Long Stroke ES2

The 19S barrel is taller, needed for the extra 13mm of stroke. If you are looking for a suitable barrel at an autojumble or online a quick identifier is the number of fins - 11 for 19S, 9 for ES2. There are 2 versions of the 19S barrel, up to '56 and '57 onwards. Functionally interchangeable but the later ones have deeper fins which looks odd if paired with the earlier head. The ES2 cylinder head should fit the 19S barrel.

The above info applies to mid 50s ES2/19S, based on the age of the used crank offered in the NOC shop.

There is a long tradition of adding a packer under a cylinder barrel when you fit a longer-stroke crank. It may be that the lower skirt of the barrel is long enough for this, so it would be worth checking.  Then you could just add longer pushrod tubes.

Hi Don,

   The issue here is that the ES2 con-rod is 7 inch centres and the post war Model 19 rod is 7.5 inch centres. The rod length to stroke length needs to be a certain ratio to cope with the oscillating forces at high revolutions. The con-rod length varied on some Norton engines over the years, but the Model 19 was always 7.5 inch centres. This, combined with the longer stroke, makes the engine 7/8th inch taller than an ES2 and means you will need push-rods and tubes as well. If you have a 1948 to 1954 ES2 you will also need a later cylinder head.

As Ian Mac points out::'The ES2 cylinder head should fit the 19S barrel..'

Therefore, can I assume that the reverse is true?

I have a late 19S head and would like to use use it on an ES2 motor for my 57 Model 50.

I was thinking of sidecar use when the pins give out...A balance factor not of the mechanical kind.

(The long intake should not be an issue?)

Hi Neil/ Don,

  The 1948 to 1954 ES2 barrel is used with the cast iron head and has a 3/8th inch spigot. The 1955 version uses the Alfin iron skull alloy head and has a 1/4 inch spigot. The overall length is the same and the fins are the same size. For 1957 the fins were larger to suit the AMC all alloy head and was still the same length. The post-war Model 19 was only made from 1955 and used the 1/4 inch spigot.

Many thanks, Richard.

It would appear the head I have is sound for an ES2 motor going into a pre-F/bed.(57)

Don

The other/another option is one of Mike Pembertons 520 conversions, that will make it a short stroke but it is 1/4 shorter overall than the ES2! But I can vouch for how well they go. 

Dan 

Best to give Mike a ring (Pushrod Performance) he’ll tell you what he can do to liven up the engine.

The 520  involves using a 350 crank/rod and one of his purpose made barrels.

Or you can use the ES2 bottom end as is, and fit one of his barrels, pushrods and pistons to take it to 600cc.

You can add high performance cams, increased inlet and lightened rockers if you wish.

Dan

http://www.pushrod-performance.co.uk/services.htm

Or just a pair of new cams 

My big bore ES2 is 530cc

I did this using an 81.5mm piston @ +40. Standard 100 mm stroke.

It starts easy and runs very well. (28mm Mk 1 Amal.)

The bit of extra umph means a 20T gearbox sprocket and relaxed cruising. 

... the 81.5mm piston from Neil?

It came from a Fiat car, though I'm not certain what model..

It is also + 40 and the next step up is a Matchless 82mm. that would give 528cc.

Only thing I had to do with the Fiat piston was to make a new little end.

This was around 2002. and it took some running in.

But not long stroke: Just the standard 100mm with 7 inch rod.

Long enough stroke !

... worth considering if / when I need a rebore!

Next step could also be a Big 4 piston at 82mm

Drove down from Edinburgh to take mr Pemberton my engine years ago,but he then charged me £100 for sorting the exhaust threads when it was (is) New Old Stock!!Had the original tag from the factory but he  likes to "do"three engines at a time,I have photos to prove it.Everything should be labelled.Neil

My big-bore 350 uses one of MP's alloy barrels and a BSA b50 +.040" piston to give 85x88 (499cc), I would love to tell you all how well it goes, but I haven't finished it yet...

Hi Albert,

   Yes, you are correct. There are sometimes too many numbers for a low capacity brain too retain, plus it's 25 years since I had mine apart !

   I have ammended my previous post and my apologies if I misled anyone.