blueovalz

The only reason I went to a 17" wheel was due to the width I needed to fill the flares (I used to have 16" racing wheels and tires under them). The DOT 16" tires, in the width I wanted, where not available in a size and aspect ratio I needed, so I went to a 17" set-up to get what I wanted. But, as Mike and Aux said, they are heavy (mine are almost 60lbs per corner) and IMHO, the 17" wheels are just at the limit in regards to aesthetic appeal. Any bigger and I feel they would look "odd."

False, I know you can go at least one inch wider. Maybe 8.5" Depends on how wide the flares are. I made flares, and used a coil-over set-up. 17 X 12 in back (when I raced but now its the same as the front at 17 X 11) and 17X 11 in front. There should be tons of info in the archives, but I must admit, last week I seached for a string that never displayed the intended target, even after using the same exact title (and key words as well) the string used (I found it, but not by using the search).

Pete, My pistons are of a convensional design with the OEM compression height and typically longer skirts than your piston has. I did get off the phone with a guy I trust that works a great deal with stroker motors. I explained the situation and he felt the rocking motion parallel to the pin was normal if you've got the typical stroker type of piston (short skirts with short compression height). "You've got nothing to worry about" was his comment.

I followed the same method as you did just to keep the comparison as equal as possible. The parallel-pin rock for the most part did not exist. The gauge would bump .001" or so, but bounce back to normal (on both sides) but the .018" rock perpendicular to the pin was "set" with each tap. The question I ask myself (or you) is, "are you using floating pins?" And if so, is .019" movement abnormal? Assuming for argument's sake you had a piston pin that was .007" smaller diameter than the rod's small-end pin journal was, and this journal was 1.5" wide with a 4" piston, then that .007" (with no oil to take up any slack) would allow a rocking motion that would translate to .019" at the edge of the piston (2.00"/.75" = .0186"/.007" where the 2" is the middle of the piston, and the .75" is in the middle of the pin bore (the rocking pivot, or axis point)). This ratio pushed out to the edge of the piston allows about .019" or total rock movement. Just trying to justify, or figure out by so much movement parallel to the pin.

It's hard to imagine the CF being loose being it compresses the inner races for the wheel bearings. But I'd go ahead and tighten it down all the way, and drive the car, testing for bearing noise.

My pistons (as measured last night) have .018" rock side to side, and about 1 to 2 thou rock parallel to the pin. I wonder why yours has so much parallel with the pin

Thanks for the updates and the comparisons.

Fascinating post Pete. I'm in agreement as to being puzzled by the fore/aft measurements. I'm going to check mine tonight when I get home as I know my port/port variance is similar to yours (but my skirts are longer with an OEM compression height, but the fore/aft measurements are very small (my pistons are pressed through the rods). Now, my pistons will slide fore/aft a bit, but does not rock in this dimension. I'll measure mine tonight and compare.

Something to throw in here as well is with large positive offsets, camber greatly effects the "feel" on uneven surfaces as well. For the street I've found that the negative camber brings the feel back to a more OEM feel during normal driving. I had to experiment with it for a while once I starting driving the car on the street, but it has helped a lot.

Further analysis may prove me wrong, but I cannot see any difference between a spacer inside the rotor verses a spacer outside the rotor. It would seem the same shear forces are involved (with longer than normal studs) in either set-up, whether it be between the wheel and the rotor, or between the rotor and the axle flange. I personally don't like spacers (even though I recently had some machined for me) that only use a "pass-through" stud, but I would definitely stay away from multiple spacers (ones on both sides of the rotor), especially, as I said before, if you're only using a single long stud passing through all these parts. I've no emperical evidence to prove this, but smooth surfaces stacked up together would scare me in that I would believe any slipping between parts (unless there were some really close tolerances in the stud holes preventing any slipping) would really stretch the studs out, perhaps beyond their failure limit. I guess the reason I fear this is that one day I removed some spacers on a car many years ago, and saw on the aluminum surface signs that there was movement between the rotor and the spacer, even though the wheels were bolted on tightly (both surfaces were very smooth). Perhaps indexing pins would make me feel better about all of this. Anyway, on the 1/2" spacers I had machined, the stud holes were so snug on the studs that I had to tap them on with a hammer.

I don't think this one has been tried yet. So far as I can best recollect, the only hybrid IRS set-ups so far are the 240SX/300SX rears, and the Corvette rear. The GTO looks very nice, but very wide as well. This is where you'll need some FWD type offset on the wheels and/or flares.

Is that 3600 instead of 360?

1/2Mass X velocity squared?

I've no recommendation. Potatoe/Potawtoe, who knows?

I've interchanged between flat and tapered plugs, and yes, the tapered ones slightly deform the seat (and adjacent first thread), but once you remove the plug, the last thread is returned to normal. You don't want to cinch down hard on the tapered plug, just snug.

I went to the extreme. Unable to find an adaquate air filter holder for my K&N filter to fit under the hood AND within the strut tower reinforcing, I fabricated a fiberglass filter holder that allows the filter to fit under the hood. I've pushed and pulled on it after the engine bay was up to normal operating temperatures, and the part did not soften any appreciable amount. Underhood temperatures concerned me at the time of the build, but after 4 years it has held up well. This photo does not show it, but I finally refinished it and then painted it to match the exterior paint color. So in short, the fiberglass hood will not have any problems with typical underhood temperatures.

Use care in that the fiberglass and gelcoat will soften if excessive heat is built up. Too much heat will allow the scraper (putty knife, etc) that you will use to remove the paint to "dig in". Fiberglass has a high expansion coeficient when heat is applied as well. This will cause the panel to look odd if heat is only localized, but should even back out as it cools.

I don't know all I should know about this subject, but my understanding of roller cams is that a bronze gear is required (with some few exceptions), which helps prevent this from happening. I've been told the first (break-in) gear (again, a bronze gear) should be changed within 5k and that subsequent gears should last 25K-30K. Again, I've read that some roller cams are made out of a material that will not chew up the steel distributor gears, but I don't know the details of this. With the bronze gear, the worn material will not affect the bearings, and yes, it can be seen (just barely) in the oil if you look real hard. I don't know if the same can be said of the steel gear particles.

Well, this was what I always thought as well, but with all that clearance between the piston and valve (it was actually a lot more than I thought), I am beginning to wonder if the springs have softened up some and perhaps some clearance problems are existing at red line (7500). Anyway, thanks all for taking a look at the post and the responding.

I bent two pushrods (same cylinder) two weeks ago on the highway at normal speed. I heard an irregular ticking noise develop (with ear plugs in as I couldn't hear it without the earplugs) for about 15 minutes prior to them really letting go. All parts looked good, and there did not appear to be any backed off parts (polylocks, etc). By the time I pulled over and pulled the covers, I had one broken and one bent pushrod. Two rockers damaged, and 2 valve tips wiped out. I put clay in the piston valve reliefs today, and the results of turning the motor over with the starter at speced lash, and a compressed gasket, was a measured .140" Piston-to-valve clearance (and about .090" on the sides of the valves). No carbon was knocked off the valves or the pistons upon initial inspection. I've not actually tested them, but the springs are supposed to have a 500# open pressure. The cam is a solid roller of relatively mild specs. Anybody have any ideas on what caused this. I've decided to have the springs checked out anyway prior to buttoning this thing back up and getting it on the road. I'd sure like to figure out what caused this and any ideas would be appreciated.

I had a great ride for the street with 200 front and 235 rear.

I think your 1850 is a 600 cfm carb. I think the 390 cfm carbs used a 8007 number (not sure on that last part)

The diaphram may also be ruptured. If there was no work done on the carb in the time that it worked before, and now, I'd consider this as well (especially if it worked fine on another comparable V8). If indeed you were "oversized" on the carb to where there was not enough air flow to open the secondary, then by theory, the engine does not need the additonal flow, but if, as you say, the engine feels choked down by using only the primary metering, then it sounds like there should be plenty of vacuum drop to open the diaphram.

I believe that construction of the tire had some major importance here as well. My take on this was that the failures of the tires where at the corner (where the sidewall meets the tread area) of the tire section, that was failing due to the high downforce experienced in the banked turn. Higher tire pressures helped prevent the separation at this location. But higher tire pressure meant an extended period to bring tires up to temperature, which nobody wants. Is this correct?