ConchZ

If by blowback you mean that it is backfiring or popping through the carb, the first thing to try is to richen up the mixture on that carb, as that will cure "lean pops" through the carb.

I think you also need to consider the vacuum line for the power brake booster. It's a preformed rubber hose and the routing is slightly different for a 73/74 than an older balance tube. I have a 73 with round tops. My PO kept the original intake and balance tube, but I have a really nice polished set of intakes and matching balance tube that I want to swap on there this winter. However, I'll have to buy a different vacuum line.

The fuel pouring out of the overflow on the float bowl is a big clue that you've got a float valve problem, and it's stuck open now, but it could also stick shut. This worked for me once. Use the back end of the screw driver to whack the float bowl to see if you can jar it loose for at least long enough to get you home, then take off the float bowl covers and clean it up/out. If you're having problems with the float valve, that's the place to start for your drivability issue. I've had mine stick open and stick shut. Either way will cause the car to buck and hiccup. You gotta clean them up and reset the float levels once you are done. You could spray carb cleaner down and around the valve and work it to see if you can loosen it up. Blow through the inlet on the top of the bowl to verify the valve is opening and closing appropriately. Next place to check is the choke cables. Are they still set right, or did one of them come loose,, leaving the nozzle too far down/up. Sounds weird, but it's happened to me. After the above, recheck your timing, then take if for a ride. If you still have problems, go after the ignition components.

Does anyone know where I can get a new set of downpipes for the stock 1973 manifold? Do I have to get them custom made? Has anyone done that, and what did it cost? If I can't get new downpipes for a reasonable cost, my only options are: 1) Headers, or 2) Find an older exhaust manifold and use the MSA exhaust kit (MSA doesn't make it for 1973 manifold). Any other ideas? Thanks!

http://www.thezstore.com/page/TZS/PROD/23-4166 or http://www.zcarsource.com/upper-strut-spacer-rear-70-78-new_8_54060_48618.html There used to be a diagram in the blackdragon catalog, but I can't find it there anymore. Maybe someone can post it for you. Without these little 1/2" spacers, you get a slightly sagging rear end.

You are correct, carb cleaner is flamable. My bad. However, spraying it into the carb of a running car in my experience usually results in a stumble. It isn't flamability, but rather liquidity that is the problem.

I think that if your strut mounts aren't falling apart, then you don't need to replace them. I lived on a small island when I redid my suspension, so I ordered pretty much everything I thought I would need, including strut mounts, just so I would have it. The new strut mounts looked just like my old ones, which were probably original. One thing I didn't order was the spacer that goes between the spring perch and the strut mount. Originally rubber, they disintegrated quick. Go with poly here, just because the part takes a lot of wear. MSA sells them, or you can make some out of a poly bump stop by cutting it down. As for KYBs, I have them, but I also have the Eibach springs and poly bushings. The ride is rather rough, but I don't think its because of the Eibachs.

Starter fluid or ether would make the idle go up, but carb cleaner isn't combustible. As for throttle shaft leakage at highway speeds, you are probably right. The unmetered air getting past the throttle shaft bushings would go down as a percentage of total air flowing through the carb, as compared to its percentage at idle. Since I don't have idle problems, is it safe to say that my slight leaks around the throttle shafts is pretty normal?

Starter fluid or ether would make the idle go up, but carb cleaner isn't combustible. As for throttle shaft leakage at highway speeds, you are probably right. The unmetered air getting past the throttle shaft bushings would go down as a percentage of total air flowing through the carb, as compared to its percentage at idle. Since I don't have idle problems, is it safe to say that my slight leaks around the throttle shafts is pretty normal?

Ok, I swapped over my other set of SUs. Car fired right up, idled too high...oops, forgot the return springs. Put them on, and it idles just fine. Sprayed a little carb cleaner around the throttle shafts, and got the same effect as with the other carbs. A slowing of the idle speed. Maybe this is normal? I can't imagine throttle shaft bushings being air tight. There must be some leakage. Why am I worried about this in the first place, you may ask? The car runs fine. It all started with diagnosing hot running at highway speeds. After checking everything I could think of, I thought maybe its running lean, so I started looking for air leaks. I may have solved the highway heat problem, it was bad connections in the inline fuse holder on the electric fans. I just need a hot day to test if it's cured. Should I just stop messing with these carbs? BTW, I also solved the vapor lock problem. First, I bent the fuel rail back as far away from the head as I could. This helped a lot, but didn't cure it. Next, my other set of carbs came with insulators that were over twice as thick as the ones with the other carbs. These cured the problem. Matt

Thanks P and J.

I would caution everyone to use Teflon(PTFE) rings, and not plain rubber. Just imagine a ring deteriorating in gas fumes and heat to the point that it breaks and gets sucked into the intake. Where to get some PTFE rings of the appropriate size?

That's awesome. Might have to try it. Wonder if my grandpa's old shopsmith can be used to turn that.

Thanks again Leon. Your explanation about the timing makes sense, and fits with articles I've read. My heater hoses are a few years old, and I think I put them on right. I don't think they would have fit any other way, and the heater works when needed. The thermostat is a 180 Nissan unit that I tested in a pan on the stove. It starts opening around 180, and does open up fully. Out of curiousity, can someone hit their thermostat housing with an infrared thermometer after a long drive and tell me what it reads? I wonder if the outside of the housing reads 200 on everyone's due to the exhaust manifold below it. I may be chasing something that isn't really a problem. As for the carbs...well darn. At least I've got some other ones I will try.

Blue, were you happy with this fix? Did it last? Matt

Thanks Leon. I did change the water pump and thermostat when I did the fans and radiator, which was somehow dented by the PO on the bottom right and had a slight leak around the hose neck. As for timing, I set it to about factory. I couldn't tell you if I'm losing power over the previous too advanced setting, but it does seem to take less throtle input to cruise on the freeway, otherwise the performance is unchanged. I wanted to set it to specs until I diagnosed everything else, and may raise it back up a bit later. In any case, it's just nice to be able to adjust it, now that I figured out that optical trigger. I'm pretty sure my piston/head combo is stock 73. I don't think the head's ever been off. The car only has 105k well documented miles. The original owner kept every receipt and even logged his gas mileage... Like I said, I have a really nice set of polished SUs and pretty intakes that I got from another member. I was planning to put them on this winter, when I had time to also pull the exhaust manifold and clean it up. I then want to sell the ones on the car, but I want to be able to honestly represent them to potential buyers, hence my recent hot weather testing/tweaking. They come with nice K&N filters with internal air horns, and they look decent. Guess the value drops significantly with a throttle shaft leak, though. Think the idea in this thread would patch them up for a while? http://www.classiczcars.com/forums/thread43184.html So you say 200-210 degrees at the thermostat housing is normal on a long freeway cruise on a hot day? Think its normal for that to drop 20 degrees after idling in stop and go traffic with the AC running? Let me close by saying the car seems to run perfectly, other than the highway cruise temps, and the recently increased exhaust temps. It starts first try, with a rock solid idle and revs to 6500 rpm under load just fine. Maybe I should just leave it alone until I have time to swap to the nice carbs.

Hi all, As some of you may remember, last summer I improved my AC cooling by installing MSA's dual electric radiator fans and aluminum shroud. The side effect was that it made my car run hotter on extended freeway drives. It was really strange. The temps would drop as soon as i got off the freeway and into stop and go traffic. Thinking that the shroud was blocking too much airflow, I removed one of the fans. The summer heat let up last year before I really had time to decide if that made a difference, but I think it helped a bit. Well, it got worse this summer. The temps would get up as high as 210, as measured by an infrared thermometer pointed at the thermostat housing. This has been causing vapor locking, and the car will ping under acceleration when it gets that hot. I mostly cured the vapor locking by bending the fuel rail back from the head. I think it was pushed towards the head somewhere in its life. I then tackled the pinging. The original owner replaced the points with a Crane Fireball 700 optical trigger system, and I could never get the initial advance set below 18 at 750 rpm, with it at 43 when at 3000 rpm. Except when it runs hot, there's never been any pinging. Since it recently got worse, I studied the optical trigger and noticed it was adjustable, so I moved it a bit and was then able to set the timing to about 8 initial and 32 fully advanced. The car seems to now run a little cooler, but it still creeps up to 200 degrees on a long hot drive. The exhaust temps now seem hotter, as evidenced by my warmer feet and butt. The infrared shows the manifold is around 350 degrees. Is that normal? Thinking that the extra exhaust heat is related to lean fuel mixture, I remembered that I can never get the rear carb adjusted right. I sometimes get lean pops out of it on a cold start up, even with the mixture nut down a full 5 turns, and lifting the piston a bit always causes a stumble, indicating it's too lean. Using plastic tubes on the drain plugs of the 4 screw carbs (it's a 73 with older carbs), I have set the fuel level to 23mm below the rim of the float bowls. At that level(5 full turns down and 23mm fuel level), there's not any gas pooling on top of the jet, so maybe I need to raise the float level? I would think the top of the jet would be drowning in fuel. In any case, last night I decided to test the throttle shaft bushings by spraying carb cleaner on them with the engine running. Sure enough, I get a stumble. I assume my lean running is at least partly caused by worn throttle shaft bushings? These carbs have been on the car for about 30,000 miles, and were not new when the original owner put them on the car. I have some really nice shiny SUs that I could swap on there, but I really want to use these as a learning experience first. Why am I not seeing fuel on the jet? Is the lean condition causing abnormal exhaust heat? Did the advanced timing contribute to the high heat on the highway? Thanks, Matt

I'm really happy with my Bridgestone Potenza Pole Positions. 195x60x14. Quiet ride with good handling for a decent price.

I think I paid about 12OO labor for a very, very nice job. They put in those bad dog pans. Good as new.

Sorry to bring up an old thread, but I have lost one of these large bolts. I cannot find them online or in any local hardware stores. The size is M22 x 1.50 x 30. Does anyone have one, or know where I can get one? I need the big washer and the toothed ring, too. Thanks, Matt

I had a red B210 briefly while in college. It was a fun little car. Sold it and got a 77 Celica liftback, which got ran over by a trash truck while it was parked near a dumpster. I'll miss out on Branson. My brother's getting married.

http://kansascity.craigslist.org/cto/2908810795.html Are these things really worth this much? A grand for a clapped out, barn yard find?

Thanks John. I think I can cut the poly bump stops that I have. Will give it a shot tomorrow.

Those door panels are getting old and crumbly. A suggestion is to make yourself a tool out of a wide blade putty knife. Cut a v-notch about an inch deep into the middle of the blade. Slip the blade under the panel so that the clip fits into the v-notch, and then pry. This will mitigate the chance that you damage the panel.

About three years ago, I replaced my springs and struts. After nearly three years, first one side and then the other developed a random thunk associated with going over bumps. I read up enough to guess that it was because the strut cartridge was moving vertically in its tube, either because the gland nut wasn't tight, or there weren't enough spacers in the tube. I dropped the rear suspension, and took a look. The gland nut was tight, but it was cranked all the way down. While the strut seemed tight in the tube, I found no spacers in the tube. I just didn't think you needed them back when I did the job. I put spacers in the tube, cranked the gland nut back on tight, and began to reassemble. I then noticed I was missing those rubber spacers that fit between the top side of the spring perch and the bottom of the strut insulator. I definitely remember putting them on, and remember using rubber ones, instead of poly. I bought them from MSA, and they were out of the poly at the time, so I went with rubber. Since they are gone, I assume they disintegrated. Well, I happen to have two never used poly bump stops. They are the about the right diameter, but taller than those spacers, but I could cut them down. Does anyone know how tall those spacers are? I seem to remember they were about a half inch thick. Also, could these missing rubber spacers be the cause of my random thunk when going over bumps? The thunking didn't start for at least a couple of years, and it started on one side, then the other, maybe as the rubber spacers fell apart. There's some extra slack in that strut assembly because I'm using Eibach springs, which are shorter than stock. Without the spacer, maybe when you hit a bump just right, you get a thunk. Everything else seems tight as can be on the rear suspension. Make any sense? Matt