308 V12 conversion begins

Good question.

It’s a shape that really wants to be cast. I’m going to price it out and see, but I suspect that to make just 2 castings will be cost prohibitive.

Trying to machine it would be a bugger because. Although is doesn’t show well in the pic, the runners are at a 60 degree angle to the engine flange, the TB mount centerline is offset from the main runner, and the runners go from round at the TB mount to an oval at the head, all adding up to areas that would need at least a 4 axis machine and a bunch of tooling/set-ups to be able to make it....and why it took me a couple days to figure out how to get the CAD software to even draw it.

So, what I’ll almost certainly do is make the engine flange and runners separate then weld them together. That makes the engine flange a simple machined plate and would let me make the runners on the lathe, then press the engine end into an oval and weld them on. 30 minutes with the die grinder later and you’ll never know it was even more than 1 piece. I can do all this in my shop at home on the manual machines I have, no CNC time required. This is the way I made the supercharger intake for the QV engine.

For this same intake for a QV, I’d CNC machine it from billet because the port are square to the mounting flange so it can be made with no special tooling on a 3 axis machine.

 

Man I wish you lived closer

It's way cool of you to take the time to share all your ups and downs since I don't think you post here 'cause you need help


Thanks again,


Sean

 

I wish you lived closer too because help is always welcome....there's sure plenty to do!

I'm a big believer that as talented as any 1 person might be, a project will just plain come out better and with fewer mistakes when more than 1 person is looking at it. I don’t always take the good advice I’m given (like 246tasman telling me to quite screwing around with the TR heads and use the ones that fit!), but I think it’s good to take a 2nd or 3rd look at how or even why each piece or decision is made.

 

Header flange drawn. Check.
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I'm sure you're doing the right thing with TR heads. The reason is that it's more challenging & more fun, which is the whole purpose of the exercise. And you'll get more bhp in the end (assuming it all works of course).

As far as the casting question goes I have heard of some outfits that now have the software to put your drawing into their machines to make the patterns. It works out the split lines, designs the seperate pieces and makes appropriate allowances for the shrinkage. Only thing is I haven't actually got a casting done this way yet. Obviously you have to use the same CAD program thay have. It should work out economic I think as the casting itself is relatively cheap. Obviously the drawing can then be used for machining the casting too.
I was on a project to cast Stratos 4 valve heads but my software man (I don't have the patience to learn it myself) got too busy and it's been shelved for now.

 

Questions:

What application are the throttle bodies from? Are the bore centers on them correct? It looks like in the pictures they are set up for FI and TPS. Is this true?
What brand of DRO is that on your mill? I don't recognize it.

Comment:

Bob Norwood expressed to me that the weak point the in the 308 tranny is the input shaft. In the 328, there were two bearings supporting the input end of the shaft. One inboard, and one outboard set in the transfer cover. He told me that without the outboard bearing, above about 350 ft-lb, the shaft tended to snap from the load. FYI.

 

The TBs are suzuki gsx1300r hayabusa. They have a 46mm bore, but 48mm thottle plates are available aftermarket, so you could open them up at least that far.

For about $200 you get a set of 4 including the fuel injectors and a TPS.

The bore space on them is too small for any automotive aplication, but the TBs are just bolted together, so it pretty easy to correct. To alter the spacing, threaded rod and spacers get the TBs in the right spot, you need new loger fuel tubes and then a spacer/extender on the throttle linkage.

My DRO is mitutoyo parts and a mount I made.

My supercharged QV was putting out over 350 ft-lbs at the wheels, probably 420ish at the crank and I'm thinking this engine is going to just about equal that number if all goes as planned. I didn't know the 328 had another bearing, I did notice the aftermarket drop gear kits had an extra outer bearing. I guess I should take a good long look at add one or some other support for the shaft.

 

Thanks for the push...I fired it out to a couple shops for quote. I think as a casting it would be better to split it in 1/2, they come out simetric, so just one 3-cylinder pattern to make....I guess I could even make the pattern, I've made molds I'd think a patter would be easier and my software will do shrinkage and draft. We'll see.

If you need a good CAD guy, I know one. Let me know if you want the contact info.

another thought, ferrari didn't change much between models..... any chance a QV head with the end whacked off would fit?

 

Here's the intake split to make casting easier....I wish making stuff was as quick as the solid model, this project would be nearly done
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I use solidworks07 it has an internal casting program. needed it many times for my projects. I've been using CadCam software for over a decade so it's fairly easy for me. for someone new, way to steep of a learning curve.

sand casting will be the cheapest setup route, perm casting costs more for the mold but is cheaper on the units.

 

Mark you're NUTS hurry up and get 'er done!

 

I need it to get FIA papers.
However, I've just bought some QV heads (too cheap not to have!) which I haven't collected yet, and will have a damn good look to see if they're near enough and might pass with the Stratos cam covers on.

Please pass on the your CAD contact, PM if you prefer.

Do I understand that your CAD works out the pattern splits automatically or do you have to do that and feed in the data?

 

I've got 07, but haven't installed it yet. I fugured I'd get back up to speed with my simpler 98 first. I just got a ProE station at work to 've got to get familary with too....me and software tend not to get on well.......

I'm definitely thinging sand cast, I can't see ever making enough of these to pay for tooling for any other method.

 

If the QV heads are even close, wonders can be worked with a grinder, a welder and a sand blaster to make it all look the same and hide the seams (if you need help with that, let me know) - that's why modern racing that requires stock parts often also requires the stock surface finish and they keep an OEM sample on hand to compare the finish - d*mn cheaters everywhere



The contact is:
David Yaeger
P: 215.239.7618
F: 215.359.0600
[email protected]

There are specific mold and casting most geared toward designing the molds. The software I have will do draft, but I need to tell it where the parting lines are, and that really an experience thing knowing what makes a good parting line and what doesn't. Normally, draft is about the last thing added to the model because it's hard to know where the parting lines will be before you know what the pat looks like.

 

Thanks for this. I'll try him.
Can't wait to check over the qv heads too.

 

Sadly the 246 has a much wider bore spacing than the V8's. Of course, because it's a much shorter stroke engine.

 

This guy walks into his psychiatrist's office completely naked with Saran Wrap around his waist. His shrink takes one look at him and says, "I can clearly see your nuts."

While I didn't see any Saran wrap in the pictures, it's obvious, Mark, that you're crazy. And I think it's awesome. I look forward, with great interest, to keeping tabs on this thread and seeing the final outcome. I imagine yours will be one of the coolest 308s around. I am curious, though, as to the engine number of the engine you removed from your 308, as well as the engine number of the 400i you'll be shoe-horning into its place.

 

What is the predicted weight distribution when the new engine goes in or better where do you want it to be front/rear?

 

This is pretty mild crazy by my standards

Here's the old engine numbers. The new engine isn't here yet, but I'll snap a pic when I get it.
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I honestly never even thought about it until you asked....I just wanted a V12

The new engine is 50% more cylinders, but not 50% more parts, so lets say it's abot 100 lb heavier than stock. But the CIS is gone, that's got to be 20 lbs, 50lb OEM muffler will drop to say 25 lb aftermarket, and my fancy carbon-carbon clutch is another 10 lb savings. So a 45 lb gain almost right over the rear axle. Stock weight is 3200, 35/65 split putting 2080 on the rear axle stock. It will now be about 2125 with a total weight of 3245, making the f/r split 34.5/65.5. Not too bad.

Before I started this project, I had a supercharger mounted to the V8. When I boxed it up and shipped everything to the new owner, it was over 100 lbs. So the V12 should be almost exactly the same weight as the supercharged V8 and the car handled pretty well with the old engine, well enough to win in the street modified 2 class at a few autocrosses. And no matter what I do, it's still better than a 911

 

So when you're done. . .How much to do mine?

 

That's a good question.

I'm doing my best to make drawings and will see if it makes any sense to offer the parts for the conversion. Final price would depend on standard engine or if head conversion stuff is needed and a few other things, but I suspect the basic stuff to install a standard 365/400/412 engine will end up running around $5k-$8k and it might be that much again to add the TR heads and final drive ratio change and such.

Should I just go ahead and make 2 or everything then so it's ready for you?

 

I started working out the throttle body respacing tonight and it seems pretty straight forward with 1 small exception. The fuel rail has a 0.178” ID, which seems absolutely tiny to me. I normally use ½” ID fuel rail on everything I do. In a quick search I didn’t turn up anything about the bikes running crazy fuel pressure, but I did find a bunch of larger aftermarket fuel rail kits. So I’ll make up the TB spacers like I was planning, but I’m going to make new larger fuel rails so I know I won’t have any problem. I’m going to try to get everything ordered for it tomorrow.

I’ve also decided to go ahead and fab the intake instead of casting…I just don’t see how I’d ever justify the mold cost. So I’m going to get that material on order too. I’m going to try to get the TBs and manifold knocked-out before the engine gets here.

Michael out at http://www.ferrariservice.com where i bought the engine (and also the TR heads) has been pretty busy I guess, but says the engine will go this week for sure, so 1 more week before the real fun begins.

 

In a quick sidetrack Paul got me thinking about variable valve timing. I can conceive how I could roll one of both of the cams around, but I can’t get my engine software to tell me it helps very much. I spent a hour trying all the viable timing options. What it says is that there is the right timing +/- 1 degree where I pick up about 3 or 4 hp on top at the expense of 3 or 4 down low and then the wrong timings where I loose on both the top and the bottom. Surprisingly, the right timing is….. exactly factory euro spec.

I also played around with lift and duration numbers and the answer is…..factory euro spec again. At least with the flow numbers from the ported QV heads. Adding more flow adds hp everywhere which is not a surprise since the QV head flow came out a little low for a 375cc cylinder, so it’s even more low for a 400cc cylinder. If I could get the flow up to optimal, I can reduce the cam duration about 5-10 degrees and gain about 30hp from idle to redline.

So, the computer things I should spend my time on porting the heads and leave the cams and cam timing alone.

 

Awesome. I can't find your car through the engine number - though I found two Boxers that share that exact same engine number - can you tell me your serial number...?