No offense but I don't think you do get it. The combination I put together for Carl was designed to perform the way Carl wants his engine to run. Deviating from that path can put him on that "path of disappointment" I wrote about in a previous post. The torque from a big block isn't all from just more cubes, the rotating inertia has a lot to do with it. Getting the heavy rotating mass of a BB spinning makes it harder to slow down = torque. With lessor air flow using a heavy rotating assembly makes it want to peak at a lower RPM because the air flow available isn't enough to overcome the heavy mass of the rotating assembly. Sure Chris did a hell of a job on his build, but cutting corners using the lesser expensive parts lead him down that "path of disappointment". Here is a quote that Chris wrote on page 23, post number 338 of his thread; "I know I'm crying over spilt milk, but I would have never spent so much time and money on this engine if I knew I would only get 250 HP out of it. I'm literally 50 HP less than the minimum number I was hoping for." The 130 grams per rod heavier the cap screw rods are more than the rods I posted a link for, plus the heavy cast pistons but not as heavy as a sbb 350 piston but still heavier than the ones linked to. There was a sbb 350 repair build because the hypers failed. A set of the linked pistons were made to the same compression distance, both sets of pistons were weighed and the hypers weighed 2.8 lbs more than the linked pistons which comes out to be 1,270 grams heavier! So the weight difference should be compatible from the Ford piston to the linked pistons for the demonstration below to be as accurate as can be without the actual parts in front of me. 1,270/8 = 158.75 grams per piston. 158.75 x 2 = 317.5 and 130 x 2 = 260, now we add both together and we get 317.5 + 260 = 577.5 grams more. This would be the weight taken off of the crank's bob weight measurement which is quite substantial, it could take the crank from a portly BB bob weight of 2,000 grams to a stealth sb weight of 1,422.5 grams! To more accurately compare the rods, the big end and small end need to be weighed to get actual bob weight numbers but would probably make the weight difference even greater?(Tony?) Already air flow limited with the sbb 300 factory head engine the heavier rotating assembly slows down even quicker than from its original much better air flowing counter part, the sbb 350 with around 50 more CFM on the intake side. Chris probably would of been better off with the older lighter nut and bolt rods being that they're around 580 grams compared to the 680 gram cap screw rods, for his application and power level to try to keep the rotating assembly's weight in check. It also was probably a waste of $$ making it internally balanced being that he doesn't spin it over 6,000 rpm anyway.(or should I say can't spin it over that much because rotating assembly to heavy and not enough air flow) The cam chosen probably wasn't the best idea either with the extra cubes with less air flow. The last posted HP and torque at the wheels numbers posted were 266 HP and 351 ft lbs. Without knowing it Chris built a mini Nailhead that has gobs of low end torque with not so high of a HP number. So what did we learn from Chris' build? If you want to spin these sbb engines with limited air flow using factory heads its probably a better idea to do the one time charge of $454 more for the lighter custom rotating assembly and skip the internal balancing unless you want to spin more than 6,500. o No: Just because you can find cheap off the shelf parts to slap together to do a sbb 300 stroker doesn't mean it will run the way you want it to. And again, not trying to take away from what Chris achieved, I think in that little car that engine runs pretty dam good. But I think Chris was hoping for more HP and probably not as much torque in such a light car, like Carl probably wants. And what I mapped out a path to get him there with is why I recommended Carl's build the way I did. Buick designed these little engines to try to get torque out of them without having to spin them to the moon to get there, making the rotating assemblies in there small block engines heavier than other brands. And thus the progressively taller deck heights with every cube jump more than 10. Making the sbb engine something its not requires changing the parts from something they didn't come with. Other small block platforms with shorter deck heights are easier to bring the power curve higher with just a cam swap because their rotating assemblies are already lighter with better flowing heads to top them off. But with Buick back in the day being all about the torque, they went in a different direction than the other OEMs. The heavy rotating assembly engines would be more at home in a Skylark or the other cars a sbb 300 came out of rather than a MG, unless its a pro-street MG with huge rear tires on it to try to get that torque to the pavement. :shock: I noticed that Carl was there in the thread on the other site when Chris built his engine and seen the results and probably wasn't interested with something than runs like that in his car. But with a destroked crank, lighter rotating assembly and 56 less cubes I'm thinking the power band will be totally different than what Chris built. Inexpensive reconditioned rods, $120, cheap cast pistons, IIRC $120. 577.5 grams lighter rotating assembly, priceless. Because that's what it takes to make these sbb engines something they're not. One of these sbb engines in an MG I would recommend getting the rotating assembly as light as possible. For more budget minded doing a sbb 300 stroker build, forget about the cap screw rods and opt for the nut and bolt rods that are about 100 grams lighter. Even with the Ford pistons that should help a lot, may even be able to internally balance a later model crank that came with the heavier rods, with the Ford pistons and pre '73 rods without any heavy metal added to the crank? With the lighter than factory sbb 350 piston the older rod with the Ford piston on it with the lighter smaller wristpins should enable the engine to safely spin to 6,000 RPM and perhaps visiting the 6,500 RPM range on occasion without any problems, perhaps even more because the MG cars are so light? The race prepped cap screw rods are for the people that think they can make 600 HP with their sbb 350 without spinning it past 6,500 which would require boost. Derek
Can you elaborate on that? I know a little about balancing from being around when its being done but never done it. I'm a tool and die maker/tool and die machinist/CNC lathe programmer/gauge builder/machine builder by trade, this simple engine building stuff and custom machining is just a hobby when I want to do no-brainer type work(play), I leave the engine balancing to Dave though because that's his machine. Anyway, with the difference in weights how much would that effect the bob weight of the rotating assembly? Were my numbers close? IIRC you use the weight of 2 pistons and rod assemblies because one throw has 2 of those bolted to them, is that correct? Derek
Copy/paste (quicker than my feeble way of explaining this one) http://www.enginebuildermag.com/2014/03/weighing-balancing-work/ You'll have to double check your numbers, I briefly skimmed it and it didn't seem quite right o No: If you don't have the balance card from a previous build, you can find an example under image search to 'assign' an estimated weight for both rod ends. More importantly than a dyno # is the acceleration change to the running driving vehicle due to the reduced mass. This isn't always reflected correctly by load testing at a controlled sweep rate. Dynos themselves as used by the hot rodding market generally have some engineering flaws regarding inertial compensation, so they don't compare things apple to apple all the time, well...ever. I support your post 1000% Derek. The end result of just a lighter flywheel change is usually profound, imagine several pounds of moving engine parts. My CRS memory leads me to believe that the reduction of moving engine weight has 15x greater contribution than vehicle weight, and that there are formulas to calculate change in acceleration. What I see with my continued engine 'hobby' is that with a much lighter assembly, even a much greater stroke, combined with a capable top end will 'grab R's... MUCH quicker than a heavy assembly having a short stroke and mild top end.
Thanks, and WOW! 2,520 grams is a heavy bobweight! I think Andy's sbb 350 to 380 stroker came in somewhere around the 1,600 gram range. I did a sbc 400/434 4.00" stroke crank that came with a 1,850 gram bobweight that we got down to 1,645 from the part choices and had a lot of drilling to do on the crank throws. That one is setup to rev to 7,000 with occasional 7,500 RPM blasts. :Brow: In the bold, the point I have been trying to get through to everyone with these sbb engines and why I like trying to incorporate the very light very affordable nascar take out rods in a sbb build. Adding even more stroke to the 350 crank for more cubes helps to get the low end torque back lost from the lighter rotating assembly, while still maintaining spinability. Probably not so much needed for a MG sbb 300 stroker build though, standard stroke is probably more than enough. I would hazard to guess that the 294 that I came up with for Carl would get him to 300 RWHP with around the same torque if his heads flow at least 150 on the intake side with a cam in the mid 230s to 240s duration @ .050" range with the lifts in the low .5s range or higher with the Joe Sherman sbc roller rocker conversion if he still has those for sale from the HRM article? Dan jones' guy got the '64 sbb 300 heads in the 200 CFM on the intake side, that would be good to easily get that 292 close to the 400 HP range if its setup to spin to 7,500 + range. A more of a sports car engine, rather than a muscle car engine, perfect for an MG, unless someone wants a lot of torque for their MG? Stroker engines are cool, but probably not so necessary for an MG, a sbb 300 destroker would probably be a much better option and the crank work would cost less than the stoker version, plus a sbb 350 crank wouldn't need to be sourced. And if a little more than 300 cubes is wanted, the 300 crank can be stroked as well for an extra 18 cubes with a .030" overbore and still be able to rev it to the moon with the nascar stuff in it. Like the old Nailhead engines with the smaller cubic inch ones able to spin faster because of a higher air flow to cubic inch ratio. Fun stuff. Of coarse for a Skylark or Special I would recommend the even more stroke for the sbb 300 stroker above the standard 350 crank to get the torque up with the 1,000 lb heavier car. Derek
Your above comments on bob weight and stroke effectively illustrate how a rod should be viewed as 'rated' to a certain rpm. Average piston speed, stroke, weight, yank, etc...all factors needed.
I totally agree with you guys. I think you can see that in my 340 build, where rod weight was 405.5/159g, and piston weight was 454.6g bare and 579.7 loaded. (I do not recommend the teflon buttons, they added 19g but I didn't know that when I ordered them.) Not the lightest weights possible, but then this isn't a drag race engine either. I think it might be more helpful if you posted actual piston weights rather than just how much heavier one was. Anyway, I was not aware of the weight difference in the capscrew rods, that's pretty huge. The early rods would probably make more sense. But with that one change I'm still willing to stand by my opinion that this build will appeal to a larger number of owners. Look guys, it's hard enough to interest any owner in a "stroker" engine. Usually that sort of talk just ends the conversation right there. The only reason the SBC 383 stroker is popular is because you can buy it cheaply as a crate engine. No thinking involved. The package is simple, straightforward, and anyone can build one with off the shelf parts. Any talk about having to do stuff like narrowing rods and offset grinding is going to make most folks eyes glaze over. It's bad enough having to turn down the mains. That is enough of a handicap without making it worse. And having to sleeve the rods already IS making it worse, so a piston like the Ford one that could use the Buick pin would be that much better, especially if it was lighter. Reliably being able to ream the piston pin bores would he helpful of course but nobody has looked into that. I don't see the goal here as building the ultimate engine. I see it as building an engine that is better than any Rover engine you can build for the same money. I'd say Chris has accomplished that. Don't put too much weight in his complaints, he has recently stated that occasionally he just needed to "vent" during the build and that he is currently quite happy with the engine. Also, he could put TA heads on it if he wanted and that one change should make a substantial improvement and work out pretty well with his existing parts and cam I would think. Or go the way some of us have with forced induction. He's mentioned that. For your average owner though the TA heads can only be justified by telling them they do not need to pony up $2000 for top hat liners in their Rover block. I haven't checked lately on the cost of a set of bare Rover TA heads with CNC porting but suspect it is competitive with that. Which at least brings good heads into the realm of the possible. So you combine good heads with a 350 cid short block of almost any specification and you are well out in front of even the best 5 liter Rover that can be built for similar money. That's the fight to be won here, not the most powerful build. The handicap is an 80 pound weight penalty, 50 lbs at the very least. (Late Rovers reportedly are heavier) So the power and reliability has to offset that. There is also a size penalty, about an inch wider and taller. It's not like it's an easy sell. It HAS to be simple. Of course you guys are right. That much is obvious. But I am too. The targets are not the same. Jim
Yeah, but it seems that the Canadian guys are more willing to consider a nascar take out rod stroker builds than the US guys, there are 2 of them working on nascar take out rod sbb 350 stroker engines with one of them planning on boost. The one guy had his machinist call me to help him out with how to narrow the rods, it was a no brainer ah ha moment after explaining it. Really nice guys from up there, wonder why there aren't more guys willing to go the nascar take out route from here? I can advise the machinists down here if need be as well, hell I can even do the work for $50 plus shipping if their local machinist can't handle the job. I was even thinking of buying a few sets to make work in a sbb to see if someone wanted to buy them ready to bolt in? Possibly some rotating assemblies ready to install in their machined blocks even? Would rather do that made to order though. I hate seeing those threads where they are disappointed how their sbb runs after the rebuild. Why is it that guys will pay $500 for just pistons for their snowmobile that only comes with 2 pistons but the guys that play with sbb engines won't pay a one time charge of $649 for 8 pistons and 8 sets of rings?(that's pretty much $500 for the 8 pistons and $149 for the set of premium rings) o No: Derek
Well, why would anyone pay $300 for a set of off the shelf cast pistons that aren't quite right when they could get state of the art forgings perfectly matched to their build for $200 more? Amortized over the life of the engine that is nothing. A few tanks of gas, no more. A night or maybe two out on the town if you are scrupulous. Doesn't hardly make sense does it? Yet they do it. Over, and over and over again. Because they have this figure in their head of what an engine should cost to build and don't want to go over it. Maybe it's the price of a bargain basement Summit crate SBC. Well yes, it IS possible to build an engine for that price, and even maybe come out smelling like a rose. But it takes a pretty savvy person to do it, and doing it on a regular basis of any sort is very near impossible. Yet it does happen and every time it does it feeds the myth. Did you just happen across those NOS forged pistons that only need a little machining to work, and you found that with a drill press, hours of work, and extreme attention to detail you could make it happen? Cool! Never happen again. But you fail to mention that part. I think most people realize this, but another thing is that people are in too much of a hurry, especially Americans. We want it yesterday, only if it can't possibly be had any sooner. Extra machine work always slows things down. Always. Off-the-shelf parts are attractive exactly because they are sitting right there ready to be one-day or better shipped. Things that come ready to be installed trump things that work better nearly every time. I don't think there's really a way to fix that either. Jim
The length and detail of the posts on machining and stroker combos isn't meant to make things difficult for the 'project owner'. What's complicated to the enthusiast is child's play to any machinist. I think the objective is to illustrate a couple of things... 1. let the machinist or builder handle those details. 2. why would anyone consider using stock inferior parts if the cost could be similar to use ones that can handle extreme duty? I can attest that engines built with vastly superior parts to stock will outlast OEM engines, have similar reliability, get better mileage, etc. There's a definite favor to this viewpoint coming from machinists that can negate many of the costs involved due to having the equipment. I know it's tough for the 'project owner' to justify throwing $$ at machining labor rather than better parts, which is solely the point Derek is trying to make...better parts can be had for similar cost to the OEM stuff. I call that basically 'free' if one doesn't mind changing the digits on a finished dimension. Good point about the cost of small engine parts. Some of the costs of machining have been suggested high I think, but it's tough to say what they are in other areas of the country or "through personal connections". One thing for sure...if you are paying for machining A-la carte, it's going to really add up. Crate motor or short block packages have been hinted at before here. Another thing is pride. What skilled machinist or hobbyist would be proud to say, "I bored a guy's block today so he could fit some expendable OEM pistons for his well thought out stroker package. He saved $100!! Yay!!!" Finding machinists who have pride in their work justifies 'the tiny bit more they charge' over saving a buck or two at a place that only cashes the check and doesn't care about what they do, but hey...their prices are the BEST 100% agree with your above post. Mine typed at same time.
Incidentally I wanted to post on this thread that the current price for bare TA Rover heads which include guides and seats is $1500. CNC porting which is through a 3rd party and handled by Mike is $1000, claimed to be a maximum porting effort. Considering the cost of building a big Rover may include top hat liners ($2K), bellhousing and flywheel ($600+) and the same loose parts the TA heads need, that sounds like a pretty darned good justification to me. Jim
Good points guys... I paid good $ for the machine work on my engine and that included the custom girdle fitment, specifying the details for the custom crank, cutting custom valve reliefs etc but it really is worth doing it right the first time to me... I could have saved some money paying a lower cost shop to build it but then what happens when it all goes to ****. https://m.youtube.com/watch?v=DXjx6h3aZco https://m.youtube.com/watch?v=1gHKzzDJ1wo
I've been following this thread for a while without commenting much further, since my input would be more like 'hey cool' or 'that sounds doable' type stuff. Though to the text in bold, I'd like to comment: I have said in the past that someone(s) should make a "kit" for a stroker engine using the 350 crank and (non-OEM) rods, etc. so that it would be easier for your average enthusiast to make the conversion, much like the SBC '383' stroker (350 block .030 over + 400 crank and rods). If a package deal could be put together using an offset ground crank and the rods to make it all work, and if it wasn't that much more than just building a vanilla 355 CID engine, I think it would appeal to a lot more people. Someone like Derek could stay busy as bee putting these together and packaging them up to ship out. Sounds like a plan to me! Maybe he could get a deal on the machining required if there were many sets to do at a time to keep prices down?
For those of us who don't make six digit figure incomes, much more has to be considered. I think everyone realizes this isn't a cheap hobby, and most are willing to pay for quality stuff, but only IF they CAN. Thousands or even 10's of thousands of dollars of 'play money' isn't a reality for a very large amount of people, even people who frequent this website. A 'kit' for a 'generic' conversion would be appealing to more people I think, myself included. Otherwise, you're all talking to a very narrow audience who enjoys reading, but ends up saying 'oh well, that's not in MY budget' and clicks the next link. It isn't that we're 'cheapasses', it's that we simply don't have it. lol I'd be willing to pay for a stroker kit, rods, the rebalancing required, and higher silicon forged pistons. Knowing what I know now about how durable it all is compared to the stock stuff (which is still pretty durable) and how long it will last, it is a wise investment if one intends on keeping their engine for a very long time.
It's also a bit unfair to say that a crate sbc is a no brainer in the same sentence as suggesting that a 50 year obsolete engine is 'only going to have $2k spent' on it. I don't think there are reputable 383's being sold for $2k as a crate package. There were large quantities of raw 300M and 4340 rod forgings ebayed a while back. Those were pulled before the listing closed. I'd be curious of where they ended up.
For the budget minded buying the parts for the build piece by piece as your wallet heals is a bit more budget friendly than buying a balanced rotating assembly that would be a BIG hit, I would think. The key to doing a build like that is patience which it would seem most are running short on that rare commodity. The 2 guys from Canada took(are taking) their time as the funds become available to do their builds. o No: Someone with a running car that wants to do one of these builds can buy an engine core of choice they want to build. As the wallet heals from that hit the next step would be to source your nascar rods and have the work done to them to make them fit in your sbb application. If the sbb 300 stroker is the project then I would suggest buying a whole engine, '74 or newer sbb 350, I bought a '77 sbb 350 from a guy for $150 to source a crank, sold the rods and pretty much scrapped the rest because block was cracked, still have the heads though. Next step would be to get the crank work done, put that on the shelf after done, now after your wallet is ready, you take the block to the machine shop to see what size pistons to order. Ask if they can skip boring the cylinders if they can get away with just honing them to the next good ring size. On the 300 block starting with a standard bore would be 3.756" or 3.766", if it has a standard bore on the 350 block would be to 3.810" which would be no problem to hone that amount out. Now you also have the machine shop measure the deck height for you so you can order your piston and ring kit. It takes about 4 weeks for the pistons to be machined to order, and shipped so you have that time for your wallet to heal. Next step is to bring all your parts to the machine shop so they can do their magic to them to make it ready to assemble. Spreading out spending the $$ for a build over 3 months to even 2 years depending on how fast your wallet heals allows for a bit more in the budget without leaving you short in your day to day expenses. Plan ahead and buying the better parts won't be as painful and you'll end up with a much better running engine that you will be happy how it runs. There would be no thinking what ifs, just driving enjoyment. GL Derek
Good advice for everyone, Derek. Thanks I guess making a 'kit' (for lack of a better term) for a stroker wouldn't really be feasible then? I was kind of hoping there would be some ideas tossed around on how that could become a reality, or list the pros and cons of doing it piece by piece vs what it would take (and cost) to put together a 'ready to install' stroked crank with rods. If the cost isn't that much more than using the stock stroke and rods, then the 'kit' would make sense, I'd think. One would also need to consider what the engine would be used for, and if stroking it (and the extra expense involved) would be worth it. Would it really be necessary for a mild engine is the real question. If you could gain as much or more out of your engine by using stock stuff along with head work and headers, would kinda make stroking it not really cost effective. Or perhaps the stroking would be left to more involved building plans and goals for a more specific result in mind, such as what we see here in this thread. Share your thoughts?
Here's the deal, if the intension for the engine is to be a N/A street cruiser with zero future plans for one of the TA aluminum head upgrades with only mild ported or no porting factory heads then for a boring 350 HP or below and below 6,000 RPM build, the good rods probably aren't necessary. I would still recommend using the good pistons though, being 1270 grams per set lighter than the hypereutectic replacement pistons would help safely eek a little bit more RPM out of the engine without much worries of breaking a cast rod. For an upgradable engine to be able to stay together with the aftermarket heads for more RPM above 6,000 then a engine with good rods and pistons would be a good idea, or if plans involve any kind of boost. Even if there aren't any plans for later upgrades a solid bottom end can be a good resale feature for the next owner to add those things instead of having to start from scratch. As far as making stroker rotating assemblies available, that's not as easy as it sounds because of the lack of block-less cranks. Pretty much would need to source a crank to stroke, I could do a made to order balanced rotating assembly with the person wanting that supplying a crank. Made to order would be a better way for this to work, but why pay all that shipping when it can all pretty much be done locally? Then there is the need to know if the person wanting a stroker wants to save a few bucks by skipping having the block bored or perhaps the block is already bored oversized? All these things need to be considered, these small block Buick engines aren't small block chebbies that you can buy aftermarket stroker cast cranks for $160 shipped(that right there is less $$ than it costs for a fricken re-grind crank!!), you need to find a good used one and have it machined. All this makes it more expensive to play in the Buick sand box. That being said, if you want your Buick car to be powered by a Buick engine you go the extra yard and bite the bullet and do what it takes to build it better to be competitive with brand X. Why do all of you think the reason these Buick cars are less expensive than other brand cars? Not as popular so there is a lack of aftermarket support is the answer, both for replacement body panels and for inexpensive go fast parts. Well the $$ you saved buying your Buick Skylark instead of a Chevelle you should have plenty of $$ leftover to be able to spend a little extra for crank grinding to use the good inexpensive nascar take out rods and get the good pistons, all the while still coming out WAY ahead of buying a Chevelle. Kicking sbc but with a sbb is all I want people to be able to do. I'm not trying to solicit work, I would rather see your local machine shops do the work for whoever wants it, but I don't mind lending a hand if anyone needs assistance either. Remember, we have a weight advantage with the sbb platform over the other brand engines, especially if an upgrade to the yet to be released or the TA Rover heads are in the plans for your build. Lighter in the front will help handling as well as weight transfer to the rear in the Buick cars, maybe not so much in an MG though but not so much heavier to make a difference either. Derek
