3.0SC 1980 Engine build
 

Hi guys, I´m about to rebuild my 1980 SC engine.
I´ve dissembled it all, so time to start cleaning and inspecting all the components.

So after cleaning the aluminum cases :) : http://forums.pelicanparts.com/uploa...1589915698.JPG

http://forums.pelicanparts.com/uploa...1589915698.JPG

http://forums.pelicanparts.com/uploa...1589915698.jpg

http://forums.pelicanparts.com/uploa...1589915698.jpg

http://forums.pelicanparts.com/uploa...1589915698.JPG

This is an US version 3.0sc which means is a small port engine, so I was wondering if replacing the heads with 3.2 heads would be a good idea. Nothing wrong with my heads but :confused:

This build is going to be for a mostly street driving car maybe an ocasional track day.

I´ll be installing SSI for sure, maybe cams and I don´t know what to do with the CIS.

If anybody can help me here?
Thank you in advance!

I´ll keep you updated.

Something i would consider doing when my time comes.

https://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/1030224-remanufactured-911sc-3-1l-pistons-cylinders.html

Hi Pete, thank you for your answer!
Being my car a 930/07 it is allready 9.3 CR so is it worthy to spend over 3000$ just for 0.2CR increase and 100cc?

If I´m going to increase maybe I can go even higher, I live in Europe and here I can buy 98 Octane unloaded fuel with no problem.

I´m also somehow intriged about how the Row 3.0sc was able to get 200hp with almost the same engine I´ve got. The main difference I think should be intake ports, that´s why I was thinking to swap my head with the 3.2 ones.

The 3.2 heads are a different height on the intake as the 3.2 used a spacer between the head and manifold. Early big port SC heads might fit better depending on what you use for intake. You could port your existing heads as well. You really need to think thru the whole engine and match. Matching the cams, compression, intake and exhaust as a system will get you the best results.

john

It is not a huge undertaking to enlarge your ports. The valve size is the same as with the large port heads. The difference is, the smaller ports decrease in size towards the intake manifold. You would only need to enlarge the port to match what ever new intake system you are planning on running.

So basically, what new intake system are you planning to run?

If you don't feel confident using a die grinder, or similar tool, there are a number of outfits that specialize in porting heads.

The basic question, is why do you think you need to do this?

I would like to get the same hp and torque of the Row 3.0 motors.
I don´t have to pass any emission test so I would like to by pass all the compromise decissions porsche made to get throw emisions on the US small port Sc´s.
Early big port heads are not easy to find anymore.

From what I know so far intake ports, CIS and distributor curve were the main differences. My car is 930/07 code so 9.3CR so I´m not so far from 9.5.

I can port my heads but apparently Carrera 3.2 heads combustion chamber dessign is better and both port are already enlarged.

I do have to keep CIS (classic car restriction here) but i can try to find a Row fuel distributor and spark distributor, my car was already upgraded to MSD when i bought it.

Exhaust I can go to early type or SSI

My car is a 1975 911s, I´ve found a magnesium case 2,7 i can exchange for my 3.0
I´m not millionaire so budget is also something to do not completely forget...

What would you do guys?

This is my first 911 so I´m all ears.

Keep in mind that the large port 3,0s had larger runners in their CIS. Unless you do something to enhance your intake, porting alone will not make a noticeable difference. If you search there are some comparisons of large port and small port motors HP numbers.

Back dating your exhaust and retuning your CIS, plus tweaking your cam timing and ignition will give you some good gains.

BTW, I have a large port CIS gathering dust. Make me an offer if you want to go that route.

Trackrash sure I will contact you!

2.7 VS 3.0 is an old topic but difficult to extract conclusions as everybody keeps defending what they have. If I understand well 2.7 is more revi and more expensive to upgrade vs 3.0 has more torque, stronger aluminum case and higher initial hp.

What I want is a fun car to drive, reliable, it has to be CIS and not too expensive to build.

What would you do?

I have a ‘76 with a relatively healthy 2.7 with CIS. I have purchased a 3 litre for long term reliability as I really don’t want the hassle of rebuilding a mag case engine down the track. If I were you I would keep the 3 litre and port the heads to suit the large runner CIS.

And how can you be sure you port all the heads the same amount? Of course you can port them using a 5axis CNC machine...

This is why I liked the idea of swapping them with the 3.2 heads. Valve size are the same so only difference are the ports. I don’t think the manifold spacers would be a big issue.

I would like to use 964 cams as well.

Max Moritz
 

I have been collecting parts for my pending 3.0 (‘82) build for several years. After I read through countless threads on 3.0 performance, I ended up going the old school route with a combination of engine and transmission enhancements.

My plan is a classic short stroke with MM P&C’s, early 3.0 large port heads & CIS, 964 cams, turbo oil pump, and SSI’s with an M&K exhaust (I have all of these parts).

I also have a short geared (2nd thrust 5th) 915 built with a Wavetrac, Wevo gateshift, one piece bearing retainer, reinforced side cover with 930 bearing and a lightweight flywheel & aluminum PP sitting in my garage.

I spread out the costs over many years to limit the budget shock (the $10k+ gearbox was a big enough shock). I am still saving up for my engine build, but at least I already have most of the the big & hard to find items. I am really tired of my stock SC falling off cam at little more than 5,000 rpms. I hope to raise my redline by at least 1500 rpms with decent low end torque (assisted by my lower geared 915).

Good Luck, parts and labor are very expensive these days - I’ve got more “invested” in my 915 than I paid for my good running and driving SC a few years ago...

If you haven’t stumbled on it yet, this is worth a read to double check components of 1980-1983 RoW v US Spec.

http://forums.pelicanparts.com/porsche-911-technical-forum/85905-difference-3-0-vs-3-0-euro.html

And I’d say this is worth a read for a simplified blueprint: https://www.pelicanparts.com/techarticles/911_engine_rebuild/911_engine_rebuild2.htm

While I’m at it: http://forums.pelicanparts.com/porsche-911-technical-forum/701117-9-8-1-c-r-pistons-late-cis-2.html

How do I have all these at my fingertips? My 1980sc engine just told a mechanic to tell me it needs a rebuild also.

Good luck with your project.

OP has more ambitious power gains but perhaps this is a somewhat related.

Has anyone got a sense for power gains from 9.8:1 compression in an otherwise stock US 930/07 911sc (9.3:1 compression)? Ie, no commensurate changes to porting, intake runners, distributor curve etc.

Presume breathing/fuel supply too anemic but curious whether this is overcome by higher pressures from smaller port (with some tuning to US distributor)? My understanding is bigger runners would only deliver power at higher RPMs.

Is consensus still that this is too much static compression for these engines?

Roughly, 1 point of CR will provide about 4% power.
So, 9.8 from 9.3 will provide about 2% power gain. Also, you have pump gas considerations.

Also, OP, what size heads do you have,,,early or late SC? Porting is not as easily done as it is made out to sound.

That is my concern, taking a dremmel and opening is not difficult but having all of them equally made sounds like mission impossible to me.

This is why I really like the idea of using the head of the 3.2. Valve size remains the same and it´s just port size that is bigger. The only thing that stops me from doing it is the cc of the 3.2.
Is it the same as the 3.0?
Are my 1980 9.3cr pistons ok for the 3.2 head? Am I going to still have 9.3 cr?

A lot of questions that blocks me right now...

I can´t believe nobody has tried to swap the 3.2 heads?

It looks like a great idea in my head..

Check the link in my sig below.
Squeeze it through an online transator and you'll understand the curves/diagrams further below in that workshop.

A friend of mine who bought a cpu controlled ECU for his 930/07 engine from me, used new P&C with 9.8:1 from te 930/10, SSIs when doing the rebuild and uses an initial ignition timing of 10-12 BTDC at 900 rpm and the engine ... also pulls really strong. In my case I have the same setup with SSIs and same timing, same small ports but still the 9.3:1 CR and I fell "almost" no difference, well, not that significant as someone would expect.

PM william knight, he'll tell you if bigger ports will make a difference for the other mods you're proposing.

Sent from my Nokia 7.1 using Tapatalk

Thank you Pelicans!!

AndrewCologne kein problem, ich verstehe ein bisschen ;)

Good morning Pelicans,

A little question here, are the following ones ok for a 1980 3.0Sc?

GLYCO - H949/7 STD (main bearings)
GLYCO - 71-3426/6 STD (rod bearings)

I would be checking clearances with plastigage green.

A lots been said about quality control issues at Glyco coming out of a handful of factories. I went with clevite rod bearings and dealer main bearings. Some poor fella in UKs crank took the gas after 600 miles!

964 101 901 00 - main
930 103 148 82CCL - rod

** Edit: main is the OEM part not Glyco. Costs an arm and a leg and more than a few people use GT3 bearings instead.

Out of interest, what did you decide to do with your build? Back date to 930/07 or stick with the 930/10 and optimize from there? What about cam choice?

Check out this discussion on a good dyno comparison of a pre-80 big port v small-port 83 with 20/21: http://forums.pelicanparts.com/porsche-911-technical-forum/163860-best-cam-profile-stock-sc-2.html

Not sure if the below will post but this is the chart in question. Believe in the chart, Dane had the pre-80 big port and Jim had the small port heads (both 20/21 and back dated exhaust or SSI):

http://forums.pelicanparts.com/uploads3/chart31085158938.gif

Close to 900€ for the main bearing set? that is a total abuse..
Is it GT3 bearings any cheaper?

Thanks Glenfield! I haven't read that post, very interesting.
Stock 930/07 is not an option, one piston has to be replaced my mistake...don´t ultrasonic clean them..

I´m between three options:
-Option1: 9.5CR 95mm CP pistons and William Knight custom cams, ssi exhaust, maybe 123 distributor and try to find early type fuel distributor, small port head?

-Option2: Henry Schmidt Porsche 911SC-Leistungsgesteigert (97mm pistons and enlarged cylinders with 964 cams), small ports head?

-Option3: 3.2 heads with maybe 3.2 crank and, CP 9.5 pistons.

I would like to have a big amount of low end torque and 200hp at 6K. And not

As I understand it, you’re going to be out of breath (or running out of puff) at 6000RPM with small port SC heads. Cam and exhaust get you a little closer, but don’t overcome the reality which is just not enough air/fuel. Then I think you need displacement for the HP you want.

If you’re changing P/Cs, Option 2 may help you represent your car as “quasi-stock” since it was a Porsche option, but don’t think it gets you heaps more performance does it? And you still have the breathing issue of the small port. May as well go the whole nine yards and do a 3.2 or 3.4?

#1 would be a good way to leverage what you have ... Is only one data point, but there does seem to be a great dynamic at play with the combination of small port / 9.3:1 compression / 20/21 cam. The compression meets higher fuel velocity of smaller port meets short duration / highish lift of Web 20/21 for great torque down low. Opening up ports with your compression would give you more top end but don’t think it would give you the HP you’re after. With your gas in Euro, could probably go to 9.8:1 if you do have to or want to change your pistons.

Just my thoughts based on research alone. Those with practical experience will shoot me down but I wouldn’t take their silence as agreement / acquiescence. At the very least, you’ve got another data point to bounce off people.

So you think opening the ports/ using big ports early heads is a must to achive my goals?

I‘m open to go any way...I don‘t like high redline configurations, hi horse power at the expense of low end torque.

Any opinion is highly appreciated here!

Hoping one of the builders weighs in for you on the porting and more involved options. Also on realistic performance outcomes. I know it’s about balance once you start more major surgery.

My 0.02 kroners is 20/21, high compression (9.3 - 9.8:1 for single plug) and small ports looks to be a good combo for street revs at decent bang for buck. But it is more of a “stock plus” option for the 930/07 motor. My guess is you can have a lot more fun with it if you’ve allocated the budget.

Good luck. I’ll be watching. Will share result of my 930/07 with web cam 20/21 once it’s broken in.

Hi Glenfield,
I'm redoing a 911 81sc. Bought S.Africa rod bearings. The bearings would position themselves diagonally in the rod, Even After shaving down both sides of the locating tabs significantly. On the positive side the thicknesses were checked in multiple positions across the bearings, they were tight and almost dead on the original ones removed, so not an issue. The widths were good too. I think the shell is twisted a little and when you seat them in the rods before tightening, they are already off, again, no amount of tab shaving would resolve this. I have included some pictures, I'll also add this to an existing post about rod bearing alignment when I have time, just to document. These are 2018 parts, 71-3426 std stamped on it.

http://forums.pelicanparts.com/uploa...1593034272.jpg
http://forums.pelicanparts.com/uploa...1593034272.jpg
http://forums.pelicanparts.com/uploa...1593034272.jpg
http://forums.pelicanparts.com/uploa...1593034272.jpg
http://forums.pelicanparts.com/uploa...1593034272.jpg
http://forums.pelicanparts.com/uploa...1593034272.jpg
http://forums.pelicanparts.com/uploa...1593034272.JPG
http://forums.pelicanparts.com/uploa...1593034272.JPG
http://forums.pelicanparts.com/uploa...1593034272.JPG

@ahh911 that's pretty unacceptable isn´t it? Are all the new Glyco made in South Africa?
what is the gt3 rod bearing reference?

I´ve replaced many main and rod bearings on many different cars and I never had any issue, I don´t understand how can be something very simple be such as problematic. All the cars in the world have main bearings, come on this is not a premium technology...

I´ve replaced many main and rod bearings on many different cars and I never had any issue, I don´t understand how can be something very simple be such as problematic. All the cars in the world have main bearings, come on this is not a premium technology...[/QUOTE]

I don't know, I won't use them. It means to me that the shell is not set correctly in the rod, and this begins from the instant they are snapped in. If there was misalignment at the tabs but the shell was sitting parallel to the rod, as the originals, I'd probably accept that, this diagonal business is strange. I really can't identify the cause, I shaved both sides of the tabs down so they float from side to side, still same effect. I can now move it over in the rod from right to left, but the "twist/diagonal" component remains. This is true for the entire batch. By the way, the stamp date code is 11-18, which coincidentally the stamp code sits askew. (Purchased elsewhere, rebuild shopping was split between here and another large online store I normally used.)

http://forums.pelicanparts.com/uploa...1593178270.jpg
http://forums.pelicanparts.com/uploa...1593178270.jpg
http://forums.pelicanparts.com/uploa...1593178270.jpg

I recently disassembled a stock 3.0 which had never been apart before. The original rod bearings were offset and aligned with the tang. Wish I had taken photos.

Also, this thread may be of use.
http://forums.pelicanparts.com/porsche-911-technical-forum/848942-rod-bearing-misalignment.html

"I recently disassembled a stock 3.0 which had never been apart before. The original rod bearings were offset and aligned with the tang. Wish I had taken photos."

Mike,
Too bad my experience I think is about a different issue, diagonal seating across the rod as shown in the diagram. I first found this when tightening the rods bolts, the big end of the rods would rock on the granite slab if they weren't tightened right up, whereas with the old bearings in place the big end cap and rod would come together evenly and would not rock on the flat surface even when the nuts weren't tightened much. That indicated something wasn't square. That's when I realised this was different and if you look at the measurements taken above, there is a huge difference in the position of the half shells from the tang end to the other side that greatly exceeds measurement error. It's not just a fixed offset as others have found in the link you've provided, that would be a tang location or rod as some have mentioned earlier cars may have had the locating cutout on the rod at a different position, that would have been good fortune as shaving the tangs would have resolved it.
Phil