Tag Archives: technical stuff about building cars

I’m just going to think out loud about the car

I’m done with my nap now, but I already read all the web comics that post on Sundays, and missed the race from Miami. I also missed the start of game with the RPG group and one other player isn’t in for some reason. Also Discord doesn’t seem to like my mic on my computer so I can’t even talk to the group until my phone recharges.

Part of the problem about the car is I pretty much already talked the problems to death, except where I’m going to find the money to pay for it. That problem is out of my hands at the moment, but I’m trying a workaround of diverting $300/month from my SS to savings until I save enough to buy something I need. That’s a start, but at that rate I’ll be dead before I have enough to buy an engine, but I might get the project to roller status while I’m still alive.

This project would move more quickly if I used junkyard parts, but I no longer have the physical agility to wander a junkyard trying to find the parts I need. And I need lots more than to be able to just walk the junkyard, I need to be able to crawl under vehicles and remove the parts I need. And barring a miracle that takes me back to my condition pre-wreck that’s not going to happen. So, new parts that cost a bunch more. Or no car, but I already have too much invested to give up now. If I give up now I basically throw away all the money I already spent, because there’s no way to sell what I bought for anything close to what I paid for it. Also giving up means giving up on a dream I’ve had for more than 50 years… the specifics have changed over the years, but the basic thing has stayed constant since 1968.

Also, something weird (it wouldn’t be a normal blog post if I didn’t have something weird). I somehow managed to purchase a 2 year magazine subscription without knowing it. I have a 2 year sub to Hot Rod Magazine, but I have no recollection of buying it as a separate item, so I think it was bundled when I paid for something from the Motor Trend video service. I have a PayPal receipt for a Hot Rod bundle from last month, so I think that’s the culprit. But I don’t remember purchasing a bundle with 2 years of Hot Rod, just extending my Motor Trend video library subscription. I got the sub to Motor Trend On Demand specifically to watch Engine Masters building and dyno testing various engines. I really enjoy this channel on the service. I really like seeing the nitty gritty of engine building and testing to prove or not the hypothesis of the build. A good example of that was the Tunnel Ram vs Cross Ram episode (ep. 74). But again, I don’t remember buying a 2 year sub to the print magazine, but I’m not complaining.

Ooops! I got that price way wrong

Earlier post I wrote that the Ford 9″ axle was $1100, well it turns out that was just for the lightweight centersection with positraction and the fabricated housing was another $850 or so. So, $1100 for the lightweight centersection, and $850 for the housing kit plus the floating caliper bracket kit for $400 and the 9″ from the catalog looks a lot like the price of the Quick Change from the catalog, particularly if I need to buy an $1100 centersection for each ratio I need instead of a $70 (Edit $39.99 or $49.99 depending on material) set of spur gears for the Quick Change. Time to change ratios is about the same for each one with the nod going to the Quick Change by a few minutes over the Ford 9″ because you have to drop the driveshaft and do a bunch more nuts when you change the centersection compared to removing the back cover and swapping spur gears.

One thing I need to look at is the cost of a set of Helical cut street spur gears instead of the normal straight cut spur gears used for racing. I know the straight cut gears are listed at under $70, but I can’t find a price on the helical cut gears that mesh like the gears on a standard transmission and are quiet to Very Quiet depending on the ratio of the gears. Some sets have a very quiet mesh-unmesh like the gears in a transmission, some are just Not As Noisy as straight cut spur gears of the same ratio, and some of the Very Quiet gears are not swappable top for bottom and have to be installed in a specific orientation. (Edit, I found the Helical Cut Gears for the Quick Change and they are $60/set, but the Very Quiet gears that have to be installed only one way are $130)

Something not hot rod building is the continued winter weather system settling its icy butt on our weather. As I compose this the temperature for Casa de El Poeta reported by Weather.com is +13°F drybulb and -4° index, both of which are way warmer than the +9°F drybulb and -14° index I saw right before bed. Also, we have snow and bright sun right now which is making the inside of the house very bright (and also very cold, as the heat pump doesn’t have much to work with in these temperatures). Now I’m going to retire to the living room which is much warmer than sitting next to the drafty window working at my desk.

Well, the new shower stall is almost done

As I sit here they are lacking final plumbing installation (showerhead and faucet handle) and sealing the edges of the wall panels and cleaning up the mess. I will do a separate post about the shower at a later date. I took some pictures of the bathroom with the tub and enclosure removed to prepare for the installation of the shower stall.

Did anyone catch the Busch Clash Tuesday? It lacked some of the beating and banging that used to be the calling card of the race, but that last corner of the last lap pass attempt by Chase Elliot to get by Ryan Blaney, that led to Kyle Busch going from third going into the final corner to first at the line was classic Clash (the race, not the band).

And I just got back a weight quote on both the Ford 9″ full axle, and the 8″ quick change, and even got a closer estimate for the 9″ as delivered price of $1100 (there is a question of how much the lightweight locker was going to cost as it isn’t in stock and they won’t know the cost until they get it, the pandemic has severely disrupted supply chains in the automotive industry). The 9″ will be somewhat heavier than the quick change but not as much as previously estimated. I was looking at 110 pounds for the 8″ quick change and 120 for the fabricated 9″ Ford housing, which was slightly heavier for the quick change than I expected, and slightly lighter than I was planning for on the fabricated 9″ Ford, plus the Ford is steel which means brackets can be welded directly to the housing, where they have to be fabricated from a compatible alloy, or clamped to the quick change housing which would mean I have to have that work done after delivery of the housing. I do not have the welding unit to weld aluminum, nor do I have the tools to make the clamp-on bracket. The reason the 8″ quick change is heavier than I initially estimated is the weight of the locker is that much more than the aluminum spool used to quote weights for the quick change. Seriously, we are talking the difference between 5 and 21 pounds spool and locker respectively. And the difference in costs between the spool and the locker are about the same scale as the difference in weights. As in the cost of the locker is a multiple of the cost of the spool except worse, the spool is $108, the locker is $500-1200 depending on options and model. The $500 will probably do the job, albeit with great noise and drama even compared to a spool. Lockers are notorious for clunking and banging out of tight corners like typical autocrosses.

Technical aside, lockers are a middle ground between a spool and an open differential, that have a mechanism that locks and unlocks the faster wheel from the slower or just ties them both together and depending on the design they can be noisy and cantankerous about how they do it or just a slight “clunk” that can barely be heard. Interestingly enough the $500 locker has the reputation of having a quiet unlock and relock as well as a reputation for sometimes not engaging either wheel after a turn. I might get away with that one depending on how much power my engine makes. If I get the 5.3L truck engine from a junkyard then I’m only making about 300 HP at the tire which is within the limits of the cheap locker, but just barely, but more importantly, the cheap locker has better street manners away from the racetrack. So, draw, win, draw, on the merits of the cheap locker.

Well while I was working on the blog post the shower stall was installed into the bathroom and we have to wait until tomorrow evening for all the adhesives to cure before we can use it. Again, I will do a separate post about the shower stall after we get some use out of it, right now it just stinks of acetic acid while the adhesives cure. After a week we can use cleaning products on it like normal, except because of the soft material used in the shower stall (compared to ceramic tile and glazed cast iron and ceramic fixtures) everything has to be non-abrasive. That means no Comet, Ajax, Soft Scrub or anything like that in store brands. I think when the shower can be cleaned is enough time to evaluate how it performs.

And it’s about time to order dinner so I must put this post to bed.

Take cover, I’m thinking again

I’m thinking about the Sprint-T again, except I’m “thinking” with a bunch of catalogs and web pages open at various rear axle kits. I’m comparing prices and features for the Ford 9″ kits compared to the two quick change options. Now if budget was not a concern, like if I won the lottery, then my choice would be the 8″ ring gear quick change with the magnesium centersection polished in clear powdercoat, with magnesium bells and aluminum tubes, and the aluminum locker differential. This is the best balance of weight and performance. There are other options that are lighter, but at a cost to performance. There are options that have a slight potential for better performance, but at a major weight penalty.

And then there are the less expensive (can’t really call them “cheap”) options in the Ford 9″ housings. The main thing against these is because they are made from steel they weigh more, in some cases a lot more. But they are way less expensive, $1K±, compared to the $4K± of the “no budget” option in the first paragraph. This is a hybrid option, a race housing, hubs, and brakes with a “performance street” centersection, ring gear, and differential. Now for both of these the aluminum spool is lighter and cheaper than the differential, which means if I’m not seriously considering it there has to be a performance cost. Yes there is a loss in performance in the intended use with a spool, locking the rear wheels together makes the car understeer in tight turns that are part and parcel of autocross. And understeer is SLOW in autocross.

Now how much performance difference is there between the $4K rear axle, and the $1K rear axle? Maybe a few hundredths of a second, maybe nothing, depending on how smooth the track is. The rougher the track surface is, the better the $4K axle compares to the $1K one. And of course there’s the difference between a polished quickchange and a painted fabricated housing, the polished quickchange wins every time. But this isn’t a show car, it has a mission. Looks are important, but looks that don’t improve performance are expensive nonsense.

(Aside about that last word, it took forever to come up with “nonsense” because for some reason my brain wouldn’t go there, I got “ostentatious”, and “frippery”, but not “nonsense” until I started browsing thesauri online. I even knew the word started with the letter “n”, but going from “n” to “nonsense”… too far until I found the right thesaurus)

Anywho, there is another thing the $4K axle does is allow adjusting the final drive ratio from race to race and also for highway cruising between events. I mentioned this in a previous post, but it bears repeating that with the quick change I’m not stuck with a 4 or 5 speed overdrive automatic, I can get a 2 or 3 speed that might be lighter or cheaper. In other words if I spend an extra $3K± on the axle I can save a couple hundred on the transmission, or what’s really important, I can save maybe 150 pounds in the weight of the transmission. In actuality the weight savings are more like 60-70 pounds as Powerglides are about that much lighter than 4l60es unless I really need the 4l80e in which case then we are looking at over 100 pounds weight savings. Now 100 pounds less weight is a big chunk out of a car that will weigh less than a ton with driver and race fuel load. If I got my sums right, we are talking about under 1800 pounds on the starting line with driver and race fuel load using an aluminum block engine and PG transmission.

Also the $4K axle is maybe 20 pounds of unsprung weight lighter than the $1K axle. Now 20 pounds in a car that weighs less than a ton is not insignificant, but 20 pounds unsprung weight? That’s a bunch, particularly in a car that has as bad a sprung/unsprung ratio as the Sprint-T. And one of the things that has a major effect on handling on rough pavement is having a high sprung/unsprung ratio, unsprung weight is bad for keeping tires firmly in contact with the ground.

I’m not watching the football game

And if you have to ask “What football game?” you are probably one of my people.

Instead I’m here, making a blog post about arcane technical things related to building a hot rod from scratch and trying to figure out the correct ride stiffness and roll stiffness. I mentioned how I was trying to do the rear axle and figure the suspension but I couldn’t because I didn’t know which axle I was going to have? Well that’s not a problem with the front axle because I have all the things for the front end except the engine and all I need to do is leave some room for that.

I have several images and documents that have the dimensions of the LS architecture which is pretty much the same for everything from the 4.8L truck engine through and including the 7L LS7 even though some have iron blocks and some aluminum. So whatever gets stuck in front of the firewall is going to be pretty much the same externally. I know there is 43″ between the center of the front axle and the firewall, and 100″ wheelbase (center to center both axles), and the engine is going as close to the firewall as it will go without hitting anything. So I’m hoping I can get a space for the air off the radiator to make some downforce instead of running into the engine. The only thing I’m concerned about is increasing the polar moment by having the radiator right behind the front axle, but the increase would be minor compared to putting it back against the engine.

The reason I can put the radiator just clear of the back side of the front axle is I decided to put the tie rod in front of the axle instead of the normal behind the axle. This isn’t that daring a move, because back when sub-100″ wheelbase buckets were common and people were even making sub-90″ buckets for better dig off the line by increasing weight transfer, people put all the steering in front of the axle except the drag link which ran alongside the engine. I’m putting the steering box up front so why not shove the radiator right behind the axle? As I mentioned this has a slight negative effect on polar moment, but only a slight effect.

And it’s getting late now so I’m going to bed.

I paid taxes today

Today was the day I paid my taxes early. After doing the checks earlier this month, I got over giving away $2700 (almost) and took the checks to the Tax Offices and got the receipts. The receipts were the important part, so that I could prove I gave the check even if they forgot to deposit it. Now I get to keep my house for another year. I had my step-tracking apps turned on (both of them) which documented how long I spent waiting in line, and how far apart the tax offices are. Basically I walked over a mile, and stood in line about a half hour. Between walking between the offices and standing in line and shuffling forward I took 6156 steps.

Tomorrow I might commit myself to spending more money, as I contacted people about changing the tub in the bath connected to the master bedroom to a shower stall to fix the hole in the wall from where the shelf behind the tub basically collapsed, and also replace the leaking plumbing. Between the tub faucet and the sink we are leaking away over 1k gallons every month. It’s not a lot of money for the water, but our sewer bill is based on water usage during the winter. So between the water and the sewer bills, we are dumping a lot of money literally down the drain.

Other news, do you remember Arthur Dent? The space left on my neck after the useless lump of fat we called Chris Christy was removed we named Arthur Dent, and it was being a literal pain in the neck today. After I got done I was nauseous a touch because of the pain in my neck, so I had a little lay-down instead of dinner. I couldn’t sleep because of the pain in my neck (have I mentioned that Arthur is being a REAL pain in the neck today?) so I watched some idiot box (Mrs. the Poet prefers CBS) and had a little tea. I also had some dried cranberries, and cookies from Mrs. the Poet’s stash of Milanos. I really like the dried cranberries we bought, they are tangy and slightly sweet and are easy to chew.

Something I have been contemplating was the budget for the Sprint-T, should I use the stimulus $1.4k to buy a rear axle, or should I just continue to collect savings to apply to it? The axle I have been looking at the most was a quick change that was 60″ between the bolt surfaces, making it about 6″ narrower than the front axle’s hub-to-hub distance. This would be good because if I didn’t hit a cone with the front tire it was an automatic clear for the rear tire by about 3″ at any speed.

That wasn’t my plan when I bought the front axle, I chose that size because I was going to get a minivan as a donor vehicle, and the hub-to-hub on the minivan drivetrain was 66″ ± and I wanted front track to be pretty close to rear track so that I wouldn’t clear a cone with the front tire only to hit it with the rear. I could have tucked the rear wheels much closer to the engine and transaxle because not being used for steering they just had to clear in the straight ahead position, but that would have required major modifications to the stub axles that were vastly outside my abilities and tools at hand. So I just bought the axle for the width of the drivetrain, which shortly after the front axle arrived was no longer available.

But anywho, I still need to make a decision about the rear axle. The cheap thing to do would be a fabricated housing for Grand National style hubs and a Ford 9″ center section to go with the disc brake rear calipers I bought. The cool thing would be a quick-change rear with the V-8 style centersection and aluminum tubes for the Grand National hubs, which would be just as strong as the Ford 9″ but several pounds lighter and several hundred dollars more expensive. The other thing about the quick-change is what is inherent in the name, it is absurdly easy to change the final drive ratio with just a quick swap of the spur gears in the back of the housing. That means I could have a Powerglide transmission that is 50 pounds lighter than the 4l60E I would have been more or less forced to use to have decent gas mileage between races, without giving up the decent gas mileage. Or I could keep the 4l60 and use the quick-change to get the perfect ratio for racing and let the overdrive do its thing for gas mileage.

Well, it’s late and I have a busy day waiting tomorrow, so this seems to be a good stopping point.

I made the Sprint-T heavier

It wasn’t by much, but the 31″ radiator is slightly heavier than the radiator that ships with the Speedway complete kit when empty. But when filled with coolant there is a large difference between the two, roughly 25-50 pounds (10-20 Kg). This means I have to raise the weight on the starting line to about 1950 pounds from 1900 with me and a half-filled race tank of gas. 

I have been keeping a running estimate of the weight on the starting line as the design progressed over the years from basically the Speedway kit with “square” tires (all 4 tires the same size), to the current race car that is barely mostly street-legal. Now the on-the-street weight has gone up a bunch as things like fenders and bumpers and aerodynamics have been added to the street part of the build. I’m currently looking at about 200 pounds of junk removed from the car at the track to get ready for racing, plus a much larger gas tank and of course, more gas at 6.5 pounds per gallon. The race tank holds as much as 3 gallons of E85, but the street tank has room for 22 gallons of pump gas. That’s an extra 350 pounds full of gas for the street version of the car or about 2300 leaving for a trip, compared to 1950 on the line.

The kit is listed as 1700 less driver with a half-tank or 8 gallons of gas with a small-block Chevy and a TH 350 transmission. While the LS is significantly lighter, the 4l60e transmission is about as much heavier, and there is a lot more metal in the exoskeleton roll cage/frame and full bellypan of the Sprint-T than the simple ladder-and-crossmembers of the kit, and there is exponentially more resistance to twist in the Sprint-T frame than there is in the kit, and not just because there is more metal but because of where that extra metal is. For an explanation look up Herb Adams’ excellent book on the subject. It graphically demonstrates the difference between a ladder frame and a full roll cage tied into a space frame. Anywho, that’s where a lot of the increase in weight comes from. Between the pontoon fenders for the street version and bumpers and the kit’s headlight brackets also being the front shock brackets the Sprint-T has a bunch more junk in street trim, and a bunch more frame and brackets either way. Not making excuses, just stating facts.

Look at regular buckets trying to autocross at Goodguys’ and you can see what I mean. They jack up the inside rear wheel during hard turns, and try to swap ends if they haven’t gotten completely straight before applying the power exiting a turn. https://www.youtube.com/watch?v=GozWIbIetMo&ab_channel=TylerGibson

Parts have arrived

My stimulus check stimulated Speedway Motors and because they collect local taxes also the local economy. I’m continuing with this build even though it’s starting to look like I’ll never get to drive it even if I finish it. I was carrying one of the boxes of parts to the garage  when I lost my balance and had to drop the box to keep from falling, because I couldn’t stand up straight enough get my CG over my feet consistently so I didn’t fall. The only thing I could do was to not be carrying a heavy box ahead of my feet. It didn’t help that I had to leave my cane when I used both hands to pick up the box. Usually I can walk without the cane, but when I get tired I need it to keep my balance.

Anyway, the stuff that came this time was sorta heavy, some of it. I got the largest radiator they sell that doesn’t cost multiple body parts, because I don’t want an engine that overheats showing it off at the cruise-in, and because lower coolant temperatures mean better power and lower octane requirements. I might be able to get away with 87 octane regular (85 at high altitude) for highway use by using the excess cooling capacity for lower temps on the road. Basically I bought the 31″ wide double-crossflow generic radiator. If I did the math right it should work to keep the coolant temp below 205°F when racing and 180°F when I’m not putting my foot to the floor repeatedly at low speeds for racing. Interstate highway cruising I’ll have to depend on the thermostat to not get coolant temps that are too low, because I will have both not a very hard load on the engine and an abundance of airflow through the radiator.

Now in the other boxes were a U-Weld-It exhaust manifold for LS engines that will fit everything in the LS family, header wrap to prevent people getting burned on the exposed manifold, and engine mount cushions to go between the engine and the frame with the mounts I will build to connect the two. The trick is I will need to have the engine and transmission in hand to build the frame side of the mounts, because at this point I don’t know where the mounts will fall, and I’ll need the frame to know how wide to make the engine side of the mounts for the same reason. There is a lot of taper between the rails and a difference of a few inches forward or backward will make a big difference in the geometry of the mounts. The dropped box was the exhaust manifold kit because it has a lot of steel in it and was heavy, probably heavier than the assembled kit on the engine because there is stuff in the kit to keep everything lined up to weld it together that won’t be needed when the assembled kit is on the engine. After I weld it together I’ll degrease it and spray it with the header paint I’ll buy locally to keep it from rusting, then I’ll install the wrap kit so the exhaust heat stays inside the exhaust until it goes out the exhaust. I’m hoping this will also keep the HDPE body panels from sagging from the heat, but I’m not expecting miracles if the panels are mounted too close to the exhaust.

And that’s basically everything I know so far. You have a good day.

As the saying goes Eureka!

I was wondering about doing the waterpump/alternator only belt routing without adding tons of idlers to the front of the Vortech junkyard engine so when I woke up in the dark this morning I looked up where the pulleys are on the engine as it sits in the truck. Run a straightedge from the idler at about 2 o’clock from the waterpump to the AC pulley and everything clears.

I’m not enraptured by the long unsupported run from the idler to the alternator mounted where the AC compressor is on the diagram, and I’m sure there might be some slippage when things get hot, but this is doable! As in things won’t get in the way of the belt and there is some wrap on the waterpump.

I looked this up on my phone and used the “optical straightedge” of holding my phone up to sight where the belt would run from the tensioner sitting above and to the right of the waterpump in this diagram. From how I looked there was clear space from the AC compressor pulley to the idler. I was so excited I got out of bed at 0600 and started downloading the image and composing this post. I then verified with a straightedge made from a folded piece of paper held against the image on my computer that there was clearance (but I’m still unhappy about that long unsupported belt run to my alternator placement). The good thing is I can move the alternator up and tight to the block to reduce the amount of unsupported run and still use the alternator as a tensioner in the system, or use the tensioner that’s already on the engine in the truck to do the same thing. I’m also not thrilled with using the tensioner from the idler, because that puts the most belt wrap on the idler and tensioner and the least on the drive and driven pulleys on the crank, waterpump, and alternator.

I’m still thinking about it, but at this point the routing is crank, waterpump, idler, and alternator doubling as the tensioner in the system. If I find something else out when I get an engine I’ll have something else to write a post about. Also, doing it like this also allows just using the alternator on its own tensioning a 2 pulley system, crank and alternator, should I get the fundage to install an electric waterpump.

I have achieved massage

Finally I have gotten a decent massage. I managed to catch the bus outside the house (around the corner on the end of the block, but “outside”) and the connecting bus was only a little late. I had to wait a while for the tech to finish up a client, but the room I was assigned had a space heater so I was nice and warm, but not hot while I waited. This tech used an appropriate amount of pressure on most of my body, except for the back of my left thigh that caused me some kneecap pain, but she had no way of knowing about that. It was one of those “keep the lights low so the client will relax” places, and the one dim light was on the opposite side of my body from most of my scars and the scars on my knee were facing away from the tech, so how was she supposed to know about my damaged kneecap?

Anyway, I got a good massage and my neck felt a bunch better, and my legs and neck were working almost up to spec when she got done. I have been out of tolerances for so long that “almost spec” felt like heaven. There were some pops and creaks as things were pushed back sorta where they go, with minor jolts to my psychic equilibrium as they assumed spec position. When things have been not where they are supposed to be, and then all of a sudden they are, for a second or two after it takes some mental realigning to go along with the physical realigning. It’s like you have to change your mental image of how your body is and where everything is supposed to be, from “broken but still somewhat functional” to “back in spec”.

While I was waiting on the table I had time to think about the Sprint-T, and how to get more progress on the build. I have come to the conclusion that I should just start making the frame, building it up and ignoring where the engine goes until I get an engine and transmission. I should mount the steering in front of the axle and the radiator with the minimum clearance to avoid interfering with the axle’s travels so as to allow almost any engine to fit, even V-10 truck engines. Now the current situation is I’m going to use a junkyard 5.3l LS architecture engine, but I have entered drawings for Ford and FCA V-10 truck crate engines and gen 3, 4, and 5 GM small block, as well as Gen1 SBC and small block Fords of various displacements including 347 and 427 Cu. in. displacements (there were a lot of contests announced in November that were giving away performance engine builds after the first of the year). So I’m letting my Boy Scout handle this by being prepared to win any of them, or nothing. Seriously the 5.3l Gen 5 small block in stock form is just about perfect for the Sprint-T. I would have killed to have an engine like this in a T-Bucket back when I first got my license back in 1976. I’m trying to find the Richard Holdener video where he compares the various 327/5.3l small blocks, but I’m coming up empty so far. Hang on, I found it https://www.youtube.com/watch?v=NNhZXFEjkII&ab_channel=RichardHoldener

As you can see, the later engine without mods makes more power than the 60s engine with all the good stuff from the factory, and the later engine is a truck engine. It would run like that all day on pump gas and never even stutter. That would be the perfect NA engine for the Sprint-T, so if you know a truck that has one maybe find a way to send out here to the Suburbs of Hell so I can stuff it in my bucket?😇