2.8SS limited to 7500 ¿Is it a nice configuration?

[Sixforfun]

Hi all
After reading a lot of threads in this interesting forum I would like your opinion on configurations for 2 engines to built with my available parts.

Both engines will be used on street 914s.
For me the sound of the intake is what gives me most of the sensation,
I like high revs and curvy roads.
Gearboxes are 901 from 914 and 914-6, planned to be reinforced by adding the aluminum intermediate plate.
I want to reduce new expenses at the strict minimum but open to built 1 engine now and let some years to built the second, allowing more budget on 2nd engine.
I am my own mechanic and doing it for my hobby.


Available main parts:
69’ 2.0E long block (1R/2R case)
Carrera 3.0 930/02 long block
DC40 cams on small journals
10:1 2.4 pistons on iron barels
10:1 3.0 mahle pistons on mahle aluminium barrels
Set of 2.2S twin plug heads
3.6 twin plug distributor
911E distributor (same curve as S)
Carrera 3.0 distributor
40IDS carbs
40IDTP13C carbs
Carrillo rods for 70,4 crank
“S” rods for 66 cranks
1.5/8 SS headers


Possible Configurations:

Combo A could be:
Engine 1: 84x66, E or DC40 cams, 9,5:1, S heads, E dizzy, 40IDS carbs
Engine 2: 95x70.4, DC60 or RSR cams, 10:1, twin plugged, 42 or 46 EFI

Combo B could be:
Engine 1: 84x70,4, DC40 cams, 10:1, S heads, E dizzy, 40IDS carbs
Engine 2: 95x66, cams to determine, 9,5:1, re-curved 3.0 dizzy or twin plug, 42 or 46 EFI


Finally:

As you see most of the choice is on the crank size,
I really prefer the combo B for the 2,4l on DC40 cams and 2,8SS
But, i think it requires much more money to built a good, high rev, 2.8ss thinking to prep the crank, change oil pump and dont have forged rockers or rods to pass 7500rev per min.
I do not really care on the reliability of the 1R/2R case. When it break, it ends. But yes would like reliability on the 930/02 based engine.


So, what’s your throughs on those configurations?
And my main question is:
¿Is it a nice combo 2.8SS limited to 7500, and witch cams to use?


Thanks!

[targa72e]

I like your option B engines. Below are examples of two engines I put together in the last couple years that might help you decide. The dyno results are the same car with same headers and exhaust.

Blue line is 2.7 is a RS+ spec engine. The engine had RS pistons and cylinders with MOD S cams and 40MM weber carbs. head ports were stock late 2.7 36mm intake 35mm exhaust.
Red line is 2.4 engine. It has JE pistons 9.5 to 1 with E cams and Zenith 40MM carbs. Heads were bored out to 36mm intake 35mm exhaust with some blending and porting.



If you look at the peak power RPMs you should be fine with a 7500RPM limit on the 2.4.
I have a new engine in this car now that I will be dynoing soon that you might be interested in. It is a 2.5 long stroke.
86mm bore with 70.4 stroke. JE pistons 9.5 to 1, MOD S cams and heads bored and ported similar to the 2.4 engine above. It is also running 40mm Zenith carbs. I will post results once I dyno the car.

john

[Sixforfun]

Hi Targa72e, thank you to take time to show me those combos.
Yes it help me confirming I have to keep MosS cams and webers 40 on the small displacement engines.
In the 2.7 you share, it seems it is limited at 6k by ether too small venturis or cam too milds.


I will probably go to the following route: 2.2l / modS / weber with 32 vent and 3.0l / DC60 route.
Seems more logical in regards on the limit of my budget.
Major investment will be limited on bigger admission for the 3.0l


In case i choose the 2.4 and high rev 2.8 combo, necessary investment would be:
- big oil pump
- cross drill 2.0 crank
- bigger vents for the webers on the 2.4
- big admission for the 3.0
- rods for the 2.8ss
- forged rockers
… at least



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[Wrighteous]

User littleoldman has the nastiest 2.8SS that may interest you. It was built by faapgar, who unfortunately passed away. I think his son is continuing the business though. He has special pistons and some sweet tech! Could be a useful resource.