240ZMan

There is a ton of information on this site about tuneups, so I won't repeat it here, just do a search. With regard to the DGVs, they are really easy to tune, once you have them jetted properly. Assuming yours are, there is a straight forward process from weber on how to set them up which I've attached. And pay attention to the instructions' comments about what is normal for how many turns out for the idle mixture and idle speed. If you find you have to be outside that to get your engine to run, but it doesn't run well, you may not have the right size jets. There are some who put the DGVs down, but mine were great for a stock motor. I will say that once I rebuilt them, they were a lot smoother at low speed part-throttle. If you do everything right and find you still have driveability issues, that might be something to consider. It's not hard, just time consuming since you have to do everything twice - no different than for SUs Good luck! Tuning DGV carbs.pdf

I just finished rebuilding my engine and had to go through 3 sets of rings from different manufacturers before I found one with an acceptable end gap. Each one had a different shape (cross section of the ring). You need to assemble the rings per the instructions from the ring manufacturer. Just take your time and go slow. I reread the instructions several times to make sure I wasn't getting something upside down. Tunes were turned off for this step

I meant to respond to that comment in your original post. For L28s, only 81-83 came with flat tops. BTW, my machine shop wanted to have the pistons before they bored the block so they could bore to the actual size of the piston, plus .002" IIRC. They said they sometimes saw enough variation in the size of the piston from the spec that this was important. While I was working on sourcing the pistons, I found another guy who was a few weeks ahead of me with same issue. He said he had called VB and they had confirmed the pistons were from ITM. However, when they finally got back to me, they gave me some other name that I didn't recognize. Of course, they also said the 3rd rings were chrome molly, and I doubt that was true either. The person in customer service didn't even know what a piston ring was. In the end I just didn't trust what they were telling me. But I've read others say they have bought pistons from them without issues. I'll be curious what they tell you.

I just went through a similar experience. In the end I went with a set of ITM pistons and rings. They were out of the .020 so I went with .030, but they might have them back in stock now. I bought through BAP-GEON which is an import parts chain in a few western states. Top ring was moly as well - not chrome - just as I wanted. 1500 miles later and the rebuild is a complete success. FWIW, I heard that Victoria British carries their pistons as well. But when I tried to confirm this they took 2 days to call back and not answer my question fully, and then took another 5 days to finish. In the mean time I had them delivered from BAP. My guess is they would take your order and ship if there aren't any stores near you. PM me if you would like to get the contact I used at BAP. Good luck!

Ztherapy has a great video on how to tune the SUs. If you're willing to try to do it yourself I'd highly recommend it.

ZSaint, I think you are confusing Weber DCOE carbs with DGVs. The DGVs were not designed for racing any more than the SUs were. They do give you the ability to tune with a bit of finer precision than the SUs since the only way to "adjust" the relative mixture between idle, part throttle, and full throttle is by grinding the needles with SUs. I stopped short of doing that since I figured it was not a "reversible process" which killed my interest in experimenting :stupid: In my case, no amount of time spent over 2 years rebuilding my carbs cured the excessively rich idle condition nor the issue with fuel percolating in the front carb. I bought new bodies from Z-Therapy, as well as new floats, needles + nozzles, hoses, and needles and seats. The only things I didn't change were the tops and the pistons. I even bought a second set of carbs and interchanged those parts. I spoke with Bruce and Scott many times and we were all left scratching our heads. Please understand that I am not in any way trying to criticize ZTherapy. I found Bruce and Scott to be extremely responsive, pleasant to deal with, and all around good guys. It's just that after 2 years and hundreds of dollars spent chasing these issues they were still with me. Perhaps if I lived closer to Scott and could have had him look at my carbs in person we might have tried something else. What it might have been escapes me though Lest you think it's just me (and I wondered about that many, many times!), I also had a local guy who specializes in Zs spend some time with them as well. Everything he suggested I had already tried, and we eventually gave up. I switched to the DGVs soon after. I should also add that while I've modified my engine, the issues I had with the SUs were with me when I first received the car and it still had the stock L24. In fact, everything was stock, except that the flat tops had been replaced with '72 round tops. So I think it's important to keep an open mind on the DGVs. SUs when they work in a given application are a super carb. But they aren't right for every application.

I fought with my SUs for 2 years and never could get the proper balance between idle and part throttle mixture and wasn't ready to begin experimenting with grinding my own needles. I picked up a set of DGVs used and was very happy with them. I didn't notice any more or less power when measured by my butt-0-meter. Mileage seemed a little better, but I've got a 4.11 rear end so mileage obviously isn't my main concern That said, I just pulled them off and replaced them with triple webers. I've got a mild cam and hopefully a more agressive one planned shortly. There's no doubt the triple DCOEs are a much better carb for performance, but they're also more work (and more $$$) to tune. The only thing you might want to fabricate would be a heat shield if you you've got a header like I did. I had already made one for the SUs so I just used it. I don't know if it was necessary.

Bill, you have a PM from me.

A man is not old until regrets take the place of dreams - anonymous

Yes, you need the key! A "real" auto parts store should have them. Here in CO the larger Napa stores carry them. The Autozone/Checkers don't. I don't know how they are sized, but I'd measure the keyway on the crank as well as you can and then buy a few of them around that size. They're not expensive and once you're back home you'll be able to see which fits best. Perhaps others can be more specific, but that's how I'd solve it. Good luck!

I'm a big fan of that 5 speed. It's got a much closer 2-3 ratio than the earlier 5 speeds, and yet the 5th gear is a bit longer (taller) than the later 81-83. I'd suggest pairing it up with a 3.90 diffy, or a 4.11 if you like revs:) I have the '82 and 4.11 in my '73 and it's a lot of fun.

Now you're making me nervous. I was just getting ready to go out to the garage and put my pistons in. :paranoid: When I put the bearings in this weekend, for each journal only one half had a hole. I assumed that was to provide oil to the crank. Not sure how that would provide oil to the chain tensioner?

Randy, on my '73 with the dealer installed AC I too had the 3rd pulley. However, it turned out that the middle pulley was the one that lined up with the AC compressor. So I left the outer (3rd) pulley off. I figured less mass on the crank was a good thing.

Here's a scan of mine. I cut it out of some scrap 3/4" pine I had lying around. Just put a strong piece of cord through the hole at the top so you can be sure to pull it out. This one fits VERY snug, probably more snug than is necessary. That's just the way it turned out. Trim to fit Timing chain tool.pdf

I don't think you'll want to go more "aggressive" than stock with the coil if you still have points. The lower resistance of the coil will not do well with mechanical points. I'd strongly suggest you consider upgrading to an electronic ignition. There are lot's of choices out there based on how much/little you want to spend, how electrically inclined you are, and how stock you want your car to appear. For a mostly stock appearance, the Pertronix approach is quite good and easy to install. You can upgrade with one of their coils at the same time. I did that 3 years ago and haven't touched it since. Or you can go with a later 280ZX distributor and module, or with products from MSD or Crane, etc. Search the archives here, this topic comes up a lot. Good luck!

As a single data point, when I still had my L24 stock motor with 200k miles, I damaged the valves on the stock E88 head. Rather than rebuild it, I picked up an E31 head that had been freshened a few thousand miles earlier, but was otherwise stock. The rest of my engine was stock, except for the pertronix ignition. While I had hoped I'd feel some big difference in power, the reality is that if I was honest with myself, I couldn't feel any difference at all. Of course, the rings were tired, I used my "butt-o-meter" as my only performance measuring tool, etc. It was not a controlled test at all. But to Arne's point, for a stock motor driven on the street, the choice of head probably makes little difference. A modified motor on the track, now that's a different story And lest I give anyone the wrong impression about myself, I've tried dozens (so far) of mods to get that last bit of performance out of my Z. I won't bore you all with everything, many of which others from this site have tried. For me, the chance to participate in all this bench racing, followed by experimenting in my own car, is a big part of why I have my Z and hang around this site.

Just finished installing the crank. Took almost 3 hours. Following JZM's suggestion I wet sanded the thrust faces to make them consistent from side to side and between the top and bottom bearings. They seemed to fit well, but after assembling everything there was less than .002" clearance. It turned easily, but I did the right thing and tore it all down, and sanded some more

Clockwise.

I suspect they are describing coils that have a higher resistance as "point style". Points can't handle as much current from low coil resistance as electronic ignitions can. I think the issue you need to resolve is if the pertronix can handle the low resistance of the blaster coil. They may suggest you put the ballast resistor in series with the coil. If that's the case, I'd suggest you either use pertronix' coil, or do the switch to the MSD 6AL/Blaster. I had this exact conversation with them 3 years ago when I made the switch. The resistor limits the current through the coil (to protect the pertronix) but also limits the voltage of the coil. So going with a "hotter" coil doesn't really buy you anything. That's why I went with the flamethrower. It was the best comprimise for me. Still, it's been 3 years since I spoke with them, and my memory may not be complete :stupid: You'll probably have to talk to them to be sure.

These are Hi-Tech sold by Checker, I believe made by Clevite? I haven't put the caps on yet to measure any other clearances. I stopped when I couldn't turn the crank without any caps on. In looking at the crank I can see why you don't turn the thrust surfaces. There's barely any material left to remove - looks like you'd be on the unfinished portion of the crank before you knew it. The thrust surface on the bearing is copper in color, and it looks to be just on the surface. The rest of the surfaces are silver in color. Does that sound right to you? Any problem with taking .010 off of it?

Wow, that surprises me that I need to sand down the bearings to fit. Given the kind of tolerances here (.005" between min and max), I'm a bit uncomfortable sanding by hand. Is this how all undersize bearings are delivered? I'm wondering if there is something wrong with this bearing? I don't mean to challenge your advice, JZM, it's just not what I expected

I think the pertronix has a minimum resistance it can handle, although I don't remember what that value is. Given its small size and that it's inside the dizzy without air circulation, I'm sure it can't handle as much current (in other words, as low of a coil resistance) as the external units like the MSD. I'd verify the resistance of the MSD coil and check with pertonix to be sure it can handle it. I suspect the pertronix might be damaged otherwise.

I run pertronix with their flamethrower coil (1.5 ohms) with no issues. I had considered going with the MSD, but this route was much simpler. Once I had the pertronix installed, I just replaced the stock coil with the new one, and put a jumper across the resistor. IIRC, there wasn't much difference in the specs of the flamethrower and the msd blaster... just something to consider.

I think it's going to be really hard to get the bolt loose with the engine in the car, especially if the radiator is still in. I've always used an air gun with the engine on a stand. I suppose you could put it in 4th gear, set the parking brake really tight, get a big wrench on it, and maybe if you're lucky, get it loose. However, even if you succeed, you're going to need to put a gear puller on the front to pull the pulley (damper) off the crank and I'm sure you don't have enough room to do that. And when you put it back on, it will be hard to get it tightened enough. And you definitely do NOT want the bolt to come loose while the engine is running! Pulling the engine isn't fun, but I think you may be better off doing it. BTW, why do you need to take the pulley off with the engine still in the car?

You're correct that the engine turns clockwise when you are looking at it from in front of the car. However, the timing marks are reversed from the way you described them. Remember, the marks are referenced to BEFORE top dead center. Hence the bigger number is what the timing mark comes to FIRST. As for how much advance to have at idle, there is much discussion on this, especially depending on how you may have modified your car. For my '73 w/L28 and carbs and mild cam, header, etc., I find I can go about 12-14 degrees advance at idle without pinging using premium fuel. That gives me about 36 degrees of total advance as measured at revs above 4k with a timing light. That's at 6000 ft elevation. I also found I could advance a few more degrees on cool days, but that would lead to pinging on the really hot ones. Since I'm sure I can't accurately hear the onset of pinging until it's quite severe, I backed it off a few degrees to be safe. I doubt your situation is the same as mine so you'd have to experiment. I think the factory spec is 8 degrees FWIW.