this always starts some hot debate on a forum so why not here??
lightened crank pulley’s (not under or overdrive) are out on the market for a lot of imports without dampeners. some say it won’t hurt, others say its damaging to the engine.
what do you guys think, and is there any concrete evidence either way?
pontiac did it on the 301s, its just a ring for the pulleys to bolt to, and has the timming mark on it. The crank also dosnt have conter weights. Intake dosen’t have runer dividers, lots of other gay stuff, but it is a hunk of shit. whatever
A harmonic dampeners job is to do just that. Dampen harmonics that the engine produces. Harmonics vibration can damage parts. No dampener = greater chance of damageing parts especially main bearings.
You might save 2-5 pounds.
…while eating up cranks, rod caps, bearings…
ok, so here is my obvious question…how are all the aftermarket companies still selling these units and not getting sued by people with engine problems?
and here is a really stupid question…would stiffer motor mounts, torque dampener help if it kept the whole engine from rocking back and forth?
For the same reason that people buy high performance fuel filters, Grade 8 valve cover bolts, and color matched wire loom.
They do not get sued becuase you use the product at your own risk. Now is someone really wanted to go after them im sure they could find a loop hole but for the most part there are too many variables in High performance to place the blame on any one thing.
Stiffer engine mounts and torque dampeners have nothing to do with the harmonic frequencies that are made by parts moving up and down and turning. (pistons, rods, cranks)
^wrd
but then again if you are using it on a well put together modified engine, I would not expect any noticeable decrease in operating life from one. Honda makes a ctr pulley that does not have a harmonic balancer in it for their race engines, which people run on daily driven cars for years with no problems. Is it technically worse for the engine? Yes, but not measurably imo; I wouldnt plan on getting 250k out of a built engine, if getting those kind of miles out of a engine were a priority, I wouldnt run an un-damped pulley. At least for Honda engines- I’m sure there are engines out there which rely more on the harmonic balancer than others, and on these it would probably be a more noticeable detriment to the motors life.
are there examples anyone can point to specifically where an engine had a problem, at x miles and the cause was proven to be an undampened lightweight pulley?
I have not personally seen any…
It would be hard to find conclusive evidence of increased bearing failure at x rate faster than stock unless a test were done on two or more idential motors in a controlled environment with stock and undamped pulleys. There are too many factors in real world driving to be able to pinpoint a specific increased failure rate.
Again, these results would be unique to each model of engine tested, so I would search around on whatever forums are specific to your car. I researched b-series motors, and I found no evidence to convince me not to run one, and plenty of people who have been running them for a quite a long time with no ill effects. Maybe a hyundai v6 will explode in a week without a dampened pulley, but I have no idea.
Their only real benefit is how fast the engine will change rpms, just like a lightened flywheel, which you will find beneficial if you heel-toe downshift/revmatch. If you are looking for the 1hp it will gain you but dont care about how fast your engine changes speed, save your money for real power building mods.
Not having a tortional dampner can lead to rod bearing failure, busted timing chains, eratic ignition and cam timing, unpredictable valvetrain behaviour and alot more I’m too lazy to list. All you have to do is search the net for a few facts on what the damper does and how it works.
Any engine builder will tell you that it is not acceptable to trade reliability for horsepower. So think about it that way.
It matters on some engines, it doesn’t on others. How do you find out if it matters? Try it.
Except any modification that increases horsepower sacrifices reliability. Think about it that way. :bloated:
I would like to be shown one example where an undamped pulley caused a failure.
a couple of the guys I work with race sprint and midget cars. the engines they run crank dampers, and don’t even have crank pulleys. think its the water pump thats coupled onto the snout of the crankshaft and there’s just a driveshaft adapter bolted to the other end of the crankshaft.
kinda wierd because if you read the majority of drag racing general rules and a lot of other kinds of racing, you HAVE to run an approved crank damper.
bike engines don’t have them, and I don’t think that the majority of F1 / sportscar (LMP) engines have them either.
sounds like it really isn’t that much of an issue, at least not for extended periods of time.
I asked the same question about my SHO and again nobody has personaly seen any cases where it as caused damage.
I contacted a vendor in GA and he has been using them on his personal carss for 8 years, and agin there has never been a case on SHoforum, shotimes, or shotech where they have had any bottom end problems traced to the pulley. the only threads we get on the forums are
“when should i change my rodbearings” my car only has 200K on it. and the answer is change your rodbearings 150K-200K and don’t bother with your crank bearings unless your S/C then you have to change them every 100K or so becasue the tention from the S/C belt wears the bearing on the top and the end.
Think about it this way when comparing your daily driven car to and F1 any other race car, they rebuild their motors every race or every drag race the motor is torn down.
How often do you plan on tearing the motor apart and putting it back together? If you plan on running your engine for 1-5years without pulling it appart again run a dampner like the oem one or aftermarket like ATI or Fluidampr.
Factory OEM Engineers > *
There are only a few instances in terms of “drivability” where Factory Engineers may sacrifice performance. Balancers are one of those safety factor issues… I’m sure every engine has some point in the RPM range at which it may equal the critical harmonics of engine parts, when undamped cause a forever increasing rate of harmonics ( or vibration ) and ultimately lead to failure of said components. What are the chances you run the engine at this critical RPM for a determined amount of time as to cause engine damage? Probably very low to nil. What are the chances that this critical RPM is a range from 7k and up? or 6k and up? who knows? I bet the Factory Engineers know. 
I’d do a lightened flywheel before a lightened pulley… but that again has it’s drawbacks… it’s give and take, no free lunches.