The 2.7, something to stay away from? |
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The 2.7, something to stay away from? |
drewvw |
Apr 13 2006, 02:19 PM
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#1
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new england car guy Group: Members Posts: 1,631 Joined: 24-February 06 From: Boston, MA Member No.: 5,630 Region Association: North East States |
A friend of mine who has a couple porsches mentioned today that its a good idea to stay away from the 2.7 liter motor. That can't be right...don't a bunch of you guys run those? are there any major glitches/PIAs with the engine? continuing my education through debate as per usual... |
Allan |
Apr 13 2006, 02:31 PM
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#2
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
I think the weak point on the 2.7 is the magnesium case. It's soft and the head studs can pull out. I have one and that is exactly what happened. If you're gonna go through the motor you can install case savers and the problem is solved. The /6 guru's will let you know if it has other issues but that's the one that sticks out in my mind.
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lapuwali |
Apr 13 2006, 02:41 PM
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#3
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
The problems with the 2.7 were that they stretched the mag case to its limits, and in the 911, they made a number of gaffes that seriously affected reliability, like a fan with fewer blades, and thermal reactors in place of catalytic convertors. If an 11-blade fan is used in place of the stock 5-blade, and headers or 914-6 HEs in place of the stock 911 exhaust, a REBUILT 2.7 appears to be reasonably reliable. The mag-cased 2.0, 2.2, and 2.4 engines all were reliable, so it's not really the mag case by itself.
The good thing about the bad rep the 2.7 has is that they're fairly cheap relative to many other 911 engines. |
Dr Evil |
Apr 13 2006, 02:47 PM
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#4
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Send me your transmission! Group: Members Posts: 23,000 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region |
Yup, pulled head studs are the biggest concern. Case savers are fairly inexpensive to have installed and do solve that proble.
Regarding what James said, the thermal reactors and fan are huges contributers. Thus, a '74 is your best bet in that it had no thermal reactors or extra smog BS really. Of course I am biased as that is what I have. I have not even run it yet, but it did have the case savers installed already before I rebuilt it. You want to get the 7R case if you are lookng for one. |
ArtechnikA |
Apr 13 2006, 02:53 PM
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#5
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rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
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Dr Evil |
Apr 13 2006, 04:11 PM
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#6
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Send me your transmission! Group: Members Posts: 23,000 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region |
Sometimes I thin k that you are the only one that gets me, Rich (IMG:style_emoticons/default/drunk.gif)
I was being fasheesus (IMG:style_emoticons/default/rolleyes.gif) |
Eric_Shea |
Apr 13 2006, 04:57 PM
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#7
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PMB Performance Group: Admin Posts: 19,275 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
QUOTE The 2.7, something to stay away from? All of the ones that haven't been rebuilt properly. I always thought the main problem was the thermal expansion of the new Nikasil cylinders vs. that of the studs not the mag. case. (IMG:style_emoticons/default/confused24.gif) |
Joe Bob |
Apr 13 2006, 05:15 PM
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#8
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Retired admin, banned a few times Group: Members Posts: 17,427 Joined: 24-December 02 From: Boulder CO Member No.: 5 Region Association: None |
The scariest fast 914/6 I ever drove was a 2.7 with Webers.
They would have been fine if the US hadn't made them put smof devices on them....Porsche chose thermal reactors ....dumb move.....damn things cooked the motors. THAT plus the soft magnesium cases attributed to the pulling of the studs. |
lapuwali |
Apr 13 2006, 05:41 PM
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#9
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
QUOTE The 2.7, something to stay away from? All of the ones that haven't been rebuilt properly. I always thought the main problem was the thermal expansion of the new Nikasil cylinders vs. that of the studs not the mag. case. (IMG:style_emoticons/default/confused24.gif) The mag case caused the main symptom, which was that the studs pulled out of the case. The early SC engines with the aluminum case broke their studs instead. (IMG:style_emoticons/default/blink.gif) But yes, overboring the mag case, using a new cylinder material, reducing cooling with the 5 blade fan, and adding thermal reactors all added up to one of the worst periods in Porsche's history. Once they're rebuilt with thread inserts and strong studs, a proper fan, and no thermal reactors, they seem to be perfectly decent engines. |
scotty b |
Apr 13 2006, 06:16 PM
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rust free you say ? Group: Members Posts: 16,375 Joined: 7-January 05 From: richmond, Va. Member No.: 3,419 Region Association: None |
Thermal reactors : pulled studs : shitty compresion : shitty cams : all can be corrected with a PROPER ($$$) build and will produce a very nice engine. I among others have a 2.7 that will be going in my 914. Stock yeah they're kind of a piece o' poo As for the pulled head studs ask some 3.0 guys if they've ever had a stud pull........or break (IMG:style_emoticons/default/dry.gif) or burned a valve. 2.7 is just a previously misunderstood engine, kind of like a certain little car was (IMG:style_emoticons/default/driving.gif) Previously. Now it's got some street cred (IMG:style_emoticons/default/laugh.gif)
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J P Stein |
Apr 13 2006, 06:26 PM
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#11
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
I "properly rebuilt" my 2.7L....all on myownself + less that 500 bucks of machine work on the short block.
I've been flogging it for 4-5 years now....I've kinda lost track of the time. It's not as "crisp" as it was, but considering the abuse, I'm happy with it. |
Dr Evil |
Apr 13 2006, 06:59 PM
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#12
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Send me your transmission! Group: Members Posts: 23,000 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region |
As for the broken stud issues, many of them were Delrin which was an alloy that they experimented with as its thermal expansion properties mirrored that of the other materials of the case, heads, barrels, etc. Problem with Delrin is that any scratch in the surface lend it succeptible to corrosion and fracture as is the nature of the alloy.
For more deacent answers, you can consult Wayne Dempsy's book. I had to change the cams in my engine from the stock '74 to SC so that the Tq curve would flatten out. It should be a hoot. |
scotty b |
Apr 13 2006, 07:06 PM
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#13
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rust free you say ? Group: Members Posts: 16,375 Joined: 7-January 05 From: richmond, Va. Member No.: 3,419 Region Association: None |
2.7 J.E. pistons, 930 oil pump, pressure fed tensioners, Solex cams, Raceware tsuds (anything better ?) full balance job, little head play and either Webers or PMO's scootin bay (IMG:style_emoticons/default/driving.gif) Now all I have to do is finish the 944, dads 914, my CJ and knock over a bank or 3 (IMG:style_emoticons/default/ph34r.gif)
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GeorgeRud |
Apr 13 2006, 07:16 PM
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#14
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Advanced Member Group: Members Posts: 3,725 Joined: 27-July 05 From: Chicagoland Member No.: 4,482 Region Association: Upper MidWest |
Even the 3.0, 3.2, and 3.6 liters are getting to be old engines, almost all need a rebuild. Parts are not cheap on any of these engines.
I have a 2.7 that has had the timecerts installed, pressure fed tensioners,dilivar studs, RS piston and cylinders, Garretson cams, webers, and Electromotive ignition. It's a kickbutt engine, revs nicely, and pulls like a SOB. But, if I had it to do over again, I'd start with a 3.2 as it has almost all the nice things included in the base engine, and the Motronic is very driveable with today's gas. The Webers make my old engine smell like the Exxon Valdes ran aground in my garage if I don't remember to shut off the fuel pump a couple of blocks from home to run the float levels down and stop fuel perculation. Just my 2 cents. |
Dr Evil |
Apr 13 2006, 07:24 PM
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#15
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Send me your transmission! Group: Members Posts: 23,000 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region |
Dilivar = delrin
I kept the CIS on my engine so I would get good mileage (28-31) and easy maintenence. 165hp aint bad and when the time comes I may put carbs on for a little more fun. I personally (IMHO) feel that the pressure fed tensioners are all hype. I used hydro locks on my tensioners and kept the mechanical spring type.Agian, MHO. |
Eric_Shea |
Apr 13 2006, 07:57 PM
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#16
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PMB Performance Group: Admin Posts: 19,275 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
Thermals were only on Kalifornia cars no? (IMG:style_emoticons/default/unsure.gif)
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Aaron Cox |
Apr 13 2006, 10:38 PM
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#17
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
correct me if im wrong,
they went from the 11 blade to the 5 blade fan, BUT!! downsized teh crank pulley to spin it faster.... i read it somewhere |
lapuwali |
Apr 13 2006, 10:41 PM
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#18
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
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