FastWoman

Hi Mike, I saw the bullet mufflers on the DynoMax website. They only attenuate the noise by 4 dB, which isn't much at all. I suppose that would be good for a tweak (e.g. to interrupt a drone frequency), but I don't know that it would make a major difference. I wish there were stats reported on other mufflers. What sorts of problems do you see with SS and heat? Cracking? My '92 Saturn (which I've owned since it was a baby) has still has almost all of its stock SS exhaust, from headers to tip. I did have to replace the cat because the ceramic honeycomb crumbled. The exhaust note has changed a bit over the decades, but not much. The exhaust is still in excellent condition, even holding up through over a decade in Ohio snow. On the original matter, I think all of you have convinced me I don't need the flex coupler. I appreciate your reassurances.

Ztrain, the muffler provided with the exhaust kit is a DynoMax, model 17733.

Mike, maybe I used a term incorrectly. By "down pipe" I meant the first pipe that leads down from the exhaust manifold to the first straight section of pipe. It has two smaller pipes converging into one. Does "down pipe" mean something special? Anyway my engine and exhaust are 100% stock. I understand from my local Z specialist that a midpipe muffler does a pretty good job of taming MSA's exhaust. Maybe a 3-chamber muffler would also do the job. However, either way I'm going to have to buy something extra. In referring to the muffler, the compactness is in the diameter, not the length. There seems to be plenty of room under the center tunnel for something long and skinny, and the resonator currently under the car is maybe that size (only shorter). Thanks for the link, BTW. Summit is a lot cheaper. Ztrain, the MSA premium exhaust has 2 1/2" pipe. It comes with a muffler, and I had no choices as to which one. It's the DynoMax Super Turbo. Maybe a 3-chamber muffler is in my future. Dunno.

Ztrain, I understand from multiple sources that the MSA exhaust has a rather annoying drone at cruising. I don't have much in the way of sound deadening materials in my car. And yes, I want to kill the raspier notes (e.g. as in Mike's exhaust). I'd never miss the small performance difference, and it's a great investment in happy neighbors. My Mustang had a very aggressive exhaust, and it wasn't really my cup of tea. I apparently put up a link to the wrong page for the muffler (corrected now). Do you think this muffler (a Magnaflow 4" dia x 14" long glass-pack) would be well suited as the "resonator?" It's rather compact and shouldn't have a rust problem.

Thanks, Mike. The flex coupler seems to be constructed of a metal bellows. Would that mean it would bend but not twist? If it only bends, I suppose it would need to be inserted somewhere perpendicular to the axis of the drivetrain, so that it would bend when the engine rocks. There's no way to insert it that way on the MSA downpipe. Or does it twist too?

Hi all, So I ordered and received the MSA premium exhaust, and I already know I need to put a resonator in the middle. I'll get a local welder to modify one of the pipes with the resonator, so that it will all still bolt up. But since I'm doing the modifications, I'm wondering whether it's also a good idea to include a flex coupling to isolate the bulk of the exhaust system from engine movement and vibrations. I've seen these couplers on transverse-mounted systems, but don't know if they're also useful/helpful/beneficial for rear-wheel-drive cars. Any thoughts? I'm looking at this coupler... or better, maybe this one in SS. Also I'm looking at this muffler as a mid-pipe resonator. Any thoughts? I'm guessing I would insert the flex coupler between the down pipe and the resonator, with the rest of the exhaust attached behind the resonator?

geoyam, I think that's perfect! Thanks!

Welcome! Unfortunately I don't have any idea about the worth of ZX models. They're an entirely different generation (with a few things in common with the Z models). You're likely to find better information in the ZX forum: http://www.classiczcars.com/forums/forumdisplay.php?f=153

Loren, you shouldn't be smoking your wiring if everything is properly fused. The fuses should take the damage, not the wiring. I'd guess it's more than a socket issue. I know it sounds like a lot of work, but it's less work than what it sounds like: Start unwrapping the wiring harnesses. Look for burnt wiring, wire-to-wire shorts, etc. BTW, I was thinking about you as I passed through Blue Moon, MN, en route home from WA.

That happened to me once with my '75. After not running the car for a year, I fired it up. Ran a bit poorly, but not bad. Ran a couple of errands, returned home. The next day all my valves were stuck, valve train fell apart, banging and snapping, and the head had to be rebuilt. The mechanic said my gas had gone REALLY bad -- that it drained from the tank like syrup. My theory is that someone had put sugar in my tank (for the gas to be that thick).

It could be any number of things, alone or in combination. However, your air flow meter certainly sounds like one issue. Try using a contact cleaner, both on the connectors and on the contacts inside the air flow meter. (Open it by carefully prying off the black, plastic cover on the side.) In a pinch, WD-40 works quite well.

Reddie, I had assumed there would be a screen on the intake of my pump, but there appears not to be one. As I look down the bore of the nipple, it appears to lead directly into the innards of the pump housing, sans filtration. There is no mention of an inlet screen in the FSM. Is this something that might have changed by year? Mine is a '78. Fortunately my tank is in great shape. There was some soot-like debris from decomposing rubber in the bottom of my tank, but there's only maybe 1 cm^2 of rust inside the tank -- in the deepest part, near the drain plug (obviously where there was a bit of water in the tank). I pressure-washed and rinsed with acetone and B12. I stripped, de-rusted, and acid-etched the outside of the tank and will finish repainting tomorrow. I think my goal with a prefilter would be to catch any rust or hard debris, but to pass softer/smaller debris like the decomposed rubber. It's the smaller, softer debris I would want to catch in the finer, larger filter in the hood compartment. That way I can dispose of most of the debris with changes of the latter filter. Gnose, I see plastic Holley ProJection fuel filters, manufactured to go with their ProJection throttle body FI systems (ONLY! -- their emphasis). They're about 1" dia and 4" long. I also see some Holley VoluMax aluminum billet disc filters in various diameters for different flow rates. They come with 28, 60, and 115 micron screens. I'm guessing I'd need 60. Working pressure is overkill (~150 psi). Fuel flow rates are 14 and 35 gpi for the 4" and 6" dia units, respectively. I'm guessing 4" would do it? See here. Of course that's an awfully pretty filter to mount on the underside of my car.

My old '75 Z also had the mono speaker in the left quarter panel. No room in the right, because of the enormous fuel/air separator.

Mike, I just cleaned out my tank and am ready to repaint and reinstall. I had lots of the "soft" black debris in the bottom of my tank -- like little globs of soot -- from degraded rubber. After shaking/rinsing with lots of acetone and Chemtool B12 and STILL not dislodging all the debris, I finally pulled out the pressure washer and blasted out the inside, finishing off with a rinse of acetone and B12. I wish I had done the pressure wash first, as I would have saved a lot of time, effort, and materials.

Thanks!

Is this a new pump or a used one? Do you get an appropriate fuel pressure reading (30-someodd psi, as I recall)?

@Gnose: Well, the car has run very well for over 3 decades now with the stock design, so I don't think it's as dire as all that! But yes, I always carry tools and my AAA card. I think those are required items for any antique car -- and really any other car. @Nick: No, there's no way to remove the screen or even to see/look at it without cutting the tank open. The radiator guy insists there's one inside, because he says he's refurbed a couple of Z tanks and even modded one for racing. I have no reason to doubt him. He does that sort of work. He had a late 60's vette and a nice 40's Chrysler in his garage when I was there. The inside of the tank frankly looks amazingly good, aside from a couple of very tiny spots of rust near the drain hole. It's hard to believe the tank is 30+ years old, until you look at the surface rust hiding under the paint on the outside (about what I'd expect). Anyway, for an external filter, I'm thinking I need a high-flow design, and not a filter meant for a carbureted engine, right?

Resurrecting an old thread here, because I still have no answers to my fuel pump/tank questions (and my thread seems to have disappeared)... I am told by my radiator guy (who sometimes refurbishes gas tanks) that the Z's tank (at least the one on my '78) has a filter screen in the sump. The sump apparently is this cylindrical thing, about 4" in dia, standing up vertically from bottom to top in the center of my tank. It's impossible to see the filter screen because it is inside the cylinder. He cautioned me that acid-etching and then epoxy coating the inside of the tank can eat and clog this screen, respectively. Anyway, I have no idea what the filtration properties are of this screen, but would this not be an adequate pre-filter prior to the fuel pump? Thanks!

Funny story! I'm not fully picturing your filler tube issue, as my '78 has a completely different filler design, but I've had success glopping together odd tubes with gorilla glue. It's also good for backing cracked plastic parts (interior panels) with reforcing material. It's actually a very dense polyurethane foam. I don't know whether it will stand up to gasoline, but that's for you to research!

I can't remember the specifics, but the 1, 2, and 3 on the camshaft sprocket is used to compensate for timing chain wear. With a tight, new timing chain, the proper position would be 1. As the chain wears, it can be shifted by a tooth and the sprocket moved to 2... and then another shift to 3.... and then it's worn out.

Is your gasoline fresh?

Yeah, it's the fan clutch. It comes apart the way it looks like it should. Nothing blows up or pops apart into a shower of springs, so it's pretty easy. Once you get it open, clean out the old silicone oil thoroughly. You'll need to circulate some sort of cleaning solvent through it with the halves reassemebled. Then fill up the deeper half with 90 wt gear oil and reassemble. Done.

Jan, those should make a huge difference. I used to live in Texas and had a '75 there. It had a louvered ('78 model) hood on it when I bought it. When that hood perished in an accident, I replaced it with an unvented '75 model hood, which I felt looked better. Unfortunately there was more heat build up, and I do think I had a bit more difficulty with fuel vaporizing in the FI rail after engine shutdown. It might not make much difference in AZ, but keep in mind that the stock lefthand vent (on later years) has a rain deflector to keep rain from coming down directly on the intake system. This blocks much of the needed airflow. FAIW, I don't find the replacement vents that objectionable, but I sure wish I could find some aftermarket OEM style vents to replace mine. Mine are only barely holding together. I think you could make these blend a bit better with some paint that's close to your body color. It wouldn't even have to be an exact match -- maybe a complementing shade in the same color family.

Hi Carlos and Randy, I had the same crumbly fusible link assembly problem on my '78. I couldn't find used blocks anywhere, although I didn't make a completely heroic effort of it. I ultimately switched to maxifuses after briefly considering automotive circuit breakers (which are pretty cool). It's all described here: http://www.classiczcars.com/forums/showthread.php?t=35588 ... with photos. I also did an alternator wire upgrade and headlight relay conversion while I was into the harness. Diagrams are in the above thread.

Thanks, everyone! Steve, if a Flowmaster can last me 10 years, that sounds like a strong contender! From what I'm seeing, I think 2.5" is about the large end of what people are using on these cars. I think I'm reading/learning/hearing that smaller pipe, within reason, results in higher exhaust velocity and therefore better exhaust scavanging. This, in turn, results in more power at lower RPM. I suppose the benefits of a larger dia are seen more at WOT and high RPM, and depite my list name, I'm not really a WOT sort of person (anymore). So I'm thinking 2.5" might be a bit big for my purposes. Even so, it seems to be a rather standard size for exhaust. Fixitman, what does your exhaust sound like, now that it's completed. I'm skeptical of the glass-pack design. Is it loud, mellow, raspy? Does it produce a drone sound at cruising? I might be interested in your tubing and fittings, but might be using another muffler. Care to PM me with your asking prices? I'd still need to find a local shop to put it all together.