Ok.. This thread is to let everyone know any tricks or just common sense ways to trouble shoot problems with engines or anything Z related.
i'll start with a quick example...

Dont you just hate it when your engine wont run on all cylinders???
could be a plug??? could be a burnt valve???
This is a trick i found to find out which cylinder is at fault.
Usually u can use a pair of INSULATED pliers and take each lead off to listen for a difference in the engine idle.. If there's a big difference when you take the lead off then you know that cylinder is firing. if there's no difference or very little usually you've found the missing cylinder..
Try this.

start the engine for about 30 seconds. Then turn it off. use your bare finger to feel the exhaust of each cylinder. you should only have to touch each exhaust pipe for about quarter second to see if its hot.(if that) If you can keep your finger on it for more than a second then that cylinder is not firing.
extractors make this really easy. its a bit harder with a stock manifold.
otherwise try feeling the spark plugs.

Everything should be really hot. if you feel its cooler than the rest then you've probly found the problem.

After you know which cylinder is off you can go ahead and check plugs/lead etc.

This will work on any engine too..
i hate pulling leads off and getting Zapped!!!!!!! heheheheheh

I did this trick this morning when it sounded like it was not on all cylinders. i quickly found number 2 extractor was cool compared to the rest which just about burnt me touching it.
Pulled the plug out and it was fouled up. gave it a clean and she was back to normal..
this took all of about 2 minutes to diagnose and fix...

Let us know your quirky tricks....

Gearsticks for 240-280Z
if you cant find one the Datsun 120Y (B210) has the same stick and input.
there's alot of different sticks. Mainly its the bends in the stick. watch out for this!!!!. i converted a 240 to a 260 box and cut the hole a little so the stick would clear it only to find that when i put the console back in it got in the way.. grrrrrrr....

Can I add one?

Elusive Vacuum Leak......"someplace"......

1. Your engine is running rough and acting like you have a leak, but you can't find it. You've sprayed the (cold) running engine with starting fluid but the RPMs never jumped up (which would indicate the location of the leak).

2. With the engine idling, STEP ON THE BRAKE. If the engine dies immediately, you PROBABLY have a small tear in the brake power booster diaphragm. The tear might be small enough to let the engine run and even idle (rough), but when you press on the pedal, the plunger inside the booster opens the tear, opening your intake manifold to atmosphere and killing your engine.

If the engine stumbles but doesn't die when you press the pedal, your leak is elsewhere. The stumble is your engine's reaction to the vacuum booster using most of the remaining vacuum in the manifold when there is already a leak somewhere else.

3. Test the booster by disconnecting the vacuum line from the manifold and fully plugging the manifold hole. If the engine smoothes out and idles nicely, you've isolated the problem to the brake system. *(plugging the booster end of the hose doesn't necessarily test it, since the hose itself might be the source of the leak. Always plug the manifold instead).

AND of course, make sure your one-way NON RETURN VALVE is installed properly! Mine was reversed, causing air to flow only INTO the booster instead of into the manifold. That stalled the engine and gave me no power brakes until I reversed it. Duh!:lol:

Frank

Thats a good one Frank,,
got any more???

poor idle can usually be the result of a leaking manifold. problem is there r soo many spots it can leak from. best thing is too completely tear it down then put it back together with new gaskets and even plumbers tape on things like the pc valve.
The heat spacers between the carb and manifolds can be a problem too. Make sure the gaskets r good on both sides.

Here is one of my favorites:

- Trying to find a vacuum leak or just want to know if there is a leak somewhere in your intake system? Take a spray can of carb cleaner and spray a shot at places you think there might be a leak (carb cleaner is safe). If the engine speeds up a few rpm you have found your leak as the engine has sucked the cleaner at that location (and burned it).

_________________
Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

Yup! did this before on an old carbed camry (or corolla? I forget) and it works like a charm. Found the vacuum leak in no time.

_________________


-Chris

haha..
i just use straight petrol...
what can i say, im a bush mechanic!!!!

i got another one....

if your having problems with spark then try this.. instead of having 2 people handy, 1 to crank the engine 1 to watch the spark gap (points)..

Turn ignition ON.
get a insulated flat head screwdriver and touch the points with it.. you can even pry the points open to touch the matting surfaces. you should get some arching or sparking..

sometimes with new points i've found i've had to do this to get the spark going.

one more..

If you need to rotate your engine slowly to get it to TDC or wherever.
put the car in gear. 4th or 5th.. Handbrake OFF..
Then push the car forward (with a bit of effort) till the engine has turned to where you want it...

Take it out of gear again before starting!!!!!!!!!!!!!

Ahhh, sparkies. My dad taught me this one when I was a kid:
Engine skipping or missing at speed, and you suspect a bad plug wire? Take the car someplace completely dark and have a friend race the engine while you look under the hood. You might be able to SEE the sparks.

We had a '56 Chevy 265-V8 which ran fine at idle and lowspeeds, but broke up at higher RPM. Took it to the dark and took turns watching it while the other raced the engine. At higher speeds (anything above 3,000rpm for those old chevys:lol:) it looked like a Christmas tree under there. Sparks were bouncing around all over the engine.

I stress "taking turns" with one guy watching while the other works the gas, because that means the 'watcher' doesn't have to stick his hands into a dark, running engine bay to work the throttle. Many of us have got away with that over the years, but it only takes ONE contact with a moving fan (or getting your necktie caught up in the moving belt pulley like my buddy did) to make a real believer out of you.

OH, and Cross-Induction!

Did you know that if you run all your sparkplug wires directly beside each other, you can cause them to cross-induce?

Each wire creates its own Electromagnetic field when it sparks. When that field collapses, it can also create a weaker spark in adjacent wires. If you run your wires exactly parallel to each other for a long distance (many like to do that for show because it 'looks better'), they can actually cause each other to spark when it isn't their turn.

Better to cross them up like a Bundle of Snakes.

Also, the better (thicker) the insulation on your wires, the less likely they are to cross-induce. Cheap ones can do it easily.

And setting the proper fuel level for SU carburetors:

Bryan Little, author of THE DATSUN Z GARAGE, has deviZed a neat trick to ensure the crucial fuel level of his SUs is exactly correct. Using the first level invented by Archimedies in 200 B.C., Bryan attached a clear plastic tube OUTSIDE the SU, connecting the floatbowl with with the fuel jet.

Watching the fuel in the tube, he then sets his float bowl level to hold EXACTLY the right amount of fuel. That ensures the fuel level inside the carburetor completely fills (but doesn't exceed) the fuel jet well where the needle enters the jet.

If the fuel level is BELOW the surface of the jet, the carb will run lean and starve for fuel at different engine speeds. If the fuel level EXCEEDS the level of the jet, the engine will run rich and load up at various engine speeds.

Bryan reports that since he did this to both his carbs, his engine idles better, has instant throttle response, and runs smoothly thru the entire engine rev range.

Trying to set the exact fuel level by following the manual's instructions simply doesn't work. The manual only tells you how high the fuel level should be inside the floatbowl, but it's the level AT THE JET which is crucial for optimum performance, and without an Archimedian Level outside the carb, you can't see that inside the SU.

I'm trying to convince Bryan to give a SHOW AND TELL on his discovery at one of our future meetings.

What a brain this guy is!

hey that sounds great about the SU floats...
i can see how it would work but i cant picture the set up???
would be reallt interested in a photo walkthrough

He has already updated his website (DATSUN Z GARAGE.Com) with a better explanation than I gave. On our Homeage, press his DATSUN Z GARAGE link in the left margin, then press PERFORMANCE TIPS. Scroll down 'till you find the diagram of the SU.

He's also preparing to explain and demonstrate at an upcoming monthly meeting. (Why not come along and sit in on it, Pete? Free piZZa and soda! )

yeah sweet i'll be there...
it'll only cost me $5000 and 10,000 miles worth of travel..heheheehehe
darn!!