BC

The nikasil is the "chrome" that you are talking about. One in the same. It allows the use for JE, Arias, etc aftermarket Aluminum but forged pistons. It would allow you to specifically design your pistons to suit your needs, as in some more valve relief, and a much higher compression ratio. You could KEEP the custom rods, and the custom crank, and only slightly change the block.

BUT, another issue is that the steel rings would be an issue during the chroming process - as all steel must be removed. I'm not sure if they could be taken off or not.

Aftermarket pistons are used extensively in racing. Please remember that Mahl is the Porsche piston maker that was tapped by Tim to make thier batch of custom pistons in the first place, and as he posted, he was not really that happy with thier wear patterns.

hacker-pschorr

Thanks Brendan, beat me to it!!
I'm working on those details - yes the block would have to be stripped first (studs) - this will be part of what I'm talking to Todd about & the vendor I'm talking to who works with US Chrome. Murphy may also have some insight on this. Hell, if it comes down to it, I'll take the damn thing apart and deliver it to Fond Du Lac (where US Chrome is) myself.

Larry928GTS

From what I've read on the subject, Nikasil is supposed to be supperior to the Alusil, but it's more expensive, which is why some auto manufacturers have used the Alusil instead. I think the new Porsches use Nikasil now. The Carerra GT does, and it was also supposed to have been used on the Porsche factory 917 and 935 race cars. It's also claimed to be used on NASCAR and Formula One engines.

Mahle and Kolbenschmidt do know how to make pistons that will run in the Alusil bore, but apparently the coating and process that was used on the original pistons in our engines is environmentally unfriendly, and that's why those companies started experimenting with different coatings. While those newer coatings are supposed to work in the Alusil bores, I've heard of at least two or three instances now where they quickly resulted in scuffing in the 928 engines that they were tried in. If Mahle will custom make a set of pistons with the exact same coating and process as the stock original pistons, go that route. I don't think they'll do it though.

I don't know if anyone is using "chrome" plating in the way that people usually think of chrome. There may be some misunderstanding with that term, and it may really be refering to the Nikasil stuff. I think Nikasil is a registered name for the coating from one company, and so the same process may use different names from different companies.

If anybody is sucessfully using either Nikasil or custom coated pistons of some kind in a stock Alusil bore, post your experiences. The same goes for any failures of any kind that have been experienced with this kind of thing.

BC

And the rings around the cylinders.

BC

Joe Fan is Nikasil. RobR is Nikasil/JE , and he is not nice to his car.

It works because the aluminum with the silicon content is not very.... Flexible - and therefore will not shift much under the nikasil.

the flyin' scotsman

I used Nikasil on my cylinders for a HRC Grand Prix race motorcycle and ran aluminium pistons. Exellent wear on the barrels considering 15k rpm lasting most of the season.

BTW, I always sent the pistons with the cylinders to the platers so they got the exact clearance to spec.

hacker-pschorr

They pull right off a cold motor.

BC

The man is a genious. PLease say hello when you see him.

BC

Very good point. Hacker- decisions on the pistons will need to be made BEFORE the plating.

mark kibort

Steel sleeves..... sounds heavy. does this mean i have to cut more weight out of the hobert car to keep my current weight? :-)

mk

BC

Who said steel sleeves? Hacker -do you have a link for the engine pics on page's site? The steel that I was talking about mark is a 2 inch deep ring that was used to control the (possible) boost-related tower ballooning on Tim's motor. Hacker says they are removable when cold. Perfect. That was the only issue that I could see. They weigh very little relatively. The crank is heavier too, but I don't see anyone compaining about the extra torque.

hacker-pschorr

Here are the sleeves:

http://members.rennlist.com/pageauto/block.htm

FlyingDog

I recall BMW and Mercedes having major problems with their cheaper alternatives to alusil. Nilasil is cheaper for manufacturers from what I've read. BMW ended up paying severely for using it when they had to replace thousands of blocks for free link to info.

Ironically, Mahle developed nikasil.

hacker-pschorr

Major problems? No. An issue to be aware of? Yes.
Don't forget Jaguar either - they coated the 4.0 motor used in the majority of XK8 & XJ's between 1996 - 2005.

The key is high SULFUR fuels. Not very common in race gas.

the flyin' scotsman

I ran VP race fuels mixed with synthetic Motul; never had an issue with barrels, cranks, rods, brgs etc.............octane was 105 or so.