This must be the yearly " My car is gonna esplode with the lightweight pulley " thread. Check back as this is an annual event and has been going on for over 4 years now. You would think with what has to be millions of miles driven there could be ONE instance where damage to a motor was directly related to a lightweight pulley. There have been far more cars sidelined with bad heads and there is never a cry to arms over that.

Here is my post from Feb of last year . I think I will just cut and past it annually

This is good news actually . This thread is just about 2 years old now and there have been no issues reported which have been directly attributed to the lightened crank pulleys. I know of one engine failure but the car was run up to 8400 rpm and the oil pump gear gave way. We thought it MAY have been an issue but it was never fully proven. With thousands in use and hundreds of thousands of miles driven it would be safe to assume that the lightened pulley is a fairly safe bet


Here is the thread that was started back in early 06

https://www.northamericanmotoring.co...ey-survey.html

Randy
M7 Tuning

 

LOL

 

thanks for the link. an even better read!
i'd say it's worth bumping threads like these anually since newbs like me are getting sucked deeper and deeper into the world of mini modding.

it's addictive, especially since the car is so damn fun to drive!

 

oh man - wait a minute - someone said something about an engine - these cars have engines. i'm still trying to figure out where the blinker fluid goes....

sorry that i created (or re-created a beast) - however, it's interesting that a topic like this drums up so much controversy and still really never leaves a good clear answer (unless you're an automotive engineer!!!)

 

I am only posting what I found when I swapped the stock crank pulley for a lightened +2% aftermarket pulley on my JCW MCS.
I got a 5.6kW gain, I then changed the JCW S/C pulley to a 16% and got 3.5kW gain.
Take it how you like...
As for you calculations I believe your math is flawed as you are simplifiying it and not taking into account the lightened rotational mass... reducing from 7lbs and a diameter of 140mm compared to 1lb is going to do something.

 

I always get a kick out of people who don't build engines talking like they know something. We get engines in all the time and when they have had oil pump FAILURES........everyone of them had an aftermarket crank pulley on them.......................................

Coincidence?

 

Everyone can debate whether the Trirec engine needs a dampener or not, my opinion is pointless. But from my experience, some of the data here could be a bit misleading in making a decision. To my knowledge, a damper is used to dampen crankshaft harmonics, not NVH, etc. Some cranks will snap quite quickly without one, or when the installed unit fails. This also implies that each an every engine and crankshaft design will have different harmonics and different needs. It's entirely possible if the crank is not being dampened properly, this vibration would make it through to the oil pump drive and cause failures. Once you change the harmonics of the engine, anything is quite possible and all bets are off.

I've never heard of the dampener being installed to address the accessory drive or to stop transmission of NVH in the car.
Anyone here a ASE certified mechanic? Remember the questions about dampeners and crankshafts?

 

Mileage of the car, how the car was maintained, how often the oil was serviced, what oil was used, if they had stiffer engine mounts, whether or not it was getting the **** beat out of it on the track daily etc. all can contribute to the failure of an oil pump.

An unmodified motor will have the oil pump fail in time with perfectly flawless maintenance and granny driving the car.

Coincidence? I don't know, nobody has shown a damaged oil pump and demonstrated how it was lack of damping of the crank harmonics that killed it.

If I buy a Jesus head get an RMW tune and beat the **** out of my car, use garbage oil, change it every 10,000 miles and it destroys the oil pump with the stock damped crank pulley will it be coincidence? Give us a break Jan go polish some heads and stop searching for posts by Randy just to start ish.

 

I doubt your oil pump will fail in that scenario but you sure are likely to spin some rod bearings. Oil pumps fail all the time, it's HOW they are failing. Having the inner gear split into 6 distinct pieces is NOT NORMAL FAILURE..... but coat it how you like I could care less I guess it just means more engines for me to rebuild

 

D-MAN: Adding 8HP would be more than 4% of the total power output of the MINI engine, and that's just not happening. I'd be more willing to believe the figure you quote if you had then quickly replaced the stock crank pulley and measured again to validate the numbers, but no-one ever does that.

I know I oversimplified and I didn't mention the rotating mass, but if you got 2HP from the extra boost from a +2% crank pulley, that would leave 6HP from the reduction of rotating mass.

It does not take 6HP to spin up a ~5lb-heavier pulley that's less than 5" in diameter. My table saw with a 1/4HP-rated motor can spin a router blade of roughly the same size and weight up to 3600rpm in a couple of seconds. Yeah I know it's electric and has torque out of proportion to a MINI engine, but it's not too flawed a comparison to get a sense of the magnitude of power required.

I'm not about to spend the time calculating how much power it takes to accelerate a small 5.5lb. pulley, but one could set the pulley on an inclined ramp, measure how fast it rolls down a fixed length, and calculate the required power to accelerate it from there. Basic high-school physics, but no-one has mentioned performing the experiment to get some real numbers.

If you measure 8HP from the crank pulley, try a lightened flywheel - that might measure 50HP.

And yeah, I know I should be out driving instead of bickering about this nonsense, but there's ice on the roads here - so it must be time for the annual bickering match...

 

Uhhh, yeah, I think we all know what this topic consists of. It's been pretty much on topic except for a few head butts between some people in here. I think the fact is, until someone from BMW or the ****** Tritec Engine plant personnel themselves comes in here and explains things, we'll never know. Everybody is guilty of speculating, but there has been no conclusive data to support whether this is a good idea or not. We all know the Tritec engines are internally balanced, so the harmonics are going to be a problem, if at all. Not all manufacturers put harmonic balancers on their engines. It would seem BMW added this on for safety measures.

 

It actually does not have much to do with being internally balanced. It's all harmonics. This is dictated by: length and design of the crank which results in a certain "springiness" of the crank. Rod to stoke ratio, firing order(not a big deal on 4 cylinder engines) etc. Everything about how the engine and crank is designed contributes to these harmonics. Most of the time an engine is designed around many constraints that are more important than whether it can run without a dampener or not. Then the engineers go and figure out what design of dampener is required to make the engine/crankshaft live.

 

Are there any aftermarket oil pumps that don’t have this issue? I’m sticking with the 05-06 stock cs pulley, but I did throw a bearing on my car shortly after I bought it, fresh flushes/fluids and all. Keep in mind it had over 80K on it and I have no clue how the person before me drove it. Hopefully better than I do, hah! So after seeing the mess that got sucked into the pickup for the oil pump, I want to replace my oil pump now too. Is my only option to go new oem? I did a search and did not find much on oil pump discussions.

 

yes OEM is your only solution short of a full dry sump system

the oil pump gears are the problem and they are a problem on the SRT motors as well. Being made from powdered metal isn't the answer. I have looked into billet gears but how many people are interested in doubling the price of the pump for safety? Mini owners are notoriously cheap when it comes to safety but will spend ridiculous amounts of money on bling

 

Thanks for clarifying that Jan. I knew if I poked you you'd spill some details I will now apologize for my initial post towards you being a bit snippy. (but it worked)

Now the big question is at what frequency? What is the rpm or rpm range that does the most damage if there is one? Do lower rpm seeing city driven daily drivers die sooner than high revving race cars? Vice Versa? On the ones you have seen Jan I am going to go out on a limb and say the drivers were pushing their cars hard solely based on the fact people usually come to you for more power.

Also if the vibration is enough to kill the oil pump I would think there would be some damage to the bearing(s) closest to the oil pump as well no? Has that been evident? I haven't heard anyone say there was. I just find it suspect that a crankshaft would flex at the oil pump and nowhere else.

Just looking for as much concrete info as possible. I (and others) don't usually believe something simply because so and so says so. I'm in the high performance motorcycle parts business and have seen bad product. I can say all day a part sucks and some will believe me but if I can say and demonstrate why a part sucks then I've earned a customer.

Jan if you sold a billet oil pump people would buy it.

Does anyone know if a PT Cruiser uses a damped crank pulley?

 

jan that was way harsh man ouch

 

Some of the reasons why I don't always come out and give the pertinent info on the web is our competitors try to gain knowledge of what works and why without having to spend the money to find out themselves.

Those that came in with broken oil pump gears (had aftermarket crank pullies) and were cars that also had over 220whp and regularly saw 7k rpms

Hard to tell how the mains/rods were wearing as when the pump goes it totally wipes out the bearings before they can shut it off. It's catastrophic.


I have found some interesting info on the mains but don't care to share it here.

If we can find 10-20 people who would want billet oil pump gears made I will be glad to start the project

 

I've spoken directly with the chief engineer of the Tritec project. This person held full responsibility for all technical development. No I won't give you his name, nor is it possible to offer a sworn statement from him, as that would violate his job contract. We've spoken both on the phone and in person over a cup of coffee. This is 1st hand conversation, not fourth-hand hearsay as you would prefer.

Listen to yourself. You're offering articles relating specifically to the E36 M50 and S50 engine, yet you are disregarding facts about similar engine configurations to the engine in question.

Again, you fail to look at the whole picture. BMW has drivability requirements that dictate a certain level of NVH. The various crank pulleys they've put on the Tritec fit within their NVH parameters. It's within their planned budget to create a certain level of NVH. The aftermarket billet aluminum pulleys are most likely more expensive to manufacture than simple stamped steel plates with cheap rubber poured between them. BMW only needs the engine to last for the warranty period. After that, it's in their best interest to have it self-destruct to extract maximum repair costs. Obviously there's a fine line between repair bill engineering and angering customers, but as Mercedes-Benz learned back in the 80's, there's no reason to engineer the car to last forever, or you won't have any business either in the showroom or service department. All car companies are in business to make money first and foremost.

Ok you're starting to understand, but you contradict yourself with the next paragraph:

Hardly. Dinan re-uses BMW OEM pieces to create boutique products that fail to push any envelope. This is why Dinan has an agreement with BMW dealerships to maintain the factory warranty; because there's essentially no change. Your flippant comment pedestaling Dinan using "actual engineers" is speculation on your part, both that Dinan hires professionals, and not a single other aftermarket competitor has any engineers whatsoever. Your bias is amusing.

Ahh, now we're getting somewhere. Jan claims there is a causation through correlation between oil pump failures and aftermarket crank pulleys. Now, logically speaking, this is invalid. If Jan has some data that shows that an engine with only an aftermarket crank pulley, and nothing else aftermarket, then there is a possible direct correlation. The coincidence may have a causation, but I would bet the engines that Jan has seen with failed oil pumps have a vast array of other high-performance parts.

The Tritec engineers did longevity testing with solid crank pulleys, lightweight crankshafts, high flow cylinder heads, and greater supercharger overdrive, and found they did not detrimentally impact longevity for minimum engine life [at the time considered to be 100k miles of effective testing]. At no time during their testing did they do durability testing at RPMs higher than 7250, if I recall correctly. Considering that most of Jan's customers run RPM higher than that, he may have inadvertandly found a weak link in the oil pump design. As such, his idea for a billet oil pump may be good business practice for high-load engine setups [like racers].

Cheers,
Ryan

 

Thanks for that information Jan. I would put money on the oil pump failures are due to high RPM and high power rather than lighter rotating assemblies. At high RPM the firing pulses are so close in time domain they are not only nowhere near the crank resonance but if there were a damper it cannot respond quick enough to damp effectively.

 

Like I said before ONLY the ones with crank pullies failed. (all broke exactly the same way) I have run ONLY stock crank pullies after seeing them fail. I haven't had these issues and neither has Hubie and we both are running more hp and RPM than anyone else out there without the oil pump failures.

There is more info out there but this isn't the place to talk about it

 

Unfortunately you still only have correlation, not causation. You might be onto something, but most likely neither of us are willing to do the massive testing required to make any solid conclusions beyond what Chrysler told me off-the-record with their durability testing. How about lightweight flywheels, or different camshafts, or even oil starvation? You may have been the unlucky recipient of a bad batch of oil pump assemblies, or the failure mode may have been something beyond what the owners care to admit [missed shift/massive overrev?] I can only assure you that OEM durability testing is far beyond what anyone in the aftermarket has the capacity or budget to undertake.

If I were in your shoes I'd simply restate your position as "I don't recommend billet crank pulleys as their may be a correlation between them and failing oil pumps".

 

until I see an oil pump break like these have with a stock crank pulley I stand 100% behind what I said

 

Please, show me some proof that the resonance created by the engine will destroy the crank or cause the oil pump to fail at that. Oh, and since BMW was NOT the engineer of this engine, this dampner they put on was more than likely cheap insurance for them. Maybe on the R56 since they were involved with the development of that engine. To them it was pretty much "Put on zee dampner Heinreich just for insurance measures." I highly doubt BMW tested this car through rigorous tests to find out that the engine needed a harmonic balancer.

 

Fair enough.

--->big howe & Fatherdeth: Inline-6's and cross-plane crank V-8's are notorious for having massive crankshaft flexing. Those two configurations pretty much laid the groundwork for people assuming all engines require a big damper. A co-worker of mine races circle track, which uses small-block Chevy engines. They learned the hard way that cross-plane crank V-8's need dampers to survive. They experiemented with solid lightweight pulleys and broke bottom end bits several times before finding correlation. Going to a damper [actually it didn't matter if it was a damper, spring-loaded, or just mass, as long as it was heavier than what they had] eliminated their breakage. They ended up using a heavy solid pulley and the engine survived longer than any previous builds. This only proves the case of the cross-plane crank V-8, which is inherently a very weak crankshaft design with big flexing even with 4340 forged cranks. There are two points here: engine configuration mandates minimum rotational inertia, and perceived NVH does not equate to reliability.

 

If a billet oil pump would allow for a lighter/reduction crank pulley it would be a snap for you to
a) find 10 customers
b) bump the final output of the sc only rmw cars with a reduction crank pulley. even if it is only a slight bump.

anybody want to make a 2% reduction damped crank pulley?
I'll offer my car as a mule.