I picked up this 2.4 six awhile back and I'm gonna use this thread as I develop the engine which will eventually go in my gold car.

I'm starting a little out of order, but too bad.

So I have this aluminum flywheel. No manufacturer stamps or numbers on it whatsoever. I'm thinking that it might be too light for a street car, so I may not use it. It's about 3lbs by itself. I've got a 914 clutch adapter (basically a cut down 914/4 flywheel that bolts to the outer edge) and that brings the total flywheel weight to about 10lbs.

I want a streetable car, is this thing too light?

Try it...

I have a lightened Patrick Motorsports flywheel on a 2.4 that I'm building. Its not aluminum and weighs 7.00 lbs. If yours is not less than 5 lbs, it should be fine, depending on cams.

I'm using e cams based on Dempseys book.

I am, by far, no expert tho.

your right at a stock 2.0 6 cylinder flywheel weight.. do you have an aluminum pressure plate the would be great, unless its for a LIMO, Then get a cast iron anchor..

old and new flywheels

of course we don't have the torque of a 2.4
and we use an F first gear

oh Brant that aluminum one is real vintage alright

its Frank Becks toss off.....
he went to a 4.5 diameter clutch to save weight

I've had a 6.75lb Patrick Motorsports aluminum flywheel and a push-type clutch on this 993 engine since 1999. No problems. Clutch/pressure plate/flywheel assembly weighs in at about 18#.

Good luck

Too light? I think you just killed a little part of Ury with that comment

how light is your flywheel?

I'd say it's somewhere between a medium silver and light gray, about the same color as yours. Not dark at all.

My daily driver 914 turned cafe racer AX weekend warrior turned semi-daily driver has a lightened flywheel. It's 12 lbs I recall, behind a stock 1.7 TIV. When the engine is cold, it dies more often than it should. When warm, usually no problem. If you rev up in neutral, the drop back down can sometimes cause the engine to die. It just doesn't have that rotating mass to keep it smooth. I am really good at re-starting the engine no matter where/what. I like that my 914 is so sensitive to driver inputs w the light flywheel, turbo tie rods etc etc

Go for it

Figure that the heavy outer starter ring is at the perimeter, I think this should work fine. Just don't put a 'puck' type clutch disc in the car if it's going to be a street driven car!

Cool. Sounds like this flywheel will be fine. I can always swap it out later if need be.

On to the next subject!

These are the throttle bodies I will be using. They are from a Polaris 650. They line up perfectly with the intake ports, but I'll need to make adapters to make them fit. They're fairly large at 46mm, but I think they'll work okay.

I need to transition from the intake port size (36mm I think) to the TB size (46mm). There are two options I can think of that I like. Have a flange cut from 1/2" aluminum and taper the inside. The other is to have longer transitions, but this would mean CNC milling.

So there's the question: longer smoother transition intake, or short quick transition?

With a 2.4 I'd go with longer to get a smidge more torque....

Those throttle bodies look really cool, can't wait to see what you do, and if you want to make another set...let me know.

Love the polaris TB's! Great Idea!

What cams are you using ?

Remember that the factory went to high-butterfly throttles in some of their race motors. I bet that was to allow them nice longer transitions in diameter, plus a longer distance after the injector squirted the fuel into the air stream for it to mix and vaporize.

I think you should go for the longer intakes. Can you do the machining yourself, or do you have to farm it out?

--DD

Longer runners will give you better low end torque. Shorter will move the torque curve higher typically.

What is your goal?

Make sliding adjustable runners with O rings. Then tie a linear actuator to them. Control the actuator with an rpm counter to raise and lower as you drive... EASY!

Mazda did this on racing engines. a NA 4 rotor did over 750hp. The RX-8 has multiple runners that are rpm/load controlled valves to lengthen and shorten the runners.

Street engine. I like torque.

2 flanges cut.
Two pieces of tubing, cut stretched, welded.
Then tig it all together...


As I was thinking about it, you should be able to hammer a tube to get 10 mm out of one end....
I would think a bit of time on the sharp end of an anvil, with some patience, you could make the tube cone shaped..

Just a thought.

Also, aren't the Ida carbs 46 mm?
What kind of parts can you find using that stuff?

Might want to contact Eurometrics, he specializes in the old carbs...

Carbs for up to 3.0 are typically 40, but this size will work well with EFI, as the computer can better control the fuel delivery. Seems like a good size, from the little bit I've heard.

Okay, time for another thought/question. The engine is a bit unknown on the inside. Here's the story that came with it.



Question is, should I pull the heads off and check what all I've got? Maybe a valve cleanup job?

Open it! You know you want to. DO IT!!!

Slippery slope.

Do a leak down first and make sure you "need to"

It's more about knowing what heads, cams, pistons and compression ratios.

I have been dying to build another six engine. This isn't exactly a build and I don't have the funds to actually change anything so it can't get too crazy, other than possibly adding spacers to lower compression so I can run dual turbos. (yeah, I have the disease)

Hey Mark - is this the motor I dropped off? If so, I have details on the build.

What does this mean?

a. Port size 36X35 38mm intake

36 intake
35 exhaust
38?

Only two ports per head.

that configuration only has about 8-1 compression.

sell the 69 S heads and buy find some 2.2-2.4 heads.
T and E heads have the same port size. You will get easy to find valves, 40/46 and get back the .5 compression
they are easy to port to 36mm intake, Well depending on how you do it..

Or just run it, since you want to TURBO

Bolt on a set of carbs and run it on the test stand.


KT

The $2500 carbs I don't have? Life is so simple when you're spending someone else's money. Plus, what do I learn from bolting on carbs. I'm not building a car. I'm building an education.

I've been wanting to start familiarizing myself with AutoCAD and this seemed like a good project for this since the intake adapters I'll need are relatively simple.

I started with an intake gasket and scanned it. Then cheated and drew the outline in Illustrator since I can bang that out in about 2 minutes. Then imported that into AutoCAD and did the extrusion. It's pretty boring at this point. Gotta measure my actual intake port size, the OD of the throttle bodies, and decide on the height of the adapters I need/want. Then I'll start working on the actual tapered tube portion.

Finished the intake drawing (I think). Now I need to find someone who can print a prototype for me.

will those Polaris fuel injectors provide enough fuel?

The injectors are pretty standard. So I was already planning on swapping them, I just haven't done any research into finding what I want to use. Something high impedance is certain, but I also need to find out what flow rate I need.

Do you know what distance is from the throttle body to the valve on the OEM Porsche high butterflies throttle bodies?

From looking at the Rothsport versions, it looks like the manifolds are around twice the height of the throttle bodies

Not sure. I drew up 'shorties' because once I looked at the room in the 914 engine bay, there's only about 11" overall of space from the cylinder head mounting to the top of the engine bay. The TBs are about 4.5" and short, individual K&N filters are about 2", which leaves 4.5" of room for the adapters. And that's if I use all the available space. So I decided to just design the shorts ones and get a prototype made so I can hold it in my hand and see how it looks.

I was under the impression that this was an unknown condition motor that you were trying to determine whether or not it needed rebuilding.

I have a set of carbs/manifolds you could borrow for testing off my 2.6 race motor.
I still have that 6 into 1 tee pee off road exhaust for full effect...


Click to view attachment

Click to view attachment


KT

Ahhh, thats makes more sense. I expect it runs. I'm just planning on pulling it apart to know for sure what's inside and what the compression is, etc

Prototype printing underway (not by me).

All done an ready to ship to me.

Cool.

What is the material, Mark?

why the groove seen from top? is it a two piece part glued together?

so the printer does not cut material away from a block of material - instead - it builds material up and up and up till a part is done ?

I hope Mark doesn't mind my response. I am printing the prototypes for him.

I am many have seen/heard about 3D printing. It is a pretty cool process.

The process starts with a 3D CAD file. There are many ways to get one of these but the process involves modeling in a CAD program. The CAD file is then transformed to a "surface" file that is a map of the external surfaces of the part. The printer software then slices this into invidividual layers. These are cross-sections cut to the plane of the base substrate. Its kinda like a stack of Pringles Chips.

Once the software knows what each layer looks at it starts the printing process. The printer is a hot filament extruder. There is a feed stock roll of plastic wire filament. There is a pinch roller and toothed gear that forces the plastic through the hot extruder tip (230 deg C). The tip is then numerically controlled via a standard coordinate system. Its like putting a tube of toothpaste on a XYZ positioning system.

The part prints the inner and outer perimeter first and then fills in the void space with a criss-cross pattern. The density of the fill is adjustable. The grove in the top is a software glitch where two perimeter lines close together do not get adequate fill due to the narrow space between them.

If you look at the part you can see the individual layers that are stacked. This is the concentric surface finish. There are ways to smooth this easily. The pictures just show the raw part off the printer to check for dimensional fit.

I printed these parts in ABS plastic. This does not print as smooth as the other common filament , PLA.

The prototyping process is VERY fast with one of these printers even if the print process is slow. This part took about 3 hours of print time. Material cost is just a few $. The process creates an accurate part for mock up and test fit. It is easy to modify parts without spending a lot of machine time and cost at an outside vendor. Compared to prototyping in a machine shop there is no cost comparison. Cheaper. Faster. Simpler.

PM me if anyone has an interest in having parts made. I have very reasonable rates.

I hope Mark likes the part. I plan to ship it out today.

Very cool to see the cutting edge printing edge applied to our cars.

Thanks for chiming in Jamie. I didn't know if you wanted to be identified.

Apparently this ABS plastic is suitable for actually running on the car, but once I have a design that works, I'll be researching aluminum CNC production.

Did you ever consider using Boxster/997/996 parts, seeing the port spacing is similar, although the water stuff have oval ports

http://forums.pelicanparts.com/porsche-911...rt-spacing.html

http://www.ebay.com/itm/OBX-ITB-INDIVIDUAL...3d8&vxp=mtr

(I know some, if not all OBX parts suck)

Cool! Hadn't seen that. I'd like to try that sometime.

This looks very cool! What are you going to have them cast/molded out of?

What is your plan for engine management?

Thomas

If the prototype adapters work ill send the CAD files out to mill from billet aluminum.

I'll be using a MegaSquirt system I picked up. Still have to modify it for COP.