Do I build with my nikasil cylinders or not

[n9pv]

I purchased my aerovee a couple years and am just now putting it together. It is going in a Pober Pixie and should be ready to hang it in the spring.
Last summer at airventure I went to a forum where Jeremy talked. He was specifically talking about the turbo when he said not to use the nikasil cylinders when adding the turbo. This got me thinking. You should not use them with the turbo, and they are no longer a purchase option. That is mainly due to availability but it has me wondering. Do I build with them or replace them. Also, if I do replace them with cast iron, which ones do I buy. There are just way too many to pick from. They are not listed on the sonex web site but I have not contacted them to see if I can purchase them from them. Right now I am just trying to figure out if I need replace the nikasil now to avoid the possibility of having to do it later. Thanks for any suggestions, Charlie N9PV

[MichaelFarley56]

Unless you're going to add a turbo later on, I don't see any reason why you couldn't use the cylinders you have. Remember that, if you do install the Nikasil's, you'll save 10 lbs on the finished weight which is always nice. There have been several people with issues when using the Nikasil cylinders, but many people (I'm one of them) have used them since day 1 with no problems.

If you decide you do want iron cylinders, they're available from Sonex. ACV-P02-14 is the part number for the steel clyinder. I think they're around $130 each.

[marsolgp]

Like Mike says they seem to work fine… I ran them on my AeroVee for about 100hrs with no issues. But, when I decided to go Turbo, I went ahead and changed them out with new steel cylinders and new pistons. That's when I noticed a problem. I think I've read it here, some other users with a similar issue, The heads would not come off!

I ended up removing two cylinders and a head as an assembly, on both sides. Once these were off, I worked for several hours to get the cylinders out of the heads. All cylinders had gone 'plastic' at the top and rolled themselves over into the head. (the top of the cylinders were bigger than the cylinder opening).

Again, I had no issues running them and the engine was never overtemped and I had had no oil consumption issues. The heads were serviceable and I've used them with the new cylinder assemblies now for 30 + hours.

I guess I would say, go ahead and use them, they're a good light cylinder…. Just remember that when it does come time for top end overhaul you MAY have a problem… then again, you may not. Not everyone has had a problem. Good Luck

[MichaelFarley56]

Again, I had no issues running them and the engine was never overtemped and I had had no oil consumption issues. The heads were serviceable and I've used them with the new cylinder assemblies now for 30 + hours.

Just out of curiousity, when you swapped to the iron cylinders, did your engine run any different? I've heard different reports and I'm curious what your experience is.

I'm currently in the process of pulling my Nikasil's off to replace them for iron cylinders to prepare for the turbo. Looking forward to it!

[XenosN42]

I had the exact same experience as 'marsolgp' when I did some engine work (occasionally low oil pressure) on my AeroVee after about 60 hours. Couldn't separate the Nikasil cylinders from the heads without a major effort. I replaced all the cylinders. Engine ran fine before with Nikasil and runs the same with the new cylinders.

-- Michael
XENOS N42XE; flying 3-1/2 years
OneX N169XE; goal is first flight in April 2015

[marsolgp]

To Mike, no I didn't notice any difference in the steel cylinders. The one nice thing about them was that since we already had the AeroInjector 'tuned' as soon as the cylinder replacement was done and leak checked you could go fly immediately… No long ground runs, worrying about overheating, etc. They've been fine for 30+ hours and the head retorques have shown no new movement of the head nuts, like the Nikasils did. I don't like the extra weight, but maybe it's just up to me to loose the extra pounds myself…

Oh, and when I installed the new cylinders, I shimmed for 7.5:1 compression ratio. For the turbo.