Hey guys, I need your help. I built this 454 030 over about 3 years ago for a friend´s 64 Chevy Truck. Speed Pro pistons, Edelbrock heads, brandnew Eagle crank. I had the whole rotating assembly weight matched and balanced by a local dragster engine builder who got a very good reputation and is supposed to know what he´s doing. He also align honed the main bearings to be sure everything runs straight. I assembled the engine, bearing clearences were all fine, and one could spin the engine by hand easily. Last week , after 12000 miles of trouble free driving, the engine went out cruising at about 1800rpm. Oil pressure was at 50psi, temp at 190°. No knock, no sqeeling, just "zip" and done. The bearings are all ok besides the front ones, where the crank broke. Looks like they were kinda wedged out when the crank broke and canted. Here are some pics, any hints and suggestions are highly appriciated. I just don´t want to get another crank and have the same shit happening 12000 miles ahead Sorry for the large pics, but I figured the details could be seen better than in small ones.
Sounds like you may have had the incorrect harmonic balancer on the nose of the crank. The balancer is there to absorb the 'twist' of an uneven load on the crank - then release it inbetween pulses. The wrong balancer will place stress on the front half of the crank - eventually fatiguing the metal to failure. The clue is where it broke - if it were farther down the crank, I'd say you wound it tight one too many times, but a break between #1 and #2 cap is usually attributed to the balancer. Also - metal is known to have occlusions (flaws) in it - you'll have to pull it apart and examine the break.
Since the 454 is an externally balanced engine the correct balancer and flywheel must be used! Torsional stress will break a crank....If the incorrect parts had been used an engine vibration should have been noticable.
When I was a kid (mid 20's) my harmonic balancer was loose one day, so,,,,,,,,, not knowing that it cracked at the key-way, I just tightened the bolt and then wondered why it had this funny high frequency at around 6500, next day it broke as I'm backing out of the garage to go to work. Specs;327 block, steel 283 crank, TRW 12.5:1's, .030-.030 cam, powerband 3500-7500, another crank fixed it right up!
flaw,wrong balancer,fuel nock=timing for fuel used,"some fool hammering balancer on or off at anytime in the passed,droping of crank at anytime in the passed/could of been way befor enginebuilder ever saw the parts at all"
Were the rods re-ground undersize? If so check the radius's. Many crank grinders in a hurry to just get it done won't take the time to re-radius a freshly dressed stone. Result-Sharp corners and a break waiting to happen.
I almost forgot: The engine was running smooth and timing was correct. No pinging or vibration until the big bang.
Was the new shaft magnafluxed? Not unusual for new shafts to be cracked. Was it straightened? Also not unusual for new shafts to be bent, especially nitrided ones. Need some better pics of the front and second main journals and the bearings. From that last pic it looks like the bearing damage may have come first but there's not enough information yet.
Does look like an existing crack from what I can see in the pics... Was it magnafluxed prior to assembly? Cheap insurance against incidents like this, unfortunately.
I don´t think they magnafluxed the crank when it was balanced, not sure about that. I had 1500$ in the balancing job, last thing I thought could happen is break the crank The damage on #2 main bearing was caused by the wedging and spinning action when the crank broke I think. The bearing surface showed no wear, only scuff marks due to the canted crank. All of the rod bearings are looking new too. BTW, is there a way to save a block that had spun a main bearing?
I just called the guy who did the balance job. Nope, the crank wasn´t magnafluxed. He said, he didn´t think it was necessary with a brandnew crank right out of the box.... Maybe it had been dropped by one of the shippers.
You can bore the saddle - pin a section of sleeve in and then rebore the main. It's a lot of labor - not sure if it would be cost effective versus another block. I'd still like to see better pictures, looks to me like the main may have gone out first, leaving the crank unsupported at #2. That's a lot of bearing damage if it broke and stopped suddenly. Usually with a break like that #1 bearing would look the worst of the two. Also, how much belt load was on the front of the crank? Too much can break a crank in the front.
Make sure the outer ring on that damper hasn't seized to the hub. I don't know what kind it is, but the chinese ones tend to be junk-they haven't got the elastomer technology figured out yet. As far as Eagle cranks go, they're notorious for their lack of QC. You can get low priced offshore cranks that are far better than that.
I try to get a better pic of #2 main bearing. There were only 2 belts, one for power steering and one for waterpump/ alternator... The balancer is Chinese.... :-(
Getting a good look at the other side of the #2 main it looks like it burned half way around. Now it looks to me like the break started first and the crank was getting hammered into the bearing like you said. Once a crack opens up the crank runs bent. Good chance it was flawed right out of the box.
I don't know about Eagle, but there's been a LOT of aftermarket engine part castings that have been outsourced to China..........
I'm not sure what things cost in your area....but from what I see in these pictures, if you were charged $1500 dollars for balancing job....I'd really really look into the machineshop that did the work. Judging from the pics I cannot see much work done to the connecting rods, just a lot of grinder/sander marks on the crank throws...to me not a $1500 job by no means. Pull every thing apart, and just do a quick check on totalt weights of the con rods to eachother, and do the pistons as well....if the wights are not identical between each rod...and then between each piston....you need to have a talk with your machine shop. I have replaced many many broken bbc and bbf cranks in work trucks and tow rigs in my area...all broken from the drive belts on the front of the engine being over tightened! make sure that all your pulleys are straight and true...and when you put it back together and fire it up...make sue that the drive belt are running smooth/true and not jumping around at all. Most people will not believe this, but it is vary true that it will break the front of the crank just as yours has. Not saying this is the case, but a possability. My main suggestion would be look long and hard at the balance job/work...this bottom end does not look anything like it should if it is supposed to be balanced to 8000rpm as you said.
Thanks for that, lots of good information! I thought that 1500$ was quite pricey too; just for comparison a good bore job for a V8 is slightly under 400Euros over here, maybe around US $500. The belts were true and didn´t bounce, yes they were tight but not overtightend. I´ve just weighed the rod and piston assemblys, they are all within 1 gramm. I can´t say anything about the crank´s balancing, I have no chance to check that.
Looking at your location,good chance shipping damage may have happened on a journey that far.Too bad the crank wasn't magnafluxed before assembly.Unfortunetly new parts sometimes have hidden damage,especially parts that are heavy but fragile,like cranks.
I don't like those cranks, I would go with a SCAT crank, they are a little more money, but I think they are better.
Sorry for the late comment on this old post. Please note that Scat and Eagle are 100% Chinese cranks. I'm not saying that facts makes these bad cranks, I've seen many high power engines using these parts without trouble. (Scat does make some excellent high dollar cranks from billet, which they do in the USA). The main issue I've seen with the China cranks is the QC. It's done by sorting. You can't guarantee quality by inspecting for the defects. Bad parts will ALWAYS slip by. Quality is assured by proper design and process so that defects are prevented from occuring. It's cheaper to slam out a crap load of product and sort through it all to find the few "good ones" to sell. Unfortunately, this approach is making it's way into everything sold in the USA.
I don't mean to be negative here, but almost everyone that makes cranks and I beam rods has them done in Main Land China. The foundry does the smelting, pouring, and then they are usually (but not always) send them back to the Good Ole US of A for final finishing. As long is there is 35% USA content in the crank it can be called "Made in the USA". The good cranks along with billet ones are made here, Moldex, SCAT, and others, but then again you will pay $1500/$2500 for a good one. The old adage, "You get what you pay for", certainly means everthing today. I've seen (cranks made in China) cranks from big name people break under load, more than once................. I would also question any engine builder that does not mag everything that rotates and sonic test blocks................I've put together many race engines since the 70's, and brand new is not always better than a good used piece. IMHO
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