1973 911T Engine conversion to 2.8 RSR Engine. Need help.

[porschenut]

Originally Posted by NavySailor47

Well call me crazy, but I have fallen in love with the RSR. It's just so beautiful. I really have nothing better to spend my money on, and what better way then to spend it on something that I have been dreaming of having my whole life.

If it's the looks you're after, go for it! No reason not to. But remember, the RSR engine is not a street engine - it's a race car and it wasn't designed to last very long between rebuilds. It's just not practical for a street-driven car.

I suggest you lighten up your car as much as possible, put some shorter gear sets in the 915, and hot rod the 2.4 engine you have. Or put in a 3.2 instead, with carbs, S cams, JE pistons and headers.

[Dan Morton]

I have a set of 2.8 RSR mahle Pistons in my 2.0 ('68) mag case courtesy of the PO. I just rebuilt the engine and saw that they bored out 2.7 cylinders, machined down the cyl walls plus machining on the case to make them fit. The crank and heads are still original spec to the 2.0 and the cams were re-ground to be more mild vs. aggressive. The engine has a flat torque curve, pulls great and was dyno'd at 170rwhp. This has easily outrun my buddies '89 carrera and leaves my '70 2.2E in the dust

I'm certain you can find a set of 2.8 RSR pistons without breaking the bank. Not sure what other mods you would need to do but buy Bruce Andersons book as recommended by others.

My '68 was converted to an RSR look by the PO. I like the looks of it but if I were to do it myself I would go with an R or ST look.

-Dan

[RWebb]

the mods & cost est.s were itemized above by an expert

it will be very very spendy

another expert said buy a 3.2L motor - also good advice

[chiroracer]

Anyone mention backdating a turbo? El Burro

[NavySailor47]

I am pretty sure that I am going to go with a 3.2 or a 3.0, whichever seems to be a better buy when the time comes for me to buy an engine. I'll probably rebuild it myself.

There is just something about this car. And I don't mean the looks either. There is just a beauty to it. It is truly a work of art. The sounds, the looks, the thrill of driving it. Everything that this car has is what I am looking for in a classic car, and nothing is stopping me from getting it.

[RWebb]

welcome - I see you have now been assimilated into the Borg...

[Lukesportsman]

Going 3.2 gives you more flexibility and the use of EFI. The 3.0 CIS can be dead reliable, but limit you in cams and compression. Neither will sound like MFI or ITB's or sadly even carbs. A 3.2 would be a good starting point in my opinion as its got great heads, EFI, and more cc's. As your build continues a switch to ITB's (Jenveys or TWM) will get you much of the sound/looks back and make it rev opening up cams and exhaust options.

1. Swap and get it running with 3.2
2. Backdate exhaust
3. Change induction and add cams

This will be cheaper and likely faster in street trim to the high strung 2.8 for much less $. IMHO

[NavySailor47]

What type of exhaust would you recommend with the 3.2? How about with the 3.0? Thanks!

[Plavan]

Save that early narrow car and buy this and cut it up... 73 911T with 2.4L/cage RS Clone- race car. $28k

Shameless plug

[Shaun @ Tru6]

I'm going to be a wet blanket here and recommend that you put some money into a 2-day driving school that will make appreciate what your car, and you, can do now. What you will learn over the 2 days will make you a better, faster, slower, more responsible driver. Going fast is rarely about just plugging a bigger motor into your car.

[Plavan]

Originally Posted by Duckworth

I understand what the RSR represents to you... They have a certain charisma all their own. Just raising the possibility of falling out of love with it in favor of something that may return you more enjoyment in the long run.

Navysailor, just shootin' the bull a bit with you. Consider - hoards of 911 enthusiasts are swayed by the flared fenders of an RSR - myself being no exception. Many times I woke up in in bed saying, "I GOT to have an RSR..."




..It took me a good while to evolve out of that mindset. But then I started noticing on Pelican - some of the outstanding early cars like this one :





It has some of the 'feel' of an RSR - without all the sheetmetal work required.


Best wishes to you sir !


____________

Right when I was considering making it a 911ST you have to post that with my favorite picture of my car....shame on you

[YTNUKLR]

I have built one, and am currently finishing another, 2.8 "Short Stroke" RSR engine with NOS High-butterflies, NOS RSR 2.8 Space cam in the MFI pump, RSR new billet camshafts, RSR forged steel rocker arms and lash caps, special machine work, original Marelli distributor, German twill fiberglass, stainless steel headers, all the cosmetic "fixins". Both of these "RSR Spec" 2.8 MFI engines are based on a 1976 3.0 930 Turbo case (aluminum block, "911SC" head stud spacing, 95mm cylinders, big valves, etc...very much like 3.0/3.2) using a 2.0L/2.2L crankshaft to bring the stroke down to 2807cc, exactly 1 cc less than the original (2808cc 92x70.4 bore/stroke).

Absolutely, bar none, the sexiest thing a vintage Porsche guy could like. The only thing sexier, perhaps, is dropping a 956 2.8L Crankshaft and GT3 Titanium connecting rods into a brand-new 2010 GT3 motor (I envision that it becomes a 3.5L super-short-stroke, ~9500rpm storm in a teacup).

What Dave says is completely spot-on. These are $50-55k motors. There is still more optimization you could do. The clients' goals were a complete original look, spellbinding performance, 8500 rpm redline, and I've imposed a goal of 110hp/L (what the original RSR did--I think we'll "break on through" that).

If you have the money, you've thought about it for a long time, have everything else taken care of, and know in your heart of hearts it is something you cannot be without, there are others in that position who have taken the leap. BUT, if that is not the case, freshen up a Euro 3.2, put in a Steve Wong chip, headers, a pair of supercup 993 cams and a lightweight clutch, and spend the balance on trackdays and having a good time.


my 2 cents.

[Will post dyno sheets as soon as I get this done.]

[TR]

Originally Posted by NavySailor47

I really have nothing better to spend my money on, and what better way then to spend it on something that I have been dreaming of having my whole life.

House , Wife, Kids, land rates, electricity, water, gas, phone bills---Not necessarily in that order---------------Porsche.

Good luck with the RSR

Terry

[NavySailor47]

Originally Posted by Terrance Raath

House , Wife, Kids, land rates, electricity, water, gas, phone bills---Not necessarily in that order---------------Porsche.

Good luck with the RSR

Terry

Military = Free House, No land Rates, Free Electricity, Free Water, Gas is Cheap, No phone bills. And not to mention; I'm not married, nor do I have kids.

You'd be surprised of how well our military takes care of us. I know a Chief Petty Officer who owns four completely restored vintage mustangs, and a Brand new Shelby Mustang. We work for it. And when we're done working, it's great to have things like that to play with. But my Porsche is much more than a toy to me.

Thanks for wishing me good luck.

[NavySailor47]

I never stated that I wanted to go faster, but okay. I do plan on going to a driving school the next time I am authorized leave. I do know how to drive pretty well, if I may say so. I'm not the best, and I do have a lot to learn, but I certainly know how to appreciate an automobile. I know when to push it, and when to take things slow. Thanks for the advice.

Originally Posted by Shaun 84 Targa

I'm going to be a wet blanket here and recommend that you put some money into a 2-day driving school that will make appreciate what your car, and you, can do now. What you will learn over the 2 days will make you a better, faster, slower, more responsible driver. Going fast is rarely about just plugging a bigger motor into your car.

[NavySailor47]

I'm definitely going with the Euro 3.2 or the 3.0 SC. To spend $50,000 on an engine alone, is illogical. Sure, I have the time and money to build and RSR replica, but I don't have the money to just be rebuilding a engine like that, (from the information that I have been receiving). Thanks for the advice. Keep it coming. I am wanting to learn everything that I can before I start this project.

Originally Posted by YTNUKLR

I have built one, and am currently finishing another, 2.8 "Short Stroke" RSR engine with NOS High-butterflies, NOS RSR 2.8 Space cam in the MFI pump, RSR new billet camshafts, RSR forged steel rocker arms and lash caps, special machine work, original Marelli distributor, German twill fiberglass, stainless steel headers, all the cosmetic "fixins". Both of these "RSR Spec" 2.8 MFI engines are based on a 1976 3.0 930 Turbo case (aluminum block, "911SC" head stud spacing, 95mm cylinders, big valves, etc...very much like 3.0/3.2) using a 2.0L/2.2L crankshaft to bring the stroke down to 2807cc, exactly 1 cc less than the original (2808cc 92x70.4 bore/stroke).

Absolutely, bar none, the sexiest thing a vintage Porsche guy could like. The only thing sexier, perhaps, is dropping a 956 2.8L Crankshaft and GT3 Titanium connecting rods into a brand-new 2010 GT3 motor (I envision that it becomes a 3.5L super-short-stroke, ~9500rpm storm in a teacup).

What Dave says is completely spot-on. These are $50-55k motors. There is still more optimization you could do. The clients' goals were a complete original look, spellbinding performance, 8500 rpm redline, and I've imposed a goal of 110hp/L (what the original RSR did--I think we'll "break on through" that).

If you have the money, you've thought about it for a long time, have everything else taken care of, and know in your heart of hearts it is something you cannot be without, there are others in that position who have taken the leap. BUT, if that is not the case, freshen up a Euro 3.2, put in a Steve Wong chip, headers, a pair of supercup 993 cams and a lightweight clutch, and spend the balance on trackdays and having a good time.


my 2 cents.

[Will post dyno sheets as soon as I get this done.]

[Hebrewhomeboy]

Originally Posted by YTNUKLR

I have built one, and am currently finishing another, 2.8 "Short Stroke" RSR engine with NOS High-butterflies, NOS RSR 2.8 Space cam in the MFI pump, RSR new billet camshafts, RSR forged steel rocker arms and lash caps, special machine work, original Marelli distributor, German twill fiberglass, stainless steel headers, all the cosmetic "fixins". Both of these "RSR Spec" 2.8 MFI engines are based on a 1976 3.0 930 Turbo case (aluminum block, "911SC" head stud spacing, 95mm cylinders, big valves, etc...very much like 3.0/3.2) using a 2.0L/2.2L crankshaft to bring the stroke down to 2807cc, exactly 1 cc less than the original (2808cc 92x70.4 bore/stroke).

Is it possible to put a 2.0/2.2 crank in an SC 3.0 engine? And by possible of course I mean will it fit without tons of modification? Seems like if it will fit, you could put the smaller crank in an SC motor, install some bigger cams and webers/JE pistons/SSIs and a good exhaust and have a really fun motor that would be budget friendly. Well, budget friendly from a Porsche perspective.

[YTNUKLR]

hebrewhomeboy-

No, it's not possible with an SC engine block. The 1975-1977 Carrera 3.0 and 930 Turbo (3.0) engines used the aluminum block and 911SC head stud spacing, however, they used a 6-bolt 2.7L crankshaft originally, which has the same stroke as the 3.0 crankshaft. When Porsche made the 911SC engine, they changed the crank to a 9-bolt updated unit, and made corresponding changes to the case. Since the 2.0/2.2L 66mm Short stroke crankshaft from the early engines is a 6-bolt only, it will not work in anything later than a '77 C3.0/930 case or 2.7 case.

There is however, a very rare 956 2.8L crankshaft that Porsche made, that has a 66mm stroke, fits inside all dry-sump engine cases from 1978-2010, and has 911SC rod journals.

[GaryR]

Originally Posted by NavySailor47

I never stated that I wanted to go faster, but okay. I do plan on going to a driving school the next time I am authorized leave. I do know how to drive pretty well, if I may say so. I'm not the best, and I do have a lot to learn, but I certainly know how to appreciate an automobile. I know when to push it, and when to take things slow. Thanks for the advice.

Your first PCA Driver's Education day will quickly show you how little you know about driving a Porsche well, trust me.

[boba]

Originally Posted by YTNUKLR

hebrewhomeboy-

No, it's not possible with an SC engine block. The 1975-1977 Carrera 3.0 and 930 Turbo (3.0) engines used the aluminum block and 911SC head stud spacing, however, they used a 6-bolt 2.7L crankshaft originally, which has the same stroke as the 3.0 crankshaft. When Porsche made the 911SC engine, they changed the crank to a 9-bolt updated unit, and made corresponding changes to the case. Since the 2.0/2.2L 66mm Short stroke crankshaft from the early engines is a 6-bolt only, it will not work in anything later than a '77 C3.0/930 case or 2.7 case.

There is however, a very rare 956 2.8L crankshaft that Porsche made, that has a 66mm stroke, fits inside all dry-sump engine cases from 1978-2010, and has 911SC rod journals.

Scott, I think Henry at Supertech had some cranks made which can be used in the 3.0 SC case that had 66mm stroke. He may still have some.

BTW I agree the 2.8ss is a sweet one.