Diseazd

Nyuck! Nyuck! Nyuck!

Bruce and Steve are "The Man". Good job on making your 73 much improved!

I'm betting it's electrical now.......plugs, points, condenser......maybe a bad plug wire.....I once had a similar problem with almost new plug wires. When I put a new distributor cap on there was a green electrical corrosion where the wire snapped into the cap.

I need a reaction disc out of an early master vac brake booster. Anyone got an old brake booster that they could dig one out for me. Happy to pay for your effort and postage. Thanks Guy

Clean up the contacts at the battery and the starter.

Jeff.....Please do......anytime you pass thru Richmond, you've got a place to stay.....some good whiskey to drink.....a good steak and some good car talk from both me and Five and Dime.......would love to meet you. Guy

He makes the "Old Man" proud!!

Ditto that....

Great practice for your first Z!!

Your problem is in the ignition. Like Steve said.........get a copy of How to Rebuild your Datsun/Nissan OHC Engine. When you install the distributor drive/oil pump shaft, pay special attention to the tang position (half moon tang) that hooks up with your distributor. When your engine is on TDC (compression stroke), if installed correctly, the distributor rotor should be pointing to the number 1 wire in the distributor. Then, remember that the rotor turns counter clockwise.......verify firing order. Sounds like one of these items has been overlooked. If you have a new chain and a stock cam, degreeing your cam is not your problem. All of this assuming that you installed the timing chain correctly (of course).

Re the revving.....If it's not the pedal getting stuck on the floor mats, check the brake booster line on the firewall. If the hose gets out of the bracket, it can lodge against the throttle linkage. It doesn't take much pressure to keep the linkage from returning to idle.

I agree with the Captain........Install a set of working carbs and eliminate carbs as your problem. This thread is going to last forever.

The bottom of the shank should be flush with the bottom of the piston....not the bottom of the groove.

Chach.....My guess is the previous owner did a conversion on your diff. The early cars had the half shafts coming forward slightly to the diff. The fix was a slightly longer (later Z) driveshaft, a 72 or later hanger and a 72 or later mustache bar ( not straight like the early cars) and then you would reverse the diff mount or use a 71 or later mount (which moved the diff back a couple inches). All of this moved the diff back, made your half shafts come straight to the diff and got rid of a vibration found in early Z cars. However, when this was done , the diff strap now was 2 inches or so forward on the diff.....it was obstructed by the two bolts. It could be put on, but was stretched tight. Look at your mustache bar. If it isn't straight, you probably have a converted early Z.

Zedy.....One more thought. I know you replaced the distributor with Steve's with no change, but my guess is you still used your distributor cap. Cracks in a distributor cap or rotor sometimes can be almost invisible. Have you tried a new cap and rotor? A hairline crack in the rotor or distributor cap can leak voltage at high RPM causing symptoms similar to yours. Just a thought. Guy

Certainly smells like a vacuum leak.....

first I need to get my fuel level in my carbs verified beyond a shadow of a doubt. As far as air leaking on the throttle shaft, I have to believe that Ztherapy carbs with their patented seals and bearings have eliminated this as a possibility... But a carb swap would be an easy way to verify this... I agree....and I would assume the floats were set correctly also.

Could it be a leak on the other side of the throttle plate (maybe shot throttle shaft bushings)? Zedy....If I were you, I think I would accept Steve's (tt) generous offer to try his SU's. This would eliminate the carbs as a source of your problem. It's only a 30 minute swap. Why not?

http://www.classiczcars.com/forums/showthread.php?42465-Proper-vacuum-readings&highlight= Zedy.....You can check for vacuum leaks (which would cause your problem) with the info that BLUE provided. I would just pull the exhaust and intake manifolds off and install new gaskets. It's a 1 1/2 hour job.

Zedy.....I'm coming in late on this thread so I hope this hasn't already been checked. Most popping through the exhaust in my experience has been caused by air being drawn into the intake or exhaust manifold. My green car had a popping because I had replaced the 3 studs in the downpipe with the wrong studs (from the head instead of the right ones ). They bottomed out before sealing the little downpipe gasket tightly. Took forever to find that one, but completely quiet now. Also, headers are notorious for poor matching of the flat area that snugs up to the intake/exhaust gasket. An intake or exhaust gasket leak will cause a popping......oxygen burns! I would start by checking your downpipe gasket (make sure it seals), followed by pulling the intake manifold and exhaust header and checking the intake/exhaust manifold for leaks (replace the gasket). All IMO......Good Luck Guy

PB......You will have to cut the tunnel and modify the console ( pain in the azz ). You can use the early 4 speed from your 70 with the L28 motor. Your early car has a short drive shaft and the half shafts are at an awkward angle. You should probably use your early 4 speed, a long driveshaft, a 72 or later mustache bar, 72 or later diff hanger and a 72 or later diff mount. This would be what I would do if I were you. IMO. Guy

The P79 head shaved, shimmed, rocker geometry centered and ready for installation. Note shims under cam towers.

My Christmas present from Brenda.....

Jonathan.....I always use Clevite main and insert bearings........just heard good things about them from people whom I respect. The pistons in all of my motors are flat top Nissan with Nissan rings (Total Seal are excellent also). Head gaskets are Nissan with Turbo head bolts from MSA. If you get a cam ground, Isky is tops IMO. It's important to use an oil with zinc......I use Valvoline Racing Oil VR1.......good insurance. Rocker arms can be shipped to Delta Cams to be reground.....$4.00 each.....they'll come back like new. If you have any other questions, just let me know. Good Luck. OZ......Turbo....Nice!

Happy New Year OZ! The engine is ready to assemble. The P79 head was shaved .080 inches and shimmed. SS swirl valves, Stage II Isky cam installed and I completed all of the rocker geometry work. It's a winter project and I haven't been pushed to finish the project since I really don't have a car to put it in (all 4 of my Z's have new engines in them already), but when I do finish it I'll pull an engine to install this mystery motor. Good hearing from you mate! Your engine sounds great. Guy