Short Stroke 2.8
 

Almost done, what could be nicer?

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Is this 66x95? Early turbo C3.0 case? I think we all want more details.

A 2.8SS is indeed a 3.0 carrera/turbo case w/ 95mm pistons and 2.0/2.2 crank by defintion (unless for some crazy reason he has a 962 crank in there; then you can use an SC case). SWEET motor. I bet is runs ~11:1 CR w/ those twin plugs and RSR cams for over 300HP at >8000RPM when installed. I must stop typing before the drool fries my laptop...

Cool!

zzzzzzzzzzingggggg!

I recently picked up a '76 turbo case and talked with Henry about building a similar motor using 46mm Webers. The compression ratio would be around 10.? /1 and would run on pump gas. I wanted to use it in a street car and as a backup race motor. After looking at that picture the best use might be in the living room as art.
3.4 twin plug in the works
2.8 twin plug in boxes
906 cams for sale

HEY GUYS, THANKS FOR THE KIND WORDS.
What you are seeing is what happens when you love what you do. It's a blessing to be able to make a living doing what you truly enjoy.

Just a note: Dean Polopolus of 4 cylinder 911 fame is standing in while my arm heals and it's like having Babe Ruth coming in off the bench.
Even though his own engine building company keeps him busy, he found time to help a friend.
Come by a meet a legend.

Henry,
What type of header system are you going to use on this engine?

It's hard to teach an old dog new tricks.
 

1 and 5/8 inch flat collector header system with cookie cutter megaphones from European Racing Headers. Old school but very affective. We tend to lean towards old school solutions when building our engines because we like the overall feel and performance of the things we know work.

I'm only guessing but I don't think it's that straight forward because I think the head combustion chambers are different, SC is 90cc and Carrera 3.0 is I guess 76cc? so it'd be difficult to get decent compression out of it. And I don't think they are interchangeable due to different head stud spacing?? And Just my .02
Correct me if I'm wrong!! ;)

The heads on a 3.0 Carrera and a 911 SC are identical.

IT'S DONE
 

AFTER OVER A YEAR IT'S DONE

2.8 SHORT STROKE 66 MM STROKE 95 MM BORE
2.2 "S" CRANK
3.0 TURBO CASE
TURBO OIL PUMP
SC HEADS PORTED TO 40 MM IN 38 MM EX
TITANIUM VALVE SPRING RETAINERS
TWIN ANDIAL DISTRIBUTOR
DC80 CAMS (JOHN DOHERTY) camgrinder on this forum
10.5 TO 1 COMPRESSION
MODIFIED 2.2 '"S" MFI PUMP, SEALED W/ BREATHER
41.5 MM BUTTERFLY HOUSINGS
41.5 X 46 MM MAG STACKS
SUPERTEC FUEL INJECTOR LINES
SUPERTEC ENRICHMENT DEVICE
EURO RACING HEADERS (George does a nice job)
226 FAN W/1.3 TO ONE DRIVE RATIO
SINGLE WIRE ALTERNATOR
RSR SHROUD ( GETTY DESIGN)
SOLID TENSIONERS (never fail)

THIS BAD BOY SHOULD MAKE 300+ HORSE POWER AND TURN 8500 RPM

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Holy Schmoly. That looks the part!

Truly a work of art..I bet the inside looks even better!

I'm interested about the MFI pump..I can see the enrichment mod..neat..what else is done to it?

And, I'm about to set up to machine a batch of heads for twin-plug for me and some buddies..

Not having access to any Factory twin-plug heads to compare, I'm planning to copy the 3.6L heads positioning for the second plug..I have some here to copy..
I'd be truly grateful for any hints please..

Kind regards
David

Very nice looking Henry.
Please say hello to Dean for me too.



Hey! this is my 500th post! woohooo

What flywheel are you using?

Thanks

Eddie

Factory RSR

Beautiful work Henry!!! Dan

Which distributor is that?

-Wayne

Dick Evelrude (sp) sold by Andial mid 80s.

The one with or without advance?

-Wayne

Those units made by Dick have no advance,......:)

(I've used them for 15+ years when he was making them right here in River City)

This distributor has a very nice fully adjustable advance curve. This is the second one I've used (strangely enough both in SS 2.8) and both of them had nice advance curves .
If you say the distributors that Dick builds have no advance curve then someone else built this distributor.
In that case I don't know where they came from.

Dick's units all used a GM HEI trigger and no advance whatsoever. We used them with MSD ignition systems and MSD retard box for starting.

LOL,..I watched him build the majority of them,...:)

Henry,

What's the overall weight of the engine?

shipping weight was 350.
We have no real weight on the engine alone.

Henry,

Sorry if it's a strange question :D but are the exhaust valves sodium-filled like the pre 74 ones?

The core heads used in this project were 930 Turbo. 930 exhaust valves were used in this engine. Turbo exhaust valves are sodium filled.

hallo
Very nice work , i love the old Twin plug Distributors , are they still available in the US ? i havent seen them here for sale for the last 10 - 15 Years .
harald

Thanks Henry,

Would you say a 2.8SS is a better engine than a 2.6SS?

I know my opinion wasn't asked but we aren't shy here right? :D

The strength of the turbo case, coupled with the fact that you have to do less machine work to it (no need to add oil bypass or squirters), plus the additional displacement says a lot. Even if you build a 2.6SS on an early Al case, it won't be as strong as the 2.8 and it needs a LOT more prep. Last, you can build the turbo case all the way to 3.1 liters on a 66mm crank, so you have room to grow if you are truly insane.

Better, maybe. It is a lot more extensible, though.

The true magic of the short stroke 2.8 is the bigger valve heads.
I have tried to make big valve heads out of the 2.7 head but all we could do was 48mm in and 40mm ex.
The 3.0 heads have 49mm in and 41.5mm ex and they have a better valve angle.
The strength of the 3.0 allow case is also a bonus for longevity and it weighs more so that might be a toss up.
92x66 is nice but 95x66 is great. I believe it's the best of all 911 air cooled two valve engines.

Henry, What's the fuel consumption like of that 2.8SS? How many miles to the gallon?

Mileage ?
 

At 8500 this gets fuel yardage not mileage.
Joking aside, this engine like all other MFI engines is very thirsty.
I don't have any real fuel consumption numbers but I would guess 8-12 depending on right foot flexibility.

If you don't have to comply to any displacement regulations has the 2.8SS any performance gains (hp) over a 3.0?
I mean if you just switched the crank 66 -> 70.4.

If your only criteria is horse power, the answer is no. It is reasonable to assume that a larger engine (all other things being equal) will make more horse power.
The benefit of the SS 2.8 over the 3.0 is that the engine will spin at a higher RPM safely.
The rod length to stroke ratio is better.
A relatively low conrod-to-stroke ratio such as the 3.0 produces greater rod angularity with the cylinder’s centerline as the crankshaft turns from top dead center (TDC) to 90 degrees after TDC than that of engines with higher conrod-to-stroke ratios. (Note: conrod-to-stroke ratios in Porsches range from about.1.66:1 [3.3 - 3.8] to 1.97:1. [2.0-2.8 ss] As rod angularity increases, the piston accelerates away from TDC more quickly than in an engine equipped with a longer rod; engine designers refer to this phenomenon as “piston dwell.” Short rods generate abbreviated piston dwell; long rods have prolonged piston dwell. The trick for designers is to match piston dwell with the fuel’s burn speed to produce an acceptable increase in cylinder pressure without introducing detonation (a destructive, power-sapping combustion defect). Many experts believe that the most important benefit associated with long connecting rods is the reduction in piston side thrust, which increases friction and promotes cylinder-sleeve distortion.

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Isn't there also theory regarding ideal bore to stroke ratio? If so, do you know how the 2.8SS measures up?

Henry: conrod-to-stroke ratio, I haven´t heard that before, obvious when you think about it for a while :)

Different question on the same subject: If you have an SC engine and you have a goal of making 250 N/A hp at the wheels.
If you want to do it as reliable and cheep (the wrong word maybe) as possible. How would you go about it?
What displacement (2.8, 3.0, 3.2, 3.4) and induction would best suit the criteria reliable and least expensive?

If I understand Henry right the bore/stroke ratio has little to do with conrod-to-stroke ratio. It´s the legth of the conrod that makes the engine rev better or am I wrong?

In general short sroke / big bore are used for high RPM (big ratio). Long stroke / small bore work well for engine torque at low RPM (small ratio).
3.6 engine have a 1.3 to 1 ratio. Good low end torque.
2.5 engine IMSA race engine 1.36 to 1 well proven hi RPM race engine
2.8 short stroke engine 1.44 to 1 My favorate
2.8 959 Super Car 1.42 to 1 Dream car
3.5 Benetton F1 engine 1.90 to 1( 16000 rpm 95x50)

Remember that there are many factors that effect torque and rpm. This is just a general rule.