Henry,

Care to share the proper adjustment? I am leaning this way after much thought, it is just simple. I tend to like simple, the motor is for a 914 so not a simple adjustment but not impossible either.

Thanks for the input.

PFM

Henry

What chain do you recommend? When I have purchased them from standard sources, they have all been one brand.

Walt

Using solid tensioners is like driving a car with a solid suspension (as in no springs/shocks). Because a solid tensioner doesn't 'give', the chain experiences very high forces causing it to wear out much quicker.

A chain gets long because of the wear between the pins and the holes in the links--there is no 'stretching' going on. The reason why chains appear slack on engines with solid tensioners is due to the high wear that has taken place.

Now a solid tensioner may be a better solution than one that fails, but you should be aware of the extra wear the chain is experiencing.

Happy racing!

Although in theory there may be more wear but in application I have never noticed excess wear in properly adjusted chains with solid tensioners. I have however noticed major intermediate bearing wear in mag case engine using late style Carrera tensioners.
I have always noticed excess wear in all parts associated with racing stresses but never chain wear causing failure.
I have noticed over and over again race weekends ruined by collapsed tensioners and even catastrophic failure leading to a season ending explosion.

As for type: Iwis Racing is the brand we use.

As for adjusting, it is a judgment call because different engine cases and cylinders expand differently.
As a general rule, the chain should lift off the outer chain rail (closest to the cam) about a 1/2 an inch when lifted with a thumb nail. Mag cases with Nikasil cylinders set slightly looser.
Looser is better than tighter.
A loose chain may rattle slightly when cold but that rattle is of no consequence.

Wow, this has covered many years, and is a great thread, so after a year of being dormant, I am posting now. Ok, one, Henry, how did those cranks come out, and what is the cost? I have a 3.0 liter that I want to put into my 69 912, which has steel flares from an 87 930S and still have not grafted in the front ones. I would like to built a fun revving street engine, and the 2.8SS sounds great. I drive my cars like I stoled them, and this car will be no different. Since I have the 3.0 SC case, it would be nice to use it, because I am not racing the car, just beating on it. Ok, two, who makes a MFI setup, or is it better to just try a find a used one and have it modified, or would carbs be the way to go?

Cranks are a work of art. They were designed to use the Pankl GT3 titanium rod but with the new (stupid) price a few people have ordered RR rods fron Charles @ LN.


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As for MFI: PMO now makes an MFI manifold set up if you don't want to modify the stock Bosch set up.

PMO
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Modified Bosch

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Wow, those are nice cranks. I have wanted to do a turbo for this car, but a fun NA engine would be fine for now. The car has been sitting in my shop for a few years, and I need to get moving on it, so it is out of my shop, due to my business. Thanks fo the info.

What exactly do these cranks do for you? You mentioned before the possibility of going 66 x 102 for a 3.24L.... I assume this could be done with MFI and the twin plug setup? What case would be required, does the new crank allow use of a more available case than the 3.0 carrera/turbo?

Assuming one has no core parts at all... what kind of ballpark would I be looking at for one of these bad boys?


Terry

the new cranks allow you to short stroke on a late case (SC, 3.2, ..)

The "old" 66 mm cranks only worked with the old cases , (2.0, 2.2, 2.4 , 2.7, 76-77 3.0 Turbo or Carrera.

i think somewhere in this thread there were prices mentioned for just those new cranks, 4 or 6 K, can't remember which.

Here's a silly question. Would it be cheaper to have a newer case welded up, and line bored, or have a crank welded ground, and rehardend? Just had to ask.

i think neither are scenario's that are typically done on 911's..

Why welding/machine case when you can just buy a turbo or 3.0 carrera case that already has the right specs?

Like I said, silly question, but I thought I would ask. Those cases are not so easy to find. I would love to build one of these, but since I have an 81 case, or complete engine, I am just going to leave it that way, but wow, this 2.8SS would be a blast.

They can be found, might take a while, but they are out there.
Got one right here, though it has minor external damage. (missing a strenghtening rib and an eye for a case bolt, must have hit a rock or something in a previous life, but still perfectly usable).

I was just asking the question about welding the case or crank. After seeing the cost of the new cranks for the large journal cases. The smaller journals would be the way to go, for the simple fact of the crank being lighter, plus a smaller friction surfaces lets the crank spin up faster.
I would really love to build one of these, but it has to wait until my CNC starts making some money after dumping all of it into it.

Henry's cranks aren't cheap - as if any race parts are!

But stock 66mm cranks are all over 30 years old. Some may be newer replacements, but hard to tell. Think about a crank which is older than some of you are.

And Henry has put in all the bells and whistles: crossdrilled and grooved (that's really groovy, because you don't have to have bearings grooved). And it is lightened. And the 9 bolt flywheel attachment seems not to have the issues that the 6 bolters had at 8,000 rpm and above.

Where would things pencil out if you added the cost of all these modifications to an aged stock crank, and offset the lower cost of the much much more common (and thus less expensive) 9 bolt 3.0/3.2 case?

I already had the special case and older crank when I embarked on the SS2.8 adventure, so I've not done that math.

As to 912 guy's question, I suspect he will find that adding the cost of welding and machining, even if that doesn't have other issues (messing with the heat treat of the case, or part of it, and not just a small bead of weld either) means making the #1 journal of a regular 930 case smaller isn't cost effective. Now if you can do the welding and machining yourself and don't allocate a cost to that, your figures will be skewed.

Walt

i just re-read this whole thread. What a wealth of information. thank you Henry, and others, for sharing this kinda info.

The crank can be fitted into any case from 78 to 97.
The cranks use a more modern oiling design and are considerably lighter than conventional Porsche cranks. To build a 66x102 you need a 964 or 993 case unless LN makes a Nickie that is a 102 with a 105 spigot.
What you get from one of these cranks is a rod length to stroke ratio that allows for very high RPM. With the titanium rods and the big valve capability of the 964/993 heads you get the ability to turn RPM numbers close to 9000. This is practical unheard of with the two valve 911 engine.

Cost? Depending on the intake/ fuel management system, exhaust and core chosen you could build one of these for a little as $30K or as much as $50K+.

It was a little difficult to tell from the photos, but have you made provisions to squirt fuel into the base of the Mag stacks (like the Plastic Stacks have) for cold start, in addition to the manual enrichment (that replaces the original thermal stack)?

Thanks!

There are no provisions for cold start injection. Squirting raw, unmetered fuel into an engine is in most cases just a bad idea.
In deference to spraying raw fuel into the engine we have developed a starting procedure that works pretty well.

Thanks, Henry!

I just stumbled onto this thread after a search for 2.8SS. Thanks to all that shared their knowledge. I have a fairly rust free 1970T chassis with steel turbo fenders front and rear. I've been searching for the "right" engine for it. The quick solution is to build a 3.0, put on PMOs and trot around. But with this BAD BOY I can prance around all day long. Thanks Henry!

For all those with knowledge, if I were to build this 2.8SS using PMOs instead of MFI, would I need to change any of the intake/exhaust sizes?

2.8ss
 

Hi,in the mid 90,s I started using the early 3.6 heads on my 2.8 ss engines.I had been using 3.2 heads which worked quite well.I use Ti valves that are larger as well.Also ti-rods that are 132mm long to get a 2 to 1 rod ratio.Stud spacing needs to be narrowed a little bit on the heads.I use a 3.2 repair head gasket to seal it up tight.930 104 381 01 and there are no leaks.This motor spins to 9300 rpm and makes 248 ft.lbs. of torque with a very long flat torque curve.Outer portion of the piston is trimmed to get proper head clearance with the longer rod.Like Henry said the best motor that Porsche never built.I use 45mm slides with Motec and a hand built step exhaust to let it breath.Makes 374 H.P.at 9300.Power starts to drop off a bit a 9100.It is simply a stunning engine and revs way quicker than larger motors.Fred

All I can say is .....wow!!!!

Back in the day I raced a 3.8L 993 RSR with what I was told had everything including the sink thrown at it. It made just over 400 BHP. It also ran out of gas at just over 8200 RPM. Your engine makes almost as much one whole litre of displacement smaller and still makes power almost 1000 RPM higher.

You sir, need to go looking for the holy grail. You will probably find it!!!

The latest adventure into short stroke magic was the 3.1 liter engine we built for a customer in the US military stationed in Sicily.
Supertec 3.1 liter Short Stroke 9000 RPM 2 valve
1982 930 Turbo case (GT3 squirters)
Shuffle pins
Boat Tail
Supertec SuperCrank billet 66mm full cross drilled
R&R billet connecting rods (GT3 config: 53mm big end, 21mm small end & 130mm oal)
GT3 Bearings coating by Calico Coating
996 TT oil pump
Racing IWIS chains Supertec idler arms
964 steal countershaft
Supertec Head studs
LN Nickie cylinders 100mm
Supertec 906 cylinder tin
11.5:1 JE FSR pistons, 60 grams lighter than conventional pistons
Custom DC 90 cams
Early forged rockers w/dry film pads
Xtreme Cylinder heads
50mm PMO Carbs (manifolds 47 x 50mm)
Burnham Motorsport Twin plug distributor
Burnham Motorsport sump cover
Series 900 fan shroud
Supertec Power Pulley
Supertec RSR flywheel

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2.8 extreme heads
 

Wow,great motor.Heads are just gorgeous.What does a motor like that cost roughly?Did you dyno it?I built a few 3.1 ss for Imsa 911 in the 80,s & the limiting factor was enough fuel .We used the Kugelfischer Rotory pump as well.Beautiful build Henry.Fred

I believe LN does make 102 cylinders / 105 spigot for 3.2 cases. However, wouldn't that make for rather thin walls at the base? Would that make for an inherently weak area or is it a non-issue?

subscribed

Wow, I am really digging those rod holders to mate the case halves, nice. Any chance of getting a close up of those things, purty please.

Love that oil plate

Were the heads chamfered for the 100 Nickies? Nice :cool:

I don´t know if I asked you before Henry, but why not, 70.4 stroke with 102mm pistons on 993 case? that would make same bore/stroke ratio as the 2.8SS we can have all the benefitt of the 2.8 plus we can have twin plug for free.

I have all the parts to build it, to my twin turbo engine. Ti rods from Pankl, turbo oil pump, or GT-3 oil pump, all the good stuff;

thanks
Tadashi

Rod length

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Rod length.

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Just read thru most of this old thread......one of the best threads ever and worth revisiting again & again.

Agreed!

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Talked to an engine builder last week that went the other way. Custom designed 85mm crank, 102mm cylinders for a turbocharged 4.2 liter engine.... Not sure how he got the crank to fit in there...

Probably used Honda bearings, to start.

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I found this old thread and thought it was worth another look.

very nice engine !!! :eek::eek::eek:

I'm loved with this thread !!!

Please the gurus of this engines .....

I'm thinking one 2.7 engine....because i have one crankshaft from engine 2.0..... I'm thinking make the conversion to short steoke !!!

Please give me ideas and view points for mount on my conversion to 914 6 GT thinking for make rally car

Thanks in advanced :D:D:D

914/6GT 7200 rpm
2.5 liter twin plug. 66X90 (short stroke 2.6- 66x92 is also cool)

DC 43 camshafts
Oil Pump upgrade
Crank shaft 2.2
Supertec Head studs
Aasco valve springs and retainers
Clevite rod bearings
2.2 connecting rods ARP rods bolts
Gasket set Viton (Wrightwood Racing)
12 spark plugs ngk-bkr6-ekub 46 mm PMO or Webers
6 PMO 34 mm venturis
6 PMO main jets 130
6 PMO idle jets 55

Venti port 36mm
Machine piston dome & massage transition ridge (compression adjustment) 10.0:1
Valve job & surface heads
Machine valve covers twin plug
Case Savers and 8mm stud inserts
Replace studs & surface gasket surfaces (heads)
Rebuild, convert to ARP and balance 2.2 connecting rods



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Henry - is that an oil shedding coating on those rods? And you balanced the rods after the coating? Or was that a second balance for those which changed a bit?

While you are sharing some of your specs, what cam or cams do you suggest for a SS 2.8, twin plug, EFI, ~11:1 CR, 3.2 heads, oversized valves.