It's gettin' good....

More problems. 5 speed Nissan 280ZX transmission, supposedly rebuilt seems to suck. It's very noisy, only on deceleration. Mainly 1st, 2nd, 3rd gear. It's got a 12 month, 12,000 mile warranty, which is supposedly supposed to cover labor. Well see about that.

My other problem is carb related. Since the addition of the aluminum flywheel, I get a rich spot from 2K-3500K rpm. This has been verified as rich because I spent some time today on a friends dyno. Cannot get that leaned out at all. Tried numerous idle jets to no avail. This only just started since the addition of the aluminum flywheel. Anyone know a good shrink??

Look for bad second motion shaft bearings when you take it apart. The bearings that support the second motion gear set (cluster gear) are probably on their way out to lunch.

Could be a first motion or third motion shaft bearing, but I suspect that if that were the case you would have noise in fourth gear too.

Fix? Depends...Perhaps only the bearings, but I would pretty much count on the inside of the cluster and the bearing surface of the shaft being bad too. This is usually caused by LONG gear oil change intervals and/or low lube levels. maybe you might want to swap the outfit for another transmission.

Jack

Wouldn't seem like the flywheel would cause a richness problem. I tried a very light flywheel once and didn't like it, seemed to have much less torque.

Horst Wrote:

This is the first (first-and-a-half?) time I think somebody's posted here about problems with a Datsun box. It does sound like a good thing you got the warranty. :(

Assuming you're still running the DCOE clone, I doubt the idle jet is your problem. That's about the RPM where it's transitioning off the idle jets and onto the mains. If your idle jet is rich, it should show up at lower RPMs. Sounds more like your mains may be too large, or the air correction jets too small (a one step change in mains is equal to a three step change in the air correction jets.

What happens above 3500 RPM? You don't want a jet swap to cause you to be too lean at high RPMs?

Maybe a different set of emulsion tubes might help...but those things are total voodoo to me...

The top end is fine. Air fuel nearly 13.5 to 1. This all started as soon as I got the lightened flywheel. The 45F8 idle jet is rich!! The transition to the mains happens at about 3700 rpm on this OER 45 DCOE clone. We(tuner and myself) tried different airs, emulsion tubes(F9, F16), the mid range cannot be sorted. If I go to low on the idle jets I assuming the mains will kick in sooner. This may be what I need. Tomorrow's a new day.

Might it be an igniton issue? Try different timing settings to get more advance in that range? That'll lean things up! It seems to me the main jets and the emulsion tubes together should be creating the mixture at that rpm range.