Alusil pistons in Nikasil Cylinders

[Walt Fricke]

If the proper rings were installed, what problems would arise from using Alusil pistons (with their iron coating over aluminum) in Nikasil cylinders?

Since Nikasil needs to be honed with diamond paste/tools, I infer that it is pretty hard. And that therefore the coating on the Alusil pistons ought not to hurt anything (that conclusion, obviously, is a guess). If somehow the iron (ferrous?) coating caused some kind of problem, could that be solved by applying one of the standard anti-friction coatings to the pistons? Like what Calico, among others, do all the time for us?

I actually have an ulterior motive for asking this, as what I am especially interested in is the use of 996/997 pistons with those motors which have had the Lokasil liners replaced (because of damage of one sort or another) with cast iron or Nikasil, but I thought I'd tap into the Alusil/Nikasil knowledge found here first. I am gathering ideas for possible PCA Club Racing engine rebuilding allowances for certain models of these motors which have problems those of us who are still aircooled guys don't have to worry about.

[Flat6pac]

Walt, without doing a lot of thinking on it, the interface would be the rings. Alucil rings would tend to be less harsh on the alucil than nikisil rings so going the other way, if you found nikisil rings to fit the alucil pistons it should run without problem.
Bruce

[SCadaddle]

1 Question posed
1 Reply
174 look-sees to date

Data point: Recently finished top end job on my 82 SC with the original Alusil pistons running in the original Alusil cylinders that were Nikasil plated by EBS Racing in Reno; EBS supplied the Goetze rings as well. Nothing done to pistons with regard to any type of coating. 500 miles so far. No smoke and runs cool as a cucumber on the top shelf of your refrigerator.

[SCadaddle]

[SCadaddle]

[KTL]

As time marches on and more Alusil cyls get re-plated Nikasil, the exterior telltale signs of Alusil vs. Nikasil will have to be ignored and the true test will be the magnet and visual/color inspection!

[SCadaddle]

As an update and hopefully not jinxie....

3,400 miles to date on the Nikasil plated Alusil cylinders running the original Alusil pistons. Runs nice, hasn't blown up yet.

[Kemo]

thanks for keeping us updated!

[Henry Schmidt]

The only issues I see with using Alusil pistons in a Nikasil barrel are the material compatibility. The Alusil pistons are iron coated and iron will be abrasive again the Nikasil coatings. There is also an expansion difference between cast Alusil pistons and forged Nikasil pistons. This difference should be considered when sizing the pistons to the cylinders.

[SCadaddle]

Update:

Just passed through 5100 miles. Oil consumption is less than a quart in 1500 miles. It should have blown up by now.

[arbita1]

Good to hear.

[cgarr]

Should we get a pool going? I'm in for 20 bux says 8500 and boom! Jk that was uncalled for.

[SCadaddle]

6,431 miles to date. No boom. Place your bets!

[Kemo]

[Steam Driver]

After reading this thread I contacted EBS for a quote on doing the cylinders and the reply I got indicated I would need new pistons as well. Did I ask the wrong question or something? They would of course supply those, but obviously I would like to reuse mine, which mike out fine, if I could.

Before I read this thread I was intending to (and may still) reuse the whole set as-is.

[tom1394racing]

The experienced engine builders I have talked to say that there is no problem using Alusil pistons with Nikasil rings in Nikasil cylinders. It is the interaction of the rings with the cylinder surface that is determining wear characteristic.