All Aluminum Nikasil cylinders

Nikasil coated aluminum has a closer expansion rate to that or forged pistons. If we used Nikasil coated alum cylinders then we could go to tighter clearances. The Nikasil coating holds up much longer with less wear and the cooling is much improved. Junkyard dog mentioned that getting rid of the cast iron sleeves in his Yam twin was a big improvement and solved a lot of problems.

But no one is offering all Alum cylinders even though a few Norton owners in this forum have said its working. Comstock tried it back when he was racing but said he had some distortion where the bores are closest.

I’d like to see all alum cylinders in Nortons so I checked into this. The 1st concern was the distortion. Exactly how much is there? So I borrowed a couple Alum cylinders from Ken Canaga.

Iron sleeved cylinder below. This is what we are using now. The cast iron wears faster than Nikasil, they get too hot and the expansion rate could be better. When heated to 375deg F. I noticed a small amount of distortion where the bores are closest. Not much. About .001” gap over about ½” of radius.



Next I tried out a bore with the iron sleeve removed. Gave it a light hone to clean it up and fitted a top ring as below.


Then I made a stepped aluminum plate to fit into the ring (shown with blacked surface so I could gauge the heat with a laser temp reader). Using a lamp in an otherwise dark room I wore magnifying glasses to check for light leakage around the ring (works better than measuring tools in a hot cylinder). Light works very well and any gap over .0001 or .0002 is easy to see. Tiny flaws or scratches in the honing process were detectible as microscopic pin holes. It was tight when cold with no distortion or leakage.



After heat soaking the cylinders in a oven for over 2 hours at 375deg, I checked for distortion in the all alum cylinders. There was none. NADA, ZIP, (remember that there was some distortion with the iron sleeved cylinders).

Now I’m thinking that Nikasiled alum cylinders in Nortons would be a good idea and should be tested in real life street and racing conditions. Bore tech can accomplish the machining and other details no problem.

What does everyone think? Is longer life, better cooling and tighter clearances with forged pistons as offered by modern technology worth a few bucks more? Seems like a few people (and vendors) would be jumping all over this. The next thing to check is aluminum sleeves in Alum cylinders. This should be OK as its being done currently.

I think one of the problems will be getting any of the suppliers of alloy Norton cylinders to cast them in one of the alloys compatible with Nikasil coatings. My understanding is that most of the common alloys used for cylinder casting are too soft for Nikasil to work. If you want to use existing alloy cylinders, you will probably have to use aluminum sleeves of the proper alloy. That's not all that bad. Aluminum liners for Nikasil plating can be pretty thin.

We need to be kind of careful with terminology here. Bore Tech doesn't do Nikasil plating. They do a silicon carbide mechanical impregnation into the existing bore material. That might actually work with the existing Norton cylinder alloys, typically something like A356, or it might not. I don't know, but I'm sure Bore Tech can tell you. In contrast, the Nikasil process plates the cylinder bore with a layer of nickel with silicon carbide dissolved in it, and then hones the finish to expose the carbide particles in the nickel matrix.

Don't get me wrong about the Bore Tech process. I think it's great, and plan to have more cylinders done by them, both cast iron and aluminum with iron liners.

There are other possibilities that might be used. Ford has a process where they use explosive arc deposition to plate the bore of their aluminum blocks with cast iron. Always something new going on.

I don't mean to say we can't come up with alloy cylinders that will work for our Nortons with direct Nicasil plating on the bores. After all, Porsche has been doing it successfully for a long time now. But it will take some effort on someone's part, and they're probably not going to get rich doing it.

Ken

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I think I've seen some explosive arc deposition in a few Norton motors. :wink:

To answer your question directly Jim, yes, I think there is a market within which people would happily pay a few bucks more for lighter, better wearing, cooler running cylinders.

But, and its a big but, I think 99.9% of that market would still be quite unwilling to partake unless the process, and products are proven. There may have to be quite some trial and error based engineering before the optimum clearances are arrived at for example.

This is where Maney scores, his barrels are not cheap, they're not perfect, and they most definitely are not pretty! But they are proven, and you know what you're getting, and therefore they sell.

I imagine this is part of what Ken was getting at when he said that 'no-one will get rich doing this'!

Jim, if you can get this sorted, I will definitely buy a set. But only when I'm sure its fully sorted...

jseng1 said:

But no one is offering all Alum cylinders even though a few Norton owners in this forum have said its working.

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There is an engine builder in Germany called SMA who does Nikasil-plated cylinders for Ajays and Triumphs. However I have to add that a friend of mine used one on his Bonnie and had lots of problems which ended in returning to a cast iron part.

IMHO there is a fundamental problem with aluminium cylinders on all air-cooled transverse mounted P-twins: The temperature distribution is quite uneven and thus the bore distortion also is rather uneven. On said cylinder a clearance of 6/100 mm was not enough apparently.



Tim

I have sometimes thought about making a set of barrels which is a through-bolted assembly, using a thick aluminium base plate to hold the cam followers and with separate Porsche type cylinders - with pushrod tubes and possibly also with a thick top plate. I think that even with cast iron cylinders I've seen internal polished high spots where the heads bolt on. The beauty of the assembly would be that the cylinders would be easily interchangeable, without involving the complexity of the current big machined casting. At worst it might involve right and left-handed cylinders.
I note with the photos in the above posting, the tapped threads in the stud holes come very close to the cylinder bores. If the head was through-bolted to the base plate, the threads would not be there. The top and bottom plates could be made from high-strength aircraft alloy or even steel.
I have never laid a head gasket on top of a cylinder base gasket to see what collides.

The actual nikasil process produces excellent results. My guzzi has 160,000 mile with no discernable bore wear - I did change the rings once, because I could, not because I needed to.

The difficulties with uneven expansion and consequent distortion is a parallel twin foible, but because the base material would be more conductive, perhaps thicker sections could be used? Maybe doing away with the air passages as many engines run siamesed bores these days? Alternatively, as Alcotel suggests, two independant barrels?

I have heard of people classic racing Triumph triples who remove the cast iron liners and press in an aluminium liner that is then nikasil coated. I don't kow how successful it is , but it might be worth finding out about.

edit: here's a place that seems to make their own barrels with "nicom"


http://www.triplesrule.com/about_nicom.php

By my first visit to Mandelo in 1982, guzzi had apparently fallen out with Gilardoni - a well known piston and cylinder maker also from Mandello - and had set up their own plant.
There was a just smallish tank in the corner where, according to the translator, was where all the guzzi barrels were coated. I remember no technical details, but I was impressed by the compact size. It seemed that any competent engine machine shop could have set one up and running, given access to the proper chemistry.

You did your test of barrels in an oven where the whole cylinder reaches thermal stability all over. How will the size differ in use...where the temp is not the same across the whole barrel? It might work OK in a liquid cooled engine but air cooled makes me wonder. :?:

I have heard of people classic racing Triumph triples who remove the cast iron liners and press in an aluminium liner that is then nikasil coated.

Click to expand...

PES Uk do the same for B44's, B50's and CCM's, well anything you throw at them if you ask and pay.


https://www.ccm-britain.co.uk/searchforapart/?ptno=E56A

pommie john said:

I have heard of people classic racing Triumph triples who remove the cast iron liners and press in an aluminium liner that is then nikasil coated. I don't kow how successful it is , but it might be worth finding out about.

edit: here's a place that seems to make their own barrels with "nicom"


http://www.triplesrule.com/about_nicom.php

Click to expand...

This seems to be more evidence that it should be possible to do a linerless aluminum cylinder for Nortons. Triples Rule has them for Triumph twins and triples, using sandcast 356 aluminum cylinders. Their "Nicom" appears to be a copy of the Nikasil process, but with a different name. Maybe something to do with copyrights and patents and such.

Ken

I suggest the barrels would have to be of the 850 through-bolted type. Otherwise they might break below the fins.

A certain North American Norton engine builder just acquired four cast aluminum barrels (none for resale) and he is going to have a go at Nikasil treatment. Hope to hear about the results in a few months.

Jim, with nikasil directly on to the alloy casting my concern is the protruding skirt on the bottom of the cylinders, do you think an alloy skirt with 3mm
wall thickness would have different expansion rate to the rest of the cylinder bore ?

I can see the advantage of plated cylinder liners or even a cylinder of a material that can accept said plating. But the "advantage" of alloy cylinders is less clear. Thermal stability appears to be an issue and any cooling advantage would be small since most of the heat is above the piston crown. Add the extra costs and the minuses outweigh the plusses by a goodly amount.

You guys out there who do the hi-po machine and engineering work are great and we all admire you for what you do for these old bikes. But there is a point of diminishing returns beyond which we're just tossing more money for less added performance and most of all, reliability.

Ken - Bore tech doesn't do the Nikasil plating but they have a line on the proper alum alloy (probably A356) and a source that can do the plating. Its all available and these people know each other.

Sure there needs to be some testing. But its not that big a deal and I think its worth a try. I'm not sure if I can find the time but it sure it tempting. If there is no distortion problem where the bores are closest as Comstock mentioned - then I think its a go. As far as spigots hanging out the bottom - see below.

There are a lot of Steve Maney cylinders out there and they could be re-sleeved with aluminum. For those who want to go a step further - solid one piece alum cylinders could be made similar to the Kenny Drew cylinders below (a few might even be available). Note that the protruding spigots could be shortened if using the JSM lightweight pistons because the distance between the pin and the crown is shorter (longer rod).

I agree, Jim, it is tempting to try to make it work. But, as satisfying as it might be, it would be a lot of effort for maybe not so much return.

I do have some of those Kenny Dreer cylinders around (four, I think) that I bought from Kenny without the Nikasil coating. He said he'd thought about fitting them with iron sleeves instead, and that's what I hope to eventually do with them. He wasn't to encouraging about his results with Nicasil bores. They do require a non-stock retainer plate for the lifters, and I only have one of those. They are pretty simple, and I plan to eventually just make some. The cylinders are another project I'm not so sure I'll get to now, so if you are interested in trying something with them, I'd be happy to sell one or more to you.

Ken

lcrken said:

I agree, Jim, it is tempting to try to make it work. But, as satisfying as it might be, it would be a lot of effort for maybe not so much return.

I do have some of those Kenny Dreer cylinders around (four, I think) that I bought from Kenny without the Nikasil coating. He said he'd thought about fitting them with iron sleeves instead, and that's what I hope to eventually do with them. He wasn't to encouraging about his results with Nicasil bores. They do require a non-stock retainer plate for the lifters, and I only have one of those. They are pretty simple, and I plan to eventually just make some. The cylinders are another project I'm not so sure I'll get to now, so if you are interested in trying something with them, I'd be happy to sell one or more to you.

Ken

Click to expand...

Ken

Are the Kenny Drew cylinders the right alloy for Nikasil coating? What cases do they fit? What were the results he mentioned?