Anyone have a 3.2 to 3.4 Conversion?
11-05-2004, 12:54 PM
#17
RL Technical Advisor
Hi:
More,....
FYI,....Mahle's 911 pistons are all forged. no cast ones. These are all high-density forgings that expand so little that they run at .001-.0015 cold clearance.
The wedge shaped dome that JE offers is similar to the so-called "Max Moritz" Mahle's that provided some real squish to help suppress the tendency to detonate with single ignition and moderate compression. The only drawback to that design is that it limits camshaft selection in higher performance applications.
Mahle does make 100mm sets for these engines but as Charles so wisely said, the Porsche air-cooled P/C's are a very low priority as they comprise a very small part of their business. For that reason, availability is very spotty and inconsistent.
There are now several importers/distributors of the 911 Mahle sets besides Andial so check around. We sell a LOT of these things,.....
Charles:
One last note,.....We've had a number of JE piston failures ranging from broken pin bosses (resulting in catastrophic failure)to cracking in the same places and around the ring lands (no detonation) so I've learned to replace them on a timely basis to prevent trouble. Its all part of using a purpose-built part.
I'd give ANYTHING to get Mahle to make individual pistons available as they promised they would. I spoke to them many times both in Germany and at PRI and was politely ignored.
More,....
FYI,....Mahle's 911 pistons are all forged. no cast ones.
These are all high-density forgings that expand so little that they run at .001-.0015 cold clearance.The wedge shaped dome that JE offers is similar to the so-called "Max Moritz" Mahle's that provided some real squish to help suppress the tendency to detonate with single ignition and moderate compression. The only drawback to that design is that it limits camshaft selection in higher performance applications.
Mahle does make 100mm sets for these engines but as Charles so wisely said, the Porsche air-cooled P/C's are a very low priority as they comprise a very small part of their business. For that reason, availability is very spotty and inconsistent.
There are now several importers/distributors of the 911 Mahle sets besides Andial so check around. We sell a LOT of these things,.....
Charles:
One last note,.....We've had a number of JE piston failures ranging from broken pin bosses (resulting in catastrophic failure)to cracking in the same places and around the ring lands (no detonation) so I've learned to replace them on a timely basis to prevent trouble. Its all part of using a purpose-built part.
I'd give ANYTHING to get Mahle to make individual pistons available as they promised they would.
I spoke to them many times both in Germany and at PRI and was politely ignored.
11-05-2004, 01:03 PM
#18
Rennlist Member
I'm glad I wasn't the only one ignored at the PRI show the last two years at the Mahle booth.
It's funny that you mention it, but the pin boss issue is the same one that I have heard about, but it seems that it's only the case in all ***** out high rpm/ high hp racing. Just out of curiousity, I asked around my area about JEs and blown race motors (sorry no p-cars, but SBC, BBC, etc) and that crowd has never had a complaint about their JEs failing, but then again, they are pretty religious about replacing components in a timely fashion. Maybe we're just asking too much of the JE in a race application, when it should be considered a disposable part (again, in race situations only)?
It's because of the whole lack of supply and lackluster quality of the Mahle cylinders as of late that I have tooled up and produced all the oddball p/c kits like the machine in 100s and 102s for the 3.0/3.2, as well as the 89mm 2.5 kits and 3.8 RSRs. I know that in the near future that Mahle may very well decide to forget about us and I'm trying to stick with it to fill the gap left by this fallout.
It's funny that you mention it, but the pin boss issue is the same one that I have heard about, but it seems that it's only the case in all ***** out high rpm/ high hp racing. Just out of curiousity, I asked around my area about JEs and blown race motors (sorry no p-cars, but SBC, BBC, etc) and that crowd has never had a complaint about their JEs failing, but then again, they are pretty religious about replacing components in a timely fashion. Maybe we're just asking too much of the JE in a race application, when it should be considered a disposable part (again, in race situations only)?
It's because of the whole lack of supply and lackluster quality of the Mahle cylinders as of late that I have tooled up and produced all the oddball p/c kits like the machine in 100s and 102s for the 3.0/3.2, as well as the 89mm 2.5 kits and 3.8 RSRs. I know that in the near future that Mahle may very well decide to forget about us and I'm trying to stick with it to fill the gap left by this fallout.
11-05-2004, 01:12 PM
#19
RL Technical Advisor
Nossir, you were certainly not alone.
I think JE's are fine products for what they are and what they were intended to be used for. IMHO, its simply good practice and prudent to replace these items on a regular basis to prevent the kind of expensive troubles that we can all live without,... Depending on the peak RPM's and compression ratio of the engines in use, I replace them every 30-50 hours on race engines and about 50K in street usage. That maintains peak performance and reliability. Fortunately, this is not very expensive to do so (aside from labor).
I am VERY pleased that you make the very high quality cylinders that you produce. Its top notch! I simply wish that Mahle would produce replacement piston sets like they promised about 2 years ago.
I think JE's are fine products for what they are and what they were intended to be used for. IMHO, its simply good practice and prudent to replace these items on a regular basis to prevent the kind of expensive troubles that we can all live without,...
Depending on the peak RPM's and compression ratio of the engines in use, I replace them every 30-50 hours on race engines and about 50K in street usage. That maintains peak performance and reliability. Fortunately, this is not very expensive to do so (aside from labor).I am VERY pleased that you make the very high quality cylinders that you produce. Its top notch! I simply wish that Mahle would produce replacement piston sets like they promised about 2 years ago.
11-05-2004, 02:30 PM
#20
Advanced
Thread Starter
Join Date: Oct 2004
Location: Warrenton, Va.
Posts: 99
Likes: 0
Received 0 Likes
on
0 Posts
Nothing quite like a REAL insider view of P-cars aftermarket goings-on. This info is almost priceless! In today's over-hyped performance advertising it is really hard to get to the bottom line; even though I'm a tech and engine savy!
Sure explains a lot especially when you look at Mahles pricing! If they are unwilling to do pistons only it's clear to me that they are making too much money. I mean they are already half-way there with the product!
Sure explains a lot especially when you look at Mahles pricing! If they are unwilling to do pistons only it's clear to me that they are making too much money. I mean they are already half-way there with the product!
12-02-2004, 12:52 AM
#21
Rennlist Member
I'm finalizing my build list for a 3.4, but will not be going twin-plug at this time. I'm about 60% sure I'll machine the heads and valve covers now for the twins, but I want to save the money for the set-up, and more importantly the added complexity when dialing in a new motor (Imy first rebuild). What kind of performance will I be giving up staying single ignition for now?
12-02-2004, 09:07 AM
#22
Rennlist Member
I personally don't think you'll loose that much over the twin plug other than from the overall reduction in CR to accomodate the single plug setup. Adding the second plug later will just allow a buffer zone against knock and detonation if you get a bad batch of gas. It might also let you run a little more advance, but I personally wouldn't go with the expense of doing the machining to the heads, valve covers, etc, unless I went all the way from the beginning, so that you could run a little more CR to take advantage of the twin plugs.
