E: Engine Muff / Liner.

[Bill Thomas]

Interesting , I thought ?.
Found a Barrel in the garage , No clue where it came from, Looks good,
I Need a Muff for a special Big Job,
So heated it up to take apart,
Never had to do this before in my life !, Needed lots of heat, ie not loose,
Found strange markings, Not full contact , So not too good for getting rid of heat ?,
We wonder why we have NIP Ups !, We really needs Bigger muffs , But with the push rod tubes ,
We are stuffed .
I remember John Richardson, West London, Many years ago saying he was going to try iron barrels !.

 

[Normski]

I had an interesting chat with a motor engineer who was changing over and re boring some Laverda liners for me. His opinion was that a ‘loose’ liner which lets oil up and around the liner transfers heat better than a tight one. (His pointed out that if you try to lift a hot pan with a wet tea towel you get burnt fingers)
The Laverda liners aren’t particularly tight and he says Honda ones aren’t. One difference that matters a lot is whether there is a gasket which seals the liner/cylinder interface at the head. Our problem with the Vincent set up is that we don‘t have this.

 

[Bill Thomas]

That makes me feel better Norm ,
When I have finished, The Muff will be a lot thinner !,
Which is why I am going with 6 thou Piston Clearance.

 

[Peter Holmes]

I think you will find your reduced thickness muff will simply stretch with heat expansion when in use and lose its shrink fit, and heat transference rapidly and permanently, even the standard muffs are a bit marginal, hence when Tony Maughan restored one of my engines he junked the standard muffs that had lost their fit and fitted his own billet turned muffs with increased material round the liner, but with reduced depth cooling fins, only really noticeable if you get down low and look through the fins.

 

[vibrac]

I thought we were all going for Nicasil coated Barrels nowadays....

 

[Bill Thomas]

I think you will find your reduced thickness muff will simply stretch with heat expansion when in use and lose its shrink fit, and heat transference rapidly and permanently, even the standard muffs are a bit marginal, hence when Tony Maughan restored one of my engines he junked the standard muffs that had lost their fit and fitted his own billet turned muffs with increased material round the liner, but with reduced depth cooling fins, only really noticeable if you get down low and look through the fins.

I tried those , Didn't like them , Don't know why they made the stud holes smaller,
Anyway It nipped up on the M4 , Playing with a Kwakasaki.

 

[Bill Thomas]

I thought we were all going for Nicasil coated Barrels nowadays....

Only you rich people !,
I have to make do and mend .

 

[Sten Jensen]

I have to make do and mend .

Hi Bill,
At one time I asked Terry Prince about using his liners in std. muffs to preserve original looks, he answered:
"A standard cylinder muff is not good to use for a 92mm liner the old racers did this most of them cracked just not enough wall thickness."
Sten

 

[Bill Thomas]

Thanks Sten, But there are so many things that can effect and make things fail,
For me this is a bit of Fun, Too old to race now,
I won't be using too high a compression,
I like to do things my way, If it goes BANG , It's down to me,
I would just like to hear it run, And see how it pulls, Long way from ready yet !.

I have said many times , People run pistons too tight and carb's too weak,
Back in the 70 s I ran my Special Twin on 12 to 1 pistons and had to bodge the distributor ,
Back down to 24 degrees, On Petrol !, It went very well, I Raced it and also used it on the road.

People also said Norton Forks won't work on the standard head angle , But worked good enough for me,
And still on there ! , It could depend on what wheels you use etc,
You have to look at the complete job.
We will see ,

As you can see , The standard Barrel is not right, With the marks in my photo ,
But I would be happy to run that on the road,
As long as it was kept cool and had big enough piston clearance.
Just my thoughts.
Cheers Bill.

 

[Bill Thomas]

Sten, Do you know the wall thickness of the T/Prince liners,
I am having a liner made, Thinking of 3 mm same as standard.
Cheers Bill.