Villiers 197

[traf]

Ages ago I posted details of my Norman B4 fitted with 8E motor. Having gone through it and replaced seals,bearings,rings and correct gearings I was disapointed in lack of power. Still using 8E barel with 40thou off top I was wondering what are the differences in the 7E barrel and compression. I have a spare standard barrel,so a case of reboring the suitable one with 1H piston,any words of wisdom out there?

[suzuki250]

Don’t expect a lot of power from the 8e or 9e engines (this can seem even worse if you have a 3 speed box)

 

The 32a is probably the better option

 

If you fitted the 1H piston you would hardly notice any power increase (if any)!

 

Edited December 24, 2015 by suzuki250

[traf]

I am loath to swap the motor, I ran it in Vintage trials in 1980's in UK and was arriving at finishing trials even if my ability wasn't there,it was a fiver,gallon of fuel and Sunday morning sweat. At that time 32A was just more Classic period and reading Don Morley books suggested old Brass flywheel was a better thing. I don't possess a 32A anyway and all the necessary bits so i just need to get on with it.

So what I have ; 8E based motor with present barrel at .020" O/S, .40" milled off top of barrel as I read in 60's this was the way,last mod was to dress bottom of piston to alter inlet port timing to 37A figure. Ignition is total loss 6 volt,4.5Ah battery and coil triggered by standard breakers.The recent addition was a decompressor type head I never had in the day. The conversation with a knowledgable colleague was modern fuel needs more compression and better flame, so it may be "off with his head" and mill some off or even reshape the combustion chamber. It's all well annd good to look at 1950's pic's and follow, but fuel,tyres,sections change. It's just a bit of fun that if it works I will take to Trials a distance away as here we get shot at by French Chasse (Hunters),already killed one rambler this year. I've had no 7E port figures so far to compare, one chap said they were hard-earnt secrets....My thought was in 20+ years of tarmac racing we always tried to encourage novices....it's not the World Championships is it.

Thank you though for taking a look and idea, traf

[norman_wisdom]

Hi Traf, 

 

What gearing are you running?

 

 

NW

[traf]

Hi, primary drive was I think off 12D 125cc, I have all the facts written down in workshop and will check if you need to know. Gearbox is wide ratio now after some muddle years ago, gearbox sprocket 13T and rear wheel 60T if I recall. Will come back on this post-Christmas, thanks traf.

[traf]

Must post pictures,see you are also B4 owner.traf

[jc2]

Traf, I'm no Villiers 197 expert but you don't seem to be getting much help here so having looked into the potential of the 197 Villiers a bit myself lately here's a few tho'ts: 

 

If you are familiar with Roy Bacon's book the 8e & 9e engines are listed with the same C.R. (7.25:1), same port durations (In 134deg, Ex 152deg, Trans 126deg) & same power (8.4hp @ 4000rpm).

 

The 7e "competition engine" does not have durations listed unfortunately, but the CR (8.25) & power (9.3hp @ 4300rpm) listed for it are the same as listed as a competition option for the 9e so I'd guess that all the cylinders had the same porting (7e, 8e & 9e); they just raised compression on the 7e (& 9e option).

 

The 7e was said to be developed for trials with available piston options from 8.25:1 to 10:1 (see http://www.users.globalnet.co.uk/~pattle/nacc/arc0596.htm) but Bacon said the 7e had a different hi comp head so it may have been a combination of both diff head & piston to raise CR.

 

 

Taking 1mm off the top of the cylinder raises the CR by approx 0.9 on the 197 engine, ie from 7.25:1 to 8.15:1 on an 8e (if the head & piston remain standard) which still isn't quite as high as the 7e competition engine.

 

 

Regarding Inlet duration, Bacon lists it for the 37a as 140deg so the suggestion to increase the 8e to that looks plausible

 

You'd think that boring the cylinder to take the 1H piston would be a useful mod too with noticeable benefit, raising capacity as it does by 14%.  But... the standard 197 Villiers porting looks to me like it already 'strangles' the engine. Apart from the physical size limitations of the ports there seems to be an issue with limited blowdown too, leading me to wonder if they could also benefit from a little raising of the exhaust port (& widening if it's not already at the limit for the rings) amongst other things.

 

Then I found this guy's experience which is more-than-a-little relevant. He got some good advice leading to what appears to be a good outcome:

 

http://fboc.niceboards.org/t2952-more-power-please

 

Useful pics too. The top-hat shaped combustion chamber is interesting. I'd have tho't they could do with more of a squish band. Either way it looks like there's a fair bit to be gained in the head.

 

 

Also, have you seen the Villiers Singles Improvement Handbook? Tho it has a fair bit that's more applicable to roadracing, you may find it useful. There are excerpts/samples from each chapter on the website at villiers.info

 

 

Edit: I corrected the link above for the handbook.

Edited December 27, 2015 by jc2

[laird387]

Hi,

 

To add to John's explanations above, like many I had my own experiences of various Villiers powered machines in my earlier trialling days but note that so far everybody is mainly commenting on compression ratio issues and porting issues, whereas in the day we found that the most useful areas to concentrate on were the exhaust system resonance and the size of the ignition spark.

 

I'm afraid I cant help with much information on the exhaust system design except to note that there were several notable examples of riders with a large expansion chamber fitted close to the exhaust port being successful, Burnard Scott Wade at DOT understood this and several of his designs featured a seemingly large box fairly close to the exhaust port.  I have one very grainy old picture of Barry Robinson riding in the 1957 Scott Practice trial on his 197cc RAC special built by Ronnie Calton, which featured a large tubular box close to the exhaust port which Barry believes was exactly equal to the entire crankcase volume.  Ronnie said, "Remove that and you'll lose power!"  Barry did then promptly put it back...........

 

In terms of the ignition spark, there is a simple modification that transforms the performance, which was developed by Arthur Shutt whilst riding for Francis-Barnett and enabled him to win the 1953 Scott trial, beating David Tye on his Gold Star and then by George Fisher on his 125cc Francis-Barnett when he took the Runner-up spot in the SSDT.

 

I have detailled the ignition modification in the next issue of our digital magazine, ORRe, where there are also several images of both Arthur and George in the back issue where we told the story of the Francis-Barnett works teams over the years.

 

Enjoy

[traf]

Well that is a refreshing change as the advert says,food for thought and tinkering in workshop. So a dormant thing under the blanket gets a bit of use. First job is top off and measure to see how far off I am. Mentioned was "top-hat " combustion chamber, well I had one of those on my Greeves Silverstone RES back in the seventies and it seemed to have edge over standard ,detonation with Champion was cured by affordable NGK's compared to a Lodge....Happy days...exchange Alpha crank 16pounds, pistons,9 pounds....you needed them missing gears gave you a 3-piece gudgeon pin! Keep you posted,traf.

[traf]

Just found my gearings of 8E in Norman, 18tx51t primary and 13tx68t final drive. I'm not sure how to load photo from my USB,but will try,tahnks,traf

[pat]

Thanks jc2 and the rest of you for this nice 6-8E info.

Looks like these engines are more common at the Pre-65 trials scene today vs 10y ago...yes.

Have tested one, fathers 197cc, rebore, only new rings, old std ign, std carb and simple pipe..not bad actually..Now sold.

Ive not read the Villiers Singles Improvement Handbook, but do remember friends ref to instructions eg inlet porting floor, improvements require hard plastic sealing a "hole in the floor" according to the handbook, no?

 

Been running a slowmo 197cc project for some years..interupted by a low budget Bantam (actually yes )...

Have finally collected most Villiers parts- and received almost all ordered spares from Steve..

 

-Regarding CR, "The 7e was said to be developed for trials with available piston options from 8.25:1 to 10:1"

As I understand my piston is std with mesaurement from wrist pin to piston top face 35mm, I would guess this mesaurement has not been altered (2-t) at different pistons for CR options, different piston top shapes vs std flat, yes..what  do you know?

 -different bottom gaskets, yes

 - taking off mtr from top of cylinder, yes 

 - and of course  ideal head combustion chamber

Im a Villiers leman and a 2-t nerd, the Villiers stroke is long and the piston is tall....

 

Question: Do you know if anyone ever offered batches of new prod 6-8E ally swan neck manifold for Amal flange/26 or S25...Swan neck is a  must have for trials as I understand..Milling a straight manifold could be done....BR, Pat

[greevesrider]

On 12/25/2015 at 12:10 PM, traf said:

I am loath to swap the motor, I ran it in Vintage trials in 1980's in UK and was arriving at finishing trials even if my ability wasn't there,it was a fiver,gallon of fuel and Sunday morning sweat. At that time 32A was just more Classic period and reading Don Morley books suggested old Brass flywheel was a better thing. I don't possess a 32A anyway and all the necessary bits so i just need to get on with it.

So what I have ; 8E based motor with present barrel at .020" O/S, .40" milled off top of barrel as I read in 60's this was the way,last mod was to dress bottom of piston to alter inlet port timing to 37A figure. Ignition is total loss 6 volt,4.5Ah battery and coil triggered by standard breakers.The recent addition was a decompressor type head I never had in the day. The conversation with a knowledgable colleague was modern fuel needs more compression and better flame, so it may be "off with his head" and mill some off or even reshape the combustion chamber. It's all well annd good to look at 1950's pic's and follow, but fuel,tyres,sections change. It's just a bit of fun that if it works I will take to Trials a distance away as here we get shot at by French Chasse (Hunters),already killed one rambler this year. I've had no 7E port figures so far to compare, one chap said they were hard-earnt secrets....My thought was in 20+ years of tarmac racing we always tried to encourage novices....it's not the World Championships is it.

Thank you though for taking a look and idea, traf

Not a good idea to remove metal from top of barrel as it will cause piston to hit the head. If you need to increase compression remove it from cylinder head.