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The benefit of itb's is primarily the freedom to use happier cams and crisper throttle response, air flow increase may or may not be useful it depends on all the other choices made
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Bill Verburg '76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone) | Pelican Home |Rennlist Wheels |Rennlist Brakes | |
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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Regardless of installed piston assembly, cylinder, and rod part conditions… all these will be replaced by default. This is to reduce in-motion-weight, add in contemporary technology, and balance parts to a very tight delta. Since dollar difference between 3.2 and 3.4 parts is invisible, going 3.4 is no-brainer. Exactly what compression ratio (CR) to go with remains undecided. To serve build's endurance priority, high CR is definitely out. 2-plug is still in for combustion efficiency. Exactly how Megasquirt (MS) and related hardware will set up for 2-plug system is---at this moment---total mystery to me. Am digging into MS daily. Right now, these parts are slated…
![]() ![]() Mahle 98mm pistons, rings & pins (normal asp.) Have not yet priced this with rings and pins. Am wondering if there are optimal type/brand rings to partner with Nikasil bores? Will balance piston-pin-clip assemblies to 0.5 gm max delta. (If I can get crank balancer to go with me to a lessor delta, then I’ll go lower than 0.5 on assemblies I’m balancing.) ![]() Carillo H-Beams $1,840 set. Need to speak with Carillo about how to achieve a 0.5 delta or better. (Believe their spec is +- 0.5 which translates to potential 1 gm.) ![]() LN Engineering Nikasils 98mm $3,880. set. Will moon cut. Wonder if there’s more easing of air flow to be created at base of cylinders (aside from boat tailing.) Compared to Mahle’s cylinders, LNs have +2 fins. Also appears to me from product images that LNs are more carefully made than Mahle. Am wondering if there’s any concern with fitting Mahle pistons into LN cylinders---Cold fit? Hot/expanded fit? Crank will hopefully call for std bearings. Will knife edge crank, bobweight piston & rod assembly then balance crank (fly wheel attached.) For daily driver use, should fly get weight reduction? Again, case gets boat tailed. None of this is carved in stone. If you find anything wrong here… say so.
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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Join Date: Oct 2008
Location: Denver, CO
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Karl:
Believe the wedge-shaped mahles you pictured above are optimized for single plug use -- the wedge focuses the single plug's off-center combustion across the combustion chamber to more fully ignite -- don't think they would benefit from a twinplug setup. Many have used these successfully without detonation issues in single plug configuration. Would also suggest that you consider the Mahle motorsports' 98mm p&c sets, as they're built to work together expansion-wise, etc. |
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Nice on line topic...
If I were doing this thinking, read been there done this, answering and or choosing/specifying these and you will have most if not all else answered... 1. Disassemble and inspect ALL = measure and magnaflux to make sure no cracks and then this really sets the rebuild direction and budget... 2. There is no replacement for displacement... 3. Camshaft profile determines 80-90% what other parts need to be 4. #3 also screams head flow needed = talk to bill at extreme in Florida... Doing these steps and your case mods and reading Bruce Anderson’s books will tell a lot of already found “improvements “ to do or consider... You could easily spend weeks researching this and that and never finish this build, SO, when does this need to be finished...? Keep this in mind too... Good luck and enjoy...!
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I live for 911 tweaks... |
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Join Date: Sep 2000
Location: Frankfort IL USA
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If you want light rods, get a set of Pauter’s lightweight rods. They take their standard 3.2/3.3/3.6 rod and go a bit lighter on it. Their rods also have the bolts “inverted” and that places the bolt heads away from the rods near the oil pump. Reason I mention this is because if you use a larger oil pump, the pump usually needs some clearance from the Carrillo rods
You’ll want to be cautious of the crank knife edging. Those counterweights are on there for a reason. Neil has a lengthy page on his website that gets into the dangers of knifing the crank weights You don’t need to moon the LN Nickies. They’re already mooned. You’re right they have more fins and they are billet cylinders, not cast like the Mahle cylinders. So the fins are actually machined/cut and not cast fins like the Mahls. If going with LN cylinders, their higher strength allows you to use thinner cylinder walls. That means you could use a 100mm cylinder that is a slip-fit (no machining of the case bore necessary) to make a 3.5. The typical Mahle 3.5 kit requires you to machine the case bores for the larger cylinder Look at all the 3.2 dyno plots (some 3.4 dynos in there too) on 911chips.com site and you’ll see the 3.2 intake hits a HP peak at 6200 rpm every single time. What that demonstrates is the tuning effect the length of the intake runners has on the engine’s power delivery. If you want to spin the engine higher than 7000 rpm to make power, that intake is a hindrance
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Kevin L '86 Carrera "Larry" |
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3.5 program... No case adjustment... what about heads? As one moves away from stock config, 3.2 in this case, is there any issue with referencing "Porsche Technical Specs"---booklet data? For example, an increase in bore and CR, does that require a new head nut torque? Larger combustion chamber... does that demand larger valves? All of a sudden I'm in paranoiaville! ...Am data-overdosing! (Will embrace the horror for as long as it lasts! Morning coffee will help ![]() Neil... ? Looked at 'Chips' dyno sheets. Saw 3.2 run. Thanks for input Kev!
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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Call Notes 12.10.18:
Rod - Pauter / Don forward to Brian / 619.422.5384 / “Light weight” rod = 550 gm. $1,776 set. Promised me they’d pluck to minimize deviation. 12.18.20 Brian said he could put forced feed pin (FPF) hole through rod. Wondered why given squirters. Reminded him of build's premise and he understood. Said journals would need to be drilled and main cross drilled. Bushings might get resevoir grove. Size of FPF bore yet to be determined. Need to consider system wide oil pressure doing this. Rod - Carillo / Richard / 949.567.9000 ext. 191 / Standard unit weight = 600 gm. Custom made is “low 500’s.” I confirmed = 525 gm. He said “probably less.” Custom = $2,070. set. Forgot to ask if it’s possible to flip bolts. They’d make small end fit custom piston---so need to know piston dimension beforehand. 12.18.18 They do FPL rods. Is straight bore into rod beginning at small end. Vid posted on page 3. 1.8.19 Spoke with Richard about boring rods for forced pin lubrication. $90 per rod to bore. Is beneficial in terms of lubrication. Downside for this build is mass needed to be added to rod to accommodate bore. Estimate is 25-30 gms per rod. JE does custom pistons. This suits build plan provided I can confirm there being absolutely no issue with JE---any piston for that matter---working in a non-matched cylinder. Being used to buying stock parts in matched sets, mixing is uncomfortable at this moment. Surly others have blazed this trail before me. Piston - JE Custom / Brian / 714.898.9764 / Profiled endurance (smooth engine) build goal for him including likely use of LN Nikasil cylinders. Said am working bobweight back from knife’d crank---so want to know what minimum piston weight JE can achieve for this build profile (911 3.4 endurance street application.) From minimum weight it’s possible to leave material in to satisfy bobweight. They’ll take existing part and mill to reduce weight rather than conceiving entirely new piston. $1,320 set including ring pack, wrist pin and retainer. Advised Brian of my research pointing to Moly or tungsten rings being suited to Nikasil. He did not say what JE ring composition is but advised JE rings being suited to Nikasil coated bores. Must be they’ve dealt with Nikasils before. He needs to calculate weight. Will get back to me on later today or Monday. Forgot to ask if JE does ceramic coating. Piston - Mahle / Zak / 888.255.1942 Ext. 2817 / Zak advises Mahle can make pistons in F1 form with coated skirts. Their ceramic top coating is coming online next year---exactly when next year was not asked. Windowing skirt's low thrust side of was not eagerly received. Comment in this regard was racers being the one's who typically push the envelop testing different ideas with windowing not having much interest. Did not discuss asymmetrical piston form. Custom piston estimates are $300 each and less than 400 gm. Pins and rings are additional cost and weight. After design and engineering is done, is 6 week production time. Printed plastic model = $100. each. He mentioned piston's metal alloy composition and oil ring being key factors relative to product running successfully in Nikasil bore. Cylinder - LN / 815.472.2939 / No issue mating their cylinder with JE piston---"...it's done all the time." Asked about best ring composition for Nikasil... no clear answer. Suggested that dedicated ring maker would be entity to speak with... Hastings, Total Seal, Goetze. ANDY 12.17.18 - No issue running F1 designed (short) piston with Nikasil. No issue with heat transfer from F1 design out through Niki cylinder. Crank - Ollies / Zak / 928.855.6101 / Said for my street application there's no need to knife but can do to improve case windage. If they do knife... Then they balance crank. Then they add fly and balance. Then add pressure plate and balance. Then add pulley and balance. 1 gm tolerance. Should cross drill main and upgrade squirters from 1mm to 2mm. Boat tailing. There is no bobweighting for boxer engines. Will update this post when missing info is had. 12.18.18 Status: RODS - Both potential suppliers can customize. Both can FPL bore. Carillo is the lighter weight---possibly below 500 gms. PISTONS - Comments do not bode well for JE. Mahle can customize piston to targeted F1 style. Keeping stock CR. Can 3D print piston proof. $100 per proof. Rings are Mahle's responsibility. They know cylinders are LNE Nikies. CYLINDERS - LN Engineering for 98 mm Nikies. PINS - still sourcing C300. BUSHINGS - Researching flow control hatching. ENGINE OIL FLOW - Need to determine how to sense and adjust flow to optimize system wide pressures based on change to squirters, FPL'ing for pins, and larger pump. .
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. Last edited by Discseven; 01-08-2019 at 08:29 AM.. Reason: Added phone contacts - Add Andy's input - Zak's input - Add FPF note to rods. Add Carillo bore notes. |
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Join Date: May 2007
Location: Fortuna, CA. On the Lost Coast near the Emerald Triangle
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FWIW the rings that I received with my 95mm JE pistons were German Goetze. I imagine to be OE for Mahles.
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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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PS Nice pistons!
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. Last edited by Discseven; 12-14-2018 at 01:00 PM.. |
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Join Date: May 2007
Location: Fortuna, CA. On the Lost Coast near the Emerald Triangle
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I used the original Mahles that were on the SC motor I bought years ago and rebuilt. The cylinders were in spec so I used the Scotch Bright method to de-glaze them.
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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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^^^ To my eye, that's an impressive crosshatch Gordon. Nicely done.
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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Ref from Trends Performance. Call them Monday to see what they can offer in C300 or H 13 in as thin a wall as they deem suitable to build.
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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Join Date: May 2007
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I can't take credit for that. That is what they looked like upon disassembly. They got slightly duller after I used the Scotch Bright. That Nicasil is very hard.
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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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![]() Mahle F1 type. ![]() F1 with window'd skirt. (Looks like window's only on minor thrust load side.) Forced pin lube. Be interesting to see if Carillo or Pauter will do this. ![]() JE's asymetrical. Above are refs are for piston thinking---plan is to design & make a minimum weight, maximum durability piston based on F1 piston design. What JE (or CP) can arrive at without a budget for specialty metals (as I'm sure F1 teams have)... we'll see what can be accomplished. LN confirms a short skirt---F1 type piston design---not being an issue with their Nikasil cyls. Short piston's heat transfer through Niki cyls is also not an issue. 2nd opinion from piston maker on these points is due.
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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That is how they looked on disassembly, BION. BTW, it is from a motor I bought a number of years ago and finally got around to rebuilding it. No idea of miles or history. When I went to look at this motor for possible purchase, I used a mirror to look underneath at the cylinders. 11 fins and I reached for my check book.
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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
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The direct pin oiling is available for the Pauters but you'd have to determine if it's really necessary. Rod Info - Pauter I'm guessing this pin oiling is typically needed in high rpm and high cylinder pressure applications. I don't know if you're planning on high rpm and I believe cylinder pressure is dictated by compression ratio, which I don't believe you're pursuing?
JE provides various coatings with their pistons as requested. They have a pretty good variety of them. See page 3 http://www.jepistons.com/PDFs/TechCorner/SCPDrawings/JE_Piston_terminology_and_features.pdf Note that several builders have started to switch to the CP Carrillo pistons. Apparently the ownership change at JE has not changed things for the better for the Porsche guys? I have no direct experience with that. But something rather telling to me is LN Engineering's website. They list CP Carrillo pistons and no showing of the JE pistons. JE was their common piston of choice for a long time in the recent past. Regarding the wrist pins, it seems the common upgrade for the Porsche pistons is to downsize from the standard 23mm pin to a 22mm pin. This is something Carrillo and Pauter commonly do and it's listed in their everyday listings of rods. https://www.cp-carrillo.com/files/porsche-flyeronline.pdf Note that of course you'd need to ensure your both your pistons and rods have the 22mm pin. The 22mm pins are used in the 3.0L rods as standard issue and therefore they're a sufficient pin size & strength. Ollie's has a great reputation for their machine work. But their service times can often be quite long if you catch them at the wrong time. If you're willing to send your parts all the way to AZ for service, you could have Marine Crankshaft in CA do your crank for you very easily and they have a great turnaround time. David Eden is a good person to speak with there. Pauter does crankshaft service too. Both Marine and Pauter make their own crankshafts as well. So they definitely have the qualifications.
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Kevin L '86 Carrera "Larry" |
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Re forced pin lube (FPL), surly not necessary but with build's goal being to adopt ideas, materials, techniques that serve parts/engine longevity, if something is beneficial to goal's end, then it's a matter of economics whether to go with a given solution or not. Believe we'll all agree FPL being beneficial. Calling Carillo and Pauter tomorrow to discuss options & costs. This direction begs larger oil pump. Any info in this regard would be welcomed. JE's status is curiously noted. I've heard this from other makers. Allowing for sales propaganda that pizzes on competitors... such commentary is taken differently when there's no slaes & marketing agenda---I'm listening. Regarding pistons, just had interesting discussion with Mahle---they will custom make F1-type pistons for use with Nikasil bores to suit this build's direction. Carillo will make small end measures per customer specs. 22mm is doable. Am researching pins made in C300 metal. Idea being to minimize pin diameter/weight. Piston's boss area is not forgotten when pin shrinking. Delivery by Ollie's noted. Being in Miami and not knowing a local Porsche oriented machine shop here... I'm reluctant to ship to Ollie's. His Porsche rep makes it worthwhile if that indeed is end path taken. Thanks for options you mention---Marine Crankshaft in CA and Pauter. You're thinking this through---much appreciated.
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
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And keep in mind the rifle drilling through the rod beam is not the only FPL method. Though it is the only place you're going to get actual pressurized oil, from the rod journal, and that also begs the question of whether it's worth it to steal precious oil pressure from the rod bearings.
JE has a nice page that shows various pin oiling options they have and they're all splash oiling. Different Wrist Pin Oiling Styles Explained But keep in mind that pistons also have a squirt of oil directed at them. Some use notches in the rod thrust surfaces to direct a squirt of oil at the underside of the piston. Of course our engines have the dedicated jets in the engine case that squirt the piston. Speaking of squirters, if you're going up in size on the piston squirters? You may need to consider a larger oil pump since those squirters are going to steal some volume from your crankshaft oil. Going by memory here: Typical 3.2 Carrera pump = 1.5mm squirter jet 930 pump = 2.0mm jet 964/993 = 2.5mm jet I don't know off the top of my head what size jet is used with the holy grail GT3 pump. But its delivery rate on the pressure side is in excess of the 930 and 964/993 pump so I have to assume the GT3 squirters are also large. There's also the argument of reduced cam housing oil delivery (the infamous reduced orifice diameter within the camshaft & rocker banjo base/fitting) which in turn sends more oil to the bottom end of the engine and reduces the need for a larger pump. The argument is, is it truly advisable to take away oil volume from the top of the engine? Heads are the part of the engine that need the most cooling (and fan air is the primary means of cooling) but any help provided by oil is certainly welcomed?
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Kevin L '86 Carrera "Larry" Last edited by KTL; 12-18-2018 at 12:02 PM.. Reason: corrected my jet sizes |
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