That's a big intake valve...
400 RWHP
When I started the project, I really wanted a C5 Z06. They are amazing cars, and I have measured my car against them many times. A stock Z06 makes about 365 RWHP. I
want more than that, and 400 has a nice ring to it. This nice thing about this goal is that it is actually possible without breaking the bank. A
stock displacement LTx with a good head/cam package can do it.
Reliable
Fixing broken cars at the track is not fun. Don't ask how I know. If I'm spending this kind of money, and taking the car down for this long, I want it to
run all the time after it's fixed. I realize cars driven as hard as this one break now and then, but I want to keep things to a minimum. This means doing
stuff right the first time and spending the time/money where it needs to be spent to make sure it will stand up to the abuse I'm going to give it.
Cool Running
The old motor ran quite hot, on both oil and water. I saw oil temps over 300 F at times, and coolant temps over 230. Temps this hot aren't conducive to being
reliable (see goal #2). Before, I was on the stock radiator, and there is no stock oil cooler. Plans include a bigger aluminum raidator with a built in oil
cooler. Right now, I plan to leave it a bottom beather and see what happens. If cooling remains an issue, I may have to convert it to a front breather.
Flexible Power Band
While HPDE/road racing is the primary use for this car (and RR performace is how the car is measured), I still use the car for other stuff. I don't want the power
band to be too peaky or narrow, and kill all bottom end power. This will mean the cam and head selection will have to sacrifice a bit off of the top end to
keep the power band broad.
Reasonable Cost
While making power costs money, and with enough money anything can make power, I really need to keep this build on budget. Wasting money now just means it
will take that much longer to get it done on the other end. While I can't skimp on parts if I want it to do what I expect, I certainly need to keep an eye
open for chances to save some cash.
More info/pics/details to come later.
Some plans have changed, some have become reality, and some were just drawn up. After some significant research into the feasibility of using a stock rotating assembly, I have come to the conclusion that it just won't stand up to what I want to do: namely rev it to 6500 lap after lap after lap. While there are some who have gotten away with it, most all agree it reprents a definite risk. Since I can't afford to build this motor again, I think it is worth it for me to do it right. The problem with the stock pistons and rod is the weight. I could reuse the crank and go with some lighter forged pistons and rods. I took my used, stock short block to a local machine shop to be checked out. The results were good and bad: the engine had spun at least 2 rod bearings, but the block was good. The crank and rods could be saved, but they would require some work (turn the crank, refurbish the rods). I really didn't want to spend money on fixing the stock rotating assembly (since that money could be spent on better parts).
So, getting some good forged rods and pistons became the new plan. Mahle Power Pak pistons come highly recommend: forged, light, and an excellent record of reliability make it a perfect choice. I was looking at some Scat rods, but I found a deal on some lightweight Childs and Alberts 6" rods for less than half price. More research, and it was pointed out to me that a quality cast 3.750 stroke crank is cheap. Hmmmmm...the pistons cost the same for a 355 or a 383, and the extra displacement will give more mid range torque and allow a bigger cam. Since the stock crank needed work, spending the money on more cubes seemed like a no brainer.
383 it is! Lloyd Elliot of Elliot's Port Works was already working on fixing and porting my LT4 heads and intake, and was also getting me a custom cam as well. After the decision to go to 383, the cam was enlarged to make use of the extra displacement. Lloyd has finished with the heads, and they are nice: 2.02 intake, 1.60 exhaust valves, enlarged ports and runners. Flow at .600" is 293/203 CFM. My cam will be right around .600" lift, so it will definitely be able to make use of these heads. Lloyd also did the intake. Pics of his work below:
That's a big intake valve...
Intake port
Exhaust port
Looking into one of the ports of the intake
Looking into the throttle body holes on the intake
The heads look significantly better than when I dropped them off. The new custom cam should pull hard all the way from 2500 to 7000. The bottom end and valve train should be able to handle 7K rpms without problem, but the typical shiftpoint will be 6300-6400. I'm very hopeful that this combo will be good for 420 RWHP, maybe even a bit more. To get that power level, there will have to be plenty of supporting upgrades: lifters, injectors, clutch, throttle body, headers, etc. This engine is going to cost a lot more to put together than I had hoped, but, when it's finally done, it should be one kick-ass ride. Also being upgraded are the cooling and oiling system. A new, larger, all aluminum radiator is already here, with engine oil cooler, as well as a Canton road race oil pan and an Accusump. The hope is that once this is all done (however long that may take), it will meet all of my goals above. While the cost one is probably already impossible, the rest are at the top of the list.
More pics and details as the project moves along (the crank will be here Tuesday).
Well, progress over the last month has been very slow. The machine shop has had all the parts for the bottom end since March 10th. Today, I called them to get an update on the current status. I was hoping it was done (or at least close to it), but instead he told me I have a problem. Six of the pistons are touching the crank at BDC. Sigh. This makes me so very sad. The entire setup is supposed to be built around 6.0" rods: pistons with a compression height of 1.125", 3.750" stroke, and 6.0" long rods. The SCAT 9000 Crank is for strokers with 6.0" rods. Clearly, something is off. It sounds like something is wrong with the rods or pistons: for same reason they aren't the proper length. I have instructed the machine shop to measure the lengths of the pistons and rods in hopes of finding the culprit. Hopefully, I can sell whatever parts aren't right and buy the proper ones.
I am a bit annoyed, however, that it took a month for them to figure this out. I understand it's a machine shop, and stuff doesn't get done instantly, but somehow I doubt they figured out this problem today. I can only hope they can help me identify the problem soon, as this project is really starting to drag out while the car continues to sit.
The machine shop called me back on Wednesday, the 9th (the day after the last update), and informed me that my pistons weren't actually hitting the crank. WTF?!?! It turns out the employee who was mocking up my engine is just an idiot. Why does the machine shop have idiots who can't assemble SBC's, and, more importantly, why are these idiots working on my engine!?! If I wanted an idiot with no experience to assemble it, I would have just done it myself.
I still have no ETA on the bottom end, and I get the feeling it will be at least 2 more weeks before it's done (and I'll probably have to call them to find out that it's done). The saga continues...