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Registered
Join Date: Apr 2011
Location: behind the redwood curtain, (humboldt county) california
Posts: 1,433
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CP or JE pistons, 74 2.7-2.8 with 10.5 compression
Evening Gents,
I, (with some serious assistance from Trackrash) am about to get into my old man's 74 engine - hopefully top end only. My question is which pistons, CP or JE, with a cr of 10.5. During this 10 year restomod, i have gone through the suspension, brakes, steering, pedal cluster, seats, new SSI, alum clutch & RSR flywheel, wheels tires, duck and spoiler, rust repairs, entire fuel system, including Al's MS PMO ITBs, crank fire EDIS ignition. The car is my dad's original 2.7, rebuilt oncce, with a top end job about 10 k miles ago. It will see "spirited road use" and a few DE's. I have tried to sharpen up the performance/responsiveness with 21/27 T bars bilsteins, Tarrett 22mm sways and HD rubber, 15x7 Jongbloed wheels with 205x50-15 Direzzionales and light clutch/flywheel. The long block is stock spec. On seeing this, Gordon graciously offered to "Help" me to bump the CR and do the cams, since the engine was still out. With the megasquirt, EDIS and the crank fire all in place, it looks like all i need to do is add another EDIS module, coil pack and another set of wires, (+ a bit of machining) to enable running 10.5 (from 8). Since it is unlikely that the pistons, rings and cylinders are still reuseable at 100k since the rebuild, it seems to make sense to go to 92 mm on the bore - hence my question: Carillo or JE for the pistons??? Some old posts seem to indicate that both are of the same alloy and costs are close. How do they compare on weight, durability, cost, performance??? This is not a serious race engine, no flow work on the heads, (only going from 32 to 35-36 on the ports, (with cc-ing to confirm cr), Torquey cams - roughly DC30-40 finishing with a scart muffler. Availability is also a consideration - who has them??? I'll likely need to ship them to EBS, or ?? to get the old cylinders bored to 92 and re-plated???? Approaching 74, i have recently, (& fairly frequently) found that i do not have all the answers - this devastating revelation reminds that i should seek advice from those who have gone before and done it. With considerable humility, I welcome all advice, chris Last edited by chrismorse; 12-30-2021 at 04:39 PM.. Reason: oomilitay |
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Racer
Join Date: Oct 2010
Location: Franklin, TN
Posts: 5,885
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CP….I would use nothing else in a build.
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Scott Winders PCA GT3 #3 2021 & 2022 PCA GT3 National Champion 2021 & 2022 PCA West Coast Series GT3 Champion |
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,695
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CP was recommended to me by a couple race engine builders. So that's where I got mine.
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Registered
Join Date: Apr 2011
Location: behind the redwood curtain, (humboldt county) california
Posts: 1,433
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Thanks Scott and Stownsen.
EBS said they were told 6-8 weeks out on piston orders. Does anyone know who has them?? Is the skirt coating worthwhile?? Thanks chris |
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Registered
Join Date: Jan 2003
Location: Langley,B.C.
Posts: 11,992
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CP is our go to. They also make all of our M96/97 pistons for us, some in custom sizes. They are very good to work with..
Cheers
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Turn3 Autosport- Full Service and Race Prep www.turn3autosport.com 997 S 4.0, Cayman S 3.8, Cayenne Turbo, Macan Turbo, 69 911, Mini R53 JCW , RADICAL SR3 |
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Functionista
Join Date: Jul 2011
Location: CO
Posts: 7,717
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Does CP offer ring land anodizing? Top ring land can take a beating on air cooleds and anodizing can really extend life.
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Jeff 74 911, #3 I do not disbelieve in anything. I start from the premise that everything is true until proved false. Everything is possible. |
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Registered
Join Date: Jun 2013
Location: Orange County, Ca
Posts: 614
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you cant really get away with 10:1 on a single plug fyi.
Also mahle is a good option.
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1976 911 1976 914 1986 951 |
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Racer
Join Date: Oct 2010
Location: Franklin, TN
Posts: 5,885
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Quote:
__________________
Scott Winders PCA GT3 #3 2021 & 2022 PCA GT3 National Champion 2021 & 2022 PCA West Coast Series GT3 Champion |
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