madkaw

Personally I would spend the money on a Nismo gasket. They are pricey, but I think it's worth it. 125$ at Courtesy Nissan.

One way to be sure is remove that carb and see if the butterfly is open at all. It wouldn't take much air to slip by. You could use a feeler gauge or probably could see visually if its open at all. If it is , ten your linkage is probably at fault. It's only four nuts!!

Isn't it righty tighty(lean)- lefty loosy( rich) I guess it could be a matter of perspective , but think of it as a bolt that your installing. No matter what angle your at, it's still the same. I would say you need to turn clockwise to lean out your dark plugs. Remember that the mixture knob does not make changes across the entire spectrum of engine performance. Give it a shot to see if it cleans things up. Other possibilities are float adjustment, piston needle size or position. Hope I answered your question

Just curious of your engine specs as far as CR?

What HG were you using? Do you run just water or Glycol ? I asked about the cleaner pistons because maybe some water was steam cleaning your pistons . It wouldn't take much of anything to pressurize the coolant system.

Lighter as in cleaner then the other pistons?

HG fire rings all look solid, no blow by anywhere? On my HG , it showed up more as a discoloration of the fire ring.

HEY I clicked on your pic and my antivirus when crazy. That picture has a virus embedded in it. See if you can remove it.

The best bet would probably be spending the money and getting them from someone like Todd or Rebello. It will be more money upfront, but a LOT less aggravation in the end. Buying from Todd will get you close to the tune you want and you know they will be serviceable units-PLUS-you'll have Todd to help you along. He's a bit gruff sometimes, but he gets down to business and he does good business. I will be putting mine on the sales block this winter to pursue performance FI. I got lucky and found a set that was almost new(500 miles) still in the Mikuni box! It will be bitter sweet to see them go.

Anything more specific - like lift and duration?

Wade, Are you serious? "Here at ClassicZ , we don't have magic bullets" - --ummm, I hope you aren't speaking on my behalf with such a pompous statement. So I guess your car never sees redline for fear of floating valves?

But WHY? Is this for you or a customer? Why this platform?

I had a bad HG and my numbers looked better then that, so not sure that tells all. The tester kit I suggested from Autozone(freebie borrowed tool) plugs into the radiator instead of the cap. You run the engine and see if the pressure rises above cap pressure. If it does, start pulling plug wires one at a time to try and diffuse the pressure. When the pressure stops rising, you found where your problem is. My symptoms were very subtle, never overheated, but I wasn't racing either. It just didn't run right, like a miss. That was a felpro gasket I believe, and it was giving out around #3. I'm running a Nismo gasket now. I also haven't read where you checked valve lash.

Soooo, what ya order mate?

Charlie, It could be several things-and one of the most important is float adjustment. Yes, the wheel is an adjustment and clockwise is lean. Make sure your needle and seat assembly is tightly screwed down and the float moves freely.

Sounds like a good time-I'm jealous

You swapped out ignitions-did this change any of your timing parameters? Have you done a radiator pressure check to insure no HG defect? Do you run with a thermostat? If so, what kind?

I would do what is the most cost effective. Have you looked at the cylinders on the 280 motor yet? These bottom ends are pretty bullet proof and most of the time it's just the head that needs the real work. Yes that head will work on that l28 block. You need to do some research ! Considering this is a school project I would think that would be part of your homework:) Things to consider CR - small chamber head on bigger bore= high CR

Go BIG!

Yes, I meant to ask about induction system. This conversation should be based on how your fueling this.

If you go thru the MANY threads where owners comment on camshaft selection- MANY regret not going bigger as it doesn't effect drivability that much to have a big cam. I'm running stage 2 and it is as civilized as stock. If you read articles by Racer Brown , he comments how these engines like big cams. I can't wait to go bigger, but I'm not disappointed with milder cam . Being you already have the L28, you have some displacement and torque, now give it some HP. Remember , the power is in the head, make use of it.

Does it matter!?!?!? YES- more importantly , I would not drive without it. You need to put a wrench on every bolt under your car. Get a bolt the correct diameter so there's no slop in there. Pretty good chance you found your rattle

When you say rear seals, your talking weather stripping right? If they are gone, then the hatch could have play in it. The hatch should be a spring fit on the seal. I would adjust it down tight on the latch so it takes some force to latch and see if that changes anything. Nothing has to be too loose to make noise, so you don't always feel anything when you yank on it. It's hard to duplicate driving conditions. All the strut has to move is a 1/32" and it would make noise.

Do it right- do it big!! Like said, get a regrind done from someone that works with these L motors

Welcome to the home of Z lovers! One drop of fuel can stink up a whole garage. Check all your lines. If its a fuel venting issue, you might try the trick I did with LIGHTLY pressurizing the vent system and then look for leaks. I have a thread on here somewhere. Good luck and congrats