Michael

Comparing what’s currently available commercially, Milwaukee is the brand to beat. Milwaukee is currently updating their product line. Stores such as Home Depot have them on clearance sale. A few weeks ago I bought a 8.5 Amp quick-change model for $50.

I have a similar mod to my radiator support on my ’78 280Z. The lower crossmember remains, but the rest of the radiator support was removed with a sawsall and the spot-welded guts were ground away from the inner fenders. A 3/4" tube with clevices on each end supports the radiator and electric fan on top, while down below a similar tube is welded to the frame rails, supporting the bottom of the radiator and reinforcing the front sway bar mounting locations. The lower tube is also braced to the stock lower crossmember. The upper tube’s clevices connect to tabs welded to reinforcement pads, themselves welded to the inner fender sheet metal. There’s a strut tower crossbar and diagonals from the top of the strut towers going back through the firewall, meeting at a dash bar. Also, I cut away the heavy-gauge reinforcements used on the 280Z to support the front bumper struts. While the weight savings claimed from bumper surgery is, in my view, somewhat exaggerated, removing the aforementioned metal saved about 5 pounds. I second what was said regarding the sheet metal forward of the strut tower and sway bar mount. It’s not important, if the strut towers are themselves adequately braced, and the sway bar mounting hard point is not compromised. Of course, front-end collision crash protection suffers, but that’s probably not your primary concern. Rigorous assessment of whether cutting sheet metal forward of strut towers is entirely harmless would require some controlled loading/deflection test. Has anyone done this? Short of that, my brief experiences driving the car showed no steering deadband, front end vibration/looseness or rattles.

The 454 big block formerly in my Z (and for the past 18 months on an engine stand!) came with small oval port heads; it’s from a 1978 Suburban. In an effort to decide whether aftermarket aluminum heads are the best approach for my purposes, of if the stock heads can be modified with reasonable success, I “ported” one of the heads with an electric grinder and a Dremel. Results were measured on a “superflow” flow bench at the local machine shop. I did not take measurements of the stock heads, but here is a comparison of the data in Chevy High Performance (available on their web site) with the after-porting results: lift int_stock int_ported exh_stock exh_ported 0.200 125 129 87 95 0.300 183 196 111 125 0.400 215 242 130 146 0.500 233 259 144 162 0.600 235 269 150 182 Both data sets are at 28” water, with no pipe on the exhaust ports. This is for stock 2.07”/1.72” valves with stock (rather poor) valve job and 3/8” valve stems. The Superflow data set include numbers for effective flow area, flow coefficient and a number called “valve velocity”. In the opinion of the guy at the shop, a 454 with ~9:1 compression, a cam “with around 230 degrees duration [at 0.050”]”, Edelbrock Performer RPM intake and 750 cfm carb will make around 420 hp, with around 520 ft-lbs in the 2000-3500 rpm range. The next day I commenced disassembly of the short block. Since none of the cylinders had appreciable ridges (carb cleaner took care of what little carbon deposits there were), the rods came out with minimal persuasion. Rodless, the crank is easily spun by hand. Oil passages in the rod journals were mostly clogged, but the journals themselves have no scratches or deposits of bearing material. So perhaps by next spring I’ll have a running engine again!

Looks good – especially how the roll bar is pushed as far outboard as possible. In your second photograph – why not weld the roll bar/diagonal junction to the unibody sheet metal (at the front-bottom corners of the valence windows)? Then the roll bar doubles as a “B pillar” for the unibody – and the unibody acts as a shear web for the roll bar.

The problem with the torque vs. hp argument (build for hp, use gearing for torque) is the fact that the engine has to spool up to reach the rpms for its “sweet spot”. Engines built for high power, without priority for high torque, almost universally have a power band that favors high rpm. In a racing situation, the driver can plan ahead, by revving the motor before he drops the clutch, pre-positioning the engine in its favored rpm band and preselecting the appropriate gear. In a street situation, off-idle throttle response (and torque!) is what produces the seat-of-the-pants acceleration. I agree that in a controlled racing situation, a mildly improved L6 can achieve similar results to that of a stock V8. But in a street situation, leaving the stop light at 900 rpm or suddenly flooring the gas without downshifting at 25 mph in 3 rd gear, there is no comparison! With an automatic transmission on the street, the difference is even greater, because it takes an appreciable amount of time for the transmission to “realize” that it needs to downshift. The gearing argument is moot if all that the driver desires is a burst of acceleration on-demand.

Lewis, Regarding the strut housings - if you have all four, and they aren't bent (many Z's have a 2 degree (or more) runout on the kingpin inclination angle), I'll pay $100 for the set. But first I have to make sure that the late 260Z is the same as the 280Z. Thanks.

In California the pick-a-part yards probably consume most of the stock parts business. The first Z that I owned was a ’72 rustbucket (back when I lived in Pasadena). I was overwhelmed with my purchase – it was useless as a candidate for daily driving, let alone a conversion to V8. When I couldn’t sell it, I tried parting it out. After about a year of advertising on recycler.com (a very useful Los Angeles-area automotive classifieds site and newspaper), I sold most of my parts, for a total of about 50% of what I originally paid for the car. I cut up the shell with a sawzall and threw the pieces into dumpsters – literally (well, I kept the firewall VIN stamp). After I moved to the Midwest, the situation changed completely. Here, Japanese cars are rare, and old Japanese cars are extremely rare. If parts do come up for sale, they’re rusted, bent or otherwise worthless. I’ve been looking for a decent set of 280Z strut/spindle assemblies since 2001 – no catch yet. Next time I’m in LA, I’ll visit the pick-a-parts in Monrovia, pull off a set of strut assemblies and mail them back to my address in Ohio.

This may or may not be an appropriate place to make this comment.... but I think that the consensus here is that an incremental approach is preferable. Begin with a stock Z. Replace the suspension bushings and brake pads. Then go to an SCCA club-racing event. Get to the point where you have outgrown the car as a competitive driver. Then consider the first round of upgrades. Maybe a typical Chevy small block, or a Ford, or a turbo L6. But such mods kick you into highly competitive racing categories. So if competitive success is more important than raw performance, consider building an ITS car. Here the path diverges: build a race car to class rules, or build a fast car for personal driving pleasure, regardless of what the race sanctioning bodies mandate. Achieve a solid 300 hp. Install a roll bar, strut tower braces, better brakes, a stronger differential. Then replace the mild small block with a hotter one. Or add turbos, or nitrous, or go with a big block. Reach 500 hp, 600. Perhaps that would be enough. Perhaps the troubles of managing all that power –living with it, not just yearning for it – will attain the point of diminishing returns. But perhaps not. Then keep going up – to 1000 hp, if that’s the next step. When I began my project, I was blessed with a rare opportunity to get professional labor at minimum wage. That’s how I ended up with a tube-framed car set up for a big block. 1000 hp? No, maybe around 400. But even that proved to be too daunting of a step. You may be substantially better prepared than I was – technically, financially, emotionally – but reach too far too fast, and chances are high that something will snap. The last thing that you want is a festering money pit, abandoned in frustration and disgust. Or an ambiguous dream that always stays one step ahead of what's achievable. Isn’t it interesting that rarely do we see posts from guys with 500 hp cars who want 700 hp, or guys with 700 hp cars who want 1000 hp? If you’re that close – if you have done the homework and made the investment to achieve a certain threshold of performance – reaching the next threshold is a logical step. What to do next becomes almost self-evident. Irksome details will still crop up, but the general roadmap is clear.

Lewis, I need McPherson strut housings (all 4 corners) – stock will do just fine. I don't need the brakes, or springs. I’m in Dayton, Ohio – evidently about a 3 or 4 hour drive from you.

Besides those mentioned already, there are several full tube frames on this board. Perhaps the most thorough belongs to “japtin”. Ron Jones has a similar variant. Mine is essentially a tube frame, though it’s welded into the unibody and uses the unibody panels as shear webs etc. It was built on a jig. The car was sawed into three pieces, the frame was welded into the unibody, and then the unibody was welded back together. The tradeoff in this approach vs. a true tube frame is less welding and design work for the frame, but more sheet metal work. A true tube frame differs from a “ladder” subframe (such as Chris Alston or Art Morrison) that slides “underneath” the unibody, then gets a roll cage added. A true tube frame doesn’t have frame rails per se; a jungle-gym-looking framework supports the engine, driveline, suspension and seats. The roll cage helps to bear the suspension and driveline loads. The retail cost of designing and building a tube frame is around $20K (mild steel – maybe $30K in chromoly). Of course, if you have access to specialized tools, a race car shop and mentors to assist you, things would be different. But if you’re shooting for a 1000+ hp road racer, $20K is probably not such a large expense. Chassis sold in catalog stores such as Jegs are just kits – collections of tubes. Welding them together is left up to the customer. The kits are generic, and will require extensive customization to fit to any particular vehicle; rest assured that none of the catalog stores will have a kit customized for the Z. When I shopped around for such kits, about 5 years ago, salesmen would tell me, “Datsun Z, right? Hey, that’s just like a Chevy Vega. I mean, Ford Pinto. Oh never mind, they’re all subcompacts. Our kit fits all of them”. An alternative approach might be to concentrate on weight reduction, rather than all-out horsepower. What power to weight ratio were you shooting for?

Grumpy – To slightly change the subject.... I’ve been following your advice on big blocks in various posts (such as the 496 marine build-up), but prior to this thread I didn’t realize that you had a big-block Z! Do you have pictures/text about this car? Would you summarize the characteristics of the engine build that you chose? You’ve heard the story with mine – chassis is together, but engine is ailing, while I waffle as to what to do with it (for instance, whether to cough up >$2000 for aluminum heads, especially when AFR comes out with oval-port heads, or to mess with my 346236 castings). 632 cu in mountain motors are wonderful things, no doubt – but I would also be curious to see your views on “budget” offshoots of the 454 As for the roll cage story – I don’t have the benefit of practical experience, but the consensus among chassis builders with whom I have come in contact is that triangulated structures are vastly superior to quadrilaterals, and swing-out bars, such as door X-bars, might be OK for rollover protection purposes, but they don’t help much with chassis stiffening. My car has welded-in X-bars which tie to the frame rails in the bottom front (diagonals inside the wheel wells), the dash bar in the top front, and the roll bar in back. By no means necessarily the best solution, of course - but it certainly feel solid on jackstands. Pete Paraska has pictures of my car on his site - http://mywebpages.comcast.net/pparaska/MichaelOlsBBZ.htm

Pondering the examples of hybrid Healeys, MG's, etc. - and the more radical Z's on this forum, I'm intrigued by the next question - has anyone built a car completely from scratch (in the spirit of something like Bill Thomas's Cheetah of the 1960's)? I mean, your own frame, bodywork, windshield, doors, everything? Considering the extremes to which some members have gone to, this would be the next logical step....

I have a '78 454 from a Suburban. Sure enough, it has the "hi perf pass" casting. My impression is that ALL standard-deck 454 blocks from the 70's had that casting. It also has the oil-line bosses above the oil filter mount, but it's a 2-bolt block with cast crank. I don't know of any post-1973 454 with had a factory forged crank. Forged-crank 454's basically died with the LS5. Heads are 346236 - yours are probably the same. 113 cc oval port heads, but they're not "peanut port"; those are even smaller. Some people claim that with pocket porting and upgrade to 2.25"/1.88" valves, these heads can support 450 hp. That got me confused over the choice to get aftermarket heads, since 450 hp is exactly my goal for the Z. If you do put a BBC in your Z, keep us informed! Man do I have some information on that topic (the hard way....).

I agree about the R/S matter. Plotting the “crank-slider” model of piston displacement, speed and acceleration vs. crank position, and varying the rod to stroke ratio, reveals how little the piston kinematics are affected by changes in rod length. And the one or two degree difference in rod angularity - yeah, I don't see how that could be significant, either. Importance of rod to stroke ratio is one of those debates that will never get settled, simply because we just don’t have a rigorous way to quantify exactly what happens – in terms of engine output or cylinder bore wear – for different R/S ratios for the exact same displacement and block architecture. That leaves wiggle room for some expert engine builders to legitimately claim one thing, and for others to claim the precise opposite.

Pete, Frankly, I find it somewhat difficult to understand how one could fret over spending an additional $300 on one set of heads vs. another, when >$30,000 was already spent on the project! Canfield might be the unsung hidden gem, and AFR the celebrated show horse, but if you buy the Canfield heads you would still wonder whether the AFRs might not have been better, whereas if you buy AFR, quite possibly you would not be concerned over the alternative. So if it’s just a matter of $300 price difference, spend the bucks! Once upon a time you gave me essentially the same advice....

Don't know if this got mentioned already or not, but there's a fellow in the Los Angeles area who did the Caddy 500 swap about 5-10 years ago. He showed his car every year at the Motorsport show in Orange County. I believe he's the same guy who recently set the top-speed record with a sorta-stock 2+2 Z at Bonneville. Anyway, back around 1998 I had a conversation with him. He claimed a 50/50 weight distribution, with aluminum intake but stock heads (if I recall correctly; also, I think he used a GM corporate TH-400, or maybe 700R4) and stock firewall location. The distributor location makes engine setback easier. He may have had a custom sump. I have a photo of his car (but nowhere to post it).

Thanks for the compliment, Mike! The guy who welded my roll cage was a rare find - and even he had some choice remarks when describing the difficulty of the job. As for books on roll cages, one standard reference among those currently in print is "Chassis Engineering", by Herb Adams. A company called Steve Smith Autosports had a series of guidebook-type publications on chassis and roll cage design, back in the 70's. They focused on NASCAR-type cars, back when they actually resembled "stock" cars. Those books are probably out of print, but try a web search on "Steve Smith Autosports".

Street Legal, You’re making the big-block installation look easy! Looks beautiful! My ’78 used to have a big block – now it just has a big hole. I’d love to compare notes on all things BBC. Unfortunately, big block activity on this site is moderate at best. Brad Barkley started a site dedicated to Chevy big blocks, but sadly, that one isn’t much of a happening place, either. Perhaps the best venue is e-mail off-line?

I also used to be a student in the school of life. I would attend class regularly, take good notes, study for the exams and perform relatively well on them. But then – perhaps suddenly, perhaps gradually – came a transformation. Increasingly I found myself losing interest. It became more and more difficult to concentrate, to make my study time worthwhile. My grades slipped. I could no longer keep up. I was losing the respect of other life-students. So, in disgust, I dropped out. On the advice of professionals, I started wearing jackets with really long sleeves. Moved to a town where most residents thought that life was a cereal box. But being a life-school dropout proved to be unnervingly difficult. Shoulda’ stayed in school. Now I’m thinking about going to night-life school, and maybe getting a life GED. If that works out, the next logical step would be to consider going to life college. They tell me that in modern society, you can’t go far without a life bachelor’s degree from an accredited life institution. Going back to the school of life certainly won’t be easy, but now that I’m older and wiser, maybe life won’t be so bad. Now I’m looking forward to the life commencement – you know, when you graduate.

Hitman47 - To somewhat change the subject, could you please provide some more information on the 540 BBC in your Bel Air? My '78 Z is set up for big block Chevy (long, long story) and I'm finally getting serious about dropping in an engine worthy of the frame; the 454 formerly in the car died last year. One plan is to get a 0.25" stroker crank for my 454 block, and get the AFR oval-port BBC heads, which supposedly are coming out this spring. But I am also considering stepping up to an aftermarket block. Budget considerations are rather elastic, but I'm eyeing something in the $5k-$8k range for the longblock (I already have all the peripherals). Forced induction is not in the plan. As for which year Z to buy, and what they weigh - I second the recommendation to go for a '72 or '73 240Z, if you can find one. But the more radical the modifications to the car, the less the original model matters. Unless you're in Southern California, the final choice mostly comes down to a matter of availability: if you can find a decent "rust-free" (big grin!) '70-'78 anything, buy it!

Update on the bent strut situation - Denny and I looked at several sets of front struts from parts cars. All of them had the asymmetry that I mentioned in my first post in this thread, though one of the non-parts cars looked to be symmetric, from the symmetric spacing between the widest part of the tire and the nearest point on the spring coils. My impression is that the tolerances on the steering angle of the McPherson struts used on Z’s is in general shabby – far worse than what’s allowable in the specs. By the way, from what I have been able to discern, there is no built-in provision for such an asymmetry. The same range of steering angles is specified for both passenger and driver side. So I decided to reassemble the struts that I have, and to wait until a nicer pair comes along. Unfortunately parts cars (or any Z’s for that matter) are tough to find in the Midwest.

The strut housings on two corners of my ’78 280Z’s suspension are misaligned relative to the spindle castings. That is, the projected angle between the strut centerline and the plane of the brake rotor is off by about 2 degrees from the specified angle (~14 degrees vs. ~12 degrees). The strut housings are not bent; they just meets the spindle castings at the wrong angle. This is at the driver’s-side front wheel, and the passenger’s side rear wheel. The result is an incorrect camber at those two locations. Neither the unibody nor the various suspension linkages are at fault. I have not been able to source used strut housing assemblies. So, I would like to correct the ones that I already have. To do that, my plan (actually, the original idea was Pete Paraska's) was to locally heat (with an oxy-acetylene torch) the strut housings right at their base, where they enter the casting. Then, to insert a pipe or breaker bar into the strut housing, and bend it back. The issue is, what happens to the temper of the steel, and how to restore it. And whether the bending procedure can be done successfully. No local shop wants to undertake this job; the mechanics in town feel that this idea is hopeless and that the only reasonable option is to scrap the faulty strut housings and find new ones. I am looking for suggestions. Is the above-mentioned approach reasonable? Any ideas as to who might be able to do it? I don’t have an oxy-acetylene torch, or the appropriate fixtures to hold the casting in place.

oops, first paragraph above - I meant displacement and velocity. late at night...

Dan, Some time ago, I derived an alternative and somewhat convoluted formulation of the piston motion equations, which give the answers identical to yours for the speed and velocity. The acceleration answer for some reason differs by a constant multiple of exactly 6, which is almost certainly an error on my part (when multiplied by 6 and plotted vs. crank angle, our answers coincide). So my point is, your formulas make sense, and you did not make an error in typing. For typical rod/stroke ratios, piston peak velocity indeed occurs at around 75 deg ATDC (and again at 285 deg); for example, for my engine (stroke of 4.00", rod of 6.135"). The MEAN piston velocity is 4000 ft/min, but the peak is around 6600 ft/m. Another typical result. For that combo, the piston peak acceleration comes out to ~87,000 ft/s^2. Peak acceleration at TDC is of course maximum. By the way, local maxima of piston acceleration occur at 135 deg and 225 deg ATDC (~47,400 ft/s^2). Another local extremum is at BDC. The acceleration curve has inflection points at around 60, 155, 205 and 300 deg ATDC. Playing with these curves illustrates an interesting point about the relevance (or rather, irrelevance) of rod/stroke ratio. Doubling the Chevy 454's stock 6.135" connecting rod length does reduce the piston peak acceleration, but only by about 12%! Also, for the fans of dynamic compression ratio - exactly the same formulas are used to compute DCR; get the intake valve closing angle, go to the corresponding point in the piston position curve, and compute the remaining swept volume.

My story - Car $600 Roll cage $2500 Cutting up the sheet metal (labor) $1500 Engine mounts, frame mods (labor) $500 Exhaust (mostly labor) $300 Misc. plumbing $200 Engine core $850 Transmission $750 Bellhousing $250 Clutch -related stuff $500 Flywheel $300 Intake, carb, headers $500 Radiator and fan $400 Driveshaft $100 Small parts (add up!) $500 Shipping cross-country $850 Seat and cover $200 Fuel cell $200 Cam kit $350 That's about $11K so far. At this point, the suspension is mostly stock, and the engine needs a complete rebuild. The car is in pieces - I might get it together later this decade. Then again, maybe not. A long time ago, before I began this mess, I thought that it would be the project of a lifetime. Looks like I was right! The main expenses were labor for the roll cage and sheet metal surgery. This was money well spent, considering the amount of professional work involved. As far as parts go, the transmission stuff was the most costly, but necessary to get this much torque (big block) to the ground - and I insisted on a manual gearbox. I'm planning on low-buck suspension mods (mostly cutting and bending stuff), but am budgeting about $6K on parts and machine work for the engine. And that's for a naturally-aspirated, 5500 rpm pump-gas stump-puller engine. Big block parts are expensive! A decent set of heads is about $2K, not including port work. Is it worth it in the long run? Surely, it is indefensible to claim anything to the contrary. But in the short term – well, if I were doing it over again, I’d buy a 2003 sports car and get it over with. Oh, but wait – there really aren’t any new cars worth buying, so maybe it IS worth it in the long run….