...Custom piston woes...nyo.

[Pagz]

Any input from people with similar experiances would be appreciated!


Email this to the suppliers yesturday:

....I pulled the engine down last weekend to find some interesting things…the only thing I really wasn’t expecting was the ceramic coating to be perfectly intact!!...amazing!.=)

The reason i removed the pistons was to find out why oil was still present in #4 combustion chamber...it now appears all 4 chambers had some oil present.

There are a number of issues we need to evaluate before we proceed with another order:

1.Piston skirt height and wall clearance.

2.Gapless rings that aren’t gapless when the gaps align under normal operation.

3.OE Wrist pin offset.

4.The presence of oil fed from con rod and oil jets.

5.Piston skirt shape

6.Ceramic coatings


1.Piston skirt height and wall clearance.

It would seem that piston skirt height and shape would play a considerable role on piston life given certain engineered conditions in this engine.

From this picture you can see the JE piston is excessively worn on the lower area of the skirt due to excessive loading on that area..this is either due to poor skirt design for this engine,or excessive piston to wall clearance…I suspect a combination of both but more so clearance.

In the second picture you can see that the OE piston has no wear what so ever on the lower portion of the skirt and the OE skirt is 5.64mm taller than the JE item.

I have measured Bore size at 3.5805” ,which is the size given to JE in the beginning.

I have taken Piston widths at exactly .500” from the skirt bottom:

-JE piston 3.5755”

-OE piston 3.5760”

In the 3.5805 bore this would make the piston to wall clearance for the JE piston .005”.

Also…as you can see the JE piston is slightly smaller than the OE piston.(original bore was 3.5785”…that would indicate the OE piston had .0025” clearance so literally half the clearance of the JE item)

Questions:

A. What was the recommended piston to wall clearance from JE for these JE pistons?(can be obtained from there website I guess?)

B. Is JE capable of producing a piston for this engine with the same skirt height as the OE piston AS WELL AS STILL RETAINING A 22.25mm internal wrist pin gap so that the piston locates the rod?.
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_387_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_388_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_389_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_395_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_396_full.jpg


2.Gapless rings that aren’t gapless when the gaps align under normal operation.

When I removed the piston the first thing I noticed on the gapless ring set was that the gaps had all moved around in normal operation…and one had both gaps perfectly aligned, this was not a build problem as

I was there the day we ran through the installation instructions provided by totalseal.

C. Are these really worth the money if they will eventually act like standard rings?


3.OE Wrist pin offset.

Given the fact JE were sent a sample piston shouldn’t this have taken at least some attention?

As can be seen from the picture,the wrist pin is offset closer to the larger skirt on the OE piston….this is the skirt which takes the most pressure on the downwards stroke.

D. Is JE capable of producing a piston with an offset of .435mm?

E. MB put an offset there for a reason…did JE decide it was not necessary?…did they not notice it had one?
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_391_full.jpg


4.The mass presence of oil fed from the conrod and oil jets.

The Mercedes engine utilises oil jets sprayed under the piston skirt which were bent by the engine builders to face towards the centre of the JE piston(they should have simply used the right tool for that job and rotated them accordingly as there is plenty of clearance to do so),it also uses oil fed from the crank through the con rod to feed the small end bearing, oil from the small end bearing then exits via the top of con rod as shown in the picture.

Note: the OE piston wrist pin bearings are milled and utilise oil from the con rod and oil jet to lubricate its bearings unlike the JE which uses oil from the oil control ring.

F. Would oil from the jets + oil from the con rod have caused excessive amounts of oil under the piston?
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_392_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_397_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_393_full.jpg

5.Piston skirt shape

Iv noticed there is a very noticeable difference in skirt shape on the three sets of JE pistons you sent me.

The first two sets of pistons you sent have a very flat vertical skirt plane…where as its very obvious from the wear(and from measurements) that the OE piston has a convex vertical skirt plane as shown in the picture below…what is also interesting is that the 3rd set of JE pistons you sent me DOES have a convex vertical skirt plane(and that’s not due to wear).

G. Why does the first two sets have an “almost” flat vertical skirt plane while the OE and 3rd set of JE have a very noticeable convex curve?...
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_390_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_394_full.jpg


6.Ceramic coatings.

Given the fact that forged pistons generally run slightly larger clearances than cast,that would make them more prone to damage when the engine is cold.

G. Wouldn’t the ceramic coating hinder the rate at which the piston expands to normal operating temperature when started from cold?...this would in turn shorten the life For a street engine would it not??....does the performance benefit out way this?...or am I just being to critical?



Cheers guys.
Paul

ps. thanks for confirming C/P in that other thread Ross...reply is still coming hehe.

Pss. sup logan,yup new pistons for sure..this time we better get it right...hope i dont end up putting OE back in...lol

[c280nz]

after reading all that you could seem to me to be more than capable of designing your own pistons, just send jE the full dimensions and instructions on how actually build pistons, and exactly how u want them for your engine.
goh everything gets fcuked up unless you do it urself eh

i reckon u shud buy a second hand engine to stick in ur car and run round in while ure building this one, and also then u can test it to the limit :D

those third pistons look to me more like they are designed for a high reving short stroke engine, were as the other ones look more designed for a car engine, from the skirt size and shape.
they are probebly more convex because the skirt is so small.
i say this cos the 3rd piston looks very similar to the piston out of my mx bike (250 4 stroke which revs to 13500 with a short stroke and goes thru pistons every 50hrs just like ur engine :eek: )

[Pagz]

Yes yes yes and yes exactly....oh and no...i think i got alot less than 50 hours lol

My thoughts exactly on the bike engine!..the M111 is quite the opposite of a high rev short stroke!!

haha Second hand engine might not be such a bad idea if we dont sort this piston issue!!!

hopefully ill hear back from these guys by tomorrow i asked if they could forward it to JE for there opinion...it maybe wishful thinking ill end up with a decent piston...im starting to think machining from a solid block maybe the only way!....we'll see.

Paul

[SLAMMED_C]

Yo Paul!!

WOW.. thats an email and a half!!! so many issues.. it seems JE were a little off with the piston tolerances.. considering there was .0025" of clearance.. it seems so miniscule, but in an engine its probably too much. why didnt they spec the pistons to OEM dimensions in the first place. it seems they were closer to stock with the first set they sent you. why they keep changing them and making them smaller?
maybe with the ceramic coating they were trying to build up the piston thickness?
It seems your Turbo project has been one headache after another.
but I hope you do see light at the end of the tunnel mate. once the pistons are right, you will be boosting like crazy!! and no smoke!

no prob on compression numbers.. I was always pretty sure it was 8.8:1.

lol.. sure sure.. you keep saying reply coming!! no worries.

[omeyhomey]

you lost me at "any input" ;) .

wow lots of information, keep up the great work 23k, you really are at the forefront of W202 230k turbo tuning. keep it up.

[Cru328prod]

dude when you finally came up with a prefect pistons.............I WANT THE BUILD NUMBER!!!!!!!!!!

[Pagz]

Ross,Cru,Omey,logan
Ok guys...this really hurts to say this.... =/

I MAY have to admit defeat to mercedes...=l

Theres a very high chance i will be ordering OE pistons to go back in this engine.

Reasons:

OE piston:
-wrist pin offset to help slap.
-correct oil lubrication setup for oil jets and oil from rod
-tight clearances
-correct rings made from correct material.
-quite,smooth running
-by the looks,extremely capable of producing the power im after.

JE piston:
...they really are for race use only...i guess we could have JE make them in a different alloy to improve clearance....but im becoming confident the OE items can do what i want so why go there?..


Soooo maybe we will see what the stockers will handle AFTER ALL LOLz...


cheers,
Paul

[Cru328prod]

DO IT!!!!!!!!!!!!

I WANNA SEE HOW FU*KING GOOD THEY HOLD UP!!!!

[Pagz]

haha,well i always wanted to know how much they handle...lets hope if i do use OE we dont find out when they break!!

price for OE $1788....O.O

they will be an oversize 91.4 though so we get an extra 23cc's of displacement ^^ ...that should help!..er

the other two options are to machine the inside of the 2nd set and use spacers...or have another set made by another company...either way those options are risky imo.

cheers,
Paul

[Cru328prod]

why can't you drop your orginals?

AS WE SAY IN AMERICA........GO OR BLOW!!!!!!;)

whats the worce that could happen, a rod threw your neck?

Just pull it out and put a bandaid...........

[Pagz]

lol

There slightly to small as we honed it.

It needs to go back together perfect this time...no exceptions! =)

...costs hundreds everytime i pull it down just in replacment parts like head gaskets,bearings,seals etc.

let you know how we get on =)

Paul

[Cru328prod]

well atleast you have a fabraicator that knows wtf he's doing....ask a engine builder here to touch a merc "i won't touch it"

[SLAMMED_C]

Originally posted by 23K
Ross,Cru,Omey,logan
Ok guys...this really hurts to say this.... =/

I MAY have to admit defeat to mercedes...=l

Theres a very high chance i will be ordering OE pistons to go back in this engine.

Reasons:

OE piston:
-wrist pin offset to help slap.
-correct oil lubrication setup for oil jets and oil from rod
-tight clearances
-correct rings made from correct material.
-quite,smooth running
-by the looks,extremely capable of producing the power im after.

JE piston:
...they really are for race use only...i guess we could have JE make them in a different alloy to improve clearance....but im becoming confident the OE items can do what i want so why go there?..


Soooo maybe we will see what the stockers will handle AFTER ALL LOLz...


cheers,
Paul
NO.. not defeat!! well JE hasnt really helped too much.. with all their sets of pistons and attempts.. must have been expensive to end up with nothing now. sucks to spend so much on custom pistons.
I never saw the problem with the stock pistons.. they seemed to look like they were built for boost!! everything is right with the OEM ones anyways.. might as well just use them. Im sure you will be able to surpass what you want them to do. for sure they will hold up.
wow.. $1700 for a set of oversized pistons??! damn!

[Pagz]

Originally posted by SLAMMED_C
NO.. not defeat!! well JE hasnt really helped too much.. with all their sets of pistons and attempts.. must have been expensive to end up with nothing now. sucks to spend so much on custom pistons.
I never saw the problem with the stock pistons.. they seemed to look like they were built for boost!! everything is right with the OEM ones anyways.. might as well just use them. Im sure you will be able to surpass what you want them to do. for sure they will hold up.
wow.. $1700 for a set of oversized pistons??! damn!

haha,yeh bro.
the real pain is that its all a mater of who you talk to at each stage of the build...When i first reseached the forged concept i was told by the JE suppliers that the JE piston will outlive the stock piston under normal driving conditions....IMO thats so not true...how can a piston that is manufactured at twice(.004 - .005" is correct size for the FSR i have) the clearance as stock,has a shorter skirt with no offset possibly last longer?....not to mention the JE really wouldnt expand to the best operating temperatures under normal driving anyway...i guess i was blinded by the brand name and sales team...lol

I called Ross pistons in the US today...same story... .004 - .005".
and they said they would ahve to run spacers to locate the rod.


So i guess the final outcome of all this is:
If your planning to turbo and track the car buy forged pistons.
If your running a street setup...ffs leave it stock inside^^.

I mean some of this really is common sense...but it very easy to be lead away by sales hype and misconceptions of what a race part can do for you steet car.

Will order the OE today,let you know what happens.

laters,
Paul

[Cru328prod]

dude i think you'll be fine......i mean for fu*k sakes i've hydro locked the motor, and she started up just fine!!! she was a knockerrr, but which bitch isn't LMFAO

[Pagz]

Originally posted by Cru328prod
dude i think you'll be fine......i mean for fu*k sakes i've hydro locked the motor, and she started up just fine!!! she was a knockerrr, but which bitch isn't LMFAO

lol

[Pagz]

Ah stuffed up my calculations is a 29cc increase in dispacment =D

might have to rename my badge to C2324 ^^

[SLAMMED_C]

Originally posted by 23K
haha,yeh bro.
the real pain is that its all a mater of who you talk to at each stage of the build...When i first reseached the forged concept i was told by the JE suppliers that the JE piston will outlive the stock piston under normal driving conditions....IMO thats so not true...how can a piston that is manufactured at twice(.004 - .005" is correct size for the FSR i have) the clearance as stock,has a shorter skirt with no offset possibly last longer?....not to mention the JE really wouldnt expand to the best operating temperatures under normal driving anyway...i guess i was blinded by the brand name and sales team...lol

I called Ross pistons in the US today...same story... .004 - .005".
and they said they would ahve to run spacers to locate the rod.


So i guess the final outcome of all this is:
If your planning to turbo and track the car buy forged pistons.
If your running a street setup...ffs leave it stock inside^^.

I mean some of this really is common sense...but it very easy to be lead away by sales hype and misconceptions of what a race part can do for you steet car.

Will order the OE today,let you know what happens.

laters,
Paul

Brotha,
of course a RACE piston will outlive the stock piston under normal use.. but isnt this supposed to be a RACE piston!!.. who uses a race piston for "normal driving" conditions!! ITS FOR RACE! stupid JE. thats too bad they didnt come through with what you wanted.
Im sure the stock pistons will do what you want.. sucks you had to find out the expensive way.

[Pagz]

Originally posted by SLAMMED_C
Brotha,
of course a RACE piston will outlive the stock piston under normal use.. but isnt this supposed to be a RACE piston!!.. who uses a race piston for "normal driving" conditions!! ITS FOR RACE! stupid JE. thats too bad they didnt come through with what you wanted.
Im sure the stock pistons will do what you want.. sucks you had to find out the expensive way.

Yo,
You mean OE piston outlast the race?=)
When i ordered the JE it was descussed that the JE piston would be suitable for my application...and in some ways it still is!...If you want to drive at full throttle 90% of the time your on the road =D...the old JE website(now changed) used to make out that the clearances they used were very tight...which was probly correct when your replacing pistons on your 90's chev...but with clearances < .002" on the merc it just aint gonna happen with a JE item...

The engine builders were the worst ever so that didnt help! =)

Anyways OE pistons have been ordered!=)

Cheers man,
Paul

[c280nz]

i dont even know what to say..........

[Pagz]

Originally posted by c280nz
i dont even know what to say..........


"...Bro...you went through all that to achieve what?...a stock engine?"



he he


well actually its been balanced,and the rods have been peened =D...oh and dont for get the 29cc's^^

ok ok just dont mention the hp/$ ratio on that mod :D

[c280nz]

u said it for me, except i somehow would ove used three more bro's more excessive language and more abuse at generally everybody including JE and you:D

as they say theres no replacement for displacment, so i think that 29cc along with 20+ (yes that is a plus) pounds of boost will make all the difference :cool:

what did u end up doing about a heavier clutch?

[Pagz]

hahahaha:D

The heavier clutch will be ordered in the coming weeks,just orgainseing shipping and prices atm.

there isnt much choice when it comes to makers so the kit will be a SPEC stage 3+,around $855 USD + shipping.

The OE Dual mass flywheel doesnt look so good at the moment either,its lost some ability to return to its no load position...Suprise lol
but i wont make a custom one just yet,as i would rather run the engine in,drive it back to auckland,make the flywheel and change the timing ring so that the motec gets the signals for a better startup,and then do the long awaited dyno tune...but before all that there needs to be a trip to the fabricators for a small mountain of things to change....then its WOF and Rego and some road time...yawn* this may all take some time as im truly over 2 mins noodles.

[SLAMMED_C]

Originally posted by 23K
Yo,
You mean OE piston outlast the race?=)
When i ordered the JE it was descussed that the JE piston would be suitable for my application...and in some ways it still is!...If you want to drive at full throttle 90% of the time your on the road =D...the old JE website(now changed) used to make out that the clearances they used were very tight...which was probly correct when your replacing pistons on your 90's chev...but with clearances < .002" on the merc it just aint gonna happen with a JE item...

The engine builders were the worst ever so that didnt help! =)

Anyways OE pistons have been ordered!=)

Cheers man,
Paul
yeh sorry.. my bad!! I mean Oe outlast the race!
yes it still is suitable if you were to race your car.. but I guess its not meant for having it be a heavy duty item in your engine so you can just crank the boost and not have to worry bout it. its really too bad the tolerances arent there.

[Pagz]

Originally posted by SLAMMED_C
yeh sorry.. my bad!! I mean Oe outlast the race!
yes it still is suitable if you were to race your car.. but I guess its not meant for having it be a heavy duty item in your engine so you can just crank the boost and not have to worry bout it. its really too bad the tolerances arent there.



Hey speaking of tolerances,would you know what the oe piston to wall clearance is for the M111.975?,iv got clearances for the N/A models only!.
Cheers dude,
Paul

[Cru328prod]

i'm sooooooooo excited your going to use OEEEEEE i can't waitttttttttttttttttttttttttttttttttt.........

[Cru328prod]

i know this may seem like a dumb question, but why can't you get custom sleeves made?

http://www.dartonsleeves.com/mainpage.htm

[Pagz]

...i couldnt even imagine the implications of doing that to this cast iron block...scary!
there is very little room between the bores,and what little room there is,is taken up by a coolant passage!..i would imagine there would need to be reassesses cut in around the top of the bores along with considerable thought as to the engineering so that we had no issues with leaking coolant or differences in expansion didnt lead to failure of all sorts of things.

it would be a wiser move to buy a second hand block if i was planning to reuse the oe's!.

Its a nice thought though,thanks.


Iv also thought about using ARP head studs for the re-build..but have been totally put off by the amount of calculation needed to spec them correctly for the engine...much rather stick with stock and call it day =)

[SLAMMED_C]

Originally posted by 23K
Hey speaking of tolerances,would you know what the oe piston to wall clearance is for the M111.975?,iv got clearances for the N/A models only!.
Cheers dude,
Paul
I cannot find this information anywhere Paul!! if I find out anything I will for sure let you know.

[Cru328prod]

hahaa i have a hydro locked motor for ya...but i guess shipping would cost as much if you were to buy a used 1.

[Pagz]

Originally posted by SLAMMED_C
I cannot find this information anywhere Paul!! if I find out anything I will for sure let you know.

Thanks Ross,
Iv recently heard that is writen on the piston crown,my OE has a triangle with 32 inside. and 28 X stamped opposite.

Maybe this means .0028" or .0032"....not really sure,its probly not .028/32 mm,that would be very tight!

I will investigate further!

Cheers dude,
Paul

[Pagz]

Originally posted by c280nz


what did u end up doing about a heavier clutch?


Shit shit shit and shit

I ordered that spec3+ kit a week ago.
was sitting at my desk before and this thought just smashed me over:

--> the Spec kit for the merc has a solid centre hub for the dual mass...im looking at remaking the flywheel into single now as well.
I NEED SPRUNG HUB.....and i think they have already sent the kit.

fark.

When you remade yours did you use a sprung hub?

dammit.

:dead:

[c280nz]

im running a solid center clutch at the moment and a solid flywheel, so its solid the hole way thru :D

its hard on everything with a solid setup tho, that is for daily driving i mean, say if im just creaping along slowly in it over judda bars etc when the load comes on and off the driveline it can pop out of gear, when the load comes on and off slightly if u know what i mean.

but my clutch +lwf cant handle what im tryina put down at the mo
(i dont know if thats a bad or good problem ;) )
i think ul find with a lightweight flywheel such as i have (18kg down to 8kg)
when the engine revs the power comes out thru the clutch that damn quickly u need a heavier clutch to hold the instant power as compared to with a heiver flywheel where the power is smoothed out from having to also spin up the flywheel weight
so im going to change probebly to a double sprung pressure plate and sprung style clutch (puck or not yet to be decided)
but thats all going to have to be custom made, but i think i know a mate capable of such a feet, im just yet to ask :eek:

[Pagz]

Originally posted by c280nz
im running a solid center clutch at the moment and a solid flywheel, so its solid the hole way thru :D

its hard on everything with a solid setup tho, that is for daily driving i mean, say if im just creaping along slowly in it over judda bars etc when the load comes on and off the driveline it can pop out of gear, when the load comes on and off slightly if u know what i mean.

but my clutch +lwf cant handle what im tryina put down at the mo
(i dont know if thats a bad or good problem ;) )
i think ul find with a lightweight flywheel such as i have (18kg down to 8kg)
when the engine revs the power comes out thru the clutch that damn quickly u need a heavier clutch to hold the instant power as compared to with a heiver flywheel where the power is smoothed out from having to also spin up the flywheel weight
so im going to change probebly to a double sprung pressure plate and sprung style clutch (puck or not yet to be decided)
but thats all going to have to be custom made, but i think i know a mate capable of such a feet, im just yet to ask :eek:


Ahhhh thought you might be running the unsprung clutch!...
lol that must be a pain to drive at times?^^
Yeh the stock pressure plate would def not handle the torque your pulling now!,have you got a pic of your OE flywheel?...i would think it would be pretty much the same as mine?.

18 to 8 kg is a truely massive difference^^!,im looking to make about a 20 - 25% reduction in wieght on mine!,trying to decide on a flashy alloy item(maybe to light) or the normal steel(the more likely of the two to achieve the wieghts im after)

How are you going to go about getting the custom pressure plate?...will you need to remake the flywheel also?...go that good fabricator friend he he =)

GOOD news,i here from the suppliers the SPEC clutch is spung(even though SPEC said it wasnt when i mailed them months back)


Pistons,pins,rings,shells,gaskets and oil jets are here.
still need to get the block bored,head cleaned before I reassemble...then onto the flywheel as funds allow.

Some noticeable diferences in the new pistons are the lack of oil grooves in the piston boss's,i guess MB decided they were not nessasary and rounded the edges either side of the rod alittle more to allow oil from the oil jets and small end bearing to enter and lubricate(which is the same Lube methode as the original setup still).Also the crown and valve pockets on the new piston are much deeper,i think this is done to compensate for the diference in displacement thus keeping the C/R the same.
the new ones look to have a moly coat spayed over the entire piston with what could be a ceramic coating on the skirts(rather then just a moly which the JE had)...
the MB items like very very nice....how did i ever doubt them^^

and pics...

http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_400_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_401_full.jpg
http://memimage.cardomain.com/member_images/3/web/735000-735999/735658_402_full.jpg


Cheers dude,
Paul