At .010"/.010" you would be able to go to a .130" max extra when grinding to a 1.850" rod journal to make the crank have a 3.980" stroke which would still make a 381.333 CID sbb, only loosing roughly 2 cubes so not that big of a deal. If the engine you have is a post '73 engine the crank can be internally balanced easier than a pre '73 crank because when they swapped to the cap screw rods which were heavier the counterweights were left heavier for balancing, also the later cranks had the 1-2 rod journal partially drilled to lighten it up further. Drilling it all the way through and grinding off that stupid boss around the hole will lighten it even further for internal balancing. Drilling the other rod journals will lighten even further if internal balancing is planned. I just went and looked at the '77 sbb 350 crank I have and the 7-8 rod journal has the stupid boss on it but is not drilled so even if its not drilled weight can be removed in that area if you want to internally balance the crank for easier high RPM use. If you're sticking with having the crank externally balanced then removing weight from the crank for balancing is included in the price of balancing. Adding weight to the crank for balancing is when extra costs are involved when heavy metal has to be added, around $100 per slug of Mallory metal!! The prior paragraph explains how to reduce weight to save a few bucks if internal balancing is preferred. Good luck trying to find a crank grinder that will widen the rod journals .055" per side!! Not to mention weakening the crank the only crank grinding shop that seems to not have a problem with doing this is the one in MN where Tri-Shield Performance, is the shop that Jim Wiese uses. Removing the material from the rods won't sacrifice any structural integrity but off of the crank that is going to be offset ground going from a 2.00" rod journal to a 1.850" rod journal and adding stroke is probably NOT a good idea, I would highly NOT recommend doing so! :shock: So with the extra cubes and the new heads your HP goals should be easily obtainable with the un-ported version if they flow at least 260 with good low lift flow as well(hopefully out of the box will be better than that though!!!). Just so you know, the AutoTec pistons are customizable for less than a custom piston price with premium rings included(a $100 to $150 value if you had to buy the same rings separately) and if you're sticking with it being N/A then the 4032 alloy is more than good enough to handle your goal. I have used the same alloy in other brand N/A engines that make close to 600 HP and have been spun to 8,500 RPM once or twice and regularly to 7,000 RPM under heavy load so anything you can throw at them at only 500 HP and under 7,000 RPM would be a vacation for them. :Brow: If you can go to a popular bore size the better rings will be available and for the included price the AutoTec piston would be an even better value because the price doesn't change to get the better rings; http://www.buyracingparts.com/pisto...stons/autotec-forged-350-buick-pistons-1.html Here's what is written about the AutoTec pistons; "AutoTec is a High Quality, Precision Manufactured piston option. That comes at a very respectable price. Our Design Specific Forging allows us to manufacture our parts with less machining time, thus allowing us to keep production cost down. Then pass that savings on to you, the customer. Made out of 4032 High Silicone Aluminum Alloy, it has great wear resistance, a low expansion rate, is very durable, and is very low in friction. These pistons accommodate multiple uses including. Your local auto shop, muscle car restorations, performance street rods, as well as many spec racing classes. They can also withstand mild nitrous kits and small turbo or super chargers. Just about everyone can benefit from the excellent value the AutoTec line carries. Keeping in mind these pistons were originally designed for about 600 Horsepower. In Small Block applications, we have customers that frequently fine tune engines that yield 850+ Horsepower with a bit of Super Charger boost. Bore, Ring Pack, and Compression Distance changes can be made to any shelf part at no extra charge. Meaning that if you do not see your application listed in the guide, we can make what you need without charging a custom price. Every part is made with same high quality machines and tools as our RaceTec line including diamond turned ring grooves, and skirts. Not to mention our parts are 100% made in the USA." Of coarse the forged 2618 alloy custom pistons would be a good option as well, dealers choice but at your power level aren't really necessary. Derek
Looking at a sbb crank, taking that .055" off of each side of the crank journal on top of increasing stroke while decreasing the rod journal diameter, I personally wouldn't recommend but like Tony is recommending you can ask the crank shop vs. your machine shop if they are different shops or if a one stop shop ask which they would recommend. IMO its not always about cost. Derek
We pulled the middle four piston/rods out to see what size they were. Yes, the throws are 0.010" undersized. There is also a small amount of rust on the crank throws that will hopefully polish out. Can you still offset grind a crank that has already been cut? I thought they needed to be able to measure off of a standard? Would it be better to look for a standard crank to stroke this engine with?
Copied and pasted from above post #161; "At .010"/.010" you would be able to go to a .130" max extra when grinding to a 1.850" rod journal to make the crank have a 3.980" stroke which would still make a 381.333 CID sbb, only loosing roughly 2 cubes so not that big of a deal. If the engine you have is a post '73 engine the crank can be internally balanced easier than a pre '73 crank because when they swapped to the cap screw rods which were heavier the counterweights were left heavier for balancing, also the later cranks had the 1-2 rod journal partially drilled to lighten it up further. Drilling it all the way through and grinding off that stupid boss around the hole will lighten it even further for internal balancing. Drilling the other rod journals will lighten even further if internal balancing is planned. I just went and looked at the '77 sbb 350 crank I have and the 7-8 rod journal has the stupid boss on it but is not drilled so even if its not drilled weight can be removed in that area if you want to internally balance the crank for easier high RPM use." Andy had 2 cranks stroked, 1 was a standard stroke and the other was .020" under before stroking, the bad part about taking the 2 cranks there at once was the !&@$$^!# ground both of them the same to the one with the lesser material to 3.975" stroke!!!!(we wanted the virgin one to be 3.990"!!!) :af: Thinking back to that still infuriates me!!! :af::af::af: So yes, an already undersized crank can still be stroked. Just don't take 2 cranks to be stroked with different journal sizes wanting 2 different strokes at one time and results should be good. Derek
I am reading your replies...I just thought I saw a post saying the shops wanted cranks to be standard size before stroking them...I apologize for the silly question. I have no idea what bearings to use with this setup. Thought I read Honda somewhere? I guess the crank has to be measured up first before anything can be done.
Dropped off the block, crank, and one piston/rod assembly today to have the block checked for square. The crank is 0.010" 0.010" under. They are on the look out for a standard crank for us. They don't have the ability to sonic test the block, but will magnaflux it to make sure it is ok, and then do a 0.060" over bore to see if the worst cylinder will clean up. (Block is already 0.030" overboard.) We will have to take the crank, and new rods to another shop about an hour and a half away for them to do the work on the crank & rods together. I asked them to just check the block out, and measure it up, along with the rough bore...then we will pick it up and grind all the cast flashing off the block, as its really bad in the lifter valley. We will also drill out the oil pickup port, and the oil path to the front cover.
Yeah, Jim said they can true up the block. They don't do cranks, so I will be taking the crank and rods to CEP in Lethbridge. Unless there is a better place you know of?
It is OK to use the .010"/.010" crank to have it stroked, all you would lose is only .010" of stroke so instead of a target stroke of 3.990" they would shoot for a target stroke of 3.980" and still be able to make the journal 1.850". Unless you're looking to get every tiny bit out of this build I would say to not sweat about using the .010"/.010" crank. So what if the mains needs ground again, .020" under on a 3.00" main is NOTHING to that sized main. If you could have spacers made the crank would still be good if the mains were taken down to 2.500" like people have done to make them fit in a sbb 300 block to make a sbb 300 stroker. What pistons did you get already? Did you order the AutoTec pistons with the right wrist pin size for the rods you bought or did you order customs? I think you're going to like the extra 20 to 30 cubes(how ever many you're adding to your build) is going to run with the little sbb 350. GL Derek
Didn't do anything about pistons yet, as we need to know if the block is good, and if it is, they will measure how much has to come off to square up the deck. (Document how much off each corner.) Then, they will do a rough bore and confirm that 0.060" will clean up the worst of the cylinders. We will then pick the block up, and take it back home, and get rid of all the casting flash in the lifter valley, and do all the oil mods. While the block is back home, we will drop the rods, and crank off at another shop....in another city 2 hours away...and have them check out the crank, and cut it for the rods...which they will check out, and recondition, if required. (Better that the shop doing the crank and rods has both, so they can get bearings for them afterwards.) Once we have the block de-blurred, it will be dropped off again to be squared up, bored out, and honed. Then we will look at getting pistons that will give us a zero deck clearance with our setup. Honestly don't have any idea what bearings would, or could work with this setup, after the crank is stroked. Custom pistons and rings are gonna be a given, I think....
Oh, I get it, you're sending one of the old pistons and rods to check the 4 corners. I would shop around a bit more to find a machine shop that is setup to square deck a block to the mains without having to measure the 4 corner method with a rod and piston and crank. Dave's shop over here use to do it that way until I took a look at his machine and seen that the mains sit on a 2.25" shaft that doesn't let mains that have a larger than 2.25" diameter sit square on that shaft(I didn't like that). I made him let me machine some spacers to the proper main housing bore diameter to different sizes so all he has to do now is indicate the spacers in when he installs them and setup the block on 45* on the spacers and the deck gets cut to within .001" from front to back top and bottom.(which with some older blocks they were out as much as .030" from front to back from the factory, mostly the Mopar machining was that bad, the General was usually within .010" from end to end back in the day) You can do a sonic test yourself with one of these; http://www.ebay.com/itm/Digital-Tes...hash=item337ec82f32:m:mOsxKjdlz89xGdIPkIzvYpg I have the same one and it was within + or - 2.5% of the test that was done for Andy's block. Use grease or Vaseline instead of the recommended glycerin or whatever that stuff in a tube that doctors seem to keep refrigerated to do sonogram testing for people, like for pregnant brauds to sneak a peak at the fetus. Basically the same stuff but is corrosive to metal(water based is why I think) so I don't like using it on a block so I use grease but Vaseline probably would work better, the grease was just closer so I used that). You may want to call your piston guy before you commit to a bore size to make sure there are good performance ring packs available at said size. For example, a 3.875" bore has more ring thicknesses available than 3.860" bore and a 3.905" bore size has even more. This is one of the reasons why sonic testing is important when doing a stroker build like this, to not only know that you're spending $$ on a block that will handle the extra power its gives you a good piece of mind when you hammer that go peddle! You were probably going to get pistons first anyway, but just in case you had the block bored to a size without honing until you have the pistons make sure you talk to your piston guy of choice. Derek
Do you think the Autotech pistons would be the best choice? I guess the only other choice mentioned is Diamond pistons.
That depends on what level you're building to? The AutoTec pistons are forged 4032 alloy while if you chose to go full on custom those are usually the 2618 forged alloy. The difference is that the 2618 alloy is a better choice for an all out race type piston for like a high boost or race gas high compression ratio that will run tons of NO2. The 4032 forged alloy can run tighter piston to bore tolerances that will run quieter but not as good for as much extreme as the 2618 alloy, but will handle around 5 to 8 psi of boost or around 150 shot of NO2 to around 600 to 800 HP. For a N/A build the IMO AutoTecs would be the way to go, RPM is no problem with them and can handle anything a pump gas compression ratio can throw at them, probably even up to around 12.5:1 compression(but not with pump gas) or maybe even more if you have easy access to race fuel? The price includes pistons, wristpins and rings, ALL of that is separate with a custom piston and is higher than the AutoTecs. Diamond isn't the only game in town for customs either, Scott Brown(from buyracingparts.com ) setup Andy with a nice set of custom Ross pistons for boost for less than any other brand I researched. Yes AutoTecs are nice, but if the plans are to add a 500 shot of NO2 or more than 10 psi of boost then you'll definitely want to upgrade now to a custom 2618 alloy piston. Derek
Derek: the shop has waited until today to tell us they are waiting to see what Pistons we are going to run... What size Pistons would you go with that would give us the best selection of rings, and compression? Going with the pin size from the rod pictures above, I have no idea what to look for....I tried looking at the Diamond Piston site, but I don't know jack when it comes to filling out the forms for custom pistons. In other news...the car has been sitting in the exhaust shop for the last two days trying to remove the exhaust manifolds from the engine...apparently every bolt is seized into the block, and they are not having any fun at all with it. Tomorrow will be day three. When we were there this afternoon, they finally had the passenger side manifold off.
Dropped off the crank and rods today to get machined. Only a 6 to 8 week wait. By then we might have the block deburred and oil mods done. Exhaust is done...got a call this morning that now the car won't start... The shop said the power light is coming on, on the MSD box, with the key on...but no power to the coil. Just one thing after another.
Went an looked at the car this morning. Unplugged the MSD distributor from the wiring harness. Disconnected the coil wire from the distributor, and put it close to a ground. Used a jumper wire on the mag pick up harness connector to simulate the mag pickup in the distributor. Key on, had no power light on the box, and no spark when I put the jumper in place, and then removed it several times. Went to check power to the box, but we had taped everything up nice, so I had to remove the electrical tape for about 6 inches, and found the problem... Mag pickup harness connector come apart in the wire loom by the box. Plugged it all back together, and it fired right up.:grin: Car sounds very nice now...my son just loves the way it sounds.:bglasses:
Got a call from the machine shop who has the block today. They punched the block to 0.060" over, and all the cylinders cleaned up. The weird thing is that the cylinder walls look like they have nickle marks in them. (they are 0.005" from finish hone size.) There are dark spots and shiny spots...hard to describe it. You can't feel it, but the darker spots look like corrosion, if you will... They are going to sonic test the block. They would like to keep at least 0.100-0.110" thickness in the walls, minimum. The block is 0.006" taller on one side, compared to the other, and only 0.002" from front to back, on both sides.
So Sorry for not responding sooner!!! It is ALWAYS a great idea to have sonic testing done when doing an extreme build with an factory block. PM me if you need help contacting Scott Brown for pistons or go here; http://www.buyracingparts.com/contact.html Scott should be able to get you the pistons you want!! If you need help choosing what you want shoot me a PM and I'll try to help before you talk to Scott so you sound more knowledgeable when you call him.(if you need help, I am always happy to help make MORE power!!) Derek
No worries Derek. I got your number now.:grin: The boy is out of money again after getting the exhaust installed by a shop in town... Its a good thing there is going to be a waiting period for the crank and rods. I will say this...he is super happy with the way the car sounds now with the Doug's ceramic coated headers, and the 2 1/2" American Thunder exhaust system on it. Sounds very throaty.
