2.8SS build on 3.0 turbo engine - questions
 

Hi,
I am the lucky new owner of a 77 3.0 turbo engine on which I plan to build a 2.8SS. The engine sat for a while, but it turns over by hand. Assuming components are usable once torn down, what should I use from this engine for my build, and what should I sell?
Things I know I should keep...
- Case (I'm pretty sure on this one;)
- 4 bearing cam towers
- 95mm Nikasil cylinders (replated if necessary)

Things I'm not sure about...
- Heads ??
Turbo heads have small intakes (32mm) , but that means more meat to port a custom shape, no? Exhausts are already 36mm, but could get bumped to 38 or more, also with custom shape. Does the "special" turbo alloy help in anyway on an NA engine? Would I be better off finding a set of large port SC heads? Are these turbo heads valuable to anyone?
- Oil pump ??
I'm not sure from BA which pump came in this engine.
- Cams ??
Can these be welded and reground or am I better off with fresh blanks?

Things I will definitely be selling...
- Crank
- Rods
- Pistons

Did I forget anything?

thanks,
dug

3.2 heads might be better - big enough ports from the get-go. Don't know if you'd come out ahead or behind with a swap.

Some cam grinders much prefer to use new blanks rather than welding and regrinding, so maybe no cost savings there?

The one thing I can tell you is that you will need to clearance some of the bearing webs, because the throws of the 66mm crank will interfere here or there. Or perhaps you can knife edge the crank some to avoid this, but that's going to have to be done before balancing. So a trial fitting, with crank and bearings in place to see what needs to be done here is in order. I had the whole case together before finding this out. At least this allowed me to sort of scribe the areas where I had to use the die grinder a bit. Not much, but you don't want a running crank to do your machining for you.

Thanks for the tips Walt. I hadn't heard about the interference with the crank before.
Cheers,
dug

Heads.....
 

I second Walt about swapping for a set of 3.2 Carrera heads. You will get nice big fat ports and slightly newer parts. If you can find a set that someone is selling off a hot street or track engine that has been dual plugged, more the better! Especially if they come with comp springs and titanium retainers (typically used on perf heads). Good luck on your project!

That makes sense to me too, and would likely be cheaper than sending them out for porting. The 3.2 port sizes match what Henry said he used in "The best engine Porsche never built" 2.8SS parts list. I also will probably use the DC80 102 lobe center cams.

Another question that keeps coming to mind... is shuffle pinning necessary or just an extra precautionary measure?

In his thread Henry mentions that "The SSI and mufflers offer a bit of a tuning challenge. With a proper size header these engines will produce close to 300hp on street gas."

This engine will be in a 914-6, so I'm not stuck with the SSIs (or I'm stuck without, which ever way you want to look at it.) What would be the "proper size header" to achieve that 300hp figure?

I plan to use EFI with a unique ITB setup. More on that when I have supporting photos of my setup.

thanks,
dug

Since a 2.8SS loves to rev, I would recommend the shuffle pinning. Even on stock-like engines, you find the bearing web mating surfaces "fretted" and they look like they have been machined that way

My 3.2SS (SC crank, 98mm pistons) engine case has been used for racing for a number of years. It was used at tracks that see high rpms for a good while like Road Atlanta. When I opened it up last year, the bearing webs show a good bit of fretting and that bugs me because that means there is considerable movement. I'm having mine sleeved thru the thru-bolt holes this coming weekend. Going to drop it off at cgarr's place (G2 Performance) in Michigan.

I second using the method cgarr is using. I would have to, because I sort of put him up to it. He had been using a junk case to index inserting bushings where the through bolts go and the webs meet. I figured out how a machinist had done this for me. Clamp case together, bore through case through bolt holes from one side to depth needed on other, insert bushings (care needed so as not to block any oiling holes, which are nearby) then shrink or otherwise fit an aluminum piece by where the bolt heads are to get that part back to size. Better mousetrap to be sure the bushings are spot on.

Better than inserting pins in one half, and holes in the other, seems to me. Locating bushings are used for the #1 main bearing. Why not everywhere?. I've never seen any fretting on my cases (three) done this way. No extra problems getting the case halves apart on the inevitably more frequent race motor rebuilds. Though traditional shuffle pinning seems to work fine also.

Yah i'm looking forward to the case sleeving. Should make the case rock solid for sure. Looking forward to hanging out with Craig & Denny for a day. Haven't seen those sons a biyatches in over a year! :D

https://www.youtube.com/watch?v=gJz-gmy8YOc

Here's a picture of the fretting from my bearing saddle mating surfaces. Ignore the ugly bearings. That's a whole 'nother story not worth getting into in this thread with you bastards!

http://forums.pelicanparts.com/uploa...1348504981.jpg

The turbo heads are made of a better material so stick with them.
Valve sizes are the same and ports can be modified to flow better than stock 3.2.
If your building a street engine, smaller ports can produce better port velocity / volumetric efficiency.
The issue with the short stork engine is cylinder filling to produce compression so they need all the help they can get.
Think towards aggressive cams if you want to make power.
One of our street 2.8SS engines runs RSR sprint cams and believe it or not, it is very driveable.

Henry, thanks for the affirmation on the better turbo head material. The information about it is vague at best. You listed 40/38 ports on the 2.8 with the RSR Sprint cams. How much smaller are you talking? 38/36?

This engine will probably share time between my historic IMSA 914 and your (Henry's) old 914-6 race car. No street time for this one, but drivability is a good thing on the track too.

Walt: I looked up cgarr's threads but couldn't find any info on his shuffle pinning alternative, except a photo of his rescue 2.7 case where you could see them. All the west coast shops list shuffle pinning on their price lists. Is the bushing method cheaper or measurably better in some way?

cheers,
dug

Yeah, that's the thread with the photo, and it has lots of cool info on checking clearances and other tweaks, but there's no actual discussion of using the case bolt bushings vs shuffle pins that I could see.

Sorry, I thought the process was described in the thread. Here's a short description:

First make accurate plugs for the mains to hold it square bolted together and use a ½ inch reamer thru the case thru bolt holes into the other case half. This creates a ½ counter sunk bore to install the sleeve which is ½ od .35 wall and 1 inch long. Then make sizing plugs for the case half was reamed all the way thru to bring the thru bolt hole back to size. This method is using the case as the jig to line up everything, it can’t be off and works very well.

The caveat is you must notch out 3 of the sleeves to allow oil to pass thru for the piston squirters, but only in 3 locations.

This gives you a very sturdy case. Pretty much the whole case looks like #1 main bearing.

39-40 on the intake part 37mm exhaust.
DC 80 cams.

Which 914-6 race car do you have? I've had a few. Pictures!!!

It's the one with the 956 rear wing on it. At the moment it pretty much looks as delivered. Slowly been making my plan.

You mean the "914 from Hell"?
Here's how it developed.

Phoenix

http://forums.pelicanparts.com/uploa...1382148204.jpg

Willow Springs

http://forums.pelicanparts.com/uploa...1382148227.jpg
http://forums.pelicanparts.com/uploa...1382148100.jpg

During the build

http://forums.pelicanparts.com/uploa...1382148022.jpg
http://forums.pelicanparts.com/uploa...1382148132.jpg

I was originally going to canabalize it for parts for my IMSA car, but it has so many cool tweeks, I couldn't break it up. My favorite part is how you widened the rear tail lights and raised the trunk floor.

I'm going to tie the cage to the rear suspension and add door bars. And now a 2.8SS:)

Henry,

What year was this? I recognize Martin's car but cannot place your 914. Mid 1990s?

That was 1995 or 6 Tribute To Lemans 3 hr enduro. That little 914 ran a 1:28 (the track was 2 seconds a lap slower than it is now) in the dark to qualify on the outside of the poll against some pretty fast cars. That weekend we were running a 280 hp MFI 3.0.

If memory serves, from front to rear:
Martin 575 HP turbo
Me 280HP na
Angel Nardi 500+ turbo
Jim Bazagalu 300 hp RS
Mark Manda 650 hp 935 factory flat fan turbo
Guy from Phoenix (David?) 3.8 RSR 360 + hp
Baddich ? 505+ twin turbo
Randy Beck carburetor 3.6 liter 914-6

Want to sell it back?

Lookin at the old pics make you want get back in the track?

Is there any one build a 2.8SS plus turbo before ??

Isn't that what's in a 962?

The 959 is a 2.8 SS sequential, twin turbo . They are 95mm bore and 67mm stroke.

77 turbo may not have a 6 bolt crank ????? Euro ? If not he will need your crank Henry ??

That's the magic of the 76 and 77 turbo (and Carrera 3.0) cases: it's the beefy aluminum design of the SC, except it still uses the 6 bolt crank from the 2.4-2.7. So you can "drop-in" a 66mm crank minus various caveats as pointed out by Walt. It has the oil bypass mod, doesn't require timeserts, etc. But there are only ~5000 of these produced worldwide, so...

Henry's crank is definitely the way to go if you already have a 9-bolt case. I was saving my scheckles for one of those eventually, but I lucked into this engine. So I can spend that dough getting the rest of the bits up to snuff to handle the revs this thing will enjoy.

I have a 3.0 turbo engine, it is going to rebuild, after reading this forum, it really help me and make me thinking, what if I made a 2.8SS with 0.5 bar turbo charge, can I still use CIS fuel system? My goal is made 400 Hps and put on my shorten bell house 930 trans then put into a 73 911.

Dug

Kevin described the method in more detail than I could. Craig had decided that bushings were going to be better in some way than pins, and came up with his "use an old case as a jig" approach, through which he worked out kinks like sizes, and the all important business of not blocking any oiling holes.

The machinist who had done this to a couple of my motors did so because he distrusted the accuracy of what he called "indicating." I take that to be machinist speak for getting the holes on one side exactly lined up with the holes on the other side. One way of doing this with mating parts like our cases is to bore the holes in one side and insert indicating tools - rods with a sharp pointy end right in the center, which just stick out a little. Then you carefully clamp the halves together, and take them apart. You have nice center punch like marks on the other case half, which you use to drill holes on that side. He thought that wasn't accurate enough, and in any case the slight misalignments were going to make the case halves hard to pry apart when you had to tear such a motor down.

I have no idea how right he was about that, but he knew a lot more than me. Maybe with CNC machines you can get things under a ten thousandth of an inch without any of this old school indicating. Lots of pin type shuffle pinned motors out there. I had one. Wasn't hard to pull apart (though it had blown up and nearly sawed one side in half, which may have made things easier in that regard). I wondered for a long time just how he had been able to go in through a hole which was X wide, and then bore something way down that hole X+Y wide. Then I took a really good look at a damaged case (another rod getting loose) I had kept for no particular reason, and saw the plugs in all the throughbolt holes on one side. Aha.

I think this is an uncommon approach largely because shops which have been doing things one way for a long time, and not having or perceiving problems with it, are not inclined to change. Most of us are kind of that way with at least something.

But I like the idea that this process is exact without anything special in the way of tooling if you are a machine shop with the usual stuff but pre-CNC and electronic digital controls.

And I have no idea about a cost differential. Craig may have no interest in doing traditional shuffle pins. He's got this bushing approach wired. So maybe you'd have to ask your usual machinist suspects. Kevin's description might be all they'd need to come up with a price.

Kevin and Walt,

Thank you so much for the extra detail on the machining process. I literally noticed the "blind-hole spotter sets" in the Grizzly catalog last night and wondered if that is how you would mark the case in order to add shuffle pins. Sounds like it is something along those lines. I can see how that wouldn't necessarily be perfect and why a line bore even on an aluminum case might be recommended after installing shuffle-pins. And I can see how the shuffle-sleave method described could eliminate that requirement.

I am a software engineer, but I love machining and obviously anything having to do with understanding my engine more. I'm no where near ready to jig up my own case halves to shuffle-pin or sleave them myself, but I am in the process of machining the first parts of my own design on the CNC mill thanks to the miracle of Techshop. The more machining I do, the deeper my interest gets.

cheers,
dug

It's up on the stand now...

http://forums.pelicanparts.com/uploa...1382523405.jpg

Dug - along the way you can put your design skills to work figuring out how to make inserts which will remove those grooves in the intake port so prominent in your picture. Needed for the CIS injectors, but seldom if ever for aftermarket EFI and never for carbs.

Unless it is purely serendipitous, they pretty much have to disturb the intake air flow in unhelpful ways.

I know some weld them up and rebore the port. Got to be a bit tricky - an interrupted cut? And I don't much like the idea of welding here, though if I knew more maybe I'd realize not a big deal. But overall ought to be better if avoidable.

I'm thinking that you could fasten an insert in place with a small allen bolt, whose head ends up flush with the ID of the port. Could epoxy or otherwise seal in place, and that would make exact match to the cast surface a non-issue pretty much, but the bolt would insure it couldn't fall into the engine no matter what. How inexpensively to make such an insert? Could it be a plastic instead of aluminum?

welding the CIS notch is no big deal, past that welding most anywhere else kills the temper..

Hi
Can I use 914/6 crank to build 2.8SS with turbo case?

I dont think you want to use the non-counterweighted cast crank to rev that high. The E and S crank is forged. I've read some people like the T crank to get the engine to spin up quickly due to the lower rotating mass, but I dont think they are revving as high.

After dremmelling off the one stubborn exhaust nut, I was finally able to teardown the top end of this beast.

Type 930/52 - 1977 3.0 turbo - the aluminum case that fits the 66mm 6 bolt cranks
Pistons will be for sale in case anyone is looking for some.
Cylinders are nikasil, I'll keep those for my build.
How do I determine if honing or replating is required?

http://forums.pelicanparts.com/uploa...1399888713.jpg
http://forums.pelicanparts.com/uploa...1399888735.jpg
http://forums.pelicanparts.com/uploa...1399888970.jpg

Cams are 4 bearing with 49mm journals, but cam housings have 901 part number.
Cams will be for sale, but there is some pitting in a couple of lobes.

http://forums.pelicanparts.com/uploa...1399889189.jpg
http://forums.pelicanparts.com/uploa...1399889222.jpg
http://forums.pelicanparts.com/uploa...1399889237.jpg

Are these heads all the better turbo alloy?
All six have 1926f casting code.

5 are matching:
5/76 date stamp (one 4/76)
930.104.341.2R
Y on upper right

1 has been replaced:
2/78 date stamp
930.104.341.3R
RR350 in upper right

http://forums.pelicanparts.com/uploa...1399889672.jpg
http://forums.pelicanparts.com/uploa...1399889693.jpg
http://forums.pelicanparts.com/uploa...1399889704.jpg
http://forums.pelicanparts.com/uploa...1399889714.jpg
http://forums.pelicanparts.com/uploa...1399889726.jpg

I will be selling these heads too since I already found a nice set of built up twin-plug heads. What's a fair price for turbo heads? There's not much in the parts forum to compare to.

Hopefully an update about cracking the case open will not take as long as this last update.

cheers,
dug