63 Impala stroker build

[Ishiftem]

For what I’m doing I would still go with the Scat. I was impressed with it and I measured everything I could. I would bet the counterweights are in a better position too though that’s speculation. If I was doing a 550 hp torque monster for the street, I would probably go Eagle because of the cost of balancing the Scat.

 

[Murphdog]

The Scat I just got has much tighter tolerances than the Eagle it replaced. It’s an all around nicer piece. The bad news is that it cost $800 to balance it due to the heavy metal it needed where as the Eagle didn’t need heavy metal.

Did both assemblies use the same pistons & rods?
Jeff

 

[Ishiftem]

The same. Pistons were about 670 grams and rods 830. I forget what the pins weigh.

 

[skipxt4]

My stroker crank was not a kit. I bought the 4.00 Eagle crank from Summit. There were a few problems. I had all the pistons installed and was in the process of installing the Cloye's Double Roller timing chain. The lower crank gear, would not fit on the crankshaft correctly. It would only go so far and stop. My machinist told me, he could take some metal off the inside of the gear. After that. the crank gear went right on. I thought I was gonna have to disassemble the engine. Timing chain and cover installed. Put the water pump on. Everything going OK. I put the Harmonic Balancer on the crank, and noticed, it would only go so far and stopped. Now what. The top water pump pulley, and the lower balancer pulley didn't line up. Eagle machined the crank wrong. Dave shortened the Balancer hub to bring it closer to the engine. After that, the pulleys lined up as they should. If I had to do it over again, I would buy the Scat crankshaft. I should have known. The boxes the Eagle Crankshaft and Eagle Sir Rods came in, said Made In China.

 

[Murphdog]

And where do you think Scat cranks & rods come from? Could be, same building, different door, different cousin, same ship!
Just better QC. Even the all inclusive "kits" from 1 vendor need everything checked.
Jeff

 

[skipxt4]

Before I bought my crank and rods, I sent an e-mail to their company, requesting information on their products. A few days later. a representative of their company wrote me back. He sent me pictures of their facility, with all the CNC Machines, with guys working at the positions. Pretty impressive.I was told, all their products were Made In The USA. H-m-m-m. Yeah Right.

 

[Murphdog]

If you are referring to Scat, I think SOME of their product is made here, some of the high end/custom stuff. Their general low end stuff I'm sure comes off the boat. I think they do some finish work of some parts after they arrive.
Jeff

 

[Ishiftem]

Both forgings are from China. So are K1, Molnar, Callies Compstar, etc. basically if you see a new crank for less than 2000 bucks, it’s forged in China. I have heard it said that they do not all come from the same factory, but since all Chinese businesses are owned by the government, it probably doesn’t matter. The difference is machining and design. The scat is finish machined and ground here so they have much better control. The eagle is machined in China and only gets a final tune up here. I like that the scat had smaller holes through the rod journal and that it doesn’t go all the way through. That’s why they need the heavy metal. Now they could make it bigger and all the way through like an eagle but they don’t. You have to ask why. I believe it’s because it makes for a stronger piece. Then there is counter weight placement. You can have two different cranks that balance just fine but will have significant differences in main bearing load. Usually on 2 and 4. I have always had odd wear on 2 and 4 with my eagle crank. Nothing severe at all but it’s there. I’m betting its counterweight placement. Time will tell if it goes away with the scat. I’ve heard it said especially with rods that all the China rods are the same and come from the same factory blah blah blah. Not true. Compare a chines forged compstar rod to an eagle or scat and the difference in design and finish are obvious.

 

[Murphdog]

The plan for my "personal" driver is a 4.25" crank with 8 counterweights.
Jeff

 

[Ishiftem]

That’s the way to go! I tried to get one from Scat since they make a 4” stroke bbc 8 counterweight and they said no. I’m like, why can’t you cut doyen the counter weights and thrust flange on the bbc and they wouldn’t do it. Maybe I talked to the wrong person. I did hear from a crankshaft designer that the extra counterweights must be 180 degrees to the crank throw or else bearing loads can be much higher though they are not all made that way.

 

[smd321]

Looks like the windage tray will clear just fine

I'm back to the standard volume oil pump. 8 pistons in. Clearances are looking good with no extra machining. Freeze plugs in. Sorting out the balancer and timing cover next. Ordered a repro timing cover since my extra was for the small balancer. Couldn't find the one that came with this block, but I did find a passenger side exhaust manifold I can use at least temporarily.

 

[smd321]

Still hung up on the damper. Turns out I have a fleet of small block dampers and no 409.

Does anyone have a recommendation of repro dampers? It doesn't seem like there are any 7" 409 balancers new.

Is it a good idea to switch to a fluid damper?

 

[Ishiftem]

You can use any sbc 7” but you’ll need to move the timing pointer on the cover.

 

[smd321]

Working on the heads. Quick question. My springs are 1.44" OD and the pockets were previously expanded to 1.63" ID. Do I need to use a spring cup or locator of some sort?

 

[boxerdog]

Depends on whether or not the springs are already internally located or not. Either way can work.

 

[Ishiftem]

If the head has enough of a raised edge to locate the spring, then you are fine. .020 on the head side on this build is zero issue. If not you’ll need an ID locator as I’m sure there is some sort of raised edge and a spring cup simply won’t fit.

 

[smd321]

My guide is .63" od and my spring ID is 1.040. The guide and pockets appear to be both machined. So not internal located either. Don't want to name names, but the place I've been buying parts from said I shouldn't need cups or locators for these heads but it appears that I do.

As it stands now, I have about .100" between spring od and raised pocket. ID is larger gap as mentioned above.

So now I'll have to do some searching for the right parts it sounds like.

 

[smd321]

The heads came with the same diameter springs that I'm using and no method of centering the bottom of the spring to the valve pocket.

 

[Ishiftem]

My guide is .63" od and my spring ID is 1.040. The guide and pockets appear to be both machined. So not internal located either. Don't want to name names, but the place I've been buying parts from said I shouldn't need cups or locators for these heads but it appears that I do.

As it stands now, I have about .100" between spring od and raised pocket. ID is larger gap as mentioned above.

So now I'll have to do some searching for the right parts it sounds like.

I’m changing my post. You DO have room for a spring cup. So whether you locate the inner or outer doesn’t matter. Just make sure if you use the spring cup that the OD of the spring is a little smaller than the cup because the lower coils will expand a little when compressed and you want it to have room to do so.

 

[Ishiftem]

The heads came with the same diameter springs that I'm using and no method of centering the bottom of the spring to the valve pocket.

They should have. You don’t want to give it the opportunity to walk around.