New build SS 3.0 IN 72 Targa Rat Rod

[faapgar]

Hi,wandering and looking around the garage I realized I had enough parts to build a short stroke 3.0 for my 72 rat rod.If you are a purist tune out now and keep your blasphemy to yourself.It starts with a 77 3.0 Turbo case.66mm crank with 98mm bore.Crank has center main drilled with 4 additional dowels to support the center of the main webs.New 3.2 oil pump with Pauter rods a few millimeters longer.I checked the cc of the heads the other day and it was 11.4 to 1.The longer rods push the piston a little higher in the head so they need some adjustment.My machinist and friend of 50 years just passed away recently.I asked around and found a guy with good hands to adjust my pistons.Trimmed the outer edge 1 mm and 2 mm off the top center and compression ratio is 11.1 to 1.Great start and off we go.I already have a similar SS 2.8 in the car.A few pics for now.


Yes Targa pics coming.

[Mixed76]

Damn, Fred.

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[47silver]

Nice

[12ohclock]

Subscribed brother.

[MST0118]

Cool Fred. I like those pistons, are they Mahle brand?

[faapgar]

They look like Mahle but are JE.The softer gray look is from glassbeading with fine beads after he machined them.I have some hand work now to soften the sharp edges for better flow and reduced heat points.Then they will go out for a heat barrier coating on the tops.Happy Thursday

[fred cook]

Originally Posted by faapgar

Hi,wandering and looking around the garage I realized I had enough parts to build a short stroke 3.0 for my 72 rat rod.If you are a purist tune out now and keep your blasphemy to yourself.It starts with a 77 3.0 Turbo case.66mm crank with 98mm bore.Crank has center main drilled with 4 additional dowels to support the center of the main webs.New 3.2 oil pump with Pauter rods a few millimeters longer.I checked the cc of the heads the other day and it was 11.4 to 1.The longer rods push the piston a little higher in the head so they need some adjustment.My machinist and friend of 50 years just passed away recently.I asked around and found a guy with good hands to adjust my pistons.Trimmed the outer edge 1 mm and 2 mm off the top center and compression ratio is 11.1 to 1.Great start and off we go.I already have a similar SS 2.8 in the car.A few pics for now.


Yes Targa pics coming.

What heads are you using? On this engine twin plugs are a must! I have a 3.3SS in my SC with about 11:1 compression and twin plug ignition and it runs fine on 91-93 octane pump gas.

[faapgar]

Heads are 88 3.2 Carrera with 50.5 Intake valve.They were done by Extreme with their Ferrara valves and of course twin plug.

[fred cook]

Originally Posted by faapgar

Heads are 88 3.2 Carrera with 50.5 Intake valve.They were done by Extreme with their Ferrara valves and of course twin plug.

Interesting, that is essentially what I used, Carrera heads, 42mm intake ports, 41mm exhaust ports, also done by Xtreme Cylinder Heads! For the intake, I used an early large port CIS air box, matched the intake runner ports to the heads and modified the CIS to be more like the 1973 1/2 design. I added a contact switch and wiring to the cold start valve so that it would open when at full throttle to give some extra fuel and avoid a lean running situation. I used a set of SSI exhausts with the tubes opened up to (again) match the exhaust ports to help get optimum air flow. I also used the XDi crank fired ignition system with the adjustable timing. The ignition interrupt is set at 7500 rpms and it pulls well all the way up! The bore is 100mm and the stroke is 70.3mm giving thee 3.3 liter displacement. Oh, yes, the pistons I used are the Mahle low dome pistons that were designed to be 10.1:1 but due to head mods it turned out to be right at 11:1 compression.

[faapgar]

Hey Fred,your build sounds great.Should make nice mid range torque as well.What cam did you use as to not upset the idle?Sounds pretty efficient as well.Thanks for adding your build and your imagination.Fred

[jpnovak]

I always thought the 3.0SS (66x98) would be nearly the perfect early car engine.

I have just never been able to find the C3.0/early turbo case to start with.

[fred cook]

Originally Posted by faapgar

Hey Fred,your build sounds great.Should make nice mid range torque as well.What cam did you use as to not upset the idle?Sounds pretty efficient as well.Thanks for adding your build and your imagination.Fred

I used the 964 cams (original Porsche) with the timing advanced just a bit. They really wake up a CIS equipped motor!

[fred cook]

Here are a couple of pictures of the heads I used:

Combustion chamber


Mahle piston


Intake port (don't know why it loaded upside down!)

[911 SLANT]

Fred why did you go with SSIs and not Headers? Wont the SSIs restrict flow? I believe largest ID is 15/8.

[pampadori]

what is the rev limit you are planning for faapgar? The 66 stroke keeps piston speeds nice and slow and we know those 2.8 motors can hum to 8500. Would love something similar someday.

I see a lot of people leave those sharp edges on the valve reliefs and don't consider them potential glow plugs! The extra effort to cut them down and smooth them could save you a lot of money on a hot track day.

[fred cook]

Originally Posted by 911 SLANT

Fred why did you go with SSIs and not Headers? Wont the SSIs restrict flow? I believe largest ID is 15/8.

I already had the set of SSI exhausts and wanted to keep the heat function. While it never gets super cold here, temps in the 30s are not uncommon. Also, the SSI down tubes are only about 4-5mm smaller than the cylinder head exhaust ports. I was able to flare the tubes to match the exhaust ports in the cylinder heads and thus keep a good flow transition. It must have worked pretty well as the engine will easily spin up to the ignition interrupt set at 7500 rpms. Pretty amazing for an engine breathing thru a CIS induction system!

[lvporschepilot]

faaaaabulous. do it

[faapgar]

I have a 2.8 that spins to 9000 with Ti rods & valves.Built for power but needs race gas mixed in to be safe with the compression.This one will run on 93 octane and get me into less trouble.I love the sound of its song when it revs and I have never kicked this addiction.As far as the details I do to get to my finished piston style I always do it right.Less than 1 hour a piston and it is ready.I will post a pic when done.I have done a bunch at much higher CR.Whole new song and sound.I have not chose a cam yet but I have 1/2 a dozen grinds to choose from.I have another week to wait for the new valve springs from lvporschepilot.I also have time on my hands.

[faapgar]

It is a 1956 Carrera color.



Chopped & Channeled

[faapgar]

A little stiffening up.914-6 style wall between front shock towers.




BBS 8 x 17 and 10.5 x 17 rears.Had slant nose but now regular 930 fronts.Lexan windshield and no other glass.Very light.Full coilover with Boxster brakes.Ciao