Yes there are many, many stories of disaster involving the front main bearing and the oil pump. Here's my take on the frustrating "facts." The Unorthodox Racing underdrive crank pulley seems to be at the center of it all, yet the whole subject concerns crank pullies without an integral inertial dampener.

Questions and issues:
- Has anyone done a test of say, 4 stock Honda's, two with and two without these UR crank pullies and no other changes? I've never seen one. It would be the way to settle this, but not realistic since all the cars would have to be driven exactly the same way for 1000s of miles.

- If someone's modified car fails, what were ALL the mods done to the car? This is hardly ever mentioned and is extremely important.

- If these crank pullies are the kiss of death, why do some owners have no problem? This makes me very suspicious of the whole issue. If the part is flat out "wrong" by design, it guarantees (by design) to ruin the engine, right? So how can *any* car survive many miles with the UR pulley? If the stock pulley prevents crank/belt/accessary resonances, that might explain why some engine's with a UR pulley last forever - the owner's driving style keeps them away from the resonant rpm...

- If the car fails, what was the driving style? Always kept under redline? Drag racing? Autocross? Hardly ever see mention of that.

- Here's a big one. How many have personally seen this failure on their own car? Not simply passing on "information", not posting "facts" of a post from someone who heard from someone else. How many have had this happen to *their* car (and not someone elses.)

- My theory below claims that the damage will occur regardless of the type of pulley installed. Has anyone seen the same type of damage to their oil pump and front main bearing with a stock pulley?

- And finally... Honda wouldn't put it on without a good reason. The big question is: What is that reason. I heard several, but I don't know for SURE.

---------------
I present this theory simply to provoke discussion. It seems like a good reason to me, but if we're to ever clear this up, we need to start coming up with theories and try shooting them down... or not:

My Theory:
Oil starvation. Most people with a destroyed engine say the crank bearings get progressively worse as you work your way toward the front of the crank. Well the oil pump is at the front of the crank, so the source of all engine oil originates from the same point. If the engine gets a bubble of air, the front main bearing will be the first to go, followed by #2 (not as bad because there's slightly more residual oil "downstream". Followed by #3 in better condition because it had even more residual oil, and so on.

Every post I've seen has said nothing about oil pressure. No one says their Low Oil light ever came on, but there's a big potential problem here. You need roughly 10lbs of oil pressure per 1000rpm. So at 7000rpm you better have at least 70lbs of pressure. Guess what pressure the Low Oil light comes on at... 4.3lbs! If the light EVER comes on while you're driving, especially under load, the damage is already done. Damage can occur even though the light never comes on.

I'm most concerned about transient conditions, where the car is probably (I'm guessing) exceeding 1G for a moment. Dropping the clutch at a drag race start, or throwing the car one way then the other at an autocross, or hitting the brake hard with sticky tires, any of these might cause more than 1G lateral acceleration for an instant. 1.0G lateral acceleration, and 1.0G normal gravity means that during this extreme condition, the oil in the pan will slosh to a 45 deg angle. In actuality, the oil will attain an even higher angle because of it's momentum.

For the purpose of my theory, lets say it sloshes to 50 deg relative to the ground. Now also consider that during this transient, a lot of oil is plastered to the side of the block. Because of the extreme side loading, the oil has a very hard time returning to the pan. So there is a double danger at this point. The reserve of oil is less than when sitting still because a bunch of it is nailed to the walls of the block and inside the head.

I suspect the combination of these create a good chance for the oil pump inlet to be uncovered and suck in air. In the above condition, this is the worst time for it to happen, at high rpm and under heavy load - damage will occur very very fast. Worse, the Low Oil light will never go on, both because the pressure never makes it all the way down to it's trip point, and because once the air bubble is past, the pump will repressurize the system, *including* the air bubble. So even if there's a big air bubble traveling through the oil system, the air is compressed to 60-something pounds. The oil light will never come on, even though the front main bearing has just been run out of oil for a split second.

The REAL TEST would be to equip a Honda with a dry-sump oil system with the lightened flywheel pulley, THEN see what happens. Second best would be to run the test on cars with an Accusump. Either way, I'd really like to hear from the few who have both the lightened crank pulley AND an Accusump or dry-sump. (I'm guessing there's probably no one with this set up unfortunately...)

I may end up having to be the test dummy on this....

 

yea thats all really good stuff and im sick of hearing the he said she said arguement too. but the stock crank pulley is not a harmonic balancer like most people believe, its a torsional dampner. think about it, most people believe it uses this rubber ring to protect the crank from resonant vibrations from the acc's, well what do you think the belts are made of? exactly. also sone people believe that the whole bottom end is balanced from honda as one piece crank/pulley/flywheel which is retarded, any company that would engineer their engines like that needs to be out of business. if they did it that way then if you needed to replace your stock FW or carank pulley you would need to balance the whole engine which is very costly. the common sense approach would be to balance each piece sperately, and if done properly the whole unit would have perfect balance as well, since UR is very particular about their machining and balancing process i see no problems there. my theory on the torsional dampner is that it is there to reduce noise, ever since i put my UR pulley set on my car i have had a very slight belt noise that i can not get rid of regardless of belt tension or and kind of belt dressing, but thats the price i pay for the added acceleration, and im happy with it.

 

Surely there's more opinions out there

 

i will not touch anything other than a stock B16 pulley until the whole bottom end is fully balanced. i will get a flywheel for it, why would i need that extra bit of supposed power from a lightweight pulley? it is not going to rev that much faster. the money is better spent on other parts: IE: retainers.

 

i know the topic says "lightened crank pulleys" but are these just lightweight pulleys? or under drive pulleys as well?

either way, i dont see how a lightweight pulley would cause engine failures, i believe in kb58's theory of driving style playing a major role in everything


[Modified by CIVICtypeS, 6:59 AM 7/8/2002]

 

nice theory, but not a new one.

Also, I fail to see its relavance to aftermarket crank pulleys, and it doesnt matter if it is just lightened or its an underdrive pulley as far as oil preassure goes. The oil pump spins off the crank, so the size of a pulley will have no effect on oil preassure.

 

Personally, I was a firm believer against Unorthodox Crank Pulleys. I will be using one on my B20\VTEC. This is because the entire Rotating Assembly will be balanced, and there should not be a problem, In My Opinion. Let me also say, that I would never use one on a stock motor.

Suprdave

 

The following is pulled directly from the web site of The Old One:

Let me begin by saying that we have always called the pulley on the accessory drive end on the Honda cranks Harmonic Balancers. People never seemed to understand what we were talking about and so the word "pulley" was frequently used to avoid confusion. If you look carefully at a Honda "pulley", you'll find that it's not a single piece of metal. Typically, there's a nodular iron or steel hub and another "ring" of iron or steel surrounding it containing the belt grooves. The two parts are joined by a rubber layer, which is highly compressed and sandwiched between them. Why rubber? If you notice, many four cylinder engines over the years have used counter rotating shafts to help make the engine "feel" smoother. Reciprocating internal combustion engines and especially in-line four cylinder versions, all produce shock pulses, which are very apparent to the occupants of the car. Every engine produces a shock pulse each time an individual cylinder fires. So, in the case of the four cylinder variety, there are four large individual pulses for each 720 degrees of crank rotation. Each time there's a pulse, it causes the internal components to do a rapid acceleration-deceleration event. When you consider the mass of all the internal components and visualize all these parts stopping and starting during their reciprocating and rotating motions, the additional stress "spikes" tend to make it all the more reason for one to wonder how any of it can work for any length of time. The harmonic balancer is made with the rubber coupling so that, when the individual "spikes" occur, the inner portion may move with the crank, but the rubber connected outer ring's mass helps prevent the hub and crank from going as far or as fast during the spikes or pulses. Remember that the outer part had considerable mass, so it tends to want to stay in motion at the speed that it's traveling and that's why it can prevent excessive harsh motion by the crank and other internal parts. To put it simply, the harmonic balancer is a shock absorber for the engine and thus prevents the individual pulses from destroying everything in the engine. A quick bit of history; Back in the late '70's, all the Pro Stock engines had been reduced in displacement to allow the cars to weigh less. At that time the vehicle weight was based on engine "type" and total displacement. Typically, the engines were in the 330 cubic inch range and running 10,000 to 11,000 rpm was normal, especially in high gear at the traps. There began to be a lot of engines that were "exploding" their harmonic balancers on the big end. Aside from cutting the steering in half and blowing the front tires, large hunks were also finding their way into the grandstands and there were numerous injuries, many of which ended in death. NHRA immediately mandated that solid "balancers" were to be used from that point on. Keep in mind that a balancer can't be solid and function properly, but the rules were the rules. Moroso and a couple other companies who were tight with NHRA began making aluminum billet "balancers" immediately and everyone bought them so they'd be legal to race. All of a sudden, racers were getting only 10 passes from their crankshafts, which had previously lasted an entire season. Initially, most people thought the cranks were "bad", but after destroying engine after engine, a few knowledgeable engine people figured out where the problem actually was coming from and several companies that were capable of making functioning harmonic balancers sprang up over night. They are all still in the business to this day and their units are actually much better than the factory units of years before, as they are made from premium materials and optimized for high rpm applications. With this short bit of history finished, I'll begin to wind it up by stating what we do with the Honda engines. If the balancer has more belt grooves than the application needs, i.e. the power steering pulley, we machine it off. When it comes to the the pulleys that are actually a part of the outer portion of the balancer, we leave them intact. This procedure will not lighten the unbalanced hub substantialy, but the outer balancer ring will keep all its mass and function correctly. I also need to say that a large driven mass such as a blower or alternator, can have a slight dampening effect, but to actually work properly, the belt connecting the components to the crank would need to be 4" to 5" wide and the belt tension would be so great that it would wear out the number 1 main bearing as well as the bearings of the the driven parts in short order. It's especially important to keep the balancer "as is", if you're running an aluminum flywheel. The reduction in flywheel mass can also increase the pulsation shock strength and a higher level of vibration will immediately be observable. So if you lighten the flywheel,it's absolutely more necessary than ever to maintain the mass or the harmonic balancer. I realize that there's a lot of hype out there where manufacturers are promising this and that. The oversize crank pulleys can drive other geared or belted components faster due to the diameter ratio increase, but if you're deleting the balancer in the process, the short and long term side effects are going to hinge on your decisions. Larger diameter pulleys for the alternator, power steering and any other belt driven accessory are good ways to slow the speeds and drag of the those components, but when doing a large diameter crank pulley, the larger pulleys should actually be designed to fit "over" the stock balancer. Perhaps, someone will begin to make some good quality "functional" balancers some day, but until they do, you need to proceed carefully, as some good looks and minimal power gains can be off set by a ruined engine. I'm sure that there will be some fall out regarding what I'm saying here and to that effect I need to remind everyone that we do not manufacture hubs, big pulleys, or harmonic balancers for Hondas and none of what I've said is the least bit politically motivated.

And yes, any engine with a non-functional hub or balancer can ruin the crank driven oil pump and a whole lot more.

kb58..run all the billet pulleys you want, test your motors with them, have fun but I'd rather be safe than sorry...

 

what!

im going home to check this out!

never noticed that before...

Honda defnitly know their stuff! if it is there - it is there for a reason...

t..

 

interesting post... and some good theories and observations and information. in my opinion, i do see some relevance in a professionally balanced engine using lightened crank pulleys vs. stock engine using a lightened crank pulley. the latter being the questionable one.

 

Here are my 3 center lower main bearings.......

[IMG][http://home.cinci.rr.com/mistab0ne/P...mains.jpg/IMG]

This is 10k miles after I installed the LW crank pulley when I installed the swap. I inspected the mains before I bought it and bearings were the normal dull gray. Motor had about 50K when installed, about 62K when the picture was taken. I slapped in new main bearings, put the stock pulley back on, and have put about another 30k miles on the engine, including 25 bottles of nitrous before burning a piston.

Engine never lost oil pressure.

When I get around to pulling the motor, I will take pics of the scored crank from first incident and how the new mains with 30k miles look now.

AEM stopped making LW crank pulleys because of this issue.

My Theory............
Hybriding started when everyone vlew up their SOHC's using LW crank pulleys.

 

You must have no idea how production engines are designed/developed/manufactured do you? It isn't always done in a "common sense" way. You may not know the real reason. Hmmm, something to think about.

I agree with others that I would rather be safer than sorry, especially if I have invested alot of money and time into an engine (reguardless if it was a street engine or race engine). Reguardless, oem Honda pulleys have worked flawlessly for me so far....so why would I change?



[Modified by SLPR, 7:03 AM 7/8/2002]

 

I tried using a HF (solid type) pully on my 88' Si. Got nothing but a REAL NASTY vibration, all the way through the band. Was even worse after the re-build and sc install. It would not take that much of a brain, toooo figure out, that it would not take long. Too shell out the lower end, with that much vibration...

You can try running one... If it picks-up any kind of vibration, get it the HELL off ASAP. Otherwise, go for it... hehehe

 

This is a little off topic but in the August 2002 Import tuner on page #174 is a product that looks like a harmonic balancer for B-series Hondas. Here it is


ATI Performance Products introduces
the SFI-approved Super Damper.
The Super Damper is avalible for Honda B-series engines


I don't think the pis in the mag is of the honda one thou I looks like a typical v8 set up.


[Modified by rolow, 4:08 PM 7/8/2002]

 

endyn don't fib...i fully agree with the notion of using the stock pulley, especially on daily-driven applications. There are harmonics that have to be addressed properly, especially @ high rpm where these harmonics' stress-potential is exponetially increased as the r's go up...spend your money elsewhere on more safe/proven/less argued areas of the engine...

 

here's the link if anyone is interested


http://www.atiperformanceproducts.co...s/pr/50302.htm

 

Honda definitely knows their stuff, and they also make SOLID UNDAMPENED
pulleys as well. So are they stupid now?

 

 

It depends on the engine. For those engines where Honda equips a solid pulley, they have measured the vibrations of the crankshaft and determined the amplitudes to be low enough to not cause durability concerns. That does not apply to each and every case.

 

Only for B18C and B16B to my knowledge.

 

only solid pulley are found on HF and VX (both are 1.5l ) low reving motors, designed for economy not high rpm power...

(also JDM CTR base comes with single solid pulley), but remeber the person who buys a race/base CTR is going to race it no matter what, something will go before the pulley will have a noticable effect on the bearings....

 

We're aware of a few production Honda engines that don't use true dampeners, however, it should be noted that they are either driving many accessories, relatively low output engines, or slated for markets where their lifespan is limited by regulation. I invite anyone and everyone to run with non-dampened cranks. That's the best way to "educate" the masses. One of my "old sayings" is: The lessons I learned the best, were those that cost me the most.
-Larry Widmer, Endyn, via email

 

About this whole crank pulley/harmonic balancer thing, everything that Earl pulled from the Endyn site is true, but one thing about the Unorthodox pulleys that I have noticed is that there is no outer hex shape on the pulley to use the honda harmonic balancer removal tool.

Also, the torque specs for honda harmonic balancer bolts are really hih, I think its like eighty something foot pounds on the H22 and close to that for the B series motors, I don't think that honda wanted any varience in the pulsations that are absorbed by the pulley side of the motor.

The more even vibration and shock can be distributed the less long term damamge that can occur in other places as well. Have you ever noticed that honda never makes a flywheel thats feather weight light, the type-r is the lightest and it still has plenty of mass. What does honda do from the factory to change the acceceleration of the engine and transmission? Change the gearing. The reason the underdrive pulleys have become so popular is that they are cheap efficent response, granted I would never use on on my motor. I don't preach longevity of a motor as much as others, because the way I look at it is that if it blows up, run around on a stock B18A block until another is built. But my main concern with using the OEM Honda piece is for another thing that alot of people have heard Larry say before, RPM=ruins peoples motors, the more RPM the assembly turns the more stress is put on every moving part, with the amount of time inbetween the pulses (given from each combustion) steadily decreasing as the engine approaches eight thousand RPM the need for complete synchronization of the rotating assembly is needed for the most complete tuning and the least amount of variation from combustion cycle to combustion cycle, that is the ability to run a reliable engine on the street, tuning, tuning is not only a word to refer to the electrical side of the motor (being EFI) but also to refer to the synchronization of every moving part on the car.

 

Are there any threaded holes to install anything to grip the pulley?

 

yea, you need to lock the flywheel to torque them , no other way!