New member from Oklahoma

[Palmettobug]

Hello! Just bought a 1973 240z. The original owner took off the SMOG compliant flat-top carbs and replaced them with a set of '72 dome SU carbs. Other than the top part of the car being the original orange, he used Ford Terracotta as a bottom-half accent color, the car appears to be stock. I have noticed the gas fumes flowing in the cabin when the windows are rolled down. Any advice on how to fix that? I think I may need to replace some suspension parts as the car shutters when going above 80mph. Not looking to heavily modify with a bigger engine, but any advice on best modifications for squeezing out more horsepower for a daily driver/ cruising on the weekends would be most helpful.

 

E88 head

orange stock air intake

original exhaust ( i can't see a header attachment)

195/70/14 tires

[Mark Maras]

Welcome

 You don't say if the car has been driven or was in hibernation for a while. As far as fumes, tail light gaskets & the hatch seal are likely culprits.

 IMO, fix the steering & suspension before you go looking for more HP. Suspension upgrades such as shocks, springs, heavier sway bars, new bushings etc. will give you more driving pleasure than more HP. When you do start tweaking the HP, a good handling car will make it more fun & safer.

[jfa.series1]

Welcome to the group.

 

+1 on Mark's comments on getting the suspension all tightened up and proper toe-in.  Z's are also very sensitive to tire condition.  Shudder is common to any out-of-balance / out-of-round situation.  Be sure to flush the brake fluid and get some fresh stuff in there.

[Patcon]

I agree with both ^^^^^

 

Tire issues would be my first check on the vibration at speed. Run the old gas out and get good fresh high octane gas in and see if the running improves

 

Exhaust fumes are almost always bad gaskets or rust holes in the rear of the car. Taillight gaskets / hatch / and vent hose gaskets...

 

Horsepower comes later when everything else is right!

[Palmettobug]

Sorry,yes; the car sat in hibernation for at least a year. I don't see any rust in the engine compartment near the battery or the wheel wells. Dog legs I think you guys call them. Thank you the suggestions on where to look for leaks, I shall try this weekend. I do know the original owner said that there were flat spots on the tires from sitting, so I'll start my investment there. Glad to be here and looking forward to more of your suggestions. 

[Palmettobug]

Ok, what does it mean when you have blue smoke coming from the tail pipe. Happens on startup and again when you rev the engine.

[Zed Head]

Could be running rich, or some oil leaking in to the cylinders  Too much of one of those petroproducts, not being burned completely.  Hard to be sure until you've tuned everything up.

 

Found you an avatar, for those that haven't experienced the large scary bugs.  They fly.

 

 

[Redwing]

And they bite!

Jai

[Palmettobug]

The ones back home in South Carolina also fly on occasion. . TY!

[Palmettobug]

OK, got a chance to play under the hood this weekend. I was able to do a compression test and I have all six cylinders running at 150. I noticed in one of the forums that all six should be at 170 or higher. Is 150 that bad? I also noticed that I am now in need of a new starter. Tried to get the old one out and found the bottom bolt is frozen. I tried penetrating oil, a breaker bar, and an impact wrench. It isn't moving. Any ideas how to get this thing out?

[Palmettobug]

So I took a propane torch and heated up the starter flange. The stuck bolt came out with no further problems. Got the new starter on and the car starts right up. I tuned the carbs according to what I learned on here and a video on YouTube. I used the 3in1 oil for my dampering oil. Seems like the idle responded better to it than it did transmition fluid. I also see where most people change over to electronic ignition. Since my 240z is an automatic, what would be best? I can't seem to find what to do if you have a dual point distributor.

[Zed Head]

The dual point problem is a problem.  Apparently, it's for emissions purposes.  It keeps idle speed up until the engine warms up.  If you can live with a few minutes of low idle it's not a big deal to switch to a single system.  My 76 had two magnetic pickups, electronic.

 

Good work on the torch.  I didn't see this until it was over but the bolt threads in to the transmission's aluminum housing so a torch would expand that well.

 

ZTherapy is the source for carbs - http://www.ztherapy.com/