Hi Comp Cylinder Heads for 2T and 3T engines

[John Wakefield]

An accurate way to measure cyl head volume is to use a clear piece of perspex, drill two small holes in it, then with a thin smear of grease or silicone to seal the surface, place it on the cyl head face with the holes near centre, fit the spark plug you intend to use, then using an accurate medical grade buerette, fill with very thin oil based fluid, the air will expell through one hole whilst filling through the other.
No false height readings, due to the inaccuracy of the eye or the slightly off level position off the head whilst testing.........

Spot on there Dave, was trying to think of a more accurate method other than doing it with the head in place but then getting seepage passed piston if oil was too thin.

[IanCordes]

Cheers Dave. Sounds like a plan. Now to find a suitable measuring device.

Just a thought, but that wouldn't give an entirely accurate CR, as it assumes the piston completely fills the cylinder at tdc. Even if the piston comes up exactly flush with the head, there is still a bit of volume down to the compression ring. Not much, I know but it will affect it, as the volume of the spark plug does.

[greeves246]

list

THE LIST i have covers all "non standard and std and tell of the modified units for specal needs even bail lifts all sorts of applications "non motorcycle applications" john vernon industries to name one pashley Ltd sharpes commecials A.C cars limited ordered villiers engines ministry of health also ordered engine U.S consessionares !

one is for a 4f engine to be used as a "outboard engine".

The engine number on Ian's engine is not a standard Villiers configuration so those lists will not help.

what was the number ian and send me a photo P.M me please

[IanCordes]

THE LIST i have covers all "non standard and std and tell of the modified units for specal needs even bail lifts all sorts of applications "non motorcycle applications" john vernon industries to name one pashley Ltd sharpes commecials A.C cars limited ordered villiers engines ministry of health also ordered engine U.S consessionares !

one is for a 4f engine to be used as a "outboard engine".



what was the number ian and send me a photo P.M me please

Will do Gary.

[dave higgins]

Ian, this is not a test for finding your compression ratio, this is a method for finding your cyl head volume...two different things.
For example, if, as has been stated that you might have to scollop out the head to lower the compression ratio, and its a twin cyl, then you must have an accurate way to syncronize both chamber capacities, other wise you will have a cylinder imbalance.
A accurate way to find your clearance volume is to remove the head, piston on tdc, run a thin film of grease around the top ring to stop leakage, pop your head back on & fill with the buerrette to the bottom of the plug hole, this will give you the correct clearance volume. for angled plugs lay the bike over to dispell air from the chamber,
you will need your bore & stroke to work out your displacement volume, then add your displacement volume to your clearance volume, this will give you your total cylinder capacity at bdc, which you then devide by the clearance volume to get your correct cr.

[IanCordes]

Dave. I was thinking the very same thing, running grease around the top ring, then popping the head on and filling, as you suggest. Ultimately it is about compression ratio, so that info will be needed. Point taken about balancing the two, though. Cheers. Ian

[Brian Thompson]

Embarrassing Dave Higgins.

Ian, this is not a test for finding your compression ratio, this is a method for finding your cyl head volume...two different things.
For example, if, as has been stated that you might have to scollop out the head to lower the compression ratio, and its a twin cyl, then you must have an accurate way to syncronize both chamber capacities, other wise you will have a cylinder imbalance.
A accurate way to find your clearance volume is to remove the head, piston on tdc, run a thin film of grease around the top ring to stop leakage, pop your head back on & fill with the buerrette to the bottom of the plug hole, this will give you the correct clearance volume. for angled plugs lay the bike over to dispell air from the chamber,
you will need your bore & stroke to work out your displacement volume, then add your displacement volume to your clearance volume, this will give you your total cylinder capacity at bdc, which you then devide by the clearance volume to get your correct cr.

Hi mate,

Yes....I'm going to embarress you now, by saying a few things that are long overdue, in my opinion, especially as I know what a humble guy you are about what you can do and what you know....and you can punch me in the grid for posting this later, because it is richly deserved.

I've been following your input on this thread, and yet again have been blown away with your knowledge, experience and expertise, which is hardly suprising when I know what you do for a living, and the complexity, rarity and value of the vehicles you work on. These simple little two stroke singles and twins must seem like toys in comparison. Ok, I'm biased here, as you're a good friend to me, but nonetheless, I want to say publically that in my opinion having your input on this forum and access to your knowledge and experience enriches it for everyone on here, as does your finely honed sense of humour, which is appreciated by many members, especially me chuckle bro!

Right...I'll leave it there as I value my teeth (!), but THANK YOU Dave, sincerely, for all the advice and help you offer members of this forum. You are a great asset to the GRA and a clubman of the highest order.

Respect.

Brian.

[John Pattinson]

2T heads

I don't want to be picky but I will! When Greeves 246 mentioned not well known companies who used Villiers engines, Sharpes Commercials was in fact the Bond Minicar producer, so a prolific user of Villiers engines. John Wakefield also mentioned that 2T and 3T heads are not interchangeable well they are, so thats two people that I have upset....Sorry but I must get out more! John P.

[Brian Thompson]

The truth is out there.....somewhere.....

On the contrary, keep up the good work JP!

Nothing wrong in being corrected to set the record straight......it happens to me all the time....

Truth is truth, and it will set you free (as a wise man once said), so how can that be upsetting....?

Brian. (enthusiastic amatuer, thank goodness....)

[IanCordes]

Buerrette

I too am grateful for all the advice which has been freely offered here, and have great respect for the wealth of knowledge of it's contributors
(although I also knew that 2T & 3T heads are interchangeable, but didn't want to upset John, as he has been so helpful!)

However, I think I know what a 'buerrette' is meant to be, but when I look it up on't 'net, I get directed to various porn sites! Naturally, I didn't go there.... ahem

In my Pocket Oxford Dictionary, and New Penguin English dictionary, there are no words which start with 'bue'. I thought of reversing the 'e' and the 'u', but likewise, there are none which start with 'beu'; so what exactly is it?

Now I am being picky, and I've only been on here 5 minutes!

Time for me to duck...

Ian

[Brian Thompson]

Did someone mention Ducks.....

Hi Ian,

Still chucklin' at that one....!

I've just tried the same search (!), but with one big difference apart from the spelling of burette - (thankfully!!....I'm a delicate ex rock muso tha knas, and know nothing of the things you mention...)

I tried typing in 'measuring burette' and got this; https://www.google.co.uk/search?sour....0.J4NjLdAGWk4

Also, by adding 'cylinder accuracy' (which came up as I was typing my search) to 'measuring burette...' I got this; https://www.google.co.uk/search?sour....0.TVCA1fY6kDc

I also found this, which may or may not be as helpful as the other two links, but you never know..... http://www.carolinecrockeroriginals....ring_ducks.htm

Good fun Ian, and best of luck with your project. Keep us appraised of progress, and without the questions we wouldn't get to share all the good info from the clever blokes on here.

bRiAn.

[IanCordes]

Oo duckie

Eh oop me duck!

I have a graduated cylinder, which i used for measuring 2-stroke when I was racing MZ's; yes, really, see:-

http://bmzrc.net/gallery/2012-gallery/#foobox-4/1/IanCordesMZExp_Pembrey0512.jpg

but it won't be accurate enough. I think it is to do with the size of your meniscus....... or so my Mrs said

[John Wakefield]

You could use a medical syringe which would be calibrated in milliliters, milliliters and cubic centimeters (CC's) are the same. It should be accurate enough to determine the compression ratio to as near as makes no difference.

[IanCordes]

You could use a medical syringe which would be calibrated in milliliters, milliliters and cubic centimeters (CC's) are the same. It should be accurate enough to determine the compression ratio to as near as makes no difference.

That should do it, John. I am just wondering where on earth I buy medical supplies; apart a medical supplies shop, that is. Can't say I have seen one around. I'll search the 'net. Cheers.

[John Wakefield]

That should do it, John. I am just wondering where on earth I buy medical supplies; apart a medical supplies shop, that is. Can't say I have seen one around. I'll search the 'net. Cheers.

Loads on eBay http://www.ebay.co.uk/sch/i.html?_fr...Text=&_sacat=0