NewZed

Curious if you know the diameter of the BMW slave cylinder. There have been quite a few questions lately about making the clutch work after an engine swap. Seems like the manufacturers would just match the cylinders and do the geometry at the pedal and fork to get travel, but who knows.

He said problem solved. He's on to the next one...

It's a well-worn path. Good luck.

This is the important part. If the pressure plate is the same type as the Z engine, and the fork ratio is the same, there's no good reason to change any of the hydraulics. Slave stroke calculated with fork ratio gives throwout sleeve travel. That's what disengages the clutch.

Got a tape measure? Take some measurements.

Try pumping the pedal. If you have air in the lines pumping will push more fluid in and compress it, causing the pistons to move. It will be a clue. And if one side(end) has air it will affect the other side. So you can't just ignore the fronts and expect the backs to be good. You might want to try a power bleeder, to push or pull fluid through. Are the bleed valve passages at the very top of the caliper piston bores? Sometimes they run a diagonal channel from the bleed screw so you have to look at the casting to see where the actual passage is drilled. It needs to be at the top where the air bubble sits. Pretty common for some of the conversion to have bleed valve orientation problems. You might have to pull a bolt and twist the caliper just for bleeding.

Describe the engine. Post pictures. Start a new thread. This one is very old and looks to be about Chevy's.

I said "dog bones" in my post, but I should have said "drop downs" or hangers. The two parts the "dog bone" attaches to to create a square support structure, that the rear of the control arms seat in.. It's not clear from their drawing if they got rid or that or not. The two studs for the mustache bar weren't meant to handle the lateral forces that they would see if those guys are really using them as the attachment points for the cradle. Those two studs just direct the mustache bar forces and have to handle the inertia of the eighty pound diff on corner. Full disclosure, I'm just here for the puzzle. Some pictures of the parts actually in a car would tell a lot. Poor marketing.

It looks like they're also using the mustache bar hanger bolts as the mounting points for the back of the control arm hardware. They got rid of the "dog bones". Definitely some odd engineering going on.

But, with the picture it is possible to guess at what you meant. There is a solid metal path from the diff's back mount up to the cradle's front mount. The bushings are basically useless, except for allowing for manufacturing error. Loose tolerance. As the diff nose comes up it will lever those back tabs because the diff's front bushings will let the nose move up. That's as the drawing shows. The drawing might be wrong. The factory Z control arm mounts have bushings at the front. Maybe they forgot to put them in the drawing. That would make the cradle fully floating, in rubber bushings. It still leaves the diff housing half solid and half bushed, as you said. It lets the diff apply bending forces to the cradle alone. So, it is kind of a goofy design. Well made though. They need to either make the diff fully bushed or the cradle. The drawing shows that they went halfway on each. Too bad they don't have some pictures of the parts in a car. Weird.

You should write better. Not kidding, your post isn't clear. The Ford diff housing is "bushed" around the mounting bolts. You only talked about the front of the diff. Maybe you meant something else. Or maybe you got the wrong bushings with your diff. Unclear - "There is no bushing where the front of the cradle attaches. There is only bushing on the mustache bar. Thus the cradle is half solid mounted half soft mounted. There is the stock bushing on the front of the diff to the cradle, but then there is just a rubber bushing shoved in as a washer between the diff cover bolts to the mounting tab,"

It is kind of funny how few pictures they have of a differential housing actually mounted in any of their systems. Hundreds of pictures of fabricated steel but almost none of an installed system. They could use a marketing class or two. Here's one that shows the Ford bushings in place, with the rest of the Z car system. Even this page and photo doesn't even really tell you what it is. Fabrication skills and business skills aren't often found together.

Stick a piece of all-thread in a drill and use two nuts to attach a piece of abrasive material to the all-thread. It took 30+ years for that rust to build up. Be careful with the POR if you put it on too thick you won't be able to get the shock in the tube. Get it too thick on the bottom and your gland nut won't fit.

They're out there somewhere... https://www.facebook.com/apexengineered/

That's a good point. I might be wrong on the second part about CR, haven't had the thought in my mind for quite a while. The displacement part is right though, and that's how engines are described. Size. My mistake. https://engineeringinsider.org/basic-definitions-used-engine-terminology/3/

They look like the T/C rod bushings.

You must be thinking of total cylinder volume at the bottom of the stroke. The combustion chamber is not included in displacement. Because "displacement" is, literally, the volume that is displaced, or moved, by the piston during its stroke. You could call it "swept volume", for example. Compression ratio is the displacement volume divided by the combustion chamber volume. All of that displaced material is packed in to the tiny combustion chamber.

The old cam probably flattened a lobe so it was repaired with that one because they had it in stock. Odd timing coincidence...

People have had problems with broken solder joints in the ECU that were fixed temporarily by tapping or banging on the ECU with their hand or foot. Easy to try, when it cuts out reach down and start banging and see if it restarts. Opening and closing the door or the hood might have the same effect, explaining why it restarts for no apparent reason. If that has an effect at least you'll know what to look at. Apparently the solder joints at the plug connection are the bad ones. Some people have success reflowing them all. The loose key is very common. Almost everybody can pull the key out of the switch at any position. That's not an electrical problem though.

So it runs now, or it hasn't started since it died? Can't tell if "ran" means just the fuel pump or the engine. The ballast has resistance so coil + ballast would be the two resistances combined. The coil reading is high though. Just get a stock aftermarket coil from Autozone. Most fo the name brand coils are plain old coils with colored labels. Check the resistance and wiring in the distributor also. Sometimes the breaker plate moving can short the wires to the pickup coil. Probably a good time to just go through all of the electrical specs and adjustments, like the air gap. Sudden dying can be the ECU also. That's a hard one to diagnose.

There are other ways for water or coolant to get in to the engine. Have you checked you oil lately? If water is leaking in to a cylinder some will leak past the rings. See if your oil level has increased. If it has there is probably water at the bottom of the oil pan, if it hasn't already blended in to the oil. If the smoke is gone after 2-3 minutes, does the smoke really matter much? Places for coolant to get in are cracks in the cylinder head or erosion of the cooling passages in the timing chain cover. Also, the bolts to the thermostat housing pass in to the timing chain cover. A crack in the cylinder head can let coolant directly in to the intake system, in to ne of the runners. From there it might drain back to the plenum where it can get in to all of the cylinders. You might pull your spark plugs and see if one is abnormally clean. Water in the cylinders will clean them up. Might help you narrow the focus. If there's no water in the oil and the engine isn't locking, hydraulically, you won't do any damage by letting it burn off whatever gets in there. People actually build systems to squirt water in to their engines. Some people pour water in through the carburetors to clean carbon out.

It's warmed up when the temperature gauge says so. I'm not sure how your engine has been modified. Sounds like you have an electric fan? Run by a thermo-switch? A stock L28 has a fan clutch. the fan can only go as fast as the engine does. A head gasket will blow exhaust in to the cooling system when the engine is running. Is it possible that you punched a hole in to your intake system or cracked something and your "fix" is allowing coolant in to the intake? Is this s turbo engine? Does the white smoke smell like antifreeze? All engines have moisture from the exhaust when cold. It's a byproduct of combustion. Just need more details about your setup. Not enough here to say what's happening.

Did you let it get fully warmed up? Won't hurt to run it if it is a head gasket problem. Make sure first. Get it to full temperature and let it run for a while. You can't overfill the cooling system. It will release through the radiator cap if pressure gets too high.

Self-adjusting just means that the hydraulic cylinder will pull enough fluid in on its backstroke to get a full stroke on the next pedal press. So, even if you adjust the rod at the slave cylinder it will still push the same distance. The ratio of your clutch pedal would need to be like that of a Supra if you wanted to compare those parts. But, it might be easier to just find a Supra manual and see what the slave cylinder stroke is supposed to be. Then do the math on your car to see what slave cylinder stroke you'll get with a 7/8" master. There's no easy way without digging in to the math, unless you just put it together and measure what happens. There is stuff in the manuals. Here are some examples, from the 78 280Z FSM. The pedal picture is probably to scale so you could take measurements and compare to a supra to see if you need the 7/8" cylinder. If the pedals are the same, Z to Supra, then you probably want a 5/8" master. I'd say, odds are good that you should run the Z parts on the Supra clutch. They're both Japanese sports cars. Put the 5/8" master on and forge ahead.

Hydraulic clutches are essentially self-adjusting. The throw will depend on cylinder travel. So it's your clutch pedal throw that will determine the hydraulic piston travel. Anyway, it's not adjustable. It's designed in to the system. And, the transmission has nothing to do with clutch fork or clutch hydraulics. The only thing the transmission does is provided a spot to hang the slave cylinder. Describe your other parts. Engine, clutch, slave cylinder, etc. You've probably done it somewhere else but it's not in this post.