Original Aluminum Cylinders With Dimple Plating

[Tom Perazzo]

I'm not sure what engine these cylinders are from, but I'm curious to know if they can still be bored and replated? Or are they junk?

[Martin Benade]

Early Supers had those, I think until around 1957. I am pretty sure I’ve heard that L&N can redo them, a modern surface minus the dimples.

[John Brooks]

Tom

The dots are silicon, drop them in the ultrasonic to remove the corrosion. Look at them for cracks with a dye penetrate and UV lamp. (zyglow) They can be bored. They will probably show not too much ware, they are pretty slick. Usually all they needed was a hone and new rings on a rebuild,

Nice new - old 911, I have it’s twin.

[Martin Benade]

John, I believe these are 356 cylinders. The dots are formed in the aluminum before the chrome plating. They will not clean off. Old tech, and I don’t think they were known for lasting too long. Often or maybe always seen with a roller crank.

[Jon Bunin]

I'm not sure what engine these cylinders are from, but I'm curious to know if they can still be bored and replated? Or are they junk?

Tom, they're Mahle Chromal cylinders. The bore dimension will help identify them.
If the bore is 82.5 mm, they're 1600 Super cylinders used through '61, when the 616/12 Super engines switched to cast iron cylinders.

Porsche continued to use Chromal cylinders in their racing engines to the end of the 60s, the last being the early 917 engines.

[Harlan Halsey]

I think Aluminum cylinders were one of the neat features of the 356. Carreras all used them. The S90 used aluminum cylinders with a sprayed iron coating. The modern solution is to replace the chrome with NIKASIL and go to 911 type rings. But if the original Chromal coating is not worn, then you can use them after consulting with your ring supplier about the proper ring material.

[James Davies]

Tom, they're Mahle Chromal cylinders. The bore dimension will help identify them.
If the bore is 82.5 mm, they're 1600 Super cylinders used through '61, when the 616/12 Super engines switched to cast iron cylinders.

To add to what Jon said, Mahle Chromal cylinders with the dimples were introduced in early 1951 on the Type 506 motor (1300) and were used throughout the 1950s. Circular 51/31 describes these.

Early 616/1 and 616/2 engines (normal and super) in 1955-56 used these, just as the previous year's 1500 and 1500S engines had. See page ~E50 in the 1956 service manual. And as Jon said, these would be 82.5mm bore.

If they're 80mm bore, then they are 1300 or 1500 cylinders, normal and super, 1951 to 1955. And if they're 74.5mm bore, then they're 1300 or 1300S, 1953 to 1957.

Further, the cylinders of 1951-54 have a smaller outer diameter where the fit into the case spigot, as they are for the VW case, and a smaller head bolt pattern, so while the same bore as the 1955 3-piece case cylinders, they are not interchangeable.

Judging by the lack of clearance arc at the base of the cylinder and width of the cylinder walls, these are early 1951 to 1952 cylinders, so likely 80mm bore.

And yes, LN Engineering and others can remove the chrome plating and Nicasil coat them. So they can be reused if not damaged too bad.

[Rudy Bernhard]

LN Engineering used to perform services on these. I am not sure if they still do. They can be slightly over-bored, and turned into Nickies. There are companies that perform the same services for other air cooled cylinders (motorcycles, and other small engines) that might offer a similar service. LN would do a great job, and provide a matching set of pistons, and they know our engines. They are ultra light weight cylinders. My 1960 Super came with them. I have heard some folks buy them to do the conversion. There may be a market. Put them on in the classified, and see if there are takers. Anyone who has Nickies care to weigh in?

[Jacques Lefriant]

Hi
EBS Racing in Reno Nevada can have them done by the same vendor that does LN Nickies and supply pistons. If you don't over-bore you will have the dimples but that is fine.
j

[C J Murray]

I had a set of 1957 Super cylinders on my shelf for 28 years. I very much like the LN cylinders and I have used those on my 83.5 mm race engine with good results. They are the best but very pricy. Shasta is excellent as well, but uncoated Durabar iron. I am building a second race engine and took the old 57 Super cylinders to Power Seal in Kimberton PA and they bored them to 83.5 and Nikasil coated the bores. The dimples are gone. LN and others use a company called Millennium. Power Seal may be the only other company doing the plating. I am not certain of that but they are the only two I have heard of both do top quality work. My motorcycle business uses Power Seal often and we have never had a problem. It is not cheap so get a quote to see what you think. Pricing is shown on their website.

http://www.powersealusa.com

[Jacques Lefriant]

Hi CJ
Besides Mellennium US Chrome is the oldest https://www.usnicom.com/
also i have used Langcourt www.langcourt.com but i would go to Millennium for 4 stroke multi cylinder processing thru EBS If you want the Latest best process is Sume-Bore https://www.youtube.com/watch?v=vZDbLfDAV4Q
j

[C J Murray]

Hi Jacques,
I imagine that they are all good. With Power Seal they do the entire process in-house, boring, honing, plating. They had my new pistons for the exact measurements.

[Martin Benade]

Do they get honed after plating too or just before?

[C J Murray]

Do they get honed after plating too or just before?

I don't know. I can find out.

[Martin Benade]

I am sure I won’t be buying any but it’s interesting learning stuff. Don’t expend a lot of effort to find out.