Engine knowledge and JE problem

[mertdastan]

I have installed a set of JE forged pistons in the S50B32.

Cylinder number 1's oil ring was damaged or had a defect right out of the JE because the moment we started the engine we saw smoke coming out of the exhaust. This smoke was blue. Oil consumption was extreme. Spark plug in the 1st bore was getting oily and misfiring. Anyhow after 400 miles we tore down the engine and changed the rings of the 1st piston.

Now what do we know about the engines of our cars?

What type of bore finish do we have?

How is the bore honed? Which stone was used during honing?

What is the clearance between the cylinder and rings?

What is the gap of the rings?

What is ring material? Steel, chrom plated, moly plated, ceramic? Did we get the proper hone and surface finish for our ring material?

What is the pistons alooy? How much expansion? Are the pistons thermally stable or?

How did we check the con rods? Their bearings?

Is the block seasoned?

What is the cylinder wall thickness?

We go fast and boost with our ENGINES. But what do we know about them?

[Bad Bimr]

I have installed a set of JE forged pistons in the S50B32.

Cylinder number 1's oil ring was damaged or had a defect right out of the JE because the moment we started the engine we saw smoke coming out of the exhaust. This smoke was blue. Oil consumption was extreme. Spark plug in the 1st bore was getting oily and misfiring. Anyhow after 400 miles we tore down the engine and changed the rings of the 1st piston.

Now what do we know about the engines of our cars?

What type of bore finish do we have?

How is the bore honed? Which stone was used during honing?

What is the clearance between the cylinder and rings?

What is the gap of the rings?

What is ring material? Steel, chrom plated, moly plated, ceramic? Did we get the proper hone and surface finish for our ring material?

What is the pistons alooy? How much expansion? Are the pistons thermally stable or?

How did we check the con rods? Their bearings?

Is the block seasoned?

What is the cylinder wall thickness?

We go fast and boost with our ENGINES. But what do we know about them?

We know JE Pistons SUCK. You are just another horror story.

That is why I am getting "CUSTOM" pistons for my car. The company I am getting them from builds them for Hendrick Motorsports. If they are good enough for Jeff Gordon, they are good enough for me.

[mrdoenutz]

im happy with my je pistons

[ehlpitel]

ive been hearing alot of horror steories concerning JE pistons lately

[moadster]

im happy with my je pistons
me too

[///3oris]

What about Wiseco pistons?

BTW, which rings did you use?

My friends' Eclipse had a similar problem as a result of detonation... another friend detonated and blew a chunk of a piston off. I know you like to push as much as you can out of your car, is it possible you blew something?

Boris

[///MCubed]

No problems with JE here either. Considering that Mert is not sure if it was a manufacturing defect or damaged caused during use, at this point it is going to be very difficult to make that determination. This is one of the reasons documenting everything, specially with pictures, is a great idea.

[ICS Performance]

Hey guys sorry for the broken ring, My guess and experience is that the rings were not properly gapped in the piston box it has different ring gaps for, turbo, nitrous, high compression. If the rings were not gapped, thell bind up and brake.

[Mikea]

No problems with my JE pistons either.

[got psi]

My J&E pistons are fine also, I did modify the wristpin before I put them together. In stock form the pin is too long and needs to be shortened .025 to make more retainer clearance. Pistons under high boost tend to flex a bit more in the pin boss area,this is normal. This keeps the pin from pushing out the retainer and causing a major catasthrophie. J.T.

[mertdastan]

It was a manufature problem.

The moment we started the engine to heat we saw blue fume or smoke coming out of the tail pipes. So we did not even drive the car 0,1 miles.

Now, after changing those rings with new ones (piston 1), we are quite happy for so far.

We boost 30-31 psi till 188 mph. So far so fast.

I sit in my friend's Supra which has a Greddy T88H, he was boosting 18 psi and the car was like a rocket. We will test both mine and his soon.

He has the N2O ready and today we started the N2O install on my M3. I am excited. But Supra with 272 cams, T88H, Distributorless Ignition System, Powerhouse racing Spec Pistons, revving 8k, having a 4" throttle body and lot of other parts was so fast. Will see soon.

[Bassmaster]

No problem with past JE pistons.

[PJ750iL]

JE workin for me

[CRISTIAN]

Mert, I think your problem is the difference between piston and cylinder.
Also the bore finish (hone) can be an issue.
NickG have told you about these issues some time a go here on bimmerforums...

When you use forged pistons you must hone the cylinders different then using stock aloy or stock cast iron pistons. Is very complicate for me to explain you, but I will try with a few words...

1. First your Euro M3 has stock ALOY PISTONS, lighter pistons, high cr shape...

2. M3 US engine has stock CAST IRON PISTONS, low cr piston shape

1. For M3 Euro S50B32 with lighter aloy pistons, your block motor has:
-max. cyl bore out-of-round =>0.005mm
-max. cyl bore conicity => 0.01mm
-Piston runing clearance => 0.026...0.058mm
-Max. total wear clearance between piston and cylinder => 0.15mm

2. For M3 US S0US with cast iron pistons, block motor has:
-max. cyl bore out-of-round =>0.005mm
-max. cyl bore conicity => 0.01mm
-Piston runing clearance => 0.021...0.053mm
-Max. total wear clearance between piston and cylinder => 0.113mm

In case 2 for M3 US block motor, ironicaly :D this has a little bit slower permitted "max total wear" about 0.0113mm, because M3 US stock cast iron pistons don't expand so much like M3 Euro aloy pistons ! Paradoxically M3 US block is better also for FORGED PISTONS.

But you can also prepare you block motor for forged pistons.
I think your "max total wear" is OUT, maybe you are close to 0.15mm but this is not good anymore with Forged Pistons and air will enter in your oil pan...

Secondary, you see the bore finish is the same between M3 Euro and M3 US. But here I can't tell you exactly how much different bore finish (hone) must be used for forged pistons... I think the major problem is your difference between piston and cylinder, to much gap... If you want I can ask my manufacturer about hone for forged pistons, is possible to be a little bit different also...

[Makr]

Cast iron pistons? :confused:

[paul e]

Is it really right to be so 'dismissive' of JE pistons? I mean, dont they have an awfully strong position in the market with their product(s)? They couldnt have attained their position, it seems to me, if their products were really so piss poor.

[Bassmaster]

Exactly!!!

[Bad Bimr]

Is it really right to be so 'dismissive' of JE pistons? I mean, dont they have an awfully strong position in the market with their product(s)? They couldnt have attained their position, it seems to me, if their products were really so piss poor.


JE was the piston of choice. They made some of the best pistons. That was then this is now. After a few different owners (now JE is owned by Deleware Elevator Company) JE is no longer the best. The guys in the board room main concern is to cut costs and make the most profit, thus quality suffers. I have read more then a few stories where the new JE pistons caused the engine to fail. I was going to get JE but was streered away for these reasons.

[paul e]

>>JE is no longer the best<<

I see. well that explains it then.. I hate it when a company works hard to build their name and their reputation, and then someone buys them out, and decides they dont want to stand anymore for what put them on the map.. they just want to trade on the former company's good name, and cut corners across the board.. Age old story... Yuch...

[///MCubed]

The guys in the board room main concern is to cut costs and make the most profit, thus quality suffers.

Not always does quality suffer when cutting costs in a manufacturing environment. Locally, I have yet to hear anyone (and that includes many outside the BMW community) have an engine go due to a JE Piston Failure. Most that I have seen fail is due to a tuning error.

[Mikea]

Mcubed-

I agree with you totally they would be out of business if they sold BONK products. It comes down to tuning.

[NickG]

Here's what I ran across with a customer's BMW.....it was a 1997 318ti with a DASC installed. The customer had another shop rebuild the engine with JE pistons to lower the compression ratio down to 8:1. The shop in question didn't have the ability to reprogram the ECU and get the engine to run properly, so the car came to me. Tuned it up and away she went.

After a few weeks, like 3-4, the customer went on a road trip. Before starting he checked all the fluid levels and such. 2 hours into the drive the engine seized. He had it towed down to me and we started checking it out.

Upon disassembly we found what we think caused the trouble. Out of the 4 pistons, 2 of them were improperly made/machined. We deemed it a manufacturing defect. The area where the wrist pin c-clips go didn't have enough aluminum. So when the final machining process was done, the groove that retains the c-clip was not properly machined. This caused a few of the c-clips to fall out (one from piston #1, and one from piston #3).

The wrist pin from #3 then started walking back and forth and galled up the cylinder wall. In the process, since there was no metal between the wrist pin opening and the oil control ring (ie, the oil ring didn't have a ring land above the wrist pin hole), the moving wrist pin destroyed the oil ring on #3. This caused all of the oil to be burned through cylinder #3 (depicted by the oil covered spark plug and the black soot covering the back of the car).

Once all the oil was burned, connecting rod bearing #1 melted and seized onto the crankshaft. This caused rod #1 to snap and go through the block.

After carefully inspecting the pistons, it was obvious that 2 of the 4 pistons were improperly made. You can see in the picture below what I mean. On the left is piston #2, and on the right #3. #2 is fine.....but look at the material around #3's wrist pin hole. See how it's pitted and not smooth like #2? It was never finish machined because there wasn't enough material there for the machining process to remove. The same applies to the c-clip groove. The groove was never machined in, so the clip just fell out.

Now mind you, maybe the shop that put the engine together wanted to save a buck and used known bad pistons (rejects if you will). Or maybe a couple bad ones slipped through JE's manufacturing process. I don't know........but these pictures show 2 different quality pistons in the same engine. One of them caused the engine to blow.

http://www.tech-nick.net/pics/P4020007.JPG

[CRISTIAN]

Cast iron pistons? :confused:

Yes "CAST-IRON"... it is a special iron very durable, the same material like your M3 block motor...

I think you confuse the term "CAST-IRON" with term "GREY CAST-IRON"... this last one is the "FORGED-IRON" used to manufacture the Forged CRANKSHAFTs from M3 motors !

But “Forged Pistons” are manufactured from treated aluminum => correct name is "Forged-Aloy"...

The term "Forged" is quiet inexplicit, is only a special treatment but the treatment is different for every material.

[NickG]

Christian......I believe you are mistaken. Pistons are NOT made out of cast iron. Nearly every automotive piston is made out of aluminum. It's either cast aluminum or forged aluminum. Pistons made out of cast iron would be way too heavy.

[Makr]

Yes "CAST-IRON"... it is a special iron very durable, the same material like your M3 block motor...

I think you confuse the term "CAST-IRON" with term "GREY CAST-IRON"... this last one is the "FORGED-IRON" used to manufacture the Forged CRANKSHAFTs from M3 motors !

But “Forged Pistons” are manufactured from treated aluminum => correct name is "Forged-Aloy"...

The term "Forged" is quiet inexplicit, is only a special treatment but the treatment is different for every material.


You may have different terms for things in Romania, but you do not "forge" cast iron. Forging is when you press a piece of material (any material)between two dies with a cavity of the shape you need, sometimes the material is heated to a below molten state before forging, sometimes not. Casting is when you melt the material to a molten state, then poured or injected into a cavity of the shape you need.

[CRISTIAN]

Christian......I believe you are mistaken. Pistons are NOT made out of cast iron. Nearly every automotive piston is made out of aluminum. It's either cast aluminum or forged aluminum. Pistons made out of cast iron would be way too heavy.

NickG, very well... my mistake. Sincerely in the past I've had in my hand both M3 US and M3 Euro pistons here at our service-shop and from exterior the material looks the same... but I was under a confusion... I read somewhere that m3 euro pistons are from lighter aloy and in my mind I've believed that euro material must be different so maybe m3 us pistons are iron. Well... if m3us pistons are also cast-aloy, then maybe m3 euro pistons are light-cast-aloy ? Maybe is only publicity about m3 euro pistons and is the same cast-aloy? From exterior looks the same... the same colour... the same rings... only shape is different...

Well then if both M3 Euro and M3 US use the same cast-aluminium material for pistons, why is a larger permitted gap between piston and cylinder for M3 Euro block motor ?

[got psi]

Don't quote me on this but I believe because the euro spec motor puts out more HP than the US spec motor. More hp means more cylinder pressure and more cylinder heat. More cylinder heat means more piston expansion, alloy pistons expand at a greater rate than cast iron blocks therefore more clearance is needed. On a scale of strength durability and expansion rates for pistons, (cast alloy) weak low expansion,(hyperutectic alloy)somewhat stronger low expansion never use with boost, (forged alloy) strong somewhat greater expansion rate, needs special attention to bore to piston clearance. Most cars come with cast pistons because they are cheaper, and quieter when the engine is cold. Who would buy a new car that has a slight piston rattle(when cold) or has to wait for the engine to reach operating temp before you drive. Just some thoughts. J.T.

[mertdastan]

GOT PSI ( Ihave plenty :) )

The second we started the car after installing JEs we saw smoke. And only the number 1 piston's oil ring was malfunctioning.

[///3oris]

Hey Mert, considering how much free time you seem to have... and I KNOW you have a video camera.... WHY DON'T YOU POST VIDEO'S?!? Also, since a "DIY Home Dyno" or even one of those "G-Accelerometers" that calculate approximate HP are so cheap, why don't you get one of those to get some APPROXIMATE power figures? I can't ever take your posts seriously because you keep claiming you have some obscene amount of HP (of which the car is CAPABLE with the hardware you have running, but tuning can make a 100rwhp difference EASY!).

Anyway... do SOMETHING scientific... your posts almost sound like a joke... kind of like that guy posting his "M3 Turbo" dyno plots... later to be discovered it was a supercharged V8 (I can find the thread for you if you'd like!).

Know what I mean? ;)

Boris

[CRISTIAN]

Boris I have a very good "G-Accelerometer" for Mert if he wants :cool:

[///3oris]

Boris I have a very good "G-Accelerometer" for Mert if he wants :cool:

Cristian, don't you live pretty close to Mert? I distinctly remember you talking about Dyno's that are some ways away (OR expensive). Couldn't Mert find a Dyno if he wanted to? I can't believe they don't have Dyno's that measure over 400rwhp!

Give him the "G-thingy" I'd love to see results. Plus, this would give mert an insight into the changes in power after the changes in parts/boost... :alright

Boris

[CRISTIAN]

My G-Meter is good for max. 1000whp :D

Btw, between me and Mert are about only 250 miles but Black Sea is between us... on the ground the distance is much larger about 600miles

About Dyno, recently I've heard that some guy from my town Bucharest, have purchased a new dyno, he program the software for Subaru and turbo audi's... I heard that his new dyno is good for 600 KW... and cost only about $ 120 :eyecrazy: Anyway I only heard yet about him... I must go a few days on the street to find more about this guy...:D