Kyle

104 octane, sure you bet... If I had a contact at the local airstrip, I might think about it. But this car is to be a daily driver (leastways, it was before it got all taken apart). The 2mm gasket has been ordered ($150, ouch!) and that will get the CR where it wants to be. The HKS gasket actually has a 91mm bore, so that raises its volume to 13cc, which in turn reduces the CR to 9.5, exactly where I wanted to be. I sure wish I'd had the sense to calculate the CR this precisely before assembly, cutting the pistons a bit would have allowed the use of a cheap standard head gasket. Ahh well. Someone on the 240Z list raised the issue of quench and swirl. The short version is that the 2mm headgasket might put the piston top too far away from the chamber, screwing up the air fuel mix and causing detonation. Any thoughts on that? I figure the pistons are closer than stock (.5mm above deck, versus .35mm below deck plus a 2mm dish for a stock N42 engine) so that puts that issue to bed. What a learning process! Even with lots of surfing and lurking, asking of questions, how-to-modify and how-to-race, I'm still basically making this up as I go along. Nice metaphor for life, there.

Good thinking! I failed to condsider that... but it will bring the CR down to 9.6. Amazing what 5cc does. So I guess this makes a new question, what CR is reasonable? That 9.6 would certainly give me breathing room. Guess I'll call MSA and see what it'd run me. Thanks for the idea!

Double checked my specs last night - the bore is 87mm, not 89. What a monster difference that makes. The CR with 45cc chambers is now 10.46. To match the chambers, I did have to do some pretty serious grinding (1cc) off the #1 chamber; I took the material near the sparkplug hole and exhaust valve... If I was able to get 1cc more out of each chamber, I could get the CR down to 10.25. But the caution you've so wisely given me, plus my urge to get this thing done, suggest I'll just get them all even, smooth the edges, and be ready to assemble. I hear ya on the L28ET. I wanted to stay with SUs, but even so, and even with a great deal on most of the parts, it's still wound up costing way more than I expected. On the brighter side, though, rebuilding an L28ET would surely be at least as costly; and if I just got a JY engine and threw that in there, I'd be where I started Thanks much for your help on this!

Ahhhh yes... unshroud the valves. Duh, I was just looking at how to modify yesterday, for the Ccing procedure. Tunnel vision, I guess. My only concern is that when taking a lot of material out of the head casting, I don't take it from someplace ciritical. The area around the valves is quite obvious, and thanks for the :stupid: mallet to the head to remind me. What about the area near the spark plug hole? I've got a feeling it's necessary to have that semi filled-in area to get the airfuel mix to gather up near the plug, so maybe I don't want to mess with it too much? Maybe just massage the edges a bit? Thanks again for any tip!

Hi all- Building up a L28 for my '72. It's an N42 block and head, +1mm overbore with flattops. The head has gotten some mild porting, chamber polishing, and portmatching. I cc'd the head yesterday, and got chambers from 44 to 45.3cc. Obviously, they need to be 'adjusted':stupid: But that then led to calculating the compression... with 45 cc chambers, 89mm bore, 79mm stroke, +.5mm deck height, and 7.6cc headgasket, I'm getting 10.93:1 CR. Ouch. My initial plans expected the engine to wind up with 10.5 using as-cast parts. That didn't count on the piston sticking up above the block deck... Now that it appears I need to relieve the chambers, I want to get down to about 10.0:1 That'd require 50cc chambers... Where can I take the material from, safely? Thus far, I've basically removed the ridge between the valves, and smoothed the transition from the ports to the chamber roof. The large protrusion near the sparkplug hole is untouched. Does anyone know what 5cc really looks like in the chamber? I'll (try to) attach a smaller image of a representative chamber, and the full size (out of focus, sorry) is at http://www.sonic.net/~kyle/Cylinder Head Chamber.jpg Thanks much for any guidance... this project has taken on a life of its own!

The grease seems to do a few things - keep the rubber insulator (between the actuator rod and the piston (pedal end)) in place, and seal the actuator rod seal to the mastervac body. I agree about the consistency - it was white, heavy, and pretty sticky, though there wasn't very much of it. Just wanna make sure it's okay to use general purpose white lithium grease in there. Thanks for the help!

Dan Baldwin (I think) put some on his 3.1L IIRC, he wasn't overly impressed with them. You might catch him on the 240Z list.

Hi all- list traffic is slow today, so here I am on the forums! My mastervac is out for repainting, and I removed the actuator rod (master cylinder side) to keep it from falling out. It's got some sort of grease on it; what is it? I need to regrease it before reassembly. Thanks!

The CPA puts on his tie and starts the billable-hours clock ticking: As regards to taking a tax deduction for the high book value of a rusted out car.... first off, a good rule of thumb is to stand in front of a mirror and see if you can say it out loud without laughing. If you even bust a grin, you're not gonna make it. A noncash charitable contribution deduction (Salvation Army clothing, f'rinstance) is the lesser of your cost basis or fair market value. If it is over $500 you need some additional documentation, and if it's over $5000 you need a written appraisal. So the $13,000 Z deduction is laughable for a number of reasons - you only paid $700 for it, so that's your max, and even so, you wouldn't get a written appraisal for $13K. Sure you *could* but that's tax fraud, and I'm too young and pretty to go to jail. Finally, this deduction is one of the IRS's hot buttons now, meaning they're going after it like nobody's business, as it's a fairly simple way to slash your taxes with minimal effort. These things are VERY likely to generate an audit. You might get away with it once or twice or even a million times, but you may also get caught... Audit Roulette, anyone?! Don't forget penalties, interest, and the 25% fraud penalty. As to making money on a Z, don't be ridiculous! Of course it is. Just make a good buy, put limited dollars into it, and turn it around. Will you make boucous bucks on a full resto? Not likely... but if you buy a decent car for $1000, get it running right, maybe make some small improvements here and there, you could sell it again for $2500. The gain is of course taxable and I'll expect to see it on each and every one a ya's Schedule D's next year... oh, and the loss on the resto is nondeductible. Go uncle sam! :sick: Hope this is helpful, Kyle '72 Resto in progress, no I don't plan to make money on it.

I'm shocked all to hell to admit this, but I kinda like it. It does look way better than the magazine and promo shots would have you believe... probably has something to do with the Kubrickesque camera angles they use. However, holey criminey! How big is that thing?!!?!? Looks roughly the size of a GM F-body. Maybe know we know what The General is doing with the leftover parts. Kyle '72 240Z project

Hi there- <p> If you're sure of which pickup to use (they're probably oriented differently with respect to the distributor cap) you can safely remove the extra set. Or! Get creative and hook up a knock sensor..... theoretically, you could have it automatically retard the timing when it starts to knock/ping. May or may not work, but I've been waiting for someone to give this a shot;-) <p> I don't know about the 'contactor', sorry... that's a new one to me. <p> I got an El Cheapo module from Kragen three or more years ago and have had ZERO problems with it. It might be prone to overheating in a big ole nasty V8; especially since they live inside the distributor. The GM HEI swap locates the module well away from the engine, on an aluminum plate that functions as a heat sink. <p> HTH <p> Kyle<br> http://www.sonic.net/~kyle/ztech.html

Hey Mikey - don't see the pictures in your post. Billy - one thing I neglected to mention in our Email - larger diameter wheels will probably have a greater ??? polar moment of inerta ??? vector transcience inhibitor ??? angular momentum ??? or something - IOW, the wheel's rim (and the bulk of its mass) is farther out from the hub centerline. Probably not real significant, especially with just a 1" diameter difference, but something to think about from a performance standpoint... and the wheels are probably heavier too, with longer spokes and a greater circumference, which means a heavier wheel rim. FWIW Kyle

I gotta take issue with your signature line, mikey.... Kyle '72 240z... I'll give it to ya in two flavas: Broken engine, body in pieces, ugly paint, spread out all over --or-- 10:1 L28/N42 cam/header/SUs, 5speed, all PU, 15x7 Panas, etc (kinda like the last one better)

Hi guys; sounds like Gary and Rob are workin thru this okay, but I thought I'd toss in my 2c... And I hate to be a yutz, but I always say start at the beginning - are your valves adjusted? Points? Cap/rotor/plugs/wires? etc. Start with one thing and keep on keepin on. That aside, it sounds like you might have a stuck piston in your carb; very easy to check - pull the air cleaner and look inside, see if the piston is sitting on the throat bridge like it's supposed to. Make sure both carbs' pistons slide smoothly in the domes, and that they slap back down at the same rate. If there's anything fishy going on, look at the needles as they rise out of the nozzle; they should be absolutely centered. If that checks out okay, double check your mixture adjustment (roughly 2.5 turns out) and reset the balance. Kinda doubt that this is the problem, but it's important to have 'em balanced. After that, make sure all your throttle linkage is smooth and silky, and that your floor mat didn't get on top of the gas pedal (been known to happen!) My 2c, and please excuse if it's been already addressed; I'm just passin the time;-) ------------------ Kyle Hagemann Moderator, 240Z list '69 2000 Roadster '71 PL521 Pickup '72 240Z Hotrod

I gotta say, it's probably a bigger job than you want. AFAIK, you have to remove the crankshaft, which requires removing the engine... this is one of those things that always seems to lead to a full rebuild and/or different engine. Is your PCV system working properly? A clogged PCV valve can cause crankcase pressure to build up, causing oil leaks. (found that out the hard way after plugging my PCV on purpose, ) Kyle ------------------ Kyle Hagemann Moderator, 240Z list '69 2000 Roadster '71 PL521 Pickup '72 240Z Hotrod