Here is a pic of 6" H-beam rod stroker clearanced that they sell for a sbc when using a 4" stroke; Notice how they cut almost half way into the bolt to get the clearance they need, and they are still rated for 700 HP. If its to hard to see in the pic I have a set here I can take some better pictures of. Derek
I'll get one in the morning. It looks like I may have to remove material from about 3/8" down the rod, and blend it in. I'll give it a shot tomorrow morning...and post close ups of the rod beams. I hope, I hope, I hope this isn't a show stopper for this build...my son's heart would be crushed.
Don't worry, its not as bad as you think it is, this kind of clearancing has been done since people started doing stroker builds. You should see how much a sbc block needs to be clearanced for a 4" stroke with just the crank installed that needs to be clearanced! And that is just the tip of the iceberg, the block still needs clearancing for the rod bolts. And the bottom of the cylinders need to be clearanced so the rods don't hit there as well. And then the rods need clearancing for the small base circle cam you have to use with a sbc stroker(unless you get the clearanced rods that they sell for that reason). The stroker sbb crank just needs a little cam clearancing on the rods and that's it. The extra stroke drops right in and spins freely, and the rods have plenty of clearance between the block and the rod bolts so not as bad as other brand stroker builds. Jim Blackwood had the same issue in his blown 340 build with a standard stroke when he used flat head Ford 7" rods, he had to grind a little(I think it was a bit more than a little) clearance in the rods and he was good to go. The longer the rod, the less it will actuate as the crank spins. This keeps a longer rod tighter to the center when the crank is spinning than a shorter rod. But the advantage with a longer rod for your application out weighs a little clearancing. When you measure for clearance, make sure to do it with the piston on the rod so the rod is centered in the bore like it will be when it is rotating so its on the correct angle for the proper clearance checking. Also IF you need to cut into the bolt for clearancing(which I don't think you will but maybe?), make sure you use a rod vise or a vice with soft jaws holding the big end of the rod when you torque together to tighten the rod bolts to the proper stretch with a stretch gauge(or the proper torque with your torque wrench if you don't have a stretch gauge) before you cut the clearance in them. Then make sure you use the same bolt that was clearanced in the same rod it came out of when you assemble it.(I'm sure you knew that but, I wrote it for the readers that don't) Another thing you may want to do is degree the cam in so you know the cam is where you want it to be. You can remove the cam when you find your zero with the #1 piston and rod in to confirm top dead center. Then take the piston and rod out and install the cam and see if the cam is in where you want it to be. JW has mentioned how poorly some of the cams are off, some as far as installing it a tooth off to get it in right! So make sure you don't grind on the rods until the cam is degreed in, this can drastically change how the cam and rods interact with each other. Derek
Something else I am noticing on your rods is that they look like they were milled to be on center instead of offset. Lets see a picture of a piston in the block on a rod on the bottom side so we can see the wristpin to see if that's off. The chamfered side should be thicker than the non-chamfered side. If the chamfered side(the side next to the crank counter weight) doesn't push the rod closer to the center of the throw(closer to the other rod) the wristpin more than likely won't be centered in the piston! It will still run that way, but according to a conversation I had with Tom Molnar that will eat up around 40 HP he said he has measured on a dyno. That's why I recommended to remove ALL of the .055" of extra material from the non-chamfered side, to get it as close to the center of the piston as possible. I'm hoping the picture is an optical illusion and the chamfered side is longer. Derek
Derek, all the material was removed from one side of the rods. (The non chamfered side) They are not "perfectly centered" in the bore. I bought a stretch gauge years ago, but have no idea what amount is required for these.
You can see in the first picture, they is next to zero chamfer on that side of the rod....it's all on the other side.
I gotta go out and buy a gear puller this morning. The crank gear is, shall we say, a snug fit. Lol I haven't tried to pull it off yet, but it went on pretty tight.
Why can't I find any thread with degreeing a camshaft! I know I have read a very detailed one on here....it should be a "sticky"
Cool, it must of been an optical illusion. That side view with the rod bolted in looks like its centered, the pic must of been taken on a slight angle? The picture measures the same on both sides. And here is the link for degreeing a cam; http://www.v8buick.com/index.php?threads/camshaft-degreeing-101.220945/ JW likes to play in the BBB sandbox. Derek
So I bought a gear puller...pulled the gear set off, and set the timing to 0* straight up. Looking at the front of the engine, cylinder #1 on your rhs, the cam's keyway is at the 9:00 position. This puts the "dot", which is on the cam gear, pointing straight down at the crank. The crank gear has the "0" right at the top, pointing at the dot on the cam gear. Note: the crank keyway is off to the right a little bit...but the #1 piston is at TDC. I have the degree wheel set up. Starting at TDC on the compression stroke, (piston at TDC, cam gear dot facing down, zero on crank gear straight up.) I can turn the assembly, and watch the exhaust lifter come up, go down, intake lifter come up, go down, and then it gets to 55* BTDC, on the compression stroke, and makes contact with the rod. I have clearanced the rod enough to get it as far as 52* BTDC, but I still have contact...and it looks like it needs way more yet. (I even pulled the rod bolt out cuz it was hitting.)
Took a picture of rod/piston in bore.... If this is not good enough......lower your standards....I got bigger issues. As an old family friend used to say: "A blind man would be tickled to death to see that."
So yeah, like I said in a earlier post, make sure you degree the cam before you grind any off of the rods. I posted the link for the degree thread in post #436, get that done first and we'll go from there. Rod looks good and centered in the piston, cool. Derek
