Chris White

You didn't say plane....the center line of the cam and the head (and crank) are parallel. Since the distance being measured is from the cam to the crank the angle of the tower to head interface does not matter since the head/block is where the material was removed. If the cam tower to head was the area being 'shortened' then that angle would be relevant.

Thom

... and pretty much the reason I question the maths behind the builder's quote mentioned earlier by Shawn, where the surface between the cam tower and the head is mentioned.

Anyway, the longest free stretch of the timing belt is perpendicular with the plane between the head and the block, so saying that 1° of retarded cam timing corresponds roughly to 1mm of skimmed surface off the head sounds pretty good to me, as per Dave's observations.

Dave W.

It's Alive!
Tonight was the first time the engine was able to start, idle, and run well enough to drive around a little. I'll be honest, I had planned to take the time to map out the new changes in the tune and build a new VE table, but I haven't driven the car in over a year so I took a shortcut on the tune and temporarily put it in full time closed loop. This let the DME take care of the fueling and fill in the gaps. I drove it around the block a couple times to see how it felt. The power was nice, very responsive and it felt great to toss the car into a few corners. I hit a few psi of boost at low rpm, just enough to load up the piston rings and start breaking in the engine. When I shut the engine off, the turbo was still spinning for a minute afterwards. I think I'm going to like a modern ball bearing turbo on this car. I can't wait for tomorrow!

I actually started the car for the first time last Sunday, but the idle was so bad it just stalled right away. The idle sounded terrible, it ran extremely rich despite pulling out a ton of fuel. I spent Monday night installing and adjusting new speed and reference sensors, plus I had to adjust the height of the trigger pin in the flywheel since it was not locked in. That was not easy! I had to remove the pin with a 3mm hex wrench, find a way to lock it in place, then reinstall and adjust the height of the pin while the engine was in the car. That was a delicate procedure.

So today the status of my car changed. I earned a little green badge that hangs from the rearview mirror that indicates it's a car that will start and drive under it's own power.

refresh951

Good to hear Dave. What turbo?

blown 944

Right on. One more on the road!!!

URG8RB8

Congrats Dave!

m42racer

I was very interested in the math part of this post. So I asked a good friennd of mine who does alot of engine building and machining what the actual Cam changes are when decking the Block and or the head.

He told me the math is simple but the issue is how you come to the dimensions used in the calcs. As best he could say based upon how they measure everything, for every 0.001" removed changes the cam timing 0.0286° retard on the Intake. So if you multiply that out, that would be 0.034" off the decks = 1° cam change. Then Thom's numbers make sense with 1mm = 0.039".

You have to love math.

Dave W.

Thanks everyone! There's still plenty of tuning to do before it reaches it's full potential. I'm sure I'll enjoy every step along the way.
I'm using a PTE billet 5558 with the CEA turbine wheel and ceramic ball bearings in the new 'bolt-on' K26 housing. It's roughly equal to a GTX3071 in size.

I still haven't paid any attention to engine vibration. I keep forgetting. I still don't know if the balance shaft mod is working or not. I started the car twice today and never noticed if the engine shook more or less than before. Maybe that's a good thing? If I haven't noticed it, it must be good.

Crazy Eddie

Congrats Dave !! There is no feeling in the world like the first time you start her up after a long rebuild .... Some rebuilds take longer than others
When you have it running to your liking, swing by ...'
I am only a few blocks away
Best regards
Ed

Tom M'Guinn

Congrats!! Would love to see it sometime. Sorry if I missed it but what engine management system and triggers are you using?

Dave W.

For engine management I'm using the stock DME tuned through an Ostrich. I've done a lot of disassembly on it so it's very flexible. On top of that I also have a MAFT Pro to handle the Speed/Density conversion and boost control. It's a handful sometimes but it works.

Dave W.

I drove the car home today. The tune is good enough for cruising and low boost, it felt great!
The engine is very responsive, plenty of power down low. Someone pulled up alongside while I was on the freeway and gave a toot and a wave. I'm not sure who it was, I responded with a wave and a BOV salute. I think I smiled the whole way home. I still need to sort out the acceleration enrichment, the car hesitates if I prod the throttle too quick, but otherwise it's good enough to drive normally.

Dave W.

Update- I had a chance to put the car on the dyno today. There's no major results, I simply wanted to spend a little time in a controlled environment to dial in the timing, fuel and boost control so I could drive and have a little fun. Results are 285 RWHP/ 314 Tq at just 14psi. I was able to add 4 degrees of timing back into the boost portion of the maps and it made more power each time. Unfortunately I ran out of time so I didn't get to see how much timing I can add back to the part-throttle portion of the timing map. It's nice to know I'm still on the safe side of MBT.



A couple of interesting points is that this engine/turbo spools up almost exactly the same as the stock turbo on the stock engine. My previous best dyno on the stock engine/turbo produced 325 TQ at 19 psi. Another interesting point is the small dip in the pink boost curve at approx 4000 rpm. That's where the boost solenoid drops to zero duty cycle, basically it's running on wastegate spring pressure from there and up. It's a sign that it should make plenty more boost at minimal BCS DC. I think it also means exhaust backpressure is very low.

Thom

Not sure I understand your logic regarding controlling boost.

You want to use the softest WG spring to be able to smoothen the boost curve with the solenoid. The stronger the spring pressure, the more the solenoid will have to work to smoothen the curve between the moment you begin to build boost and the moment you reach peak boost.

V2Rocket

That's a nice curve for 14psi.
200ftlbs at ~2800 should make it a nice cruiser...should be a beast if/when you turn the **** up.