240ZMan

The only modification you have to make is to cut off some of the brake backing plate to accomodate the larger caliper. I used a dremmel cutting wheel and it was quite easy. I would imagine this goes for the MSA kit as well. I've read that some people have had to grind down a bump on the outside edge of the caliper so it wouldn't touch the back of the wheel, but I didn't have any clearance issues with mine.

Dogma420, Autozone is where I bought mine as well. A friendly caution: on one caliper the bolts that hold the two halves together weren't fully tightened, and on the other caliper one was missing! The phrase, "you get what you pay for" comes to mind here

They have a female fitting on the end connecting to the line at the frame bracket and a banjo fitting on the end connecting to the caliper.

Sorry I wasn't more clear, mine go from the bracket on the frame directly to the caliper. Fit is excellent.

For those of you with 14 x 7 rims, what are you doing for rubber? I'm not finding any performance tires available in my prefered size of 215/60-14. My '73 is a weekend/occasional track day car only - it doesn't come out when wet or worse so all I care about is dry performance. As it's not a daily driver tire wear doesn't matter too much, as long as it's not ridiculously short. I really like my Enki 92 black mesh rims and don't want to get rid of them.

I put the MSA SS lines on with the 4 piston Toyota calipers sourced from a local parts store last summer as you described. They fit well with no rubbing and I've had a really nice firm pedal since.

Carl, from the outside all looks fine with it. Is there some way besides removing it to check its condition? I guess removing it wouldn't be so bad given how much is already off

In case you were following my fuel problem I've put it on hold due to this issue. I've got a slow coolant leak into the engine. I noticed it when my coolant was low with no visible leak and I had steam coming out of the valve cover vent. Coolant is clean, but oil is milky. Front 3 plugs look fine, rear 3 are a bit dark, possibly due to the steam coming out the vent in the air cleaner that's just in front of the rear carb intake. Compression test ranged from 155 to 175#. I've taken the head off and can't see anything visibly wrong. The N42 head looks fine, and the head gasket looks like new except for being covered in coolant and oil. FWIW, when I first put this L28 (N42 block) in the car I put my old E31 head on it. When I first started it up I saw a small amount of steam from the valve cover vent, but after about half an hour it went away and I never saw the coolant level drop. A few thousand miles later I switched to this N42 head and never noticed steam again until now. This makes me wonder about the block... However, when I installed the head the first time I put a little antisieze on the head bolts as one had broken off when I removed them during the initial tear down. This time when I took the bolts off most seemed to not be torqued down as tight as they were when I installed it, which has me wondering if: 1) shoud I have not used antisieze? 2) could the head not being torqued down enough cause a coolant leak but no other problems? I don't want to just bolt everything back up until I'm sure I've solved the problem.

I ran another experiemnt with the output of the fuel filter run into a gas can. The flow is plenty strong and smooth. I didn't measure the rate, but I can't imagine it wasn't enough for the L28. I put the fuel pressure gauge back in just after the filter. Normal pressure is a rock solid 2 psi. Blipping the throttle will show a very small movement. When the problem shows up I see the guage jumping up to 3 psi and the movement is timed with the stumbling of the engine. It appears that something is causing the pressure to spike briefly and this causes the engine to stumble. Again, only when the under hood temp is high. I also spent some time under the car looking at the routing of the hard fuel lines. This gave me an idea for a new theory. The idea is that the spiking of pressure I'm seeing is fuel percolation (not vapor lock) caused by the fuel being too warm. I suspect the fuel is getting heated some as it flows along the drive line tunnel and then with the hood closed and the engine idling for a few minutes on a warm day, the fuel is just getting too warm. But why for my car and not others in warmer climates? I'm wondering if the return flow is too slow and thus the fuel spends too much time being warmed. I have tried blowing through the return line from the engine compartment and I can blow into it, but it takes a lot of effort. Also, if I put my ear to the fuel filler when the problem is occuring, I can hear the return fuel splashing into the tank, and it's not a smooth flow, but rather a spurt, then a dribble, spurt, etc. So my question becomes what is the best way to clean the return line without removing it from the car? I'm thinking of disconnecting it at the fuel tank and blowing carb cleaner into it from the engine compartment. Any other suggestions?

Forgot to add that taking the fuel cap off doesn't make any difference either.

I tried an experiment today. I took an old electric fuel pump and connected it to the input of the fuel filter. I put the other end of the pump into a 5 gallon gas can. In other words, I took the fuel tank and the lines leading up to the it out of the equation. I let it idle for 20 mintues and not once did it have any issues. After I connected the regular fuel line back up immediately it didn't want to idle well. Also before it's suggested the problem is with the fuel pump, the one I used for this experiment was removed from this car because it was too loud, and I had the same idle problem with it when it was installed. Carl, I changed the fuel line you described but unfortunately for me, it didn't make any difference. So I figure it's either the hard line between the fuel pump and the filter, or it's the tank. What I can't explain is how the tank could be causing this problem. Remember, if I leave the hood up, the problem never appears. Does this new information give anyone some idea of what is going on? Thanks for staying with me on this one.

This discussion has me thinking it may not be boiling of the fuel. I had originally thought it was because: 1) the problem only occurs when the underhood temp rises 2) I saw bubbles in the filter 3) opening the hood and letting things cool makes the bubbles and the problem go away. I agree that I can't offer a good source of heat on that side of the engine. But I also can't explain why air would be sucked into the fuel system prior to the filter only when the underhood temp goes up. I know I'm missing something here - just don't know what it is! Still stumped!

The car used to have the dealer installed insulation and the problem was present. I've since removed it, and have temporarily used some pipe insulation. Didn't make a difference. FWIW, I don't think the problem is heat on that side of the engine. Although I have a header now, I have a very large heat shield protecting the carbs. And I had this problem with the stock engine, exhaust, emissions, etc. before.

If I let the engine idle parked for 5 - 10 minutes (more or less depending on how warm the day is) the problem appears. When I open the hood the problem goes away within a few minutes. I've definitely confirmed it's a heat issue as during the winter it rarely occurs, and in the summer, it's quite often. This problem has been with me since I've had the car (about 1 1/2 years). Since then the entire engine and carburation system has been replaced with the exception of the intake manifold and fuel rail. Once the engine is much above 1k rpm the symptoms go away. My current solution is to lean the carbs as much as I can without killing the drivability and keep the idle speed above 1k rpm. Even then it doesn't idle smoothly when the underhood temp goes up but at least it doesn't stall.

I have tried removing the cap and driving around with no difference. Sometimes there is positive pressure in the tank (the lid pops up a little) but I've never noticed a vacuum.

The problem was there when I used the mechanical pump, and when I changed to the L28 I switched to an electric. Problem stayed the same. But your thought of gathering bubbles from a leak is interesting. I'm not able to come up with an explanation for how they get there though. The electric pump is back at the tank and if there was a pin hole in a line I'd expect it to leak fuel which isn't happening. I'll guess the problem would be between the tank and the pump? And why would increasing the temp under the hood cause this? If I open the hood everything returns to normal within a few moments. FWIW, I've tried leaving the gas cap off but that didn't make any difference either. As I said, I'm stumped :stupid:

I've had the problem with both regular and premium gas across different brands as well. I did a little looking for the boiling point of gasoline and it turns out there isn't one particular temperature. Gasoline is a blend that is different for each batch. Some of the components with a lower BP start to vaporize as low as 104 degrees F. That doesn't mean you're going to have vapor lock at the temp though. There wasn't any discussion I found relating octane rating to BP.

I did run with a fuel pressure gauge spliced in just after the filter for a few weeks. The pressure seems to stay the same, about 2 - 3 psi all the time. It's a mechanical gauge and I wonder if there are spikes that it doesn't pick up. I'm not running with a pressure regulator. I toyed with buying one of those IR temp readers, but for nearly $100 I was hoping to avoid it, not that I wouldn't like to add it to my tool collection And assuming it confirms the fuel is boiling, I'm back to the question of why does it happen on realitively cool days?

Some time ago I posted this thread http://www.classiczcars.com/forums/showthread.php?t=10041 but never resolved my issue. Basically whenever the under hood temperature rises, my engine begins to stumble at idle. This happens at moderate temps, such as today when the air temp was about 60. If I let the engine idle for a few minutes the problem begins. Today I discovered that when the problem occurs, I can see bubbles coming out of the fuel filter mounted on the right fender. (The filter is clear plastic.)The fuel level in the filter is almost at the bottom of it. I'm running an electric fuel pump only (no mechanical), although I used to have the same problem when I used the mechanical one. If I leave the hood up for a few minutes the bubbles go away, the fuel level in the filter rises to the top, and the engine idles fine. I'm pretty sure now I have a vapor lock type situation, but what has me confused is what is heating the fuel on that side of the engine. I read about people in Arizona driving their carburated Z's in August without vapor lock, and I'm having problems in March in Colorado! FWIW, I've confirmed that the fuel return is indeed working as I can hear the fuel coming back into the tank if I remove the fuel cap and put my ear down. This problem has been with the car since I got it almost 2 years ago. Since then I've put a new motor in, rebuilt the carbs with Z-Therapy bodies, changed all the fuel hoses (not the metal lines though), and the problem remains. I even bought a second set of carbs on eBay and the problem remained. At this point I'm thinking it must be a fuel system problem, but I am out of ideas of what to do to prevent the fuel from boiling BEFORE it crosses over the enginer and gets to the really warm side! Oh, since my original post I've also put a new 3 row radiator in, and replaced the fan clutch. Other than this issue I don't have any heat issues. Any suggestions?

Contact MSA at 800-633-6331 for a gasket specifically for headers. Also, if the leak is in one of the corners of a port, you may have an alignment problem that a thicker gasket will have a hard time fixing. I had to lift my header from the back end before tightening the flange nuts to solve a leak.

Is there any trick to driving the races back into the hub, besides the usual "go slowly"? Anyone find a good source for a drift to use?

Will, I thought about what you said before I posted the question. However, there is a lot of experience in this group, and I'd rather do the job once, not twice. If it turns out that the hub needs to be replaced along with the bearing most of the time, then maybe I'll do it all at one time. That was the type of feedback I was looking for.

Ed, part of me thinks just like you suggested and wants to just tighten it a bit more. But the other part of me worries that if the bearing is really the problem, it may lead to the bearing disintegrating, or seizing, or worse (if that's possible) and more than likely that will happen as I hit 90 mph on the back stretch... I guess I'm wondering if others have found that changing just the bearings solved this this, or if the hub and/or spindle are likely to be bad as well.

At the recent track day tech inspection the tech was a little worried about one of my front wheel bearings. He felt that since there was a very small, but noticable, movement when you push in and out on the top of the tire that I should be thinking about changing them. A few weeks before I had retorqued them per the FSM so I don't think I can "adjust" them to deal with this. The car has over 200k miles. My question is if changing the bearings is likely to tighten things up, or if the wear might be in the races or shaft? I know it can't be diagnosed without taking it apart, I'm just looking for what others have found on older Z's.

MrMarcDude, if you're interested, I have an N47 head from my donor L28 in what looks to be very good condition. PM me if you're interested and I'll give you more details.