My 1971 911T 2.8 Engine Build

[spyerx]

Figured I'd post my ongoing build here... will update later with some pictures and some initial specs. Cases are due back from machine work in about a week, about 1/2 of the major mechanicals are in hand, rest on order as of today.

I'd posted a few months back on ideas, and have settled on a, probably mostly non-traditional approach to the engine build on my 71T. No carbs or MFI here. And most of the rotational assemblies will be from modern car designs. I purchased a core 77 7R in very nice condition, will use many of the take offs to refresh the 77 7R with carbs currently in the car for a future project... !?!?

Very much appreciate all the knowledge here to gain ideas as I worked with the builder I'm using.

General philosophy: 7R mag case, street focused, happy at sea level to 7k ft, modern/light/low friction rotational assemblies, modern engine controls to deal with how and where I drive the car. Basically, classic engine, keep many of the classic looks, but, modern 'insides'. I want it fun around town, in the hills, with good power, and, no carb annoyances as I'll drive it from sea level to the top of Angeles Crest and I want it consistent, always.

My car is essentially a sleeper, innocent looking 71T with a full refresh and updated sportier chassis setup. No flares, she's skinny and staying that way. May squeeze a 7R with a 215 out back. 911/01 trans is fresh with various upgrades already done, will be installing an LSD.

Here's the basic build spec:
Case - 1977 7R - clean core with all the tricks done by Ollies, opened up to support 2.8L
996 Turbo oil pump
Custom crank - allows use of GT3 TI rods w/ modern bearings
GT3 Titanium rods
Custom CP pistons 2.8L. Custom light design will be based on newer pistons spec
Custom / modern type rings and ring design on piston
Custom light pin / coated
Compression measured to 10.5:1
Nickies cylinders - with custom boss to attach 993 type knock sensors (1 per bank)
Heads fully re-worked by xtreme. All the tricks, dual plug, TI bits, porting etc.
Billet DLC rockers
Something around the DC60 cam profile (this we may tweak...). But my desire is decent drivability, don't want it super peaky, Power from 4.5k+ and rev to ... 8k-ish.
GT3 intermediate gear
Rasant induction, throttle bodies, high rise ITB intake
Motec M1 with dual lambda O2/knock, and all the sensors necessary for modern engine management
Rasant custom wiring harness for all sensors
Fiberglass tins
All cosmetics done done - builder going to surprise me :-)

....and some tears as I write the checks and question my judgement for spending this $ on a mag case engine...

The orange one, not the italian!

[Derek77]

Really nice looking car, the orange one!

[Hi_Fi_Guy]

As the owner of a '71T Targra I'll be watching your build closely. I hope it meets and exceeds all expectations.

[spyerx]

forged Crank (someone here may recognize this... )
ITB stacks and EFI throttle bodies (similar design to this )
Forged rockers
heads getting 'built up' for a LOT of machine work
GT3 TI rods, weight comparison to stock
the back side of the pistons, these are not the actual pistons but designs will share similarities. light and strong

[NickP]

Thanks for posting. This will be interesting to follow.

[lvporschepilot]

Wow. What are you doing to those heads! Love these builds. I have a very similar 2.8L build with ITB EFI (AEM Infinity), same compression as you (JE pistons), Carillo rods, twin plug, 39mm/38mm ports, and am running a DC65 cam. Idle is a bit lumpy at 1100-1200 (with 4-5 degrees timing), but it is otherwise very tame just driving around and revs very well to 8k. I may try a DC40 cam as I feel a DC60 or 65 wants a perhaps bit more static compression to work really well. I think a DC40 will have very close to the same rev range with all the light internal components and head flow anyway. DC40 duration is very close to DC60-65 and I feel like my heads may not be flowing way at the top end what optimizes a DC60-65. It's like I hit a wall for fuel requirements at around 7300-7400, as after that my EFI mapping requires to maintain the a/f ratio I'm going for at WOT that I back off fuel a touch to 8k. I really don't know for sure but will undoubtedly give this a shot to satisfy my curiosity and report back.

DC40 @ 1mm 266/249 .490 lift
DC60 271/255 .485 lift
DC65 272/258 .508 lift

stock 'S' cam 268/240 .455 lift

[spyerx]

Originally Posted by lvporschepilot

Wow. What are you doing to those heads! Love these builds. I have a very similar 2.8L build with ITB EFI (AEM Infinity), same compression as you (JE pistons), Carillo rods, twin plug, 39mm/38mm ports, and am running a DC65 cam. Idle is a bit lumpy at 1100-1200 (with 4-5 degrees timing), but it is otherwise very tame just driving around and revs very well to 8k. I may try a DC40 cam as I feel a DC60 or 65 wants a perhaps bit more static compression to work really well. I think a DC40 will have very close to the same rev range with all the light internal components and head flow anyway. DC40 duration is very close to DC60-65 and I feel like my heads may not be flowing way at the top end what optimizes a DC60-65. It's like I hit a wall for fuel requirements at around 7300-7400, as after that my EFI mapping requires to maintain the a/f ratio I'm going for at WOT that I back off fuel a touch to 8k. I really don't know for sure but will undoubtedly give this a shot to satisfy my curiosity and report back.

DC40 @ 1mm 266/249 .490 lift
DC60 271/255 .485 lift
DC65 272/258 .508 lift

stock 'S' cam 268/240 .455 lift

That's great info, thank you for sharing. We haven't settled exactly on the cams and this is one of those areas that experience and experimentation is really important based on the target engine performance...

The headwork is basically building up the material to reshape the chamber for the right CC needed based on the piston design... in addition to some reshape, and changing the spark plug sizing, dual plugs, port and polish to spec, and larger valves. Xtreme is doing the work and it's not cheap.... but sill about 1/2 the price a set of their full spec heads!!!???!!!

[spyerx]

Couple pics of the 'donor' as it sits. The engine in the car is nice, 77 2.7, but has #2 with a leaky valve guide so starts to smoke a bit when really warm and at idle... so will need to address that but otherwise the car goes great and runs awesome. So will save this for a 'future' something or other :-)

The last pic is a local car that Rasant build, 3.2L short stroke i believe, with some really nice classic MFI look with EFI added. Won't be exactly like this but something 'similar' but won't be using the factory red stacks...

[agav]

Sorry for being OT, but this color is gorgeous. What is it? Do you have a paint code?

[spyerx]

Originally Posted by agav

Sorry for being OT, but this color is gorgeous. What is it? Do you have a paint code?

1414 signal orange. it's very, very orange. less common than tangerine which has a bit more red to it.

[Carbster09]

The white car is rapid, if it is the same car I was following on the Targa Cali! And, I belive it is!

Funny I am in the middle of a build for my '71T.... bought a 7R case, then an SC motor .... then a 3.2 crank .... and now its mushroomed to a 3.8 build (964? based) motor that was on the TRE shelf! I wanted the Rasant ITBs ..just like the pic, but the 3.8 is running Rothsport ... what works for me!

These projects can get out of hand!

[spyerx]

^^ I suspect it is :-)

I really debated the 3L / etc - but I have a 964 hot rod already (that will be getting a 3.9-4L next) and a 997 GT3RS... so i wanted the 71 to have a feel/character of the 'older' cars so trying to keep a limit on the ultimate power, while making drivability better (I hate carbs!)

Rothsport is fantastic. I have several buddies running his engines in 964s. Another friend has a Motec 3L in his 72 that he built.

[Carbster09]

Spyerx, I agree 100% that was my intention on starting with a 7R case, but I could not resist tempation. My plan is to use next year's Targa Cali as the shakedown run! You should attend!

[spyerx]

Crank balanced.
More pics of pauter dlc rockers
Cams dc60... although we may tweak that...
Crank balanced

Heads getting close to done
Case here by end of month
Pistons and cylinders about a month out
Harness about 6 weeks out

[spyerx]

[lvporschepilot]

Fancy liner. What is the wait time for Nickie's to make one with the knock sensor boss?

[spyerx]

Originally Posted by lvporschepilot

Fancy liner. Where's that coming from?

LN, this is a 3D CAD drawing... being made now... it's a process lol. From request to delivery? I dunno probably 3mo. EVERYTHING here is a 3mo lead time. :-)

That's why I bought a core to build I didn't want 6mo in down time!

[spyerx]

Heads in process .... it’s a LOT of work to rework these.

[jpnovak]

Lots of great detail work on this build.

[lvporschepilot]

Sweet Mary. Love the heads