pparaska

Well - after replacing ALL of the electrical parts in the distributor, and going through the mechanical advance, and indexing the rotor to the cap, there were still problems. The ignition is fine, the rotor seems to last longer now, but I still had tuning issues. But these issues were related to the tach signal filtering that was going on inside the Megasquirt ECU. I tried all of the fixes I could on msefi.com find but nothing worked. I cried for help on msefi and someone came to the rescue with a better tach signal filtering circuit that works with points and the 4-pin HEI distributor TACH output and the MS ignition input. My rpm in the datalogs are now smooth, no more spiking at constant throttle position and load. Here are the threads there that cover what I did, etc.: http://www.msefi.com/viewtopic.php?t=11891 http://www.msefi.com/viewtopic.php?t=7861&postdays=0&postorder=asc&start=17 Now it's time to get the fuel map straightened out. I was having a horrible time tuning the MegaSquirt - and no wonder the ECU was pulling VE values from several RPM bins of the same MAP value rows in the VE table every run through the fueling calculation loop (think many times a second). Imagine what the engine was getting for fuel - a sometimes vastly different amount of fuel each pair of revolutions. No wonder it ran like crap and was almost unresponsive to tuning the apparent VE map value at a constant load / rpm pair. This started out as a Chevy V8 topic since I was asking about HEI parts - and you guys came through! But it turned into a problem with 4-pin HEI and the Megasquirt ECU, so I'm going to move it to the HybridZ MegaSquirt but keep a placeholder in the Chevy V8 forum.

If there's enough parent material around the insert to handle the loads imparted to the insert, and the install was good (threads for OD of insert not too large in diameter, etc.), I believe you are correct that it can actually be a better connection than when the original threads in the block were in good condition. That is, if the insert material is stronger (ought to be, were' talking good quality machined steels versus cast iron), and it spreads the load out to a larger area of the block. I had a main cap bolt strip out of a 327 Chevy. The machine shop said they'd done plenty of Helicoil inserts for such problems and never had a come back. It worked fine in my 327 too.

That's what I was getting at - the name doesn't matter if you are talking about the correct stresses, etc. I agree with what you wrote, but was trying to connect it with what 2126 posted. I think you were talking about the first thing below (ramps and shear) and 2126 was talking about the second thing below (torsion in the shank). Of course, one is related to the other. No, I think you have it right and I is an engineer (or I play one) - mechanical engineer. I just think you and 2126 were talking about different parts of the same structural problem of head bolt stresses.

Engine block casting is some of the most complicate casting there is. You'll need to work with an engineer that's experienced in designing engine castings to be successful. It might end up being less expensive to get a chunk of AL and machine it into an engine block.

I think what John is talking about is the frictional force at the threads. That cause a localized stress in the thread area of the fastener and whatever it's threading into that can be thought of as having a shearing component that's parallel to the thread helix direction. There's also a bending and a tensile stress. Torsional shear stress is the component of stress in the bolt or stud shank that is, yes, torsional, or directed around the circumferential direction. The other major stress in the bolt or stud is tensile, that is, what comes about from the stretching of the bolt as the threaded end is drawn down into the engine block, while the head remains at the same height above the block deck (ignoring the smaller amount that the head is compressing locally around the head area and below it). The threaded region of the fastener has some pretty complex stress gradients, whereas the shank has generally just tensile and torsional stress while it's being torqued. After the torqueing is done, it's largely tensile only, with the friction at each end keeping a low torque in the shank. That might nearly disappear once the engine heat cycles. Bolts can have bending stresses in them as well. But you'd better hope their a good bit lower in magnitude than the tensile stress, or the bolt may fail if taken to the torque spec. Stress is really a tensor quantity that can be explained in several coordinate directions. In this case, it's convenient to talk about a coordinate system that's cylindrical, with the axis along the bolt's centerline. You can also describe the stress in principal stress components, but that's not really helpful here, even though it is important in determining the strength of the bolt and the torque spec if a below-yield bolt is being designed.

I'm driving it now. If it's not fixed by the Summit Point FATT date (4 Nov), that's o.k. I'm more focused on getting the ignition and megasquirt working well and getting a good tune on it.

Update: The Hagerty adjuster called yesterday to find out when I was going to send in the estimate from my shop. Ugh. The shop was supposed to have done that last Thursday! Well, it turns out that they did, but it got lost somehow, and the adjuster didn't ever get it. Part of the reason that it took the adjuster to get back to me is that the Katrina disaster has Hagerty busy. They're working a lot of overtime get those folks reimbursed. I had the shop fax the estimate to her again yesterday. They got hooked up and it went through. She then talked to the shop's adjuster about the custom work, etc., etc. and felt like they knew what they were doing and could get the car back in shape. Today she called and said a two party check in the amount of the shop's estimate was mailed out today! Now to see when the shop can get to work

Not sure if I'm preaching to the choir, but the raised deck is to allow the 4.25" stroke, and still use a 6.125" rod to get a rod/stroke ratio in the 1.44:1 range and a piston compression height of 1.075. That's still very short, and will require the pin to be in the ring land. The rod angularity, even with the raised deck and 6.125" rod will probably cause more than typical piston slap and oil burning, but yeah, this is a race car, correct? I think a mild-ish hydraulic roller in a 472 with about 10:1 compression would be a really nice mild street engine . Idle like a stocker, but put down the torque like a race 355

I've always heard that the 2 bolt stock 400 block was stronger than the 4 bolt. The main bearing webs seem to be weaker due to the 4 bolt setup. Oh, do you have any contact info for Edwards? Terry - have you decided on the World block yet? Do we have to come over there and twist your arm? Hmm. Maybe go with the raised deck, raised cam (9.325 deck height) Dart block and build a 6.125" rod 472? You need a wider pan (at the rail), longer timing chain and wider intake! I wonder about header clearance in the Z.

Thanks, Davy, but I replaced that stuff with a no-name boxed version of the ProForm coil and also a new Standard brand module. New rotor, cap looks fine. I went over the mechanical advance mechanism very thoroughly, and the distributor shaft play is not even perceptible. Using a timing light, there is a good bit of jumping around when the engine is held at 3000 rpm or so in the garage. I'm going to lock out the mechanical advance and see if that's the problem. Otherwise, it might be the wires, but I doubt it. It's not visibly cross sparking, but I need to rule that out. At about 4000 rpm at cruise (TPS and MAP are constant), the rpm is jumping around about 1000rpm, very quickly. No wonder I can't tune in this region. I've done all of the known fixes to the tach input on the Megasquirt V2.2 board (Dave cap, etc.) The one thing I haven't done is a shielded tach wire. I have a microphone cable I'll use to do that mod with soon if the locked out mechanical advance takes this rpm jumping around away in the logs. The EDIS just may go on soon if the distributor is shown to be the problem.

I'd stay away from a .060" over 400 block, unless it's been sonic checked to a good wall thickness all the way around. I know it seems like a lot of extra money, but a World or Dart 400 block would make more sense for someone pushing the limit with N2O, etc. Look at what it takes to check and machine a used 400 block, and the new aftermarket ones that come fully machined (except for the fit hone) are not that much more money. And you have a MUCH stouter piece to beat on and bore more later! On that note, go for a 434 or something. The 406 is getting overdone these days . Or just buck up for a Shafiroff 472!!! It's only money! Oh, the SBC is undervalved at a 350 as it is! And under ported! Go with the 227 heads - the 190s will limit the engine you're building. If it were a truck engine not meant to run over 5500 rpm, yeah, the 190s would be fine. But they're going to be WAY too small to take advantage of a 406 or larger engine with the kind of cam, intake, etc. you're talking about. Forget what the freaking magazines say, the 190 is TOO small for 406 motors that are going to be raced! The 215 Canfields I'm running on my 406 are in no way too big - I can pull down to 1400 rpm in any gear and it will accelerate nicely from there. Look at the flow to cross sectional area ratio of the port, not just the volume to determine if the ports are "too big". Also consider that with the shorter rod/stroke ratios you get into with a stroker (even with 6" rods), the piston is being yanked away from TDC much more quickly, and a little port (and valve) will limit the initial flow.

Hagerty doesn't care for racing. Even if you know they don't cover it while one the track, they don't want to insure a car that is raced more than a few times to find out what it'll do. They made that quite clear to me. I am VERY cognizant that Hagerty doesn't cover me while on the track. It's a risk I take, but a CALCULATED ONE. People on the track days are typically not going to hit you. The risk is all pretty much either under your control (the pedals and steering wheel), or due to you overcooking the brakes or just taking parts beyond where they will work without failing. That's all a risk that I run at track days, etc. KNOWINGLY. The street is typically a riskier thing, since I drive pretty conservatively on the track. The street involves people that are near my car that are usually much less attentive to driving their vehicles than people at the track might be. So yeah, get good AGREED value insurance if you can, but realize that most of those policies are for collector cars, and don't cover you on track. Maybe a separate policy or rider for track stuff. Last but not least, realize that it's a bad investment (generally) to have any money tied up in a car. Especially a daily driver. My wife and I learned that lesson on her 1st gen Integra years ago. The companies care not 1 cent if your car was in great, way above average shape before it was totalled. Unless you can show it was a cream puff with low miles, show-type car, it's just in "good condition". Her Integra was low miles and beautiful. The insurance company wouldn't give any more than an average amount to replace it. Moral of the story - if you keep your daily driver in tip-top condition, it's at your own risk to do so - realize the insurance companies don't value it any higher than all the rest of the decent cars out there of the same model and year. The insurance companies lumps all daily drivers (under non-agreed-value policies) into one category and pay accordingly. Seen my daily driver? (At Watkins Glen! ) Runs, works, but ugly as sin! No way I'm going to put any extra effort to keep it pretty, not after that lesson. Pretty daily drivers aren't important to my joy, and I drive them until they die, so resale value isn't a concern for me... spot - good point on taking care of our bodies in these instances.

Mike - I did some googling on HEI, and man, there are alot of people that don't like it for performance! Issues seem to be the module not handling enough current to be able to run the coil, and those that do may not have good dwell properties. Module can get very hot and intermittent. Coil in cap gets hot and can loose energy and increase saturation time. Coil in cap is not a good design generally, as far as E-core, etc. I'm just about ready to call in an MSD replacement, but not HEI. Even thinking about going to the E-curve job, and getting a Blaster SS coil (good reviews on energy capability and short saturation time). But the dizzy is $350 (after rebate) and the coil probably another $50.... Brad - I even have the EDIS-8 stuff in a box! "All" I need to do is mount and wire it, and see if the 50 series 36 tooth chain sprocket will give a decent signal to the VR sensor. But I really wanted to tune the fuel only first. Chicken and egg problem!

I have some strange rough running conditions that changing the fuel map won't seem to fix. I'm beginning to think I need to make sure the ignition is very reliable before continuing on tuning the fuel map. I have a blue streak module and one of the Brute Thunder coils in the HEI cap (old style, red/yellow wires on coil, 4 pin HEI). I'm thinking of just getting some decent OE type replacements to take the parts I have in there out of the equation. Anyone have a module and coil they like, that's good to 6500 rpm, but doesn't have so much voltage that it constantly burns through the rotor (read on)? My rotors last a very short time before they will burn through under the center post. I believe that the coil just puts out too much voltage (like 50K+), and the dielectric strength of even the best rotors (Accel, etc.) can't hold the voltage back from grounding out on the mechanical advance mechanism below it. The plug wires while not new are the 8.5 msd stuff, and they ohm out o.k. and don't arc over to anything while the engine is running in a dark garage. Plugs are Accel 0414S, with a .050" gap. I'll try closing that gap, but when I've run .035", the burning rotor caps happened just as much. The cap is an Accel unit, looks great, no carbon traces, etc. I have the ground on the distributor harness that goes to the coil (3 prong connector in cap) running to a ground, so it doesn't depend on the distributor housing for the ground path only. 12 gage wire powering the coil from a relay right next to the distributor, that has a short run to my main positive tap on the ford solenoid over where the battery usually is. Power and ground should be better than a stock GM car that HEIs were put in.

Thanks, Joe. Let me share my thoughts on prized material possessions a bit. Sorry to get philosopical on you, but I think it's in order here. I have a lot of people tell me how much they love this Z of mine. I really think some people like it more than I do. But owning something that's covetted can be a sorrowful thing, if you have the wrong perspective. I learned this by watching other people get emotionally wiped out when their inanimate pride and joy was destroyed. I told myself I never wanted to be there. Hopefully, if this Z ever gets really mashed or burned up, I can stay away from the dark cloud of mourning for a sheetmetal loved one. I don't know, it's hard to imagine how I'd feel, but something tells me, I've been given a chance at seeing how I might deal with it. BUILD ANOTHER ONE OR SOMETHING ELSE is my first thought! The rule I put myself under when I got the expensive body/paint work was that I wouldn't get upset if it got messed up. Getting an Agreed Value Policy with a reputable company like Hagerty was the first step to staying away from the dark days. Luckily, when this minor accident did happen, it wasn't too bad, so that it was KIND of easy to follow my own rule. I was upset for less than 1/2 hour, really. After that, I used the realization that Geico or Hagerty would put the car back right, it wasn't that bad, and that no one was hurt (that last part was what really mattered) to look at it rationally. I'm writing this in the hopes that others might put themselves under the same rule if they buy or build a car or something that is done "nicer and more expensively than what sane people would do". I think it's important to prepare one's self for life's little bumps. And getting a grip on reality really helps here! IT'S JUST A CAR!!! Well, that's my rational point of view anyway. I hope I can keep it and stay rational if something really bad happens to my Z. The shop that is going to do the work (where Richard Glymph works, the painter that did the car originally) sent me their itemized estimate today (about 24 hours after they saw the car). $4506.67. Hmm. $1600 higher than Geico's adjuster (who looked at the car for 15 minutes and wrote the estimate on the spot in about 10 minutes). Let's just say imy shop did a much more in-depth estimate, and the amount of time they estimate for doing things seems like they won't be rushing to get it done - i.e., they'll be taking care to do it well. My shop (vs Geico estimate): 56.3 (vs 27) hrs of body labor, $38 (vs $36) per hr 16.8 (vs 10.7) hrs of paint labor, $38 (vs $36) per hr 2.3 (vs 2.3) hrs mechanical labor, $75 (vs $68 ) per hr 6.0 (vs ZERO) hrs frame labor, $55 (vs none) per hr 16.8 (vs 10.7) hrs paint supplies labor, $22 (vs $20) per hr (My shop stating 3 stage vs 2 for Geico - I think I steered the Geico guy wrong there.) $1168 (vs $1103) parts and supplies Other Differences: 3 stage versus 2 stage, higher labor rates, the frame machine setup, measure, pull, align labor (vs none) my shop including more Remove&Installs of interior, antenna, etc., including the fuel door, my shop: R&I lamps and emblems both sides instead of one, my shop: removing scuff from bottom of (EURO!) tail lense, (vs no mention) my shop: repairing the tail light finisher panels, (vs no mention) etc., etc. made the labor hrs much larger but more realistic. Basically my shop did a very detailed estimate based on knowing all the little moves they'd have to make, the Geico guy simply left stuff off, and probably hasn't worked in a body shop ever or for a long time. The more I consider getting it fixed before the Nov 4 track day, the more I think I should. The tank is really crunched up, but not leaking. What I don't want to happen is the tech inspectors seeing it crunched and not letting me run. Plus, there's a few more shows to take it to this fall, and many more weeks of nice weather I'd like to have it looking good for! Sorry for the book! But I figured Wayne would want to know how his baby was getting fixed . I wonder how long it will take for Hagerty and Geico to agree on a $ amount. Hopefully not long!

Could be. I told the shop I'd wait if it looked like it'd be stuck in paint jail.

Congrats - Wheelman, I'll bet those "yes sir" habits last for quite a time if he's going into the Presidential Honor Gaurd. I'm 1/2 hour from Andrews AFB. If you're ever here visiting, let me know. Oh, there's a speed shop right across the street from the main gate - it's been there since 1967. They're even opened on Sundays! Speed Unlimited. Air force = high performance!

Here's another way to look at it. Do you want the car to just be a cruiser? Then leave it the way it is, if the systems (brakes, diff, half shafts) are in good order. Do you want to use the engine's performance potential? Then do the mods that you think make sense. Probably the brakes first, then CVs and LSD. By changing those things, you're just adding an option that was available then (LSD) and updating to stronger, safer parts. I doubt that it would change it's value much. For that matter, does it matter if you change any collector value it might have? Well, all of those mods are easily reversible anyway, so that's not really and issue anyway. I say mod it to be safe and reliable, and drive it hard!

Wayne, the bumper was on there, shortened in the for/aft direction by 3/4", and I made strong mounts and put a piece of black pipe between them. The pipe was nested inside the bumper. The Gieco adjuster was pretty cool about things. He said that Geico doesn't low ball, they pay what it takes to make the car right. He liked the car and saw little ripples and dips I didn't see, all the way up the quarter panel. The right 1/4 is pushed down about 1/2" at the back. The car will be on the rack getting stretched back into shape, no doubt. His estimate was about $2900. He said that it'd probably be more and that supplementals are expected. He was relieved that it's being suborgated (sp?) through Hagerty, because he was going to try to force a check on me. MD makes them settle within 15 days of the report. He doesn't like that. I found that the guy that painted the car works close by at a nice new shop. I went and had his shop's adjuster look at it and he's working up an estimate. He found a bit more stuff, like the gap at the back side of the passenger door is closed up a bit. The adjuster was saying that about 1/2 of the car will have to be resprayed, to not have cut lines. These guys know what they are doing, and have a high level of quality. There was a 64 356 speedster there to get some work done, a 32 highboy body in primer, a 47 Plymouth that the painter was buffing out (jeesh, baby blue - some people's taste!!!) That car was a masterpiece and the paint as flat as you can expect from this guy (reknowned street rod painter on the east coast, Richard Glymph). Everybody at the shop, including the owner was digging the Z, so I know it'll be done right. All is looking up. Still no pains. I may go see the doctor tomorrow though. Now to get under the car and pull the back panel out of the way and replace the fuel tank and do some more tuning!!!! A C230 Kompressor wanted to play, but the Megasquirt program I have running now has acceleration and O2 correction turned off, so hammering the throttle just causes backfires and no joy in the backside. Oh, I was laughing as I pulled into the parking spot at work. Some bozo's car alarm started going off - the exhaust is a bit loud .

Umm....

I know I dug this up from the past. But I made a certain observation at the 2005 Z Car Convention Banquet that is apropos: During his speech, every time Mr. K. said "Z car" (a term he uses quite often in his speeches, I might add!), he pronounced the last letter of the English alphabet as "Zee". Since he's the father of the Z, I'll take that as gospel . Just kidding guys, I'm fully aware that he was saying it that way since the convention was held in the US, and most of the people in the audience are from the US. Just thought I'd poke a bit more fun at this one ...

I know what you mean about light impact accidents and the soreness that shows up later. Still nothing. It was a very light tap. The fact that the Z is only about an inch or two shorter kind of confirms that . These cars are so flimsy back there! Thanks for the concern though! I'll post if I start feeling anything (or if Glenn mentions it). He's on top of the world today, after starting a much better new job today (high end repair shop service manager), diagnosing a problem that 4 trained mitsu dealer mechanics couldn't solve for weeks (in another shop) after the symptoms were described to him in just a few minutes over the phone, and seeing an example of how his decision decades ago to stay up to date with the advances in auto technology have made him a valuable asset to the auto repair industry instead of being in the shoes of the old-school mechanic that came to the new place he's working at and not being qualified to get a technician's job. Just found out from Zedd Findings (Charlie Osborne) that the lower rear panel is $159 US, and $23 shipping to me - way cheaper than MSA's $250 + shipping. Of course, many of us are not surprised by that info...I'm SO glad I don't have to go to the gouge-masters out west for this part!