New Z owner with questions

[LA240Z]

Just got a 73 240. It has the N42 head and (arggg) Hitachi's. Right now it runs like a pooch. You need to really wind it out to keep it from lugging. I noticed a slight lope at idle that suggests a vaccum leak. Combined with the carbs and needing a tuneup, I figure that is most of the problem. My question are:

1. I understand that the bronze guides on the N42 can sink, leading to disaster. Is this common/inevitable (do I need to address it like NOW)?

2. What is the most cost effective way to swap out the Hitachis for early SU's ?

Thanks.

[Ed]

Congratualtions on your new purchase!

I believe you are talking about the bronze seats on the N42 head that tend to "sink". Lead to disaster, well that all depends on how many miles are on it and how often you adjust the valves. It is wise to have them replaced if you ever have the head off.

As to the carbs the way I went about it was to get some used round tops off a 71 at a junk yard. $50-100 bucks depending on where you get them. Then send the carbs to Ztherapy to have some newly refurbished ones sent to you. Either that or spend twice as much refurbishing the used ones yourself. Get the heatshield and the air cleaner "box" from the junk yard while your at it.

[beandip]

Agan welcome , and congrats. on the Z-car . You can find used good round tops at the bone yards at least we can here in Oregon. I have a friend that is parting out a '71 , and the last time I talked to him he still had the carbs . The car they came from he bought for the diff and trans. and drove it home and it was running fine. Most likely all you will need to do is mount them and adjust . Give me an e-mail and I will get the two of you togither .

[Royce]

Hey LA240Z,

Yes, congrats on the new car!

It was the E31 & E88 heads that came with soft valve seats. In US the N42 head started with the '75 280Z and with hardened valve seats so don't worry about them sinking. If in good condition it is a good head and you can use straight unleaded gas (won't need leaded substitue).

All the carb Z's came with Hitachi built carbs. They key is are the domes on them bell shaped or flat. The '70 - '71 240s came with "4 screw" Hitachi SU type carbs and the '72 240Z came with "3 screw" Hitachi SU type carbs. IF you have either of these you need not be concerned. The '73 240 & '74 260 came with the flat top Hitachi carbs that are not as desirable. But I have seen people use these with good results it is just harder to find help or parts for them.

Since your head was changed I am willing to bet you have the earlier round top carbs. I am also curious if there is a L24 or a L28 under that cylinder head.

May just need a good tuneup, some fresh fluid in the carbs, and a valve adjustment.

Hope it helps! Have fun!