JE Pistons with Mahle or LN cylinders - ??

giovanni86 · 03-06-2013, 03:06 PM

hi all,

I need to buy new piston and cylinders for my Porsche rs 3.0/IROC tribute.

I think JE 95 piston (with 9,5 CR) are a good choice for my car, given that I need a low compression ratio (the engine is not twin plugged) and enough valve clearance (I'm using rsr cams).

Do you think JE are good choice?

Furthermore, what are the best cylinder to use? I already have 6 brand new Mahle motorsport 95mm cylinders, but if it is a better solution, I would buy LN cylinders, that seems to work fine with JE pistons

Thanks a lot for your help

Bye
G.

175K911 · 03-06-2013, 03:13 PM

Good choice.

Charles Navarro- owner of LN Engineering- is the person to ask. he can set you up with his cylinders or make recommendations about the Mahle barrels. But would be hard to beat a set of his matched JE pistons and LN barrels. He's a big distributor of the JE's and can machine them with any compression you might need.

Midlife930 · Midlife930's Garage

And Charles stands behind his products!
Dave

JeremyD · JeremyD's Garage

Quote:

Originally Posted by 175K911

Good choice.

Charles Navarro- owner of LN Engineering- is the person to ask. he can set you up with his cylinders or make recommendations about the Mahle barrels. But would be hard to beat a set of his matched JE pistons and LN barrels. He's a big distributor of the JE's and can machine them with any compression you might need.

yes yes. charles is the man

T77911S · 03-07-2013, 04:09 AM

buy mahle pistons and cylinders. the JE's are not as good.

giovanni86 · 03-07-2013, 11:33 AM

hi all,

many thanks for the reply!

Now that I am convinced that JE pistons and LN cylinders are the right choice (I now that Mahle are better, but it is too difficoult for me to find piston with a compression ration lower than 10), I have 3 more question for you

1) does je piston works with all LN cylinders (i.e. I can source those parts from our host) or I have to contact LN and buy from him specific JE pistons?

2) on the LN wbsite I have read that ""All cylinders are not cut for o-ring or head gaskets". What does it means? My heads has been machined because the surface to come in contact with cylinders was not flat. I am worried that my heads will not match the LN cylinders

3) LN suggest on his website to use new studs. For first I don't know yet if my mechanics would be able to replace the studs without opening the crankcase. Then, again, I don't know if I have to buy specific studs or if good quality studs from our host will work properly

Thanks again for your help

Bye
G.

T77911S · 03-07-2013, 11:59 AM

if you have mahle, dont waste your money buying LN cyclinders for JE pistons. if you want to spend money, consider a SS 3.2 with mahle P/c's.

what CR are you looking for?

giovanni86 · 03-07-2013, 12:07 PM

Hi T77911S,

I'm looking for something between 9,5 and 10. This is because I don't have twin plug igniction. I have already burned one of my cylinders.

The only mahle pistons that I have found (and already bought) have a CR of 10. My mechanic tryed to lower the CR by using spacers between the crankcase and the cylinders but, having machined heads, he was not able to end with a CR lower than 10.

If you can help me in sourcing mahle pistons with a compression ratio of 9,5... it would be very very helpfull...I already have the cylinders

thanks a lot!

RSTarga · 03-07-2013, 12:20 PM

try andial

Scott R · Scott R's Garage

Quote:

Originally Posted by giovanni86

Hi T77911S,

I'm looking for something between 9,5 and 10. This is because I don't have twin plug igniction. I have already burned one of my cylinders.

The only mahle pistons that I have found (and already bought) have a CR of 10. My mechanic tryed to lower the CR by using spacers between the crankcase and the cylinders but, having machined heads, he was not able to end with a CR lower than 10.

If you can help me in sourcing mahle pistons with a compression ratio of 9,5... it would be very very helpfull...I already have the cylinders

thanks a lot!

Ok, I have JE's with Nikki's and a custom compression ratio. I supplied 10:5 JE's to my mechanic and he machined them to my ratio. I was told this was a very easy item to do.

KTL · 03-07-2013, 02:09 PM

Mahle pistons are better than JE pistons. Nickies cylinders are better than Mahle. So if you have to go with a custom piston, JE is a good choice were you to go with the Nickies cylinders.

I'm sure you could get some good money for your Mahle cylinders to offset the cost of the Nickies cylinders.

By the way, you can't just buy a 9.5 C/R JE piston and expect that it'll drop into your 95mm Mahle cylinder, nor can the same be said for Mahle pistons. Need to ensure that the clearances are suitable for the size of your Mahle cylinder. This is where the JE/Nickie combo is nice. LN Engineering can size the piston and cylinder set to be a proper match.

kandhmfg · kandhmfg's Garage

I have been racing a 3.2L SS with 9.5:1 J/E's in old Mahle 95mm cylinders bored to 98mm with no issues for the last 4 yrs. 7200 rpm rev limit and hot weather racing in Arizona and California. YMMV.

Spending another $3k on cyls seems like a uncessary expense. As long as they spec out okay, I would use your existing Mahles and get the J/E pistons, it will work just fine. But, others may have more expert experience and more money to spend. My local vintage RSR builder (jim hendrix at John James Racing) uses strictly J/E's in his builds and years of successful cars out there.

Again, not an expert, but if it were me, I would just go with J/E's and put the other money towards all the other expensive things we like to do to these cars.

Danish Dynamite · 03-08-2013, 03:24 AM

I am runing 10.5 JE pistons in my 3.0L Carrera/MFI engine. With a spacer under the cylinders it gave a CR of 10.2. No problems on that account without twin plugs for four years.

/Christian

T77911S · 03-08-2013, 03:59 AM

use the money to twin plug it instead of buying cylinders. yuo are gaining nothing with the LN's.
you may have run it too lean or had too much advance when you burned up you other engine. just be careful.

mahle's come in alusil and nikisil, which do you have? the alusil is junk. in that case, you will need cylinders, but find a used pair of nikis.

i went through this same ordeal when i was consdering building my spare 3.0. i was going to have close to 15k inthe motor. i sold everything and bought a 930.
in the end i think a light weight 3.2ss or a 3.6 would be a blast to drive.

db_cooper · db_cooper's Garage

Quote:

Originally Posted by giovanni86

Hi T77911S,

I'm looking for something between 9,5 and 10. This is because I don't have twin plug igniction. I have already burned one of my cylinders.

The only mahle pistons that I have found (and already bought) have a CR of 10. My mechanic tryed to lower the CR by using spacers between the crankcase and the cylinders but, having machined heads, he was not able to end with a CR lower than 10.

If you can help me in sourcing mahle pistons with a compression ratio of 9,5... it would be very very helpfull...I already have the cylinders

thanks a lot!

Very often adding cylinder spacers will make a 911 more detonation prone while lowering the compression ratio.

There is a "squish area" between the piston and cylinder head along the outer perimeter. Ideally this area should have about 1mm or 040" clearance. As the piston rises to TDC the squish area moved most of the fuel/air towards the center of the combustion chamber.

If the squish area is too large..the fuel/air mixture resides in pockets around the outer perimeter of the piston and you have incomplete or poor combustion and detonation issues.

Have the squish checked when rebuilding the top end..use lead solder with a dab of grease around the outer area of the piston, measure the crush of the solder after a trail assembly. If the squish gap is too large..some machining may be required.

T77911S · 03-08-2013, 07:24 AM

the problem with spacers is now the chain boxes do not line up with the cam housings.

KTL · 03-08-2013, 07:50 AM

Never said the JE in Mahle doesn't work. Just saying that the JE and Nickies are a better match.

I agree if the Mahle cyls check out dimensionally, certainly use them. Trick is finding a piston to fit them. You can do one of the following:

1. Get pistons custom sized to fit the cylinders as-is.
2. Pick the pistons of your choice and have the cylinders honed (if slightly too tight) or stripped, re-plated and honed to size (if slightly too fat).

I would disagree you are gaining nothing with the Nickies cylinders. The major advantage I see to those cyls is their strength & improved cooling. Their increased fin count/surface area provides a much greater ability to cool. Some may say the Mahles are just fine with cooling, who needs more? True, but more cooling in the hottest region of the engine is always a good thing. Especially on an engine subjected to hard use.

Keep in mind there are a number of cylinder alternatives to Mahle- LN Eng., JB Racing, Perfect Bore to name a few. I don't think these guys chose to make their own cylinders simply to undercut Mahle and make a buck. I think they saw an opportunity to provide an improved part.

I agree with db_cooper that fudging compression at the expense of deck height causes other problems. That squish thing is spot on. It's not a theory. It's a true occurrence. Here's a set of 9.8:1 single plug Mahle Motorsport 98mm pistons run in a 3.2SS with excessive deck height. See all those pock marks in the piston surface around the perimeter? That's the edge detonation cooper is referring to.

Not endorsing this, but chain boxes that don't line up with the cam housings can be adjusted by stacking gaskets at the end of the chain box. The misalignment between the chain boxes and cam housings is pretty common. That's why you should have your chain boxes cut on the end whenever you have your heads done (if the heads are fly-cut). Because when the head surface is trimmed, that pulls the cam housing inward. Trim the chain box by the same amount as the heads and alignment should be OK.

giovanni86 · 03-08-2013, 11:06 AM

thanks a lot for all the replies!

lot of knowledge and experience here (as I was expecting)

The news is that italian mahle distributor told me that mahle is producing for him some parts and he will be able to source 9,8 CR pistons.

I asked if they can produce for me something with lower CR.

I will let you know. I suspected that adding spacer was not a good idea... Posts on spacers are very interesting.. Thanks!

I have also contacted ANDIAL; even if on their website mahle piston with 9,2 CR are listed, they don't have them

Tomorrow I will send an e-mail to LN.

Bye
G.

toddu · 03-08-2013, 01:17 PM

I went through this scenario over and over. I decided on used Mahle 3.2 cylinders (I won the alusil lottery), j & e pistons (I believe they will be custom ordered), and decided to put the money that would have gone to new cylinders (not cheap anyway you slice it) into twin plug so I can go higher compression and be safe from detonation without mucking with advance.

Those were my choices after weighing options with the brain trust here.

Todd