3.0SC 1980 Engine build

[911S_1975]

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.

[Glenfield]

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.

[Glenfield]

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: Best Cam Profile For A Stock SC?

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

[911S_1975]

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

[911S_1975]

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

[Glenfield]

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.

[911S_1975]

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!

[Glenfield]

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.

[ahh911]

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.

[911S_1975]

@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...

[ahh911]

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.)

[mikedsilva]

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.

[mikedsilva]

Also, this thread may be of use.
Rod Bearing Misalignment

[ahh911]

"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