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Gezzer

3.2 Short stroke targa !

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Hi there, thought i'd introduce myself. My name is Steve and hopefully this will be my successful 3.2SS thread!

I recently purchased this 79/80 SC Targa from a friend after a drunken night. I had no intension on having the car having already owned a 964 years earlier, but one thing lead to another and i now have my very own money pit!!

Its not in too bad shape, laid up for five years with the front end dismantled its been hurredly reassembled and moved to my garage.

I,ve decided agains advise to just "sling it back together and use it" and go for the full rebuild.  Good thing too, engine and box removed with no bother but whilst stripping i've discovered  four dead mice and nest that filled the complete area under the shroud!! 

Also discovered 3 broken head bolts already and i haven't checked underneath yet.

Now i have to get organised!

i have most tools but i'm on the hunt for an engine stand adapter, P201. I've seen this one on eBay for £70 which seems extremely reasonable! Does anyone have any experience?

https://www.ebay.co.uk/itm/Porsche-911-912-914-356-Air-cooled-4-Arm-Engine-Motor-Stand-Yoke/263497673381?hash=item3d59af6aa5:g:vRUAAOxy--NRtOJq

Otherwise i suppose ill have to order on from the states.

Well the plan is to build a 3.2 SS motor whilst maintaining the CIS and to rebuild the gearbox at the same time. Hopefully all in my own garage! It's good to start with good intensions. Afterwards the car will be off to the bodyshop for paint and Southbound will be doing the interior.

I'm looking forward to this and hoping to get lots of good advise on the forum.

Cheers

Steve

 

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54 minutes ago, Gezzer said:

I recently purchased this 79/80 SC Targa from a friend after a drunken night. 

Best introduction ever :ani_clapping:

Good luck with the build- are there any local trimmers to you? Southbound are good but expensive...

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3 minutes ago, Dr Rock said:

Best introduction ever :ani_clapping:

Good luck with the build- are there any local trimmers to you? Southbound are good but expensive...

Well said that man, hiccup!

We do love a restoration story, so fingers crossed and good luck with the rebuild.

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I have one of those engine yokes.

It didn’t fit properly as supplied, so rather than use a stack of nuts to space the engine away from the yoke, I simply used a grinder to relieve where it was fouling (around the oil cooler area).

Engine has been sitting happily on it since I stated my ‘79 Targa resto.

Peter

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That’s the way to start a story lol. Good luck. Looking forward to following your project. 🍻 🍷 🚙 

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ditch the cis

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1 hour ago, axel said:

ditch the cis

Yeah, not 100% convinced yet.

I've been reading Phil's thread using Triumph ITB's and Megasquirt, looks interesting. Not going to carb's thats for sure, i just can't be bothered!

 

Thanks for the replies, going to get the engine stand yoke ordered and get the engine stripped down for inspection.

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cis blows arrrr5e, only thing its good for is fuel economy. response like a truck, not what u want in a sportscar.

go EFI on a budget, megasquirt and some throttles sounds like just the ticket!

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Hi there,

Well after a long hiatus i managed to get stuck into the engine last weekend.

Apart from the five broken head-studs , four dead mice and very large stash of acorns in the exhaust its not in too bad condition!!

Manifolds are junk , as is a lot of the hardware.

Next step after cleaning is to send away the large objects for machining!!

Can somebody out there recommend a machine shop for the crank and cases? I'm based in France but shipping is not a problem. Anywhere UK/EU is fine. I want to have it cleaned, measured, polished and bored if necessary.

 

My latest plan ( a rational economic plan ) will be to save the cylinders ( as they look good )  and fit high compression pistons and rings, twinspark the heads and go down the EFI triumph ITB / megasquirt route. Has anybody got much experience on this they could share?

 

Cheers 

Steve

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Cylinders can be rebored and re-plated..... Cheaper than new if they are out of spec.

 

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latest prices from EBS in the states....

Anyone have any old 3.2 barrels for sale?

 

Hello Steve, 

 
For a 3.0 liter based engine, our "off the shelf" pistons are available at 9.5, 10.5 or 11.5:1 compression.  9.5:1 work well with premium pump gas where 10.5:1 and up will require race fuel and/or twin plug ignition.  Piston sets start at $1050 with pins, clips and rings and come with coated skirts and under crown milling to reduce weight.
 
Cylinder reconditioning at 95mm is $1050/set.  To bore and plate 95mm 3.2 Carrera cylinders to 98mm is $1100/set.
 
Let me know if you have any other questions or concerns!
 
Thank you,
Don Weaver-EBS Co.
don@ebsracing.com

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10.5:1 won’t require twin spark in Europe. I wouldn’t go twin plug: load of hassle IMHO. :twocents:

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iirc. 3.2 and 3.0 use different wristpins, so you’ll need new rods if you use 3.2 barrels

so I think you need 3.0/95mm barrels and bore them out to 98mm to give you a 3.2ss

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3 hours ago, SP72 said:

iirc. 3.2 and 3.0 use different wristpins, so you’ll need new rods if you use 3.2 barrels

so I think you need 3.0/95mm barrels and bore them out to 98mm to give you a 3.2ss

Is that right?

I understood taking the 3.0 barrels to 98mm was not practical to machine due to the sealing ring issues and using 3.2 barrels at 98mm with JE pistons could be fitted directly to 3.0 conrods reusing the 3.0 heads...

Anyone have experience here?

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Both 3.0 and 3.2 p and c are 95mm.  If you bore 3.0 to 98mm, you get 3.2, and a 3.2 becomes a 3.4;  the 3.2 has a longer stroke hence the larger cc

3.0 use 22mm wrist pins, 3.2 use 23mm wrist pins - which means different rods. Unsure if there is a way around using different rods, through different bushes.

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31 minutes ago, SP72 said:

Both 3.0 and 3.2 p and c are 95mm.  If you bore 3.0 to 98mm, you get 3.2, and a 3.2 becomes a 3.4;  the 3.2 has a longer stroke hence the larger cc

3.0 use 22mm wrist pins, 3.2 use 23mm wrist pins - which means different rods. Unsure if there is a way around using different rods, through different bushes.

Thanks for your comments, i agree with all of that, but JE make a 98mm piston for the 3.0 with the 22mm gudgeon and the correct deck height, which, combined with a rebored (98mm) and replated 3.2 barrel should give you a tidy 3.2ss  with no head sealing issues no?

Anyway I'm wondering if the capacity increase is really worth the hassle, just hone, replate and fit 10.5:1 pistons with some nice cams.....

4 hours ago, Dr Rock said:

10.5:1 won’t require twin spark in Europe. I wouldn’t go twin plug: load of hassle IMHO. :twocents:

I'm thinking that this is probably the way to go !!

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I see what you’re saying - I didn’t think of it that way. I haven’t heard of head sealing issues before.

250bhp and 230 torque is normal I believe with a 3.2ss - if you’re in there, I would

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One thing to think about is what heads you have. The 78 and 79 SC used the same head as the 3L Carrera (39mm intake, 35mm exhaust) but the 80-83 SC had smaller intake ports (34mm) to improve mid-range pick-up. This might limit your ability to get the breathing right with a larger capacity engine and higher compression. The 3.2 Carrera has significantly bigger ports - 40mm intake and 38mm exhaust. You can tell from the engine type number <=930/06 is large port, >= 930/07 is small port (excluding the special 930/18 of the SC RS). 930/20 onwards is the 3.2 Carrera. (I've ignored the

Also, and I'm sure someone will correct me if I'm wrong, apart from the top mating surface that doesn't have a groove for a CE ring, I'm not sure there is any difference between and 3L SC and a 3.2L Carrera cylinders. I think the extra stroke of the 3.2 is achieved purely with changes to the crank, conrod and piston. In other words, you may well be able to re-use your existing cylnders.

Finally, as I'm sure you know, you will have to change the induction if you go for anything more than a 964 cam. The CIS can't cope with the induction pulses of anything hotter, so ITBs or carbs are a must, as are headers (no heat) or SSIs (with heat). The stock exhaust is to restrictive.

The Bruce Anderson porsche 911 Performance Handbook (worth getting) has an example build of an SC with 98mm pistons (comp not specified but probably 9.8:1) for a 3.2L ss, 40mm carbs, SSis and a higher performance cam (not specified but probably a mod-S profile) for 275 bhp and 250 lb/ft of torque.  He reckons a simple change to 98mm at 9.8:1 with max moritz CIS compatible pistons plus retaining the standard CIS, camshafts on its own is good for 220bhp from the 3L SC. However, I'm not sure you can still get these larger CIS compatible pistons. Add SSIs and that is probably around 230 bhp.

Anyway, hope some of this ramble helps ...

Good luck with the build, John

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4 hours ago, Gezzer said:

Anyway I'm wondering if the capacity increase is really worth the hassle, just hone, replate and fit 10.5:1 pistons with some nice cams.....

I'm thinking that this is probably the way to go !!

I'm in the same spot as you. Going from 3.0 to 3.2 represents a capacity increase of 6.7%. If this was translated directly into power it would represent around 12-15 hp. Not massive but extracting performance from those engines is not cheap! I'm not quite sure which way to go myself...

 

2 hours ago, jehatwhitland said:

One thing to think about is what heads you have. The 78 and 79 SC used the same head as the 3L Carrera (39mm intake, 35mm exhaust) but the 80-83 SC had smaller intake ports (34mm) to improve mid-range pick-up. This might limit your ability to get the breathing right with a larger capacity engine and higher compression. The 3.2 Carrera has significantly bigger ports - 40mm intake and 38mm exhaust. You can tell from the engine type number <=930/06 is large port, >= 930/07 is small port (excluding the special 930/18 of the SC RS). 930/20 onwards is the 3.2 Carrera.

This is very interesting. How hard would it be to enlarge the ports of a 80-83 SC? Is it worth it?

 

2 hours ago, jehatwhitland said:

I think the extra stroke of the 3.2 is achieved purely with changes to the crank, conrod and piston.

Stroke only depends on the crankshaft (2 times the crank throw is equal to the stroke.)

 

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On 12/3/2018 at 4:07 PM, Gezzer said:

EFI triumph ITB / megasquirt route. Has anybody got much experience on this they could share?

I know you are aware of my threads. Any other help I might be just ask.

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8 hours ago, jehatwhitland said:

One thing to think about is what heads you have. The 78 and 79 SC used the same head as the 3L Carrera (39mm intake, 35mm exhaust) but the 80-83 SC had smaller intake ports (34mm) to improve mid-range pick-up. This might limit your ability to get the breathing right with a larger capacity engine and higher compression. The 3.2 Carrera has significantly bigger ports - 40mm intake and 38mm exhaust. You can tell from the engine type number <=930/06 is large port, >= 930/07 is small port (excluding the special 930/18 of the SC RS). 930/20 onwards is the 3.2 Carrera. (I've ignored the

Also, and I'm sure someone will correct me if I'm wrong, apart from the top mating surface that doesn't have a groove for a CE ring, I'm not sure there is any difference between and 3L SC and a 3.2L Carrera cylinders. I think the extra stroke of the 3.2 is achieved purely with changes to the crank, conrod and piston. In other words, you may well be able to re-use your existing cylnders.

Finally, as I'm sure you know, you will have to change the induction if you go for anything more than a 964 cam. The CIS can't cope with the induction pulses of anything hotter, so ITBs or carbs are a must, as are headers (no heat) or SSIs (with heat). The stock exhaust is to restrictive.

The Bruce Anderson porsche 911 Performance Handbook (worth getting) has an example build of an SC with 98mm pistons (comp not specified but probably 9.8:1) for a 3.2L ss, 40mm carbs, SSis and a higher performance cam (not specified but probably a mod-S profile) for 275 bhp and 250 lb/ft of torque.  He reckons a simple change to 98mm at 9.8:1 with max moritz CIS compatible pistons plus retaining the standard CIS, camshafts on its own is good for 220bhp from the 3L SC. However, I'm not sure you can still get these larger CIS compatible pistons. Add SSIs and that is probably around 230 bhp.

Anyway, hope some of this ramble helps ...

Good luck with the build, John

Most euro spec SC’s have 39mm ports on both sides.

Edited by Leicestershire

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Thanks for the correction. I'd assumed that, as Porsche had started out with the intent of making the SC a world car, that the higher compression (plus matching timing and CIS set up) of the later Euro cars was sufficient for the power difference. Presumably the part numbers are different to reflect?

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