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Cosworth V8 1:12 scale

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Nigel Graham 203/12/2021 18:33:17
2133 forum posts
29 photos

A fine challenge and beautiful work!

Steve Crow06/12/2021 15:10:28
310 forum posts
191 photos

One of the most fiddly things on this build was hand fettling the bearing blocks so the camshaft turns freely with a minimum of play.


The cam shafts are supported by a sort of shell bearing. These were made by turning down brass bar to 2mm and boring out to 1.6mm.

These were then trimmed down to a semi circular C-section and burnished/work-hardened into place using a polished steel 1.6mm rod.

They are now held firmly in place by there own springiness.


I'm making all this up as I go along but it seems to be working fine.


David George 107/12/2021 08:26:29
1839 forum posts
503 photos

Amazing work! Keep up the info on here please. I wish I had the time patience and skill that you have.


Steviegtr07/12/2021 22:36:14
2432 forum posts
336 photos

That is looking stunning Steve. As above keep posting pics.


Steve Crow07/12/2021 22:58:48
310 forum posts
191 photos

My next challenge is to finish the cam gear train. The principal gears are in place and running smoothly, I just need to sort out the idler gears.


Here are some sat in their final position.



Die Hardenedbedway12/01/2022 17:05:15
30 forum posts
14 photos

So cool !! I wouldnt know where to start !

Ramon Wilson12/01/2022 17:52:00
1319 forum posts
382 photos

Superb workmanship and excellent documentation - thanks for sharing it


Engine Doctor ( Phil )20/02/2022 11:48:33
19 forum posts
1 photos

Absolutely BRILLIANT . Well done .

Hopper20/02/2022 12:28:59
6393 forum posts
334 photos

I am totally in awe. Yes, brilliant.

I have a similar-ish gear-driven DOHC V4 Honda motorbike. Ohh but those many and multiple gears make a glorious whine when they get wound up!

Edited By Hopper on 20/02/2022 12:31:02

Steve Crow28/05/2022 17:16:14
310 forum posts
191 photos

It's time I resurrected this thread. I've had a couple of months off metalwork but I'm back into it now.

Yesterday, two years to the day from the first idea and drawing, I finally finished making all the major components.

I've completed the task I dreaded most. The valves, guides, tappets and springs - 32 of each.

The valves took the most time as they are rather small with quite tight tolerances. Each one needs 8 machining processes.


Here's 16 of them on a penny.


And a close up of one so you can see the slot.


At this magnification, you can see bits of paste from when I ground them into their seats.

Edited By Steve Crow on 28/05/2022 17:17:15

Steve Crow28/05/2022 18:32:22
310 forum posts
191 photos

Here's how the valve parts fit together, open and closed.


The valve guides are brass and reamed with a 1.026mm carbide reamer (Jurassic Tools - great price). They are a friction fit in the cylinder head and the springs keep them seated.

The tappets are adjustable using the 3 holes and the slot in the valve using a tool that I have not finished yet.

Here is a tappet and an untrimmed spring. And a penny.



Andy_G29/05/2022 09:25:25
173 forum posts


Very impressive work.

Andy_G29/05/2022 09:25:26
173 forum posts


Very impressive work

[Edit: Duplicate post, but it bears saying twice, anyway.]

Edited By Andy_G on 29/05/2022 09:26:25

Steve Crow29/05/2022 10:42:43
310 forum posts
191 photos

Here is one cylinder head with valve gear installed and a cam carrier behind it.


Valves, tappets and springs (and spares) for the other head.


Ady129/05/2022 14:10:43
5090 forum posts
736 photos

Amazing workmanship

Can't wait to see her turning over

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