Iron barrel or nicasil lined ali barrel?

[Knowledge]

Which is best? Why?

Discuss

(BOK)

[Tony Hart]

It has got to be iron - because that is what is on mine . If the technical answer is actually a nicasil lined one then I will end up talking myself in to buying one

Tony

[Knowledge]

I'm not sure there is a right answer to this, but I thought it might be useful to Lambretta owners to see a few opinions before they make a decision. After all, the GT kits prove that not all after markets need to be invasion lined Ali barrels

[HxPaul]

I always thought that a nicasil lined ali barrel was better for cooling because the piston and barrel expand at the same rate.

[Knowledge]

Very true Paul, but then if you damage an iron barrel, you can rebore it, which is cheaper than re-nicasilling the ali barrel.

There are pros and cons.

Keep 'em coming

[Paulnobodyimportant]

I really fancy the new GT kit, which is cast iron, which I would fit to a TV200 engine that I would obviously need to upgrade, but with the TV200 gearing. The advantage of this cast iron kit is the out of the box performance, see current scootering issue, plus I can have the carb on the LH side, so as to avoid taking the original battery tray of a TV200 scooter. But the major disadvantage is that I would probably need to do a 1000 miles of running in, (See Edens post about having to run his in). The trouble is that for the last 2 years, i don't seem to have time to do a lot of long runs, so it would take me a long time and would be frustrating, to now run a cast iron barrel in. The other advantage is the numerous re-bores that you can have. But for the amount of miles i do and the potential time I've got left on the conveyor belt of life, this is not a consideration. Disadvantage is perhaps cooling if you have an engine running at very high revs,

With the niscali/ali barrel and i've got three such kits, after 200 or 300 miles, i took it as run in, then ran at full wack, where allowed and never had any issues. In fact on my malossi kit, it said run the engine for one hour, at various revs and off you go, which i did. So for me the advantage is lower running in periods and less fear of heat seizures due to the better cooling.

To keep standard carb side, I suppose I could go with a mugello, but they don't seem to have the same out of the box as the above GT kit; or do they.

So far, which kits are vexing you?

[HxPaul]

I thought that the GT kits were only made for small block engines.

[joespeed]

alloy barrel steel liner,this will allow for an odd mishap(seize) due to heat ,alloy with plate is the modern way to go but as fuel is crap and the lack of original heat sensors on the scooters having said that the only one i have worn out is a big 250 rapido,

alloy plated and fit a heat sensor,plus the setting up on the dyno and fit a hand operated choke on the handle bars!

[jonashford]

I have an Ally rb barrel sleeved with steel or iron im not too sure, AFS did it thru PJ lining I think theyre called. Anyway it works for me, the running in was a pain but in the long term I feel the benefits are better, wears faster but if it goes bang Ill not be off the road for very long. Which is better for me.

[Paulnobodyimportant]

I thought that the GT kits were only made for small block engines.

Keep up HxPaul

Have a look at the link below + current issue of "Scootering."

http://www.scooterotica.co/forum/viewto ... 7&p=220196" onclick="window.open(this.href);return false;

[HxPaul]

I thought that the GT kits were only made for small block engines.

Keep up HxPaul

Have a look at the link below + current issue of "Scootering."

http://www.scooterotica.co/forum/viewto ... 7&p=220196" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Wow,that looks awsome.I have a small block engine with a Casa 185 kit at the moment,but I also have a GP 200 engine case and I could be tempted with the GT 200 kit.

[dscscotty]

Having ran and tuned steel lined alloy barrels for almost 20 years I am on the side of liners/re-boreable bores as preference to nicasil. Whilst I appreciate the pro's of nicasil I have all to often seen the effects of damaged cylinders at the road side,which I'm afraid often means a journey in a recovery van. It's not a pretty sight watching the owners of nicasil lined barrels inspecting the damage after issues such as seizures as they see a piece of plating is missing from the cylinder wall. Where as iron/steel lined cylinder seem to be a little more forgiving and can often be cleaned up enough to get you going again. I know of a group 6 RB250 that runs a steel lined RB cylinder and the rider agree's that the lined cylinder offers a good advantage in that he has noticed a higher running temp on the lined barrel does not always lead to siezure as he's lined barrel has exceeded tempratures that had often led to issues on his previous nicasil lined barrel. My own theory on that is that the liner is more pliable and thus able to allow for greater piston expansion. For me lined/iron ally barrels are the best of both worlds and offer some considerable advantages over nicasil/chrome bores.
Remember the old saying "Chrome don't get you home"?

Scotty-DSC


Taken from Mitaka site (Grampians):
Plated Cylinders

Pros
Cheaper to manufacture (initially)
Lighter by about 150gm (125cc cylinder).
The plated surface is very hard and suffers almost no wear.
However the aluminium behind it is soft and “packs back” over time, resulting in an increased piston clearance, even without bore wear. This cannot properly be rectified with a larger grade of piston since the wear is not uniform and a larger grade piston will be at risk of seizure.
Can potentially run very small piston to bore clearance to give a performance advantage.
Very few engine builders, or indeed manufacturers are prepared to run so close to the edge for their customers. Almost all choose to run clearances in the order of 0.040mm, exactly the same as a linered cylinder! – Forged pistons often need even larger clearances!!


Cons
Expensive and very time consuming to re-condition – cannot be rebored.
Cannot easily be honed to remove small imperfections or damage so that even the smallest fault cannot safely be rectified.
Running an imperfect cylinder risks plating detachment and total failure with potential catastrophic collateral damage to the rest of the engine.

Linered cylinders.
Pros
Mitaka offer an economical relining service.
The initial wear can be easily corrected by honing and a larger grade piston fitted to restore the exact specification.
Extended wear or serious damage can be economically repaired by reboring.

Cons
Heavier (150gm)
Can’t think of anything else, unless you can afford a new cylinder for every race.


WHICH IS THE BEST SOLUTION FOR YOU ?

[amb]

Been thinking of putting steel liner in my ts1 225 for some time , decided to bite the bullet and go for it . would appreciate any help /thoughts ie is piston to bore the same as nicasil lined ?, pjme say no issues with heat it runs the same temp Mmm not sure about that ,not a balls out rider like to cruise at 65/70 with cht on trailtech set at 170 for danger but dont usualy get up to this , shame all the previous posts on site have gone but hey ho we will get there ,Believe Eden is the man for steel liners . Oh yea what about running them in ,might be basic stuff for some people but we need this info building up again , Thanks in advance .

[Eden]

The only down side to iron barrels ( not iron liners in ali barrels) is the cooling issue, weight is irrelevant with a lambretta barrel because the barrel is such a small percentage of the over all weight of the scooter unlike a car for example where the engine is a huge percentage of the cars weight.
However if a cast iron engine does get too hot it will just nip up and will run perfectly fine after letting it cool back down as long as it isn't a hard seize that smears piston ali over the rings and sticks them in.
As far as running in goes, if the bore is straight and to the right tolerance for the piston used it isn't as bad as many may think. Ive built and ran in many iron barrels over the years and you only need to go STEADY for the first few miles, maybe 100 or so which you can knock off in one night just tootling around locally.

Of the 4 GT200 kits ive built, 3 have been thrashed out of the box because they were all test barrels and 1 has been sort of run in. that 1 did around 100 miles at speeds below 55 mph then he just rode it normally, hes not a mad nutter rider so it wasn't thrashed but with only 350 miles on it he day tripped with the rest of us to Tenby and had to pick his pace up a little, the engine didn't miss a beat all day and has ran well since. He went to the 8 balls rally today from Birmingham in just over 3 hours with out any issues.
Also the one John has that was in scootering this month went to Cobblesoul with us in April with very few miles on it and that kept up with everyone with out nipping up once.
to sum it up, running in a cast iron barrel isn't a pain in the arse as long as the bore it true and its set up right.

The problems I had with mine during LeJog where due to a bad re-bore that was done by a mate of a mate in a rush. On Monday this week I had the barrel re-bored to the tolerances I had asked for to start with (4 thou with a forged piston), I watched the milling machine do the bore and when the machine worked its way down the bore it was taking material out unevenly due to the bore before LeJog being all over the place. it took a lot out from one side of the lower half of the barrel and next to nothing from the other side and at the top. In fact I don't think it was bored before LeJog, I think the guy tried to hone it out to size which would never work.

Plated ali barrels have more cons than pros for my taste which is why I have never ran one on one of my own engines. For race use they are better than cast iron barrels but personally I think for mile munching year on year out cast iron is better and cheaper in the long run.

As far as iron lined ali barrels are concerned, Just this week I was talking to a racer who has the quickest lambretta barrel out there about liners and he said there isn't a liner available thats hard enough for road use, most people would agree he knows what he's talking about so maybe liners aint the best way to go, I don't know I've never ran one. he doesn't like dyno bollox either but that besides the point guess who!

[amb]

Thanks for that Eden , Well i will give it a go and see how i go on .Any info i gather will be put on the forum good or bad but could be a while yet .

[dscscotty]

With regards to lined TS barrels and road use, I can assure you they offer more advantages than cons. Cooling is more efficient than a full iron barrel, prolonged high speeds can be held without the problems sometimes incured by iron barrels. They can be re-bored should wear or damage occur. There is also now more Ts1 style or similar pistons available in size increments that are suitable for Lambretta type set-ups i:e 107x 22x16 rods so they make it relatively easy to re-bore. There has been occasionally suspicion around the hardness and suitability of some liners, however this can at times down to other issues that have led to problems relating to bore wear or similar propblems. A clubmate of mine runs a lined TS1 of which I check the bore anually and at last check at the start of the year it was still running just a tad over 4" clearance. This is after nearly 4 years hard rallying which included one solo LCGB championship winning year and more recently the LCGB LE-JOG. The only service work undertaken is an occasional degalze of the cylinder and new rings which are fitted at the start of the rally season. The owner of this scooter was very sceptical when I replaced the damaged nicasil surface with a liner but now fully appreciates the advantages and has no concerns and infact prefers them.

Cheers
Scotty

[Eden]

Scotty where are those liners from?

[dscscotty]

Hi Eden pm sent:

[Bristol Daz]

It's a bit late for the Swiss adventure, but I'm seriously considering having my Monza lined, could you give me an idea of time & cost Scotty. Maybe we can get together and have a chat during the euro?

[dscscotty]

Hi Daz
Not going to Euro, however you can give us a call or pop through and I'll get the kettle on.