jt1

That's just a poorly worded question that could have several correct answers depending on the assumptions needed to fill in the blanks. When I was in school....ahem....a few years back....the correct response would be to state your assumptions, then solve the problem based on those assumptions. You could also solve the problem for different assumptions and show the variations. Sometimes that might get an attaboy, sometimes not, depending on how the prof viewed the assumptions. JOhn

That's ramairbox.com. They also make some very spiffy drop base air cleaners. jt

Quick check is to pull the pulleys, damper, water pump, and timing cover and see if the dots on the timing gears are lined up vertically. If not, revise them till they are; the dot on the crank gear and cam gear should all be in a vertical line thru the CL of the crank and cam, with the dot on the crank gear on the top. It doesn't matter if the cam gear dot is on the top or bottom as long as they line up vertically. More involved is to degree the cam using a degree wheel and dial indicator, this way you get the cam positioned exactly where you want it. BUT to do this correctly you have to know the grind specs on the cam. Most of the time the intake lobe centerline will fall between 102-110 degrees, without the cam specs you are cutting and trying in the dark. I'm pretty sure Comp cams has a good writeup on cam degreeing on their website. John

You might take a look at the chinese Summit brand cast alum valve covers. They're just a plain polished VC that is tall enough to clear my rollers and stud girdle. I've been using them a couple of years with good results. For breathers I'm using a set of the moroso oil separators, the ones used in the crankcase evac kit, with a pair of K&N filters. This is a somewhat goofy looking setup that works very well, but doesn't have the clean no BS look I like. I've been trying to come up with something better, but haven't hit on it yet. John

I had a great time running with Roddy (blue 280Z) and Mark(yellow 240Z), two well sorted, well driven cars. Roddy was less than a second off my time in the TT, Mark about a 1 1/2 second off, and that was with me putting a sec or two on them on the straight. Mayolives (Tom) was there with his 300ZXTT, Bjhines (John) was there with his black 240, althought they were in a different group and we didn't get to run together any. There were a couple of other 240Z's that I talked to the drivers but don't know them, plus a whole gaggle of 350Z's from the Triangle Z Club. It was probably the best Z car turnout I've seen. I'm heading to CMP this weekend for the Turn 1 event, they're doing a Sat - Sun event. jt

If you'd like to see some really nice track day pics from the recent THSCC event on VIR's North Course, check this out: http://www.fandsenterprises.com/photogallery2004.htm and specifically the Red group, where I was running along with a couple of super nice Z's. http://www.fandsenterprises.com/galleries2006/thscc0406red/index.htm These guys did a super job of taking pics of cars at speed, at a very scenic track. Check them out! This one is probably my favorite: jt

That's pretty normal for a diff that's got some miles on it, just the accumulation of wear in the gears and bearings. It will probably run quite a while still. If the clunk bothers you, you can rebuild it, but if the clunks bearable I would probably run it a while. jt

The canyon and desert are truly amazing. When this NC boy went there, I was stunned at the spectacular beauty. Have a great trip Big Guy. jt

I use 75 ft-# with anti-sieze on the studs, which is roughly equivalent to 90 or so dry. It's not unusual for aluminum wheels to loosen up a little after they have been run some, so recheck them till they settle down. John

We wrapped up a nice weekend yesterday evening. Weather was good all day, I spun out in nascar in the third session, just got in too hot and looped it without hitting anything, thankfully. A fellow in a Z06 behind me did a nice job of not knocking me into next week, I thanked him afterwards. I wound up fourth in the time trial, behind two full race BMW's and a 911. I got back home at 11 last night, one of the disadvantages of VIR, and have been a little slow today. CMP in two weeks!!!!! jt

Well, back again for the THSCC event on the north course. Yesterday was rainy for the first session, with a C5 having a major impact exiting the snake. The 2nd and 3rd sessions were good, then the rain set in for the time trial, which we voted to cancel. Today the sun is shining without a cloud in the sky, so it looks like a good day. I'm hoping to improve, I've run the north course only once before, and really don't have the confidence to really attack the course. Roddy and Mark, both in S30's, have a lot more experience here and are right on my heels timewise, despite my advantage on the front straight. The Mayor of Big Pine Key is riding a bike around the pits, wearing a pink flamingo hat that is at least 3 feet long. Time to get the car unloaded and checked over. Wish you were Here!!!!!! jt

Looking good John!!!! What kind of tubing did you use? Are you gonna weld it up or get Chris to do it? See you Saturday. Let's hope it's not raining. jt

When are you seeing the oil pressure bounce? Winging it in the garage or driving around? jt

Jake, have you seen any problems with the Comp cast rollers? I'm running one with no problems yet, but only 420# over the nose. John

I'm glad you found the cause of the 5500 rpm skip, I was worried about your valve springs. Valve float is a bad thing. 7200 is pretty high on a stockish bottom IMO, but it's your motor. The edelbrock tuning kit is what you want. It's got several different jets and rods, you use them to get the mixture right at cruise and WOT, then use the step up springs to adjust when the transition takes place. Ebrock's site covers this pretty good. The kit is 35 -40$ IIRC. One nice thing about an ebrock is you can change stuff without dumping gas everywhere. The ebrock's are really good street carbs, they just don't quite make the power a holley will. For timing, I usually run all the initial I can with the car still cranking fine with the motor really hot. Generally with a big cam, the more initial means cleaner idling and better throttle response. Get the advance in as quick as possible with no detonation. Tune total for max power on the dyno, with the motor really hot, again watching for detonation. I really can't advise you much on the HEI, most of my experience is with MSD's. The reason I keep yapping about detonation is because with 10.25:1 with iron heads & pump gas, you're on the ragged edge. The big cam's late IVC is reducing the dynamic compression and you'll probably be OK, but it bears watching carefully. If you have problems, reduce timing, and a little colder plug may help. Since you're planning on some track events, you will be running the motor hot at WOT for extended periods, and that is where detonation is at it's worst and will do the most damage. jt

I had a student at a track event with a SRT-4 putting down about 325 RWHP. I was very impressed with the car, smooth and predictable power. If they would just make the same car in a RWD platform...... John

IMO locking out the advance- meaning the mechanical and vacumn advance don't function, the timing stays where you set it, all the time- is a race only mod. Most people who do this use a timing retard to crank the motor, or wire the starter and ignition separately so they can get the motor spinning, then turn on the ignition. I think this would get old real quick on a street/track car. I'm pretty sure John mistyped this, meaning "vacumn" instead of "locked out". Right now, since you've just got the car running, I wouldn't throw any parts at it, I would tune what you've got so you can drive the car and enjoy the fruits of your labor. Total timing at 36deg; get the initial to 16-18deg, working with the slots or bushings, however you do it with an HEI; get total advance in between 2500-3000 rpm, working with the springs and weights. Spend half a day on a chassis dyno and get the carb tuned correctly. You'll need a tuning kit for the 750, and spend some time on Edelbrock's site, there's good info there on tuning their carbs. You'll know how much power and torque you're making, and probably pick up a good bit. There's simply no way to tune a carb as good by seat of the pants as you can do with a wide band O2. jt

Get the initial timing, total, and advance curve right, John covered that very well. Ditch the vacumn advance. Rig up a fuel pressure guage and make sure you've got adequate fuel pressure, like 4-5 psi @ WOT Take it to a chassis dyno w/wideband O2, or use a LM-1, to get the mixture right. Check with the cam manufacturer and be certain you're running valve springs that are adequate for your cam. This should probably be step #1. jt

Are you guys having runout problems sure you're using Wilwood rotors, or are they some chinese knockoffs? The reason I ask this is I've put eight sets of Wilwood front rotors on my car over the last few years, and I've never had over 2 or 3 thou of lateral runout, most of them are dead on. No turning, no clocking, no shims or filing the tabs, just bolt them on and check them with a dial indicator. In fact, I've pretty much stopped checking them. I'm using the Wilwood "GT48" series rotors, and they have "WWE" machined into the casting on one of the tabs that bolt to the hat. John

When I was younger, teens & twenties, my friends and I used to work on our cars or race cars almost every night, or go to the track and tear them up. We were all single, liked to party, and generally didn't give a @#$% which way the wind blew. Now firmly in middle age, there's always job/business/wife/kids/parents/social stuff to attend to, and my body can't run on 4 or 5 hrs sleep anymore. My friends are in the same boat and it's really difficult for us to get together once a month, let alone every day. So most of the time I work on the car myself, when I get a free moment. It's a real pleasure when we do get to work on something and talk about the old days! jt

It's been a few years since physics and thermodynamics, but I'm pretty sure there's always some enthalpy involved, even though it could be very small, and there would be a net loss of kinetic energy. jt

Some of it is transferred to the crank, some is dissipated thru friction, some is converted to heat thru elastic deformation of the parts involved. jt

Read MikeC's post about 3 times, it's good advice. The problem isn't with the main jets, it's the idle, transition, and PV circuit. Most likely the idle circuit isn't responding because you have the primary blades open enough to engage the transition circuit. Open the secondary blades enough to get the idle circuit air bleeds responding, clean the idle up, then tune the PV and then the jets and pumps. jt

That's a good article John linked. It touches on why the rocker geometry that will give the longest component life doesn't always make the most power, which is why top engine builders are changing some of the rules. This is well beyond most weekend engine guys like me. Nascar engines amaze me. They make well over 2 hp/ci, turn over 9K, and they live for say 8 hrs or so. That probably requires valve springs that would support the average tractor trailer. They run 2:1 ratio rockers, so the valvetrain to support that is mind boggling. jt

Opinions vary somewhat as to the absolute best criteria, even among respected engine builders. What's important is that all of these will give a pushrod length within 0.050" of each other, whicj is the commonly available length increment of pushrods, unless you go custom. 0.070 sweep is pretty good, as long as the rocker tip starts on the side of the valve stem closest to the rocker, travels across the valve C/L, reverses and comes back to at least the centerline, or slightly more (ideal). The rocker should be roughly perpendicular to the divided centerline of the valve and pushrod at mid lift. As always, check pushrod clearance in the heads, rocker to retainer clearance, retainer to guide clearance, and piston to valve clearance. John