JE 3.0 pistons
02-11-2015, 05:43 PM
#31
No, NiCom block. Pulled the head because of excessive smoke and bad compression numbers. The pistons and rings were from JE and the motor was built/assembled by a reputable builder. The clearance mandate using JE 2608 pistons cause slap until the pistons expand from heat. You could see the wear on the skirts and you could move the pistons back and fourth from when TDC in the bore. We assume the slap caused pre-mature wear on the rings, and caused some bore gouging. Sean Martinez helped Jeff rebuild the motor at his house in Tucson with our help. Sean has been building motors since he was a kid, and has a MS in Mechanical Engineering. I know of builders who have successfully used JE pistons these motors. Just have no idea about longevity. Just sharing my experience, no issue with JE. My 3.0 motor was built by Garrity at Motorsports. He ordered six sets of JE pistons, one for my car, and five for 911 Turbo engines. JE knew these motors were all NiCom bores, and my motor and thankfully only one of the 911 motors were built and run on the dyno. JE sent Garrity the wrong ring material and when bore scoped, there was bore damage. He sued JE, as they wouldn't fix the issue and Garrity warranted my motor using a new 968 Nicom block and Wossner pistons. Motor has been running fine.
Last edited by KSira; 02-11-2015 at 06:26 PM.
02-11-2015, 06:25 PM
#32
Drifting
Thread Starter
Cut/Paste:
I have seen alot of misinformation about the differences and which is best to use for what application. Some forums have members that believe the 2618 is the only choice for any FI, and 4032 is for N/a; which is not close to the truth.
Basically in a nut shell, 4032 has higher silicon content which makes it harder and expands less under heat-meaning you can run tighter piston to wall clearances, better wear and less noise, longer life. However, the tensile strength is not as strong as 2618 which means 2618 can handle detonation better. This is where the misinformation comes from. The reality is that a 4032 piston is actually very strong and will hold up to detonation much better than a stock cast piston. They are good for turbo applications, but if max power is what you are after, then 2618 is probably the better choice. So where is the point that you should choose 2618 over 4032? That is debated everywhere, but with about a 12% less tensile strength, it is likely only around 12% less power than 2618. So, If a 2618 piston is rated at 1200hp, the 4032 should be able to hold 1000 hp with the same effectiveness. But no matter what, any piston has the chance to melt down/crack/break apart with a bad tune.
Long post, but good information
02-11-2015, 06:30 PM
#33
Drifting
That's a very short life span even for 2618 pistons. Just speculating, but could the problem be miscalculation of the aluminum cylinder wall expansion rate, ending up with to big clearance, or maybe aluminium cylinders are just to soft to work well with the piston slap 2618 pistons will have?
Cut/Paste from Wikepedia, cracks me up:
Porsche started using this on the 1970 917 race car, and later on the 1973 911 RS. Porsche also used it on production cars, but for a short time switched to Alusil due to cost savings for their base 911. Nikasil cylinders were always used for the 911 Turbo and RS models. Nikasil coated aluminium cylinders allowed Porsche to build air-cooled engines that had the highest specific output of any engine of their time. Nikasil is still used in today's 911s.
Nikasil is short for Nickel Silicon Carbide. Silicon carbide is a very hard ceramic (much harder than steel) that can be dissolved in nickel. The nickel solution can then be electroplated onto the aluminium cylinder bore. The piston rings will then rub off the exposed nickel, leaving a very hard layer of silicon carbide to protect the aluminium piston from direct contact with the aluminium cylinder. With this setup, the engine tolerances can be much tighter for better performance. The cylinder must be re-plated after it is re-bored, but Nikasil is extremely durable, so the cylinder does not need to be reworked as often as an iron or chrome cylinder.[3]
02-14-2015, 12:06 PM
#34
Addict
Rennlist Member
Rennlist Member
Just a note here for Mahle, they now use Ferroprint Iron coating for the 944 pistons. Ferrostan has gone bye bye due to being not friendly to the environment, or rather the after product of Ferrostan coating.
02-14-2015, 03:33 PM
#35
Drifting
Thread Starter
This was one of the reasons I'm considering dry liners, plus I wonder if the hone and paste is as effective as the factory etch ?
02-14-2015, 10:15 PM
#36
Addict
Rennlist Member
Rennlist Member
I've put them in 4 engines and all still pounding the pavement but we have an engine shop in San Antonio Tx who is very familiar with the Alusil bore and finish process, he's done 8 or 9 blocks for us, including O-ringing the block on three of those.
02-15-2015, 02:10 PM
#38
Addict
Rennlist Member
Rennlist Member
What do you mean how can finish run faster? There is no vodoo in alusil it has to be done as described in factory workshop manual an it works. Problem is, every workshop thinks it is smarter than 30 years old manual and makes all kinds of stupid ****. Ecactly same as with sleeves and most of slightly out of standard jobs.
02-15-2015, 10:27 PM
#40
Drifting
After rebuilt, add some break in oil, run her easy, with plenty of engine braking on downshift, run up to 4k, and use engine braking on downshift, do it again many times. This is after oil temps are within operating specs. Drain it, put in a new Mahle filter and do it again. Then add dino (non synthetic) 10-30 and run the car for a few hundred - whatever, but run it at least 200 miles doing same. Drain with new filter, and add your oil of choice and run it like you stole it!
02-16-2015, 05:02 PM
#42
Addict
Rennlist Member
Rennlist Member
The problem with that is if they are out of round (cylinders) you just wasted money on new rings and a bit of machine shop work. It might get you by for a while but I would think you'd have serious blow by after some hard miles no matter how you set the ring gap.
The oil, slash break in by George above is exactly how we have done all the engines we've built, street and track and that has served us well. new dry engine, 7.0 qts of 30wt, run 10 minutes, filter and change to 10/30 dino, little jack stand and street time - say 150 miles, then whatever
The oil, slash break in by George above is exactly how we have done all the engines we've built, street and track and that has served us well. new dry engine, 7.0 qts of 30wt, run 10 minutes, filter and change to 10/30 dino, little jack stand and street time - say 150 miles, then whatever
Last edited by Ski; 02-16-2015 at 06:55 PM.
02-16-2015, 06:17 PM
#43
Drifting
Thread Starter
I understand what you are saying, the bores on my block are unmarked other than a very slight ridge at the top of the bores. It will be accurately measured for ovality and taper when I take it to the machine shop. If the taper/ovality is under say 0.003" could that be corrected by just honing ?
02-24-2015, 10:58 AM
#44
Drifting
Thread Starter
I contacted the UK Wossner importer and asked about custom 3.0 pistons, they came back with a price of around $400 each, so I asked if that included the coating for Alusil and they replied they didn't think Wossner has a coating for Alusil or Lokasil 
.
.
02-24-2015, 12:32 PM
#45
If you are having so many concerns on the compatability of pistons/bores why not just run some machined 968 pistons ? Hartech charged me about £300 for the work and as long as you keep sensible boost levels they will be fine. I would estimate i have around 330-350 bhp from the first engine we built and all running well.