All Aluminum Nikasil cylinders

jseng1 said:

Ken

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

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I don't know the alloy, but I'd be surprised if it was anything but A356. They fit Kenny's Norton cases, so I've assumed they will fit any 850 or late 750 cases. I'll have to try them to verify that. I'll get that done some time this week, as well as posting a picture of the lifter retainers he used. The bore size is 79 mm, which is what he used for his "880" builds.

I don't recall the details of his experience with the Nikasil, just that he suggested installing iron liners instead.

Ken

I just ran across this article in the November 2010 Classic Bike, about Des Senior's Commando and Seeley bikes. He has positive comments on his experience with Nicasil bores, which I've marked in red, as well as the short skirt slipper style pistons he used. The cylinders he's using look like the ones made by Drew Robertson in England a few years ago, the same ones Jim used for his tests above..

Just some more fuel for the fire.



Ken

Original barrels in Ally have been cast in the past, that is the very easy bit, along with the other easy bit the machining. Now there are some problems to resolve, keeping the external dimensions the same sleeve's are possible but you then loose wall thickness on the outside of the bores, not so much a problem for the 750's but a major problem for an 850. With the 850 the option to nikasil looks like it would overcome the use of a liner and the issues of fitting a liner to 850 spec. These problems have been overcome in the past but at a cost which no doubt prevents them being commercially available, and as some have suggested the benefit of Ally over cast iron in use and expense makes it a better option all round. Cast iron is cheap, easy to machine, negates the need for a liner and the fitting of it. If it was that easy all the retailers would be making original barrels in ally surely by now!!

I admire those that will try and move the technology forward, and with modern boring and honing methods along with fitting liners using Hipping to get a good thermal interface, then I'm sure someone will produce a nice looking barrel in the near future.

lcrken said:

I just ran across this article in the November 2010 Classic Bike, about Des Senior's Commando and Seeley bikes. He has positive comments on his experience with Nicasil bores, which I've marked in red, as well as the short skirt slipper style pistons he used. The cylinders he's using look like the ones made by Drew Robertson in England a few years ago, the same ones Jim used for his tests above..

Just some more fuel for the fire.

Ken

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Ken

Thats an interesting article but seems incomplete. He takes it out and races it without testing as far as I can tell and has problems. More likely he used the wrong clearance or carb jetting with his experimental setup and had a partial seizure - probably scuffed the skirts and jammed up the rings in their grooves (he mentions fueling adjustments and may have run it too lean). There is no follow up and thats what is needed here. Someone needs to work this out. Dances with shrapnel mentions that someone else is presently at it but why the secrecy? Whatever Comnoz said I missed it before he deleted his post. Maybe someone wants to be the first to be successful with this idea (and I would too). A little competitive rivalry could be a good thing here. Bets anyone?

'The more times you can make it goes bang in a given period, the more power you get, it's simple' ?
I don't think it's that simple. Horsepower is not torque. I suggest the major advantage in using lighter pistons is the reduction in the deceleration forces at the top and bottom of each stroke. I once fitted machined BSA 350 Gold Star pistons to a 650 Triumph which were much lighter and gave very slightly more comp. There was a significant difference in acceleration and engine braking.
I also suggest that even if your engine is set up to deliver more torque, lighter pistons would still help it to be quicker. To my mind revving such a long stroke motor over 7000 RPM is an expensive exercise, and there is probably no need to go there. I have only ever been impressed with the 850 motor, like anything it is 'horses for courses' and it is the complete package which is important. I would never try to out-drag a modern superbike down a long straight, you have to get past them in the corners and get a run on them coming out, and also watch out you don't tangle with them 1/3rd of the way down the straight as they come down off the ripple strip.

jseng1 said:

Dances with shrapnel mentions that someone else is presently at it but why the secrecy?

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I responded to you Jim in the PM you sent me a little while ago. For the benefit of the forum members, I was not at liberty to say whom since the individual has no interest in marketing it and does not want to be bothered with inquiries....at least until he has something tested out. He is usually way ahead of the curve on these sorts of things.

Interesting stories about how people get into the alloy cylinder (for Commandos) business. Back when I was importing the ones Drew Robertson made in England, the problem with them I noticed was the poor quality of the machining and of the liners. The actual castings looked quite good. I ended up doing some re-machining to make them right before I sold them, but that pretty much made selling them a break-even proposition, at best, so when Steve Maney started making quality cylinders, I quit importing from Drew. The interesting part is why Steve started making his own. He'd seen the ones from Drew, and was also not happy with the machining, so he tried to buy just the castings, so he could machine them himself, but Drew wouldn't sell them that way, so Steve started making his own. That's turned into a very successful venture on his part. Later, when Kenny Dreer had some difficulties in buying cylinders from Steve for his 880 motors (I don't recall what the problem was), he decided to do his own cylinders, and had patterns made for them. When he quit making them, and sold off existing stock, I bought some of them. He also offered the patterns, but I didn't want to go into that business again. I don't know if he ever sold the patterns, of if they are sitting gathering dust somewhere. They would seem like a good place to start for anyone wanting to get into the market. I think Kenny had the cylinders machined by his favorite CNC machinist, whose name I've forgotten, so CAD drawings and programs might still be available, or maybe one could just contract with the same machinist to finish them.

Both Drew Robertson and Steve Maney stuck with a Dunstall design copy to comply with vintage/classic racing rules about period pieces and replicas. If not for that, they would probably look more like the Commando cylinders, with more, thinner fins. The Robertson cylinders started out with through bolts on the sides only, but the later ones also use two through bolts at back, using two of the existing stud locations.

Ken

lcrken said:

The Robertson cylinders started out with through bolts on the sides only, but the later ones also use two through bolts at back, using two of the existing stud locations.

Ken

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Interesting concept. I wonder how that worked as the flange in the rear of a typical cylinder would then be cantilevered out and somewhat "unclamped". Compare that to the side through bolts which are pretty much solid metal from the bolt head down to the threaded engagement in the cases. Did Robertson modify the barrel casting or make some other arrangement?

Hmm...were not alloy barrels for Nortons a fad many decades ago? Wasn't there a problem with distortion due to the heat build up not being uniform throughout the barrel. Guess what is really needed is to redesign the motor making it wider to space the pots further apart to get a lot more cooling air between them.....gosh how about that as a new fad!! What next 6 start worm drives for the pump?? High lift go slower race cams for road bilkes?? And lets not forget balance pipe exhausts....... It could be I have lived through far too many fads each one of which costs money to incorporate.......but they do say a fool and his money are soon parted. One friend told me that his new 650SS was times at 118mph but after adding all the go faster goodies it only made 110mph. Ge later went on to win a few championships on his Commandos whilst learning the hard way about stress raisers left in cranks by the factory etc etc......
Did Peter Williams ever try alloy barrels on the works Commando race bikes?
Of course what goes well on a race track may not go as well on road bike which should cover a LOT more miles without problems..... Just because a bike appears at meetings on a regular basis does not mean it is not in bits having parts replaced on a regular basis. People often said our old under powered over weight under braked VIBRATING orgasm giving Atlas seemed very reliable...they were not for example standing at Oulton Park when the stress raiser left inside the crank by the factory decided to turn the crank into a 4 piece one taking the cases with it but we still had it out racing the following weekend!

Dances with Shrapnel said:

lcrken said:

The Robertson cylinders started out with through bolts on the sides only, but the later ones also use two through bolts at back, using two of the existing stud locations.

Ken

Click to expand...

Interesting concept. I wonder how that worked as the flange in the rear of a typical cylinder would then be cantilevered out and somewhat "unclamped". Compare that to the side through bolts which are pretty much solid metal from the bolt head down to the threaded engagement in the cases. Did Robertson modify the barrel casting or make some other arrangement?

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Here's a photo of the Robertson cylinders with the rear through bolts that lcrken mentions. They look fine to me and seem like a solid, better way to do it.


[/quote]

Thanks Jim. I agree, much better way to button it up.

It might pay to put some cooling fins on it .





Theres stuff around on Aircraft Cylinder Fin disposition & spacing . One model diesel 2 stroke racer
had fins to Generate Heat ( & act as a heat sink - for stability at pit stops ) in the manner of a P-51
radiator housing . Designed to GENERATE THRUST rather than create drag .

The porshe 512 Flat twelve five litre Daytona thingo went to Water Cooled Heads , turbocharged .
As Head Temp. was the ISSUE . Thus it might pay to line up so matching finned heads if you do .

To up the Anti , and get reduced temp.s , greater output ( b t u removal ) capeability ??



Might end up looking like a T 100 . thereabouts . 8)

jseng1 said:

Dances with Shrapnel said:

lcrken said:

The Robertson cylinders started out with through bolts on the sides only, but the later ones also use two through bolts at back, using two of the existing stud locations.

Ken

Click to expand...

Interesting concept. I wonder how that worked as the flange in the rear of a typical cylinder would then be cantilevered out and somewhat "unclamped". Compare that to the side through bolts which are pretty much solid metal from the bolt head down to the threaded engagement in the cases. Did Robertson modify the barrel casting or make some other arrangement?

Click to expand...

Here's a photo of the Robertson cylinders with the rear through bolts that lcrken mentions. They look fine to me and seem like a solid, better way to do it.

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[/quote]

Jim, those are the Dreer cylinders, not the Drew Robertson ones. The ones you have from me are the Robertson pieces.

Ken

Dances with Shrapnel said:

lcrken said:

The Robertson cylinders started out with through bolts on the sides only, but the later ones also use two through bolts at back, using two of the existing stud locations.

Ken

Click to expand...

Interesting concept. I wonder how that worked as the flange in the rear of a typical cylinder would then be cantilevered out and somewhat "unclamped". Compare that to the side through bolts which are pretty much solid metal from the bolt head down to the threaded engagement in the cases. Did Robertson modify the barrel casting or make some other arrangement?

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Sorry for the delay in answering, John. I was blocked from the site for a while by the dreaded PB issue.

Actually, in the Roberston cylinders the side bolts are exposed from the fins to the base, not filled in as in 850 cyinders. The ones in the rear are similar. You can see the counterbores in the top where the bolts go through in these pictures.





This picture shows the bolt holes from the bottom of the fins.



Ken

In an earlier post I mentioned the lifter locating block in the Kenny Dreer alloy cylinders, and said I would post a picture. This is the picture. The cylinders are the same as the one Jim Schmidt posted a picture of earlier in this thread. They've just been coated black instead of the natural aluminum finish.



This picture shows the solid sides, as in stock 850 cylinders.



And this shot shows the cylinders from the top front.



As you can see, Kenny also used through bolts at both side and rear locations.

The cylinders have a bore of 79 mm, finished and ready for Nikasil coating. Kenny had his Nikasil done by Millenium Technologies in Wisconsin. At the time I bought these from Kenny, he had some that were already Nikasil coated, and some that weren't. I only bought the ones without the Nikasil, because my intention was to use iron sleeves in them. As I recall, they will drop into the later 750 and 850 cases, but the earlier 750 cases will have to have the case mouth opened up to clear the bottom of the cylinders.

Ken

As long as we're on the subject, you might notice that all the alloy cylinders we've seen so far for Commandos have a small number of thick fins, copied from the original Dunstall design. Far better from a cooling standpoint to use thinner, more closely spaced fins, as you see on modern air-cooled bikes and airplanes engines. That's more difficult from the casting standpoint, but certainly not impossible. Unless needed to comply with vintage racing rules, anyone developing new cylinders would be expected to come up with more modern fin designs. If one was really interested, there are some classic papers on fin design for air cooled cylinders that are readily available for guidance.

The only alloy Commando cylinders I've seen that were not Dunstall copies in that respect was one carved out of solid by Ron Fraturelli's machinist back in the day. As I recall, he made an almost exact copy of the stock 850 cylinders. This was before the days of affordable CNC machinery, so it was all done manually. It was a beautiful bit of sculpture. Wish I had a picture to post, but I only saw it in Ron's shop, and that was way before the days of cell phones with built-in cameras.

Ken

lcrken said:

If one was really interested, there are some classic papers on fin design for air cooled cylinders that are readily available for guidance.

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I would be interested in the papers if you have a reference handy. Any of them recommend drilling holes through the fins?

Also thanks for clarifying the distinction on the rear through bolts on the Robertson alloy barrels. For what it is worth, even the Steve Maney alloy barrels four through studs (bolts) are open and bare on the sides so maybe it is not such a big deal in clamping down the barrel to case seal.

Dances with Shrapnel said:

lcrken said:

If one was really interested, there are some classic papers on fin design for air cooled cylinders that are readily available for guidance.

Click to expand...

I would be interested in the papers if you have a reference handy. Any of them recommend drilling holes through the fins?

Also thanks for clarifying the distinction on the rear through bolts on the Robertson alloy barrels. For what it is worth, even the Steve Maney alloy barrels four through studs (bolts) are open and bare on the sides so maybe it is not such a big deal in clamping down the barrel to case seal.

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The classic paper of fin design is NACA-TR-726, and you should be able to download it directly from here

http://naca.larc.nasa.gov/?N=17&Ntk=All ... 6&Ntx=mode matchallpartial

If not, drop me an email, and I'll send you a pdf of it.

No, it doesn't recommend drilling holes in the fins :lol:

Ken

I read that at some point prior to the 1985 introduction of the air-and-oil cooled GSXR 750, Suzuki came up with a new casting technique to get the thin, closely spaced cooling fins typical of GSXRs up to their liquid-cooled iterations.

Matt Spencer said:

It might pay to put some cooling fins on it .

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Maybe you noticed - I'm trying to update some Norton racing specs/products to the XR750 specs. Note the Narley ports at my website. But more cooling fins? That's a job for someone who's into casting.