datsunfreak Posted April 20 Author Report Share Posted April 20 (edited) On 4/19/2026 at 1:58 PM, dimlight65 said: So, we are basically back to where we were last month. But with better steering/header clearance and the proper clutch pedal height. 😉 Edited April 20 by datsunfreak 3 Quote Link to comment
dimlight65 Posted April 21 Report Share Posted April 21 On 4/20/2026 at 8:30 AM, datsunfreak said: But with better steering/header clearance and the proper clutch pedal height. 😉 And better header to floor clearance, and steering rod/control arm angles. 2 Quote Link to comment
dimlight65 Posted April 26 Report Share Posted April 26 So we finally got tired of the superfluous spark plugs... did a little Google searching, and discovered Honda oil drain plugs... should fill the holes in a much prettier manner. Of course, the heads of the plugs were larger than the recesses in the cylinder head, so we headed to the Dimlight Racing, Patent Pending, "Hillbilly Lathe"... and turned them down a little... Yeah, that one turned out a bit triangular. Anyhoo, we then stole the crush washers from the spark plugs we took out... and popped the plugs into the head... They should disappear once the "Dramatic Lighting" is removed. 5 Quote Link to comment
datsunfreak Posted April 28 Author Report Share Posted April 28 (edited) We are in need of a part that we cannot find. If anyone reading this has a spare driveshaft (even if it's junk) for a 240Z/260Z/280Z, 610, 710, 620, 510, whatever, we need part of it for this car. It doesn't matter what year it's from, or what engine, it just needs to not have staked in u-joints, and it can't be from a 1200/B210/B310 (uses a smaller joint). I have 3 of the 4 pieces needed to build a "new" driveshaft, but the 4th piece we need is the yoke from either end of the tube. Looks like this: Edited April 30 by datsunfreak 1 Quote Link to comment
datzenmike Posted April 28 Report Share Posted April 28 On 4/26/2026 at 12:59 PM, dimlight65 said: So we finally got tired of the superfluous spark plugs... did a little Google searching, and discovered Honda oil drain plugs... should fill the holes in a much prettier manner. Of course, the heads of the plugs were larger than the recesses in the cylinder head, so we headed to the Dimlight Racing, Patent Pending, "Hillbilly Lathe"... and turned them down a little... Yeah, that one turned out a bit triangular. Anyhoo, we then stole the crush washers from the spark plugs we took out... and popped the plugs into the head... They should disappear once the "Dramatic Lighting" is removed. Why in the fuck would you get rid of the dual plug design????????????? They are not at all superfluous and removing them is a step backwards. Quote Link to comment
dimlight65 Posted April 29 Report Share Posted April 29 12 hours ago, datzenmike said: Why in the fuck would you get rid of the dual plug design????????????? They are not at all superfluous and removing them is a step backwards. Well John, looks like "two days" is the answer to my question. What was the over/under again? 1 Quote Link to comment
datsunfreak Posted April 29 Author Report Share Posted April 29 (edited) 1 hour ago, dimlight65 said: Well John, looks like "two days" is the answer to my question. What was the over/under again? I had it pegged at 24 hours, so he's slipping a bit... 14 hours ago, datzenmike said: Why in the fuck would you get rid of the dual plug design????????????? They are not at all superfluous and removing them is a step backwards. This engine has been a 4 plug engine since 1980 when it rolled off the assembly line. About 30 years ago we replaced the stock 4-plug head with an 8-plug head that had been ported and cammed for better perfomance, and we had simply filled those superfluous holes with dummy spark plugs. All we did was switch from the dummy spark plugs (that had never fired even once) with something more appropriate (and more resistant to detonation). Edited April 29 by datsunfreak Quote Link to comment
datzenmike Posted April 29 Report Share Posted April 29 Just never seen a Z20 dual plug not used as a dual plug. All '80s didn't have the exhaust side even drilled out. In the US Z20s changed to dual plug for '81, Canada kept the single plug through '81. I had Canadian '80 and '81 Z20E 200sx heads, all single. What is the ignition timing on your single plug? Quote Link to comment
datsunfreak Posted April 30 Author Report Share Posted April 30 (edited) 23 hours ago, datzenmike said: Just never seen a Z20 dual plug not used as a dual plug. Funny, I've only seen one that was still running it, in an old Datsun at least. Most vehicles that came stock this way stayed this way, but usually when you swap a Z20/Z22/Z24 into an older car like a 510 or 1200, most people convert to an L20b dizzy and just run one set of plugs. 23 hours ago, datzenmike said: What is the ignition timing on your single plug? We typically run 12-14 degrees, and a more aggressive cam. But we also live somewhere that 93 octane fuel is available at every pump, and some stores sell as high as 95 octane. I wouldn't recommend running that much advance if you don't. Edited April 30 by datsunfreak 1 Quote Link to comment
datzenmike Posted April 30 Report Share Posted April 30 12-14 makes sense. More or less the same as the L series with single plug. You could probably run lower octane gas if running dual plugs. Timing on them is 3 degrees +- 2 degrees. That's close to TDC and there isn't much time left for detonation. Quote Link to comment
datsunfreak Posted May 1 Author Report Share Posted May 1 On 4/30/2026 at 7:57 AM, datzenmike said: 12-14 makes sense. More or less the same as the L series with single plug. You could probably run lower octane gas if running dual plugs. Engine longevity is key, that's the reason for the higher octane (and a slightly fat tune). To run this much timing advance with a more aggressive cam, and keep detonation to zero, it's just safer to run the highest ocatane available. And we will never run all 8 plugs on this or any other Z20/Z22. 😉 Quote Link to comment
dimlight65 Posted May 3 Report Share Posted May 3 (edited) On 4/28/2026 at 3:50 PM, datsunfreak said: We are in need of a part that we cannot find. If anyone reading this has a spare driveshaft (even if it's junk) for a 240Z/260Z/280Z, 610, 710, 620, 510, whatever, we need part of it for this car. It doesn't matter what year it's from, or what engine, it just needs to not have staked in u-joints, and it can't be from a 1200/B210/B310 (uses a smaller joint). I have 3 of the 4 pieces needed to build a "new" driveshaft, but the 4th piece we need is the yoke from either end of the tube. Looks like this: We finally have all the bits to have a driveshaft built... because, in addition to having non-serviceable joints, as the bishop said to the actress, my old shaft is just too long... Then we had a look at how we could make a sway bar for the front... We decided that we could do something similar to what the factory did on the rear by hanging a bar from the T/C rods... where the yellow line is. We made a template... and will have some spring steel rod bent to this shape. That will attach with the patent pending, Dimlight Racing Method... So stay tuned! Edited May 3 by dimlight65 2 Quote Link to comment
Dguy210 Posted May 4 Report Share Posted May 4 4 hours ago, dimlight65 said: We finally have all the bits to have a driveshaft built... because, in addition to having non-serviceable joints, as the bishop said to the actress, my old shaft is just too long... Then we had a look at how we could make a sway bar for the front... We decided that we could do something similar to what the factory did on the rear by hanging a bar from the T/C rods... where the yellow line is. We made a template... and will have some spring steel rod bent to this shape. That will attach with the patent pending, Dimlight Racing Method... So stay tuned! What driveshaft is that? Because if B210 driveshaft the 510 sedan shaft is just a couple inches shorter and much better. Quote Link to comment
dimlight65 Posted May 4 Report Share Posted May 4 10 hours ago, Dguy210 said: What driveshaft is that? Because if B210 driveshaft the 510 sedan shaft is just a couple inches shorter and much better. To the best of my recollection, it is either a B-210 or automatic 1200 driveshaft that I shortened some 30 years ago when I first put the Z-20 in the car. 1 Quote Link to comment
datsunfreak Posted May 5 Author Report Share Posted May 5 On 5/3/2026 at 7:05 PM, Dguy210 said: Because... the 510 sedan shaft is just a couple inches shorter and much better. FWIW, it's still not short enough, due to the 1200 having a 5" shorter wheelbase, and this having a long-tail 5spd. Center section on this will be 33", which is about halfway between a 510 and a 240Z. Also, I have spent the last 6+ months looking for a 510 driveshaft and cannot find one. 😄 The best I could find was the front 1/3 of one, which yielded enough bits to build our own with serviceable joints. This very one, in fact. I found this pic on google just to use as an example, then later realized the pic was from a live ebay auction... 😆 On 4/28/2026 at 3:50 PM, datsunfreak said: 1 Quote Link to comment
datzenmike Posted May 5 Report Share Posted May 5 On 5/1/2026 at 1:42 PM, datsunfreak said: Engine longevity is key, that's the reason for the higher octane (and a slightly fat tune). To run this much timing advance with a more aggressive cam, and keep detonation to zero, it's just safer to run the highest ocatane available. And we will never run all 8 plugs on this or any other Z20/Z22. 😉 You should run anything that reduces any chance of detonation and increases efficiency. You have 140 of crankshaft rotation after the plug fires where compression and heat from burning fuel is compressing the unburnt fuel and air towards self ignition. A lot of time for heat to be absorbed by the cylinder walls and combustion chamber and not used to push down on the piston. Dual plugs fire so late the piston is only 40 from TDC and almost all heat expansion is ATDC and pushing down on the piston. There is much less time for heat to be absorbed by the combustion chamber and that adds both power and efficiency. Quote Link to comment
Dguy210 Posted May 5 Report Share Posted May 5 11 hours ago, datsunfreak said: FWIW, it's still not short enough, due to the 1200 having a 5" shorter wheelbase, and this having a long-tail 5spd. Center section on this will be 33", which is about halfway between a 510 and a 240Z. Also, I have spent the last 6+ months looking for a 510 driveshaft and cannot find one. 😄 The best I could find was the front 1/3 of one, which yielded enough bits to build our own with serviceable joints. This very one, in fact. I found this pic on google just to use as an example, then later realized the pic was from a live ebay auction... 😆 Lol, I actually recognized that pic from the Ebay listing too. 1 Quote Link to comment
datsunfreak Posted May 7 Author Report Share Posted May 7 On 5/5/2026 at 7:08 AM, datsunfreak said: Center section on this will be 33", which is about halfway between a 510 and a 240Z. FYI, this was a typo. It's 43". Still a lot shorter than a 510, but nowhere near as short as a 240Z. On 5/5/2026 at 11:58 AM, datzenmike said: You should run anything that reduces any chance of detonation and increases efficiency. You have 140 of crankshaft rotation after the plug fires where compression and heat from burning fuel is compressing the unburnt fuel and air towards self ignition. A lot of time for heat to be absorbed by the cylinder walls and combustion chamber and not used to push down on the piston. Dual plugs fire so late the piston is only 40 from TDC and almost all heat expansion is ATDC and pushing down on the piston. There is much less time for heat to be absorbed by the combustion chamber and that adds both power and efficiency. 😄 1 Quote Link to comment
dimlight65 Posted Saturday at 09:21 PM Report Share Posted Saturday at 09:21 PM On 5/3/2026 at 2:48 PM, dimlight65 said: ...will have some spring steel rod bent to this shape. This I did... then bought four sets of sway bar bushings with saddles for it... and bolted the bar to the T/C rods... It turned out WAY better than it had any right to... A quick bounce on the fender showed a remarkable improvement. I am quite chuffed with this. We're going to paint it and the rear bar gold to "match" the T/C rods and rear control arms so I can stand back, point to them, and go, "Eh? Eh? Didja see the sway bars?" 1 Quote Link to comment
dimlight65 Posted Sunday at 09:29 PM Report Share Posted Sunday at 09:29 PM (edited) A few pages back (I'm not going back to find the post to quote it), I said this... was going to be the final arrangement for the "Zookie Lights." But since the smaller spot lights were upside down, this hood... was going to collect water. Well, today I drilled drainage holes... in them. Of course, me being me, I also drilled a drainage hole in my hand... Be careful how you hold shit when running a power tool, kids! Edited Sunday at 09:30 PM by dimlight65 1 Quote Link to comment
dimlight65 Posted Sunday at 09:46 PM Report Share Posted Sunday at 09:46 PM We are running a GPS speedo so the speedo drive in the transmission needed to be capped. I was told that the triple tree acorn nut for a Hardly Dumb-ass-one motorcycle... would thread on to it... It won't. The thread pitch is WAY finer. I googled it myself and found that an axle nut from... something would thread on though. I ran (and by "ran," I mean drove, of course) over to O'Reilley's and bought one... gave it a test tickle on a spare tranny... and then hole-sawed out a plug... and zooked that in... After it cooled, I crawled under the car and installed it... It does sit on top of the bolt that holds the pinion into the transmission... but it is hunkered down pretty tight, so I think it will be ok. Of course, after I was finished, I found a speedo cable... hanging on the wall. Oh well, it's what it's. 1 Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.