Lazeum

Thanks for the proposal. I think a lot since the last trial and the most reliable option (= less likely to fail) is to machine the pistons. From a cost standpoint, it would also be even with a new gasket: cost of the gasket, shipping & customs fees (70€ for a package worth 200$). I'll end up with a gasket at 300€ probably what the machine shop would quote me.

Hmmm. I haven't seen it on MSA. I'll give a call to them. As a club here, we have some deals. If he does not work, I can deal also thru the US with Courtesy. I used to live there so I have loads of friends who could help

@Didier, I don't think it would be bad to dessasemble & reassemble the pistons pins as long as there's no material removal in the process. Previous pins were looking fine after teardown to get the rods back to my current setup. I need to check with machinist, if they use a mill, it might fit with rods (unlikely though). @Madkaw, Nismo headgasket could be considered but it has to be accurate. If I want min 0.6mm clearance (0.023"), gasket could not be any thinner than 1.25mm, if it is 1.15mm I'm nearly out. I also have to add shipping cost which are not negligeable from where I am. I was nt going to go to this direction but seeing where I'm at now, it becomes a valid option (Would have I torn down the whole engine yesterday for nothing?? ) Would you have the part number for the head gasket? I don't see any on Nismo catalog that matches the description (p. 20). [edit]: I forgot to say thanks! and please also

thanks for the head's up Sean was also talking about them but he had no way to contact them. Are they on hybridz or any other Z forum? Good to see the clarification about Ikeushi san's car. Talking with some fellow members here, they say it was indeed a replica afterall... [edit]: he's actually on FB, we'll send him a msg thru it.

We left it in the car parked away, time to pick it up, the Z was gone

it would but how did you make sure what was announced was correct? As far as I'm concerned the stock headgasket from Ishino I've got is not at 1.25mm compressed as stated here and there on this board. My next options are: to get a new headgasket again and try it or machine the pistons to match the Felpro gasket I still have. The 2nd option is more reliable than the first one so I'm going for machining next

I feel for you The #46 is the car I'm trying to find the driver. I believe it is a replica also. Regarding the car #23 above, the pilot/owner was very nice, let us look at the interior, popped the hood, the trunk. Everything was at reach - no problem at all! I just did not take any pictures... My friend was taking pictures but his camera battery went down just before. That's amateur's work but we are learning from our mistakes! (I hope!!!)

I've never thought about using sandpaper on pistons!!! Maybe I should give it a try?!? More seriously, let's do it clean even if it takes more time & money. Let's do it right... Roads are full of salt so there's no rush to have a running engine before end of March. Regarding compressed gaskets for mockup, I start to have a tad too much for my taste Let's use the latest one the appropriate way!

Back to the original topic I've received the Ishino headgasket that was supposed to be 1.25mm compressed. I've measured at 2 locations the displacement of the head when tightening the head bolts. Under head weight, head gasket is 1.35mm thick so quite close to what a Felpro gasket is uncompressed also. Once compressed at 70Nm with ARP hardware (so not even the final torque), the thickness of the stock gasket was 0.99mm on one side and 1.06mm on the other. 1.25mm thick compressed stock Ishino headgasket is a MYTH! My story shows also that we absolutely need to double check everything we are doing during a rebuild. We should trust only what we have in front of us. So I need to plan for C plan: send pistons to machinist to have them milled by 0.3mm to match the Felpro gasket thickness I still have. I have to wait a little, it is vacations time, next steps would be only in some weeks then, maybe months since I might have to travel for business in Mexico for one month.

It's good to know. Unfortunately they won't be there this year. I was looking under the hood of the car and everything was looking as it was a old vintage car - Mikuni Carbs, square air box, etc. I will have to be more serious about taking pictures this year then it was 10°F last year, standing up in the cold for many hours made me lost my focus!

Toshimasa san was the driver of the car last year. It was coming from Japan, they have it shipped by boat some weeks before the race. That's kind of off topic there but hte last picture makes me wonder if it was the real deal since I've picked up a picture from Nissan showroom with the same plate as the one on the picture above (taken by a French/Swiss Z owner) For reference: => http://www.twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=2079707

The car I've seen last year did not finish the race back in the 70's hence the storage somewhere for a long time. I can try to get some pics from last year That was just a side comment to state we have seen some pretty cool Z's last year. Regarding my request, I'm looking for some info regarding the team who will be racing in one month here in Europe

We took the habit in France to celebrate the Monte Carlo Classic race with the French Datsun club. We found out that one US team is going to participate to the event, I'd like to get in touch with them asap. It starts from Glasgow in Scotland, from Warsaw in Poland, from Marrakesh in Morocco and also from Reims in France. Last year, we were able to meet the Japanese crew who was running the original Z car that ran Monte Carlo rally back in the seventies (the car sat 25 years in a garage prior to be bought for a ridiculous amount, less than 10k€) but also some Brits, some Dutch& Spanish people, French guys also. The whole French crew is going along the way in between starts and Monte Carlo where the race ends to see Z cars with other competitors. It has always been fun to meet other Z fanatics during this race. We usually have time to chat around, check the cars, discuss with people and give a Champagne bottle (some members here are involved into Champagne where Reims is the capital ) Maybe one of you would be able to give me some info. are they on HBZ or other forums? It would be cool to get in touch before the event so we can plan the meet Thanks!

For what is worth, this is the link of the web store I use to get all my supplies for DCOE. Fast Road Cars They have new DCOE for 277£ (40 & 45)

got it! it would make sense. My DCOE 18 did not need any rework of progression ports. As far as I'm concerned, I can switch for 3 45DCOE to refurbish for about 600€. then I can still sell the 40DCOE to cover some of the cost. it might be an option for the future

I was going to reply I have tried before with a carbide tool on a lathe but the teeth profile creates some erratic contact that would hit the cutting tool. We basically destroyed the tool after 0.1mm of material removed. I've cut mine with EMD since it was available to me but a angle grinder with the appropriate wheel would also do the trick. then, you'll have to build the insert from the other thread...

The doc above is interesting (and depressing for the ones like you & me who are thinking about going up in ventur's size above 32mm) As you said, choking up our carbs is easy. However, I don't understand your comment about depression ports with 45DCOE. On the bright side, I'm in the good side of the ocean when talking about DCOE, nobody knows how to tune them but they're everywhere in classifieds

I believe not. I think their a ratio to take into consideration into the flow equation, something such as the ratio of the sections. Venturi effect would be more important on 45 than on 40 since 18²/22.5² << 18²/20² Ratio would be 0.64 for the first one and 0.91 for the second. Suction would be 30° more important on 45DCOE. Flow however should be identical with the same "restriction". I need to get back to the basic math of venturi effect (Bernoulli & flow equations). Maybe I'm wrong but this is the way I would attempt to explain the difference

Good job, it looks good! I believe everybody working on old car should know this technique. It's my dad's blacksmith who's also restoring old guns who showed me how to proceed. Beware that this technique however would create some hydrogen molecules that makes flexible parts somehow brittle; something to think about if you try to remove rust from stab bar or springs.

Megajolt being in my future plan, I'm looking at what could be done also for MAP sensor. Have you check out the following link? A member of the board tried different solutions, quite interesting reading. plenum and vaccum hose design for individual runners

I was looking for some info when I came back to your thread. You should look for quench definition and distance required to achieve an effective design. Your 2mm head gasket planned might not be a good solution. I've done it on my build not such a long time ago => How to check quench distance?

Just to let you know, thanks to this thread and the community, I've learned a lot over the years This past weekend, I was helping a friend who was having a 280zx running rough with triples. Car was hesitating at low rpm, some backfire at carbs at idle and pops during low accels. There was some power but the car was lazy at high rpm. Car has also be tuned up with 55f9 idle jet in the past but it was running to rich and has been rejected from the MOT equivalant test here in Europe. Setup for what is worth was a stock L28 (N42 or F54? - I don't know), N42 head, dish pistons, stock EFI ignition, 40 DCOE, header & exhaust Carbs specifically were running with: 35mm chokes 150 main 190 air 50f8 idle We've plugged the wideband, we found out car was running super lean below 2500rpm and quite rich above. Exhaust is having a leak due to one stud being broken (the closest one from the firewall next to piston #6), AFR curves shown below are probably leaner than they really are. Owner is also well educated & knowledgeable about DCOE's also but he does not have the tool, the wideband sensor. We've shared on jets library for the tuning process, so we had a lot of parts to play with. It was great also to share thoughts about carbs since both of us know how DCOE works. Main jets were 150 units, we went to 145, then 140 to finish with 135. Car run better & better until 135 jets which did not make any improvements, so we came back to 140 which provided the best results from a butt feeling standpoint.. Idle jets were 50f8 so we've exchanged them with 50f9 (air hole went from 1,20mm to 1,00mm), after 10 minutes to retune idle, the car was running smooth, progression was almost perfect. We could hit the throttle above 3000rpm without second guessing about motor behavior. Screws are all around 1 to 1,25 turn from being closed. After a full day, the car was running strong up to the red line with great transition. This tuning process could have probably gone further by messing around with air jets a little bigger, idle jet smaller to make sure 50f9 would be the right ones. I believe exhaust leak should be addressed first also. Overall iIt was a very rewarding experience - first time I was tuning DCOE from someone else car

Another option as well I had an Mitsu Evo some years ago which can only use GL4 transmission oil. I was able to get some as well at the dealer. They filled up some empty bottles to provide me some.

For what is worth, on my Silvia the switch from stock Nissan oil to MT90 made the gearbox notchy. So on my Z, I'm going with stock Nissan oil (75w90 GL4) which was smoother than Redline oil. Every Nissan dealer should have it.

I'm going to order a ishino gasket for the car. I found it on Amazon. I've got a colleague who's travelling to MI this week, it is the right opportunity to request his help (he gladly proposed already to help). So I will go for it, I will skip shipping cost. Pete, thanks a lot for your proposal. This is the kind of move that makes the hbz community a great one