z24

[CharlieW]

So I ended up going with a ported cylinder head...not polished on the intake side... A high performance Nismo cam, and a Weber 38 outlaw from redline. This was against much knowledge from others on several forums that...months ago when I planned this build... said that the 38synchrous was a definite over-carb situation for a dish pistoned Z24. I set the mark on the crank pulley to the 10 on the timing tab and set the cam dowel straight up on the number 2 sprocket hole. I think the engine spun over maybe half a turn and fired up. Mind you guys, I have not adjusted the carb at all. I aired up the tires tonight for a test drive thinking that at low throttle it would fall on its face because of what I had heard...

That is the farthest from the truth. It ran flawlessly. The choke worked perfectly. The truck ran and pulled smooth no matter what the engine load was in any gear. Never one did it skip/miss or have any flat spots. It pulled way harder than it ever did before, especially in 2nd and 3rd. I didn't run it hard at all...yet..., just because it sat for a very long time before I got to do this job. I am here to tell you guys that with a decent cam, a Weber38 is definitely not an over carb situation for these trucks. Hell, Im not even running a header. I did however port match both manifolds which took maybe half an hour. I am incredibly pleased with the results, and the fact that I spent a few bucks more with redline because the carb is perfect right out of the box. I ordered a jet kit at the same time, but the technician I had on the phone said I wouldn't need them...boy was he right. Those guys are fantastic. I would be glad to help anyone that has any questions about the setup and I will post a video link to YouTube as as I take it tomorrow. One proud 720 owner here and a huge thanks to Tigerracing/Corey for the cam recommendation.

[datzenmike]

Good for you! Port matching the gasket was a great idea.

[Farmer Joe]

which nismo cam did you go with?

 

i didnt even know nismo offered z series cams..

 

with the bigger cam, do you have stiffer valve springs, or was it okay with the stockers?

 

good luck with the engine man.

 

ive got a z24 in the garage right now waiting for my 620. prolly gonna be gettin it in next week..

[datzenmike]

Good question with the springs. Popular wisdom has it they are only good to 4,500-5000 which is about as powerful as the Z24 gets anyway. A Nismo cam might rev higher and need stiffer ones. Sealick got some from a Ford? that added about 30 pounds of pressure to them.

[Farmer Joe]

hmmm.

 

yeah i looked onthe nismo website, but they dont have any offerings for the Z series.

 

COMPcams makes 2 grinds for the Z series engines.. neither says anything about heavier springs..

 

guess when i actually do get a cam, ill worry about it.

[CharlieW]

The cam is part number 99996-D1017... it is on page 83 of their 2010 catalog. It is listed as .406"/272°. I didn't have to use any different springs or shims...and it runs like a champ. MSRP on that cam is $86.20 and if you call your dealer with that part number, they will tell you its no good. Tell your dealer to call Nismo with that number and they had like 92 left available....forever. They are not being made anymore. I had heard that they were made by Mikuni

[Farmer Joe]

wow! under a hundo for that cam??

 

i think i might have to pick one up...

 

how does the idle sound with that much duration? the lift is alot lower than the COMP ones.. theyre .420 and .422

[CharlieW]

So I noticed...the guy at Nismo was especially not helpful, but I have a sneaking suspicion that those cams were the ones used in the R.V. camper edition trucks...the idle is just a tad more choppy, but not much. The difference in performance feels pretty good but I haven't stretched its legs yet....that should really be where it wakes up.

[CharlieW]

Yeah but the carb is a Weber 38 that favors the big end...my hopes are that this is a combo that will be good all around, although I do realize that a cam and carb should be a matching pair...

[datzenmike]

RV grind cams tend to favor low mid range torque and power for hauling loads. Less overlap

[CharlieW]

So far, tires won't hold air very long so I haven't gotten a chance to open it up at all...stay tuned...got new tires sitting at the shop for Monday morning, and I gotta fix the dreaded exhaust

[280G]

I am considering this cam as well. I don't want to shoot myself in the foot though, as I've heard that there really isn't much room for error regarding the cross flow head.

 

The dealership didn't have information until I started asking if he contacted Nissan Motorsports directly, to which he replied that he never had but would try... He called me back to report that the cam was available but he couldn't find where it was listed as a direct fit for my 1983 720 with the Z24 engine?

 

It's a little bit concerning that CharlieW hasn't been here since shortly after these modifications... hopefully his motor is still running like a champ

[datzenmike]

This post is 10 years old. CharlieW hasn't been back here since 2012

 

The stock cam has a 248 degree duration but this may not at the industry aftermarket cam standard that is measured @ a 0.050" lift. Stock lift is also 0.413". Something to look into.

 

 

 

The Z series valves will touch each other if lifted high enough during the overlap. In addition the valves, mostly the larger diameter intakes, are tilted far over from vertical so the bottom most point will be close to the piston top at TDC.

 

99996-D1017..... a 9999? number is a special order part not on a production vehicle.

 

 

 

[280G]

57 minutes ago, datzenmike said:

This post is 10 years old. CharlieW hasn't been back here since 2012

 

The stock cam has a 248 degree duration but this may not at the industry aftermarket cam standard that is measured @ a 0.050" lift. Stock lift is also 0.413". Something to look into.

 

 

 

The Z series valves will touch each other if lifted high enough during the overlap. In addition the valves, mostly the larger diameter intakes, are tilted far over from vertical so the bottom most point will be close to the piston top at TDC.

 

99996-D1017..... a 9999? number is a special order part not on a production vehicle.

 

 

 

Wow thanks Mike for that photo; that really puts it in perspective!

This truck (1983 720 4X4) was in the family since new. Original owner passed about a year ago and it was offered to me. I don't want to abuse it, but going from .3889 to .411 gears (I found a parts truck CA41 axles to replace HF38 axles) and a Weber This was the specs I found on the cam Lift is .406" and Duration is 272° Lobe centers (LSA) are 108° I know this is some necrothread activity, but damn I'm researching everywhere I can.

 

[datzenmike]

32 minutes ago, 280G said:

 

 but going from .3889 to .411 gears (I found a parts truck CA41 axles to replace HF38 axles)

 

 

 

A CA41 is likely a 4x4 rear end. The axles alone won't change your gearing. The C differential is a Salisbury while your 2wd is a removable 3rd member. They are completely different. You could maybe swap the entire rear axle but I bet the 2wd driveshaft yoke won't fit the differential flange and the 4x4 axles have the spring perches on top while the 2wd are on the bottom of the axle tubes.

 

I believe the L series rocker arm ratio listed is actually 1.48 not 1.50.

 

 

[280G]

38 minutes ago, datzenmike said:

 

A CA41 is likely a 4x4 rear end. The axles alone won't change your gearing. The C differential is a Salisbury while your 2wd is a removable 3rd member. They are completely different. You could maybe swap the entire rear axle but I bet the 2wd driveshaft yoke won't fit the differential flange and the 4x4 axles have the spring perches on top while the 2wd are on the bottom of the axle tubes.

 

I believe the L series rocker arm ratio listed is actually 1.48 not 1.50.

 

 

My truck is a 1983 4X4, the axle code on the inside front passenger fender tag is HF38 with automatic hubs.

 

The parts truck is a 1985 4X4, the axle code on the inside front passenger fender tag is CA41 that someone installed manual locking hubs...

 

I knew that the CA41 was a Salisbury differential from some of the posts made on this site and my HF38 wasn't... I assumed that I could swap in the entire 1985 Diff, axles, hubs, and brakes over to my 1983. If your saying that I'm opening a can of worms; then I'm glad to hear it now before I go get that parts truck!

 

And my understanding was that my HF38 signified .3889 gears and the CA41 (CA was for Salisbury) (41 was for .411, or .410)?

 

So talk me away from the edge Mike, before I trailer the 1985 home in the morning.

 

 

[datzenmike]

Perhaps you could put 4x4 in your profile? My reply was based on lack of info.

 

The  '83 4x4s with the new Z24 were H190 differentials and 3.889 and then quickly switched to C-200 with 4.11 for '84 models.

 

As both of yours are 4x4 then this swap is much more sensible.  Spring perches are correct and you have the later driveshaft if your H-190 swap to C-200 isn't compatible. It's worth a shot.

 

Remove the '85s speedometer pinion from the transfer case and put in your '83 to keep the speedometer correct with the 4.11 gears.

[280G]

23 minutes ago, datzenmike said:

Perhaps you could put 4x4 in your profile? My reply was based on lack of info.

 

The  '83 4x4s with the new Z24 were H190 differentials and 3.889 and then quickly switched to C-200 with 4.11 for '84 models.

 

As both of yours are 4x4 then this swap is much more sensible.  Spring perches are correct and you have the later driveshaft if your H-190 swap to C-200 isn't compatible. It's worth a shot.

 

Remove the '85s speedometer pinion from the transfer case and put in your '83 to keep the speedometer correct with the 4.11 gears.

Thank you Mike, I appreciate the information. I'm leaving in 20min to get the parts truck, so your timing getting back was perfect!!!!

[Datsun pickup]

Does anyone know what kind of metals the block and head are for a z24 in a Nissan 720?

[datzenmike]

Steel and aluminum. There is a known problem with the Z24 blowing head gaskets at about 100k intervals. There was talk about bad metallurgy but.... ? There is a preventative involving re-torquing the head bolts once a year to keep the clamping pressure uniform.

[280G]

19 hours ago, datzenmike said:

Steel and aluminum. There is a known problem with the Z24 blowing head gaskets at about 100k intervals. There was talk about bad metallurgy but.... ? There is a preventative involving re-torquing the head bolts once a year to keep the clamping pressure uniform.

Good information!

 

My 1983 Datsun Pick-Up Factory Service Manual 1st-Revision (looks like it was printed in 1983) shows Head bolt torque 78-88 N-m (8.0-9.0 kg-m, 58-65 ft-lb).  Are these still current specifications, or have they been updated since 1983?

 

FSM calls for Valve adjustment every 24,000km, 15,000mi. Are those intervals still a good practice?

[datzenmike]

Head bolt torque is the same, couldn't fine lash setting interval but likely the same.

 

To reduce or prevent head gasket blowing, re-torque the head bolts when engine is dead cold. Loosen only ONE bolt and immediately torque to 60 ft. lbs. Only then move on to the next head bolt. You can do in any order you like but only one loose at a time.

[280G]

On 10/18/2012 at 9:09 PM, CharlieW said:

I would be glad to help anyone that has any questions about the setup and I will post a video link to YouTube as as I take it tomorrow.

I found his video... He made this comment 5yrs ago "That was cold start. And you're right, they run great when tuned properly. Absolutely melted tires lol. I certainly miss it. It is sold now."