of the parts, there are a lot of them in a Vincent engine. The Vincent Spares Co sent me a Christmas card last year, that may be some indication of the level of shopping that has occurred!
Good luck with your project. From the looks of it, you will also become very familiar with the Spares company. :mrgreen:
Glen

Are you using Terry Princes crank also?
I have a set of flywheels modified to use a 40mm pin off a speedway engine but I'm thinking of just replacing it all

Yep, a Prince crank, bobweight type with oversized mainshafts, 102mm stroke.
Glen