Eagle Cranks

[musclecar neal]

It is not that hard to make the internal balance crank external. There is extra weight on the front and rear counterweights to internally balance the unit. You can either drill the weights or trim the OD of the weights or both. It's not that hard and you can do external with the new Eagle crank. I will be doing one in the next few weeks.

 

[Intercooler]

Since I am by far no expert on the balancing, internal, external thing I will just have to wait for the reports back from the first few that get installed. Following the machine shop jargon that was being spewed upon me it sounded like the zero balance put them in the middle making them useable. Something along the lines of what Musclecar Neal is talking about. I just hand them my stuff and tell them to balance it

 

[Lee Thompson]

hub

I have no experience with a BHJ hub. This what I have found with the 3 BMS hubs that I have had. The BMS hub is 4.75 in. in dia. (factory hub is 6.75 ) Actually the outer dia. of the BMS hub is the interupter ring. The interuptor ring and the keyway are true (identical) with a factory hub. The difference is that the top dead center mark (and I assume all the other marks ) is off around 4 degrees. Actually it is very easy to correct. Since the hub is smaller in dia. you will need to fab a new timing indicator as it is guess work trying to set the cam sensor with the indicator so far away. I made a new indicator out of a piece of sheet metal that extends down to the ring. First I made sure the eng. was at top dead center and lined the new marker up with the top dead center mark on the BMS hub. Someone once told me that Buick made a mistake on their hubs and BHJ coppied their mistake. May or may not be true. This is definately something that needs to be looked @

 

[orion]

just a quick reference question, what else is required to stroke a motor besides a special crank? connecting rods? pistons? bearings?

 

[Mike Licht]

The stock balancer is pretty easy to convert to "zero" balance. That with an aftermarket flexplate like the J&W should be pretty much most street cars need and still keep the cost reasonable.
Mike

 

[Scott231]

Originally posted by orion
just a quick reference question, what else is required to stroke a motor besides a special crank? connecting rods? pistons? bearings?

If you are "reasonable" with the over-stroke, all you need is the crank. You can run into trouble with really long throws hitting the oil pump pickup tube or smacking the rods into the side of the block. Installing shorter rods to compensate for the longer crank throw, would indicate you do not know what you are doing.

In a nutshell: the first is remedied with an external oil pump pickup and the second is remedied with block grinding.

 

[tminer]

What am I missing? I thought that the pistons would need replaced to keep from hitting the deck/valves or at least to get the c/r back to a reasonable level for a turbo motor. This would be based on the 3.625" stroke cranks.

Tom

 

[Nick Micale]

Originally posted by Mike Licht
The stock balancer is pretty easy to convert to "zero" balance. That with an aftermarket flexplate like the J&W should be pretty much most street cars need and still keep the cost reasonable.
Mike

We have not "converted" a stock balancer to zero balance and would not do so. It would have to be set up and lots of material removed by machining. Would be expensive, and with so much material removed, doubtful if it could do its job of offsetting the crank harmonics like it should?

The stock balancer is NOT a performance piece and using it as such could result in disasterous, and expensive, results.

 

[Nick Micale]

Originally posted by orion
just a quick reference question, what else is required to stroke a motor besides a special crank? connecting rods? pistons? bearings?

If you are going to use a longer than stock stroke, new pistons and rods are needed. Modifications to the block like Scott described are necessary. Depending on the crank used, it may also need to be modified.

Using a stock rod will give you too much piston side loading and too long a rod will not leave much "meat" for ring lands.

The Eagle steel crank is a great step forward for Buick performance and a stroked motor is also a welcome addition for more power. Keep in mind we are talking about HIGH performance applications where components are brought to just under their max break point. Just getting there is not cheap, and staying there is also expensive. Nice to have in a "daily driver", just be prepared to pay the price to have it done right.

 

[wicked_TurboLV]

just to let you all know im one of the lucky ones with the new crank should be getting it friday. ill just have to wait a little longer to see what nick comes up with on his crank just so i cant get an idea.

 

[chevyII]

rod width???

Is there a measurement for the width of rod for the eagle crank. Im pretty sure they are for "wide" but what are the actual size of wide and narrow rods? Im looking for a forged offcenter 6.500 length set. Are they still made new? Price?

 

[Louie L.]

I was just informed today by a vendor that this is a narrow rod journal crank. Which is it.?

 

[John Wilde]

According to Eagle it is a narrow.

 

[Lee Thompson]

rod width

chevy II.. don/t take these measurements to precise.
Wide rod---.890
Narrow rod--.840

 

[tminer]

Lee's numbers look correct.

I couldn't believe that there was only .050" difference when I saw that recently. Does that 6% extra bearing area make that much difference?

Tom

 

[Mike Licht]

Originally posted by Nick Micale
We have not "converted" a stock balancer to zero balance and would not do so. It would have to be set up and lots of material removed by machining. Would be expensive, and with so much material removed, doubtful if it could do its job of offsetting the crank harmonics like it should?

The stock balancer is NOT a performance piece and using it as such could result in disasterous, and expensive, results.

While I do agree that it is not a performance piece, It does not require much machining at all, and did a VERY good job on my Stage 2 motor. Dan Strenzo at DLS built that short block it was turned over 7000 rpm a number of times (I am NOT recommending someone else do that, I did how ever) this motor ran smooth as glass as well and ran close to 140MPH. This was Dan's idea and worked very well for me. Sounds like you have never tried this but for a street car I would do it again in a minute. If I was doing a race car I would go aftermarket.
Mike

 

[KendallF]

Originally posted by tminer
Lee's numbers look correct.

I couldn't believe that there was only .050" difference when I saw that recently. Does that 6% extra bearing area make that much difference?

Tom

The more interesting thing is that, effectively, there's no bearing area increase most of the time. There are only two common bearing widths available; the stock 3.8 and the wider 3800. You can run the 3800 bearing on a lot of narrow journal cranks, depending on the journal radius. I have them on my narrow journal crank.

Now if you want to narrow some wider bearings, or just want a really big journal edge radius, the wide journal crank is worth something.

 

[86brick]

Originally posted by ILBCNU6
I checked with my local machine shop and he can convert the flexplate and balancer to zero balance. He can even machine the counter weights of the Eagle crank to lighten it if needed. He has checked with Eagle and they are considering doing a stroker crank! So no problem to change an external balanced crank to internal! Cost should be about the same as a full balance job. Hell, he is thinking of doing his engine, his son's, and mine next winter with this crank. He deals with Eagle and will try to beat Summits price too! Maybe if enough of us want cranks, a group purchase, even doing the balancing thing too! I'll post the next news on this from my end. Gene PS. He liked the posted pictures of the crank!

Very interesting!

 

[V8Killer]

FYI, I just checked on the summit website for the Eagle crank, part # ESP-423134005967................it came up as $699.00...........WTF
Is this price right???

 

[CTX-SLPR]

Howdy,

Here is my deal, I'm building a dual purpose street strip motor that I'm hoping to make about 600hp+ off of, basically whatever I can get away with without turning the motor into an improvised explosive device. This new crank is certianly better at these power levels than the solid but still cast turbo crank I have so I want the durability of the forging. I'm not planning on pushing the motor past 5500 unless something has really spooked me or I'm late shifting. Can I use a machined to neutral balance stock balancer hub and flexplate and if I had to get an aftermarket one of either, which should I get?

Thanks,