JE Piston in Alusil Bores?
02-18-2004, 02:06 PM
#31
Race Director
Originally posted by Danno
Well, it's more of the AR-average roughness of the surfaces that's rubbing. The Alusil cylinders are fairly rough due to the removal of aluminium from between the silicon crystals. Then an alloy piston in those bores would be pretty rough too, especially with a wave-grind to hold some oil. So the stock pistons are iron-coated, to be very smooth and very tough and durable to live up to scuffing against the Alusil bores.
Well, it's more of the AR-average roughness of the surfaces that's rubbing. The Alusil cylinders are fairly rough due to the removal of aluminium from between the silicon crystals. Then an alloy piston in those bores would be pretty rough too, especially with a wave-grind to hold some oil. So the stock pistons are iron-coated, to be very smooth and very tough and durable to live up to scuffing against the Alusil bores.
It doesn't sound right to me. I cannot imagine the Alusil bores being any rougher than a freshly honed and cross-hatched iron bore.
My guess would be that the lapping process remove less material than convential honing, leaving aluminum near the surface of the bore making it likely there would be aluminum to aluminum contact, and thus galling.
02-18-2004, 09:20 PM
#32
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is Nikasil plating an option yet? I talked to the people at NiCOM in Wisconsin, they do Alusil to Nikasil on 911 jugs for reasonable money. I only wonder if that would be wiser than trying to experiment.
02-18-2004, 09:30 PM
#33
Originally posted by Danno
[B][i]
The only other thing that concerns me is that forged hypoeutectic pistons might be really strong at room-temperature, but once elevated to 350-400 degrees-F, they lose that extra strength much, much faster than cast pistons...
[B][i]
The only other thing that concerns me is that forged hypoeutectic pistons might be really strong at room-temperature, but once elevated to 350-400 degrees-F, they lose that extra strength much, much faster than cast pistons...
More info on that statement?
02-18-2004, 11:13 PM
#35
Drifting
Originally posted by JRMarchand
is Nikasil plating an option yet? I talked to the people at NiCOM in Wisconsin, they do Alusil to Nikasil on 911 jugs for reasonable money. I only wonder if that would be wiser than trying to experiment.
is Nikasil plating an option yet? I talked to the people at NiCOM in Wisconsin, they do Alusil to Nikasil on 911 jugs for reasonable money. I only wonder if that would be wiser than trying to experiment.
02-18-2004, 11:15 PM
#36
Drifting
Originally posted by Rally Guy
Somewhere along the line there was the requirement to drive the **** out of the test motor. Sign me up for that task!
RK
Somewhere along the line there was the requirement to drive the **** out of the test motor. Sign me up for that task!
RK
Notice I also volunteered my car to do it in. If the test motor were ready by late May, I could get two of my buddies to drive with me in the 12 hours at the Point. That would certainly make or break (pardon the pun) the whole issue.
02-18-2004, 11:21 PM
#37
Race Director
Originally posted by Chris Prack
Hey Juan. Nikasil works fine with a 944 and JE's. Charlie has done several and I am considering it. It ends up costing about the same as sleeveing and JE's. Nicom will slightly over bore to keep the 100 mm bore where with sleeve's I can go .040 that ITS allows. I would think that Nicom could do the same but the women I spoke with wasn't very helpful so I let it go for now.
Hey Juan. Nikasil works fine with a 944 and JE's. Charlie has done several and I am considering it. It ends up costing about the same as sleeveing and JE's. Nicom will slightly over bore to keep the 100 mm bore where with sleeve's I can go .040 that ITS allows. I would think that Nicom could do the same but the women I spoke with wasn't very helpful so I let it go for now.
Any sort of non-stock coating is strictly illegal in IT. That means Nikasil. Sleeving isn't legal either.
[edit: spelling.... I can't believe I wrote "strickly" sheesh]
Last edited by Geo; 06-14-2004 at 01:38 PM.
02-18-2004, 11:43 PM
#38
Drifting
Yeah I know but it is legal in 944 cup.I have to run a set of rules (ie ITS) and they allow extra's for lack of a better term. Interior is free as well.
My car does not have the factory dash or climate control, carpet, windows etc. It ran EP and also has a FG front clip so it's not legal for the Cup either due to the chassis. BUT, I get to run in the Super Cup at a weight of 2250 with me in the car! Oh yeah. Just for comparison 968's have to weigh 3300. You figure it out, 2250 with driver and basically an ITS engine.
Should be fun.
My car does not have the factory dash or climate control, carpet, windows etc. It ran EP and also has a FG front clip so it's not legal for the Cup either due to the chassis. BUT, I get to run in the Super Cup at a weight of 2250 with me in the car! Oh yeah. Just for comparison 968's have to weigh 3300. You figure it out, 2250 with driver and basically an ITS engine.
Should be fun.
06-14-2004, 01:50 PM
#41
Race Director
Originally posted by TheStig
Anyone know if JE actually Nikasils or Alusils the piston upon request for your 944 engine????
Andy
Anyone know if JE actually Nikasils or Alusils the piston upon request for your 944 engine????
Andy
There was talk of one of the piston manufacturers making replacement pistons with coatings, but I haven't heard anything more in the last 6 months.
06-14-2004, 01:56 PM
#42
Official Bay Area Patriot
Fuse 24 Assassin
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Fuse 24 Assassin
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I'm curious about this iron oxide coating, of course you all know rust is an iron oxide coating too (Ferrous Oxide) Lets hope theres 2 more molecules tied to that.... 
Andy
Lets hope theres 2 more molecules tied to that.... Andy
07-03-2004, 03:39 AM
#43
I'm in the process of dealing with a scorched wall, and looking to overbore to 100.5. I do not want to sleave the block, but OEM pistons are $$$$. What are my options?
Mark
951 -
Mark
951 -
07-03-2004, 06:18 AM
#45
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I suppose I should learn some metalurgy and oiling tricks as I am going to start putting together my first motor in a couple of weeks (a 9K RPM if-I-can-find-an-affordable-alternative-to-the-HK$-valvetrain and get the crank/flywheel lightened at my local cheap machine shop 4A-GTE) and want it to run proper-like. All bearings have less than 100 miles on them, the rings and bores are perfect, the motor came with all ARP hardware, and I have a new gasket set coming, so this thing should be a capable beast with a proper-sized T3/T4 on it.