308 V12 conversion begins

The tubing is 6061 T651, 2.25” OD x .25 wall. The heavy wall mean I just need to get the shape close and then i can grind without fear to the finish shape.

I have not done any heating yet other than the welding. The top and middle pieces I’ll just press….it’s a 12 tons press and you barely notice the part is even in it.

The bottom part is a bit tricky. I need to press quite a bit and the welded section is lower strength and more brittle than the rest plus I need the sides to bend quite a bit so I will press these hot…..I tried just pressing one the other day and the shape was wrong and the sides and weld cracked….basically a complete failure. On my second try I used the torch to get the whole thing hot so it wouldn’t crack and areas I wanted to bend more hotter than the rest to get the right shape.

 

I press the top part a little, the middle part more and the bottom part a lot plus reduce the OD then weld then together into an ugly thing. The taper mostly comes from grinding the OD of the top part, the OD of the middle part and a little of both on the OD reduced bottom part. You’ll see what I mean as I go.

 

I got most of the ovaling done but ran out of acetone with just 3 to go….I’m going to try to get to the store today. I moved on to grinding weld preps and got about ½ way thought. Total hours now 7:45.
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Sh*t! I ordered the ignition expander yesterday! It was only $50 more than the BIN price on the used one so it’s not that big a deal I guess but still.

I’m not sure about the multiplexer. The M800 has 4 digital inputs and I have 4 wheels so it will work without the multiplexer. It will leave no inputs available for anything else but I don’t think I actually need any other inputs…..a switch to turn the TC off might be nice I guess or a switch to change maps in the ecu maybe as a back-up (one tuned for TSP the other for MAP) but those aren’t really needs…. I need to keep my eye on the ball and stick to required stuff and pass on this one for now I think.


I got the new acetylene tank this morning and I also ordered the material for the manifold flanges. Hopefully the manifolds and all the welding on the heads will be finished this weekend…then on to the air box I think while everything is set-up and I’m thinking about it.

 

So my porting buddy says he still thinks I’m leaving a lot on the table. I posted the flow plot and it looks pretty good….but when you add the velocity plot it looks less good. The velocity tells you the port efficiency and ideally it would be a straight line……mine is certainly not. All the numbers on my graph are decent, all way better than stock and many would consider anything around 160 just fine…… but they really should all be up in the 190-200 range.

0.200-0.250 flows have been a problem for me all along and this plot says they still are a problem. This is the point where the port crosses over from limited by the valve to limited by the seat ID and my port isn’t working very well there. My buddy gave me a few suggestions to try and I think having more finished stuff will help as well. When I get the seats in I’ll spend a couple days playing with this and see what can be done. There is no question this is a problem that is right at the seat area or something about the valve.
…..but a couple days is all its getting then I’m finishing the heads……it’s time for this project to end.
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I'll post something when I get it running....but it's not going to be a screaming V12, it will be an idling V12 until It gets a few heat cycles, I get the head gaskets retorqued, I get the injection 1/2 tuned, I'm happy with oil and cooling systems.....very gentle at first.

 

I finished up the ovaling. The welds on pretty much all of welded group showed at least some sign of cracking as I reflowed the weld on all of them.

I got the 1st (2nd if you count the prototype) one welded. I took a few pics to type to show the steps between the parts. The steps get fixed a little by the weld, but mostly they get fixed by grinding which is why the 1/4" wall material is important. It toofk about 15 minutes to weld this one, so I'm looking at 2 1/2-3 hours of welding time then another 3-4 hours of grinding I'd guess. I'm at 9:45 total and clearly going to miss the 1 hour each guess....but I don't think the time will be double so that's something.
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Here the flow graph with even more stuff on it. I added a stock Tr/Qv head (they are about the same) and what I’m looking for on velocity. Ideally the velocity would be above 190 everywhere, but lower at low lifts is probably ok as long as the velocity builds as the valve opens. This is the velocity of the air entering the cylinder I’m graphing; the velocity in the port is directly proportional to flow so it always goes up as the valve opens.

Notice too that my port beats the stock port handily at all lifts and absolutely destroys the stock port up top where my new cams have the valve about 80% of the time.
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It’s the average velocity at the seat/valve. At lower lifts the Max average velocity is around the perimeter of the valve time the lift. As the valve continues to open the perimeter area exceeds the seat ID area and the seat area becomes the relevant point.

 

Its calculate. Velocity = flow/area

It's just another way to look at the data and try to understand what it means.

 

I found some cool stuff I didn’t know the simulator had…..it’s a new feature I just never noticed. It tells me about air lost out the exhaust, air lost to reversion (air coming into the cylinder the going back out in the intake) Exhaust left in the cylinder, fuel flow rates and BSFC, manifold pressure, ect.

In theory I could run a few simulations with at various intake flow rates (simulating the throttle position) and then use it to create the fuel map for the ecu by looking at the manifold pressure (MAP) and fuel flow rate and be at least in the right ball park when I fire it up for the first time…..in theory anyway.

A quick look says the 46 lb/hr injectors will be at about 65% duty cycle which is right about where I want them.

Also notice it says the MAP signal is basically nothing...14.7 is standard atmopheric air pressure. This is a big part of why race engines get tuned using the thottle position and not the manifold pressure, there is no manifold pressure to measure.
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2 hours of welding and at least 2 more to go.....6 is probably closer. I'm at 11:45 total

 

The right answer would have beed to install a TR engine/trans.....live and learn.

 

The used M800 arived from england today.......ecu, check

 

So this morning I welded...big surprise right?

Another hour or 2 and I'll be on to grinding.