Screaming Metal, You actually gave me a good idea about milling the pistons. I think I will go see Bob at Performance Research and see what he can do to lower the compression. He is the man for balancing stuff around here as far as I know anyways. I hate to waste a perfectly good set of forged slugs, but buying race fuel for the cruise in isn't doable! Thanks!
Per Lunati: on 4032 material, 2.8 grams reduces volume by 1 cc. They have a very informative site (www.lunatipower.com) with formulas, etc...I just discovered.
Don't kick yourself too hard. I hate formula's. It's not the actual math, it's remembering the darn things. When I worked on X-ray equipment, I carried a cheat sheet with my calculator, just like in school!
Update for any interested in the thread: I just heard back from Bob at Performance Research, seems he was out of town, but he said no problem with the piston milling and re-balance. Turns out this is more reasonable than I expected, he ball parked it at 15.00 per slug if I dismantle and 185.00 to balance the rotating assembly. I know his work is excellent. So that beats buying new pistons and eliminates the waste thing that I hate. Thanks again for the idea Screaming Metal! What do you guys think I should reduce the compression to? Iron heads, tunnel ram, fairly thumpy cam(haven't selected yet, but 270-300 duration range), manual shift, so I think 9.5-10:1 is about the most for street use, pump gas. I don't want to nueter it too bad. I ran 10.5:1 or so with iron heads on a stroker and had knock at low rpm light load(cruise) but was able to control it with re-jetting, timing, and finally a msd timing computer. I am not sure I would do that again because it was a pain to dial it in without a dyno and there was significant compromise required.
Great info! I was overlooking the ethanol issue and just thinking octane (advertised) levels. I know the iron heads hold heat and require reducing the compression by about 1 point or so as opposed to aluminum also. I looked into a roller cam set up and no kidding on the cost. They have went way up. I converted a pre 85 sbc to roller and had about 500. in all of the components in 2003 and thought that was a lot for a cam back then. I just looked at a similar setup and it would be well over 800. I didn't do much shopping, but that was the same place I bought the parts before. It seems the lifters went up more than the cams? I know they are much more durable, but if you decide to change the cam later, that negates that bonus. I guess that's just progress? I guess the manufacturers know they will last and need to get the money up front since we won't be buying lifters as often. (just my take on it) The engine won't be working very hard in the bucket, but I want it to be worth the effort. I do not want to fight detonation and the timing issue. Been there, and from my experience, the added compression probably provided less power than lower compression due to timing/tuning concessions required to combat detonation. I ended up going with aluminum heads to make it run right and still live long. I think I will put a blower plan together and build the bottom end with that in mind, run the tunnel and iron heads for now, and if I decide to go with a blower, it will be good to go. I suppose I could go with a little higher compression with the tunnel and iron heads, and go with aluminum heads when and if I add the blower and be good to go. I could then employ thicker head gaskets if needed to refine the setup. Sounds like a plan, sort of.. We will see once I actually get it torn town and check everything out. I may just get happy and build the shit out of it once I get into it if it needs much. Thanks for sharing your expertise!
If that is what you like, great! I applaud your effort and craftsmanship. It takes similar effort to build them either way, other than the engine. I personally like raw power in my hot rods. I want it to do strange dangerous things when I press the petal on the right! That's the whole point for ME, and the nostalgia with the old school drive train parts. I ride the bike or my little Fiat Spyder to save fuel! Lol. Hell, my bike barely gets 40 mpg and it only has 2 cylinders!
Yea, good point! I know and I will likely have to dial the whole thing back a couple clicks. I love the sound of a big cam, but they aren't very good at low rpm, but neither is a tunnel. We have temperature and worse, humidity swings, so it is a full time job to keep a high performance engine actually tuned. (makes for tricky paint work too) I will do some research on several configurations before buying parts. Again, I'm trying to make the best out of what I have to start with, without reinventing the wheel. I used to have a desk top dyno program and another one that I forget the name of that were somewhat helpful to match components, Not sure what happened to them.
I often wondered about that, but never had access to a dyno. I imagine they use manufacturers advertised best scenario numbers as their base. I don't know how close the actual numbers were because I never put it on a dyno, but I built a sbc with components matched on it and it ran very strong with similar rpm range, etc...It also had detonation just as warned, but I thought I could make it work and didn't want to buy new heads because I had a nice set of 882's with 1.94/2.02 valves. That decision cost me! Live and learn. By the way, I was also trying to make a 3.08 duration .600 lift cam run on the street, which is why I wanted to keep the compression up. It did work, but took much tinkering.
