Gary in NJ

After hearing stories about stress cracks in the exhaust stack in aircraft similar to my homebuilt I decided to use a ceramic coating on the exhaust system. I was simply amazed with how the coating pulled heat from the exhaust. Moreover, I have well over 1,000 hours on the cross-over system with zero problems. Others I know with the same exhaust system have had failures within a few hundred hours. Ceramic coating works.

When I changed my thermostat last summer I was surprised with the amount of corrosion on the bolts (one of them snapped - that's always fun). In the end I decided to replace the bolts and housing. I would strongly recommend that you use your favorite bolt-loosener liquid (I use ATF & acetone) before removing the bolt and never-seize on reassembly.

We'll need photos for the final decision.

- Float height adjustment? If the gap is too wide you will starve the carb. - Pinched or restricted fuel tube (the one between the float chamber and nozzle)? - A suction piston that gets hung-up?

I'll take the one behind door number 3 please.

Any 240Z manifold will work. Contact ZTherapy as I'm sure they have a few on-hand.

I'm not a fan of the bumpers on the 260Z and 280Z. I'm on the lookout for a 260Z or 280Z project car and one of my first mods will be the elimination of these appendages. I'm thinking about front and rear covers such as the "Stage II" or "Stage III" kits that MSA carries.

It's ethanol, not acid. Disuse is more damaging then bad fuel. That and these are 40 year old cars after all, they need some attention from time to time.

Well that's a good safety feature..now you don't have to worry about the brakes. Congratulations. Now you're down with the sickness.

My garage has always been my hobby hut. It has morphed along with my interests. 1989 - 1994: Built an airplane (RV6) 1996 - 2009: Motorcycle Mania. At one time I had a dozen bikes (GSXR1100, SV650S, VTR1100, YZ250F, KX125, KDX200, KX100, KX65, XR70, XR50, TS-185 & TRX-250). I started selling 'em in 2008 and sold the last one a few months back. 2010 - now: 240Z and I'm looking for a 260 or 280 project. Over the years my garage has also served other functions like a temporary wood shop or band rehearsal space. My garage is MY room in the house; the floor is always clean and it is always organized.

How do you "know" that? Did you perform a load test on the battery? Just because the battery can hold 12.6VDC or more doesn't mean that it can supply the necessary current to crank over a cold engine. Have you put the battery on a charger or tried jump-starting the engine?

I'd pass, afterall it's a ZX.

Have you put a fuel pressure gauge on the fuel line to confirm that the pressure is dropping during operation, or are you assuming that is the cause? You may have a vapor lock issue within the tank and fuel lines (and yes, the evap system). Try starting and running the engine with the fuel cap removed. In fact, if there is a rush of air when you remove the cap, you do have a vapor lock issue. You can check the float height (and changes thereto) by making an external float height gauge with some clear tubing. An idling engine should not produce a significant change in the fuel height within the chamber.

A compression tester and a leak-down tester are two different tools. The compression tester uses the pressure within the cylinder (through aspiration) to check the total pressure within the cylinder. It is a dynamic test of the cylinder and combustion chamber. A leak-down tester uses external pressure from an air compressor. Since the piston is held in place (or selectively moved for advanced testing) during the test this would be considered a static test of the combustion chamber. With a leak down test you can determine the cause or source of any failed or out of tolerance components. While more difficult to conduct and more time consuming to perform, a leak down test is a more useful tool for diagnostics.

I'm sure he can overpay you too, for your troubles. Yeah, some people just suck.

When I use my leak-down tester I first set a reference pressure, i.e 80 psi. My tester holds this pressure within the gauge itself while I fill the cylinder. A very good cylinder will hold about 78 psi, about 98%. An acceptable cylinder will hold between 72 to 77 psi or 90% to 97%. So my leak-down tester has two gauges, a reference gauge and a cylinder gauge. When I'm done testing all of my cylinders I have a record for each cylinder that looks like this: #1 78/80 #2 76/80 #3 78/80 #4 77/80 #5 78/80 #6 72/80 The next time I run the test I can compare these figures with the current reading. The longer the history, the more validity to the test. This is the common practice in the aircraft industry which is where I have my mechanical training.

If a cylinder goes instantly to 0, then that cylinder can not support combustion. If the engine really has three dead cylinders, you'd know it. The engine would be rough running and more then likely smoking from the exhaust. Re-run the differential pressure test, but this time do it with the valve cover off the engine. This will allow you to confirm that both valves are closed; and if air is getting by the guide you can feel it at the source. I'm not sure what tool you are using for the leak-down test. I use an aviation style differential pressure tester. I believe the inexpensive lead-down testers accomplish the same thing. I usually use 80 psi for a leak-down test. Any cylinder that can hold 72 psi is a-ok. Below that I start to look for a source of the leak.

Hold on there, not so fast. I believe the bolts are stretch fit bolts and are intended to be (final) tightened once. The tightening sequence is to tighten all bolts to 32.5 ft-lbs and set final torque to 47 ft-lbs. The bolts are tightened from the center (cylinder 3) to the outer (1 & 6). If you have a loose bolt or bolts, then you may also be in need of a head gasket. Is your head gasket leaking?

Score!

Never happened....until we have photographic evidence.

I am not using "R" plugs on my 240Z, but I am using the NGK wires. I get ZERO noise in my Alpine AM/FM/CD/MP3 head unit.

It's either missing or has morphed into a fine-wire plug.

To do a proper reading, we would need to see into the plugs to see the insulator. With that said, if these were "high-mileage" plugs (5,000 or more miles) they look good from the outside. It's hard to determine mixture from high mileage plugs because is not unusual for them to be coated with carbon. They appear to be dry with no unusual wear patterns. Numbers 5 & 6 look a little better then the others. WHen you say the engine was hard to start after the replacement, could you describe what you mean and what other work was done along with the plug swap.

Why did you change your post? Got called out on your "Marketing" position with ZCCA? Yes, you fit the classic profile of a forum troll.

I'm with you Mitch. I'm not opposed to driving in the cold, but NJ coats the roads with so much salt and sand it takes a good month of rain to wash it all away. If it doesn't snow again this year (I haven't seen grass since Christmas), my car wont see public roads until March.