Started assembly of a 408 last night to clearance everything. Come to find out the crank counterweights are bottoming out against the pistons. I think the crank may have been improperly ground for thr od combination. FWIW, I am using Eagle rods (CRS6125B3D) and Diamond Pistons (11519). Here is where the contact is:





Now I have two cranks in my hands that may be worth about nothing

 

eagle wont take responsability and fix the situation?

 

I was told that some other shops had real big problems balancing them to Todd. One shop told me it took them over 300 hrs to balance theres.......... so it doesnt look like these cranks are going to be cheap after all. Call Eagle....... You would think they would check things like this before they shipped these things....... Do both cranks do the same thing or have you no tore everything back down and tried? Workin nights too??? Or Just up late.....

 

Just woke up and couldn't sleep. Have not contacted Eagle yet. Fortunately, I bought through my local machine shop and they will have to make things right somehow. It seems the rod length is correct because the piston is good at the top of the stroke. But it can't make it to the bottom of the stroke because it hits the piston. Machine shop said the crank was nice and only had to add 40 grams to the front for balancing. Not sure if they have balanced the other crank yet.

 

Do all the pistons hit the counterweights? You can just have counter weights turned down slightly and rebalance motor. Since you had to add weight to crank, how about getting lighter wrist pins and than rebalance crank? Reducing your bobweight should allow taking material off counterweights to get proper balance. Just a idea.

 

You can also take the pistons to a good machine shop and have them machine them to clear the counterweights.

BTW~ that rod sure is offset alot on the pin

 

The weight was added to the nose (front side of the counterweight). The counterweights themselves are as shipped from Eagle. That second pic was out of the motor so I could get a close-up of the scuffing.

 

I really hate to see this, but I've seen this happen too many times to count on numerous Eagle cranks, for other applications as well. IMHO, I would NEVER buy an Eagle crank. The rods seem to be OK now, but I still wouldn't use those either personally.

 

Not as big a problem at all todd only that you balabced the rotating already

On a pre-assembly check in the engine this would have been caught and the fix I would take is to machine the counterweights to fit( easy calculation) and then balance the assembly. When material is taken from the radius of the counterweight it needs to be added back into the counterweight (below the radius) with heavy metal. Don't touch the piston in that area and take the easy way out or you may comprimise the piston strength

So not a real big deal just alot of inconveniece for the engine builder

 

sumama bitch! My crank is on the way from eagle now...I hope mine doesnt hit I was gunna use the Diamond 11504's for my motor..but I was told the eagle crank's are supposed to be used with eagles 6.100" LS1 specific rods and eagles 3.898" or 3.905" pistons to clear everything.I wonder if that is how it's supposed to be?If eagles pistons are clearanced for that.The diamonds are nice and i am gunna order the diamonds anyways and just clearance the underside of the wristpin bore if mine hit's too and then just re-blance...Crap I hope mine clears though...maybe we should start a poll post on clearance issues with the eagle, just to see how many people's are not clearing right?

Carter

 

Thanks Nick. Gonna take the stuff back to the machine shop for a look. Fortunately, the second assembly has not been balanced yet. I will ask them to shve the crank counterweights instead of shaving the pistons.

 

Are you using a 6.100 or a 6.125 rod? We always the 6.125 rod and that makes things clear much easier. How much interf. is there? Does eagle state it will fit with a certain rod length/ piston combo? Just curious

 

We measured ours and it lookslike it would have taken a 6.350 rod to clear the counter weights that they sent it with. This is why these cranks are so CHEAP!!! Not to much quality control from them. By the time you get done balancing and fixing these cranks you are going to have what you would have had into a good quality crank, such as a Callies or Lunati. Remember you get what you pay for.

Thanks

 

Using a 6.125 rod. My machine shop called Eagle and eagle stated they are aware of the problem NOW. They recommended shaving 80-thousandths off the radius of the counterweights as Nick mentioned. At least we caught it before the second assembly was balanced already. I also dropped off the assembled rods/pistons/bearings so they could verify clearance after shaving.

Nothing like doing free R&D for Eagle I guess

 

That is the Eagle way!

 

oh man, this really makes me glad I didnt go ahead and order one when my engine was apart. That would be about par for the course for me.

 

That sucks, are these iron block strokers and are they spoken for?
You can test the assembly on my car if you like
Im going to need more power now that my drivetrain is bulletproof

 

Todd, you were a victim of chinese reverse engineering. When you early owners of these cranks figure out all the problems, eagle should have a useable part.
Keep tabs on how much it costs to balance your crank.
What is your bobweight?
Kurt

 

Good catch, Todd. That sucks that you're gonna have to pull it back out to get rebalanced though. At least you didnt' balance the others

 

Not sure on the bobweight Kurt, but I think the weight is actually pretty good. I can find out. Levi, the motor was never really assembled. I just was fitting parts to see what needed clearancing when I discovered the problem. The machine shop said nothing about an additional charge for the extra work, so we'll see. I assume they will work itout with Eagle, but will post when I know.

Ray, I only build motors for folks I know, which would be OK for you. These motors are spoken for. They are also paid for in advance for the most part. I only ask for a small fee for my efforts and provide all parts and machine work at my cost. May be getting late in the game for me to build any more. Looks like I may be relocating in June to Michigan. My talents may be spoken for.