Daeron

My brothers are building an engine for their ITS car, and Chris (the elder) asked me to mine HybridZ and "talk to some of my engine buddies" to find an answer regarding (you guessed it) line boring the cam towers. They obviously want to avoid boring it if possible, but are more than willing to have it done if needs be. I searched about for a thread or two I can recall coming up in recent months, but I think the boring questions were asked in a thread that had a title about something else. The cam apparently spins freely, feels great... except for a single spot in the rotation. This is what he told me: "If you spin the cam with a bit of force, it continues for a rotation or two, but there is a rough spot. You can feel the rough spot, and after a rotation or two the rough spot halts the spin." In other words, it spins wonderfully freely, but it has one rough spot. It can be spun beyond that spot.. and through my search I see a "two fingers" rule for spinning the cam; if two fingers can spin it, it is good. I do not know how much force it takes to get beyond that spot, but I imagine not much. Is this irregularity itself enough to call for a line bore? Is it a matter of how much resistance the irregularity presents?? I am continuing my search through the evening, because I am fairly certain I can find my answer.... but I figured I would submit the question as plain as day, because this is an answer that should be more readily available through the search engine.

Short Answer is good enough, but not so good its gonna change the world.

but don't forget to factor in the ratios in the lower end of the honda engine versus your theoretical V8.... You have to know what rod length and what stroke you are running to compare cams "apples to apples" at LEAST as much as you have to keep an eye on valve size... and valve size can be "compensated for" by tweaking the lift and profile of that lift. Air flow characteristics and how they impact the six or seven phases of ignition cycling are NOT as easy to "fudge" to compensate for... I would be looking for a 1.5-1.6 4 banger that has as similar a bore/stroke/rod length as your V8, THEN analyze the valve size and camshaft specs of that engine, along with the intake ports.. In other words, start with common ground on the bottom end, then compare the top ends. You found a top end of a motor of similar displacement, but that could be an undersquare motor. A quick google suggests that the bore x stroke on the D16 is 75 x 90 mm. The r16 1600 OHV Datsun Roadster engine was 87.2 x 66.8mm. I may have overquoted the revs those engines see earlier (so I dunnot what you can do for valvetrain equipment) but the valve lift figures should transpose well... I just spent a little time looking for a page I had bookmarked on my PC that had archaic datsun engine specs like that, but i cant find it tonight. My search DID confirm the bore/stroke figures above.

Obviously you havent played too much with the old pushrod 1600 motors in the roadsters... I may be blowing smoke, but I am pretty sure the old girls used to run over 8 grand on the track all day long.. still reading the rest... Edit: I think a talk with TonyD about what he may have seen on pushrod Datsun Roadsters in Japan might be of benefit.. I am not sure what kind of bore/stroke combination they had but I know they had high RPM pushrod valvetrains, that could sustain the tumbles from four cylinder use (as opposed to the 90 degree V8 "light duty") and I will start grilling my uncle on how they pull this stuff off. Huzzah, Subscribed!

Why does an image of Al Bundy come to mind?

learn how to use the ammeter portion of your multimeter. Knowing how to test for various electrical problems is a VERY subtle and detailed skill, and chances are you need to expand your diagnostics knowledge. Try going to a library and see if you can find an Auto Mechanics textbook; I have a high school text that my dad got because the school went with a different publisher, it is one of the most valuable tools I have.

Well, my foot is in my mouth... but I am still not holding back my breath Good to see I wasn't taken in the wrong light; I hesitated before posting that but decided I did a fair job not sounding like a jerk.

What about mylar film used as a sandwiching material?? It occurred to me while reading about the heat shield idea, and it never has before. I had no idea how mylar would work in this sort of high temp situation, but it certainly makes for an absolute minimal size and weight sacrifice to a layer of your sandwich.. AND is highly reflective. any chance of getting a mylar film and wrapping the header side of your shield with any success?? Hmmmmm.... what high school?? I have several family members that work for the school board....... mwahahahahahaaaa:flamedevi

adjust the valves. That noise is one of the things I love about the motor. It IS a noisy, but that means the valves are slightly out of adjustment or something along those lines. Feels good to be working on issues with how well a motor runs, rather than making the motor run, doesn't it?

A suggestion: I know a great number of people have been suddenly cropping up that magically know ALL ABOUT how gas stations and their supply and pricing work, so I hate to talk about stuff like this, but I DO have a good idea and have known for some time now. In MY town, all the gas comes into the port, regardless of ultimate branding, and goes into one of two tanks: 87 and 93 octane. (This is West Palm Beach, Florida, USA, about 50 miles north of Miami.) Chevron tanks show up, they add the Techron ©, top off, and go to the Chevron stations; whatever additive package applies, similar stories play out for the other brands. IF the market is the same or similar in your area, you MIGHT be able to find some hole in the wall or other privately owned gas station and get to know the owner to find out if you can find gas that you DO know all of these facts about. If you're going to the lab anyhow, may as well get all the data you can walk in with beforehand, right? Just a thought; I read the update and figured I would throw it out there.

I would say make it long enough for a BMW, Toyota, or nissan DOHC I6 and wide enough for a modular ford V8 and you are golden. Still don't like the tail outline, and by increasing the size of the roof bubble you add copious amounts of space. Small increase in height plus broadening the cabin bubble adds alot of space. No offense, but I am still not holding my breath.. even if it is made I must confess that I doubt I will ever see one in person, and THAT is the judgment that I need to pass a final opinion on a new concept vehicle. It is pretty, though

whats the mad scientist rust removal, baking soda and distilled water plus 12VDC? Proportions of each? youre right, that IS a duh....

NICE, looks great!!

Heh. the move was an adventure, but all is essentially resolved; my car is now at the shop, where my dads to-be-re-turbo'd 78 is, and my brothers's racecar with a blown engine is. The three vehicles should be commencing more or less simultaneously, as my car has one man driving it, pops's has another, and the racecar is my two brothers' so each vehicles has at LEAST one whole man on it. I am hoping for some of that synergy stuff, positive feedback kinda vibe. The racecar _is_ being done, and in a timely manner, so me and pops get to hitch our inspiration trains onto that while we help, and in turn get stuff moving on the two 280s. BANZAI!!!!!!! but your comment made me think "heh, yah, thats exactly the mindframe I had about my car before my wee fire." So, in short, my problem oribably isnt as bad as you think it is... but let it scare you at least that much, because its a healthy fear

...using an intake manifold along these lines Since I am posting anyhoo, + a billion to braap for dropping the hammer on this thread. Sometimes the boot has to kick the tail before the tail understands.

http://forums.hybridz.org/showthread.php?t=135748

wigenout: that would be impossible to do, as it would wholly bugger the collector. However, the MASSIVE amount of room between intake and turbo manifolds leads me to think that one *might* be able to get enough rotational soace out of it by machining the HEAD FLANGE at a slight angle to achieve the same rotation you mention. The turbo flange itself could also be machined to accentuate this angle. Basically cut some material off of the TOP edge of the head flange, leaving the base of it untouched to angle the entire header up a bit, then machine the turbo flange in the same way (take a bit off the top, leave the bottom the thickness it is) and you JUST might get your turbo clocked up above the rail. As for cutting in the runners, I think that may be more problematic than you make it seem as well... ..but all of these are just my thoughts. I REALLY hope you guys get this baby figured out, as it is SO close to being a nice header....

:eek2: thats fast!! Did the other car jump the gun, or was that an 8.10 on a horrible R/T??? Regarding the diff, point taken; I had ignored it because I presumed that if something like that breaks on a car like this, it just means its time to get something beefier fabricated. It is a convenient blinder for helping to justify the "keep it nissan" mentality, which I know I at least am a hopeless victim of. Still, it does help to keep a good roster on one's idiosyncrasies.

Looks great, here's the sawzall! I don't want to take a jab at you stony, but lets not forget that the R230 has a ring gear that is just a hair over 9 inches in diameter.. the 230 is a pretty big pumpkin. I know it breaks like any other part, but I wouldn't lightly pass it off because one (potentially overweight?? guessing) 300ZX busted one up with a measly 600 horsies Just the indignant datsun lover in me trying to pretend that "I keep it real-er"

I think that jerry was attempting to remind you that more than just the sound will be transferring through the solid mounts. The vibrations, and all of their harmonics and reverberations, will travel throughout your entire car; just don't forget that. I personally don't like the idea of solid mounts on anything except a strictly purpose-built racecar that would never see the tarmac of a public road (if you can afford a "test course" other than the stretch of 13th street near the shop. Woops!)

Tony, THANK YOU. I have been trying to get someone to tell me that for about six months without knowing it. Kinda a "duh" moment that I grabbed onto and wouldn't let go of without the right explanation. I suppose I over-idealized my "cool return line" to the point where the idea made sense.

Good Luck, and thanks for the engine porn!

I leave it in for a few heat cycles or a hundred miles or so, then drain the oil and change the filter.

My brothers may actually be interested in those rims as well.. They have a set of four already for their ITS 240Z, not sure if they would like another matching pair.. but we have lots and lots of old school Z car wheels (read: 14") if you might be interested in a trade.

ya gotta hit the word "camshaft" just right....