The key DOES NOT keep the pulley from spinning. The only job of the key is to align the parts. The job of anti-rotation is handled by either a press fit or a fastener of some sort. (sometimes they use both)

In this case guess what? You know that bolt (hex head cap screw is actually the proper nomenclature) in the front of the crank that your supposed to tighten to 220 lb-ft...yup it's his job. That's why it's so large and so tight.

 

What's there to align??? The pulley is perfectly round.
Press fit alone may not be enough to keep the pulley from spinning on the crankshaft, due to different temperature expansion coefficients of the two, or lubrication used for installation that greatly reduces friction between the pulley flange (hub) and the crankshaft.
Buellwinkle clearly indicated that ASP people did find some stress damage to the key groove - the only source of that would be torsional forces applied by the key itself.

 

Ask yourself this...

Why did they put that big ol' bolt in the front?
Why do they want it torqued to 220 lb-ft?
Why does the original design not use materials with different expansion coeffecients?
What could the purpose for these things be?


A good engineer does not rely on a key, it will fail. Ever have an old small block chevy apart? The early ones had a press fit with no bolt. Ever have any engine apart? Most are built with press fit wrist pins, it is by far the most reliable way to retain a wrist pin- old Fords used to push out thier snap rings and trash the bores all the time- .001" is enough to keep a wrist pin from going anywhere

Older engines had timing marks on the damper, the key was there to preserve this alignment. Many new EFI engines have no timing marks and use an internal trigger wheel for the ECU to know crank position so they don't need to align the damper.
But behind the damper is usually a pulley or gear to drive the camshaft(s). This would have a key of some sort for alignment purposes.

Does this damper have timing marks? that would be one reason, or they may have left it in as a backup if the bolt did come loose.

Slip fit dampers usually have a key but they always have a good size bolt stuck in the fromt of them. Press fit dampers do not always have a bolt (it's generally smaller if they do) and they do not always have a key. The new Hemi® does not have a key, it uses both a light press fit and a bolt @ 90 lb-ft. (notice much less than 220 lb-ft, this do to the press fit)

 

Well, the fact is that an all-alloy pulley turns out to be prone to slipping - as the key groove damage clearly indicates. So in this case press-fit failed. Based on different thermal expansion coefficients of aluminum and steel alone, it seems that it wasn't such a good idea to make an all-aluminum pulley in the first place, was it?

BTW, I could easily remove the stock (steel) pulley with my bare hands after the bolt was undone. So it did look like slip fit rather than press fit. Hence, 220 ft*lbs.

 

DCX, I apreciate your input here. It is almost always in agreement with mine! Unfortunately, we can't educate those that wish not to listen. Keep up the good fight, i'm with you!

 

I just want to share the experience with installing the ASP pulley, don't meant to start a fight. Just to let you guys know, I just tighten it with a rench and extension, I have no idea how many lb-ft of torque I apply to the bolt(well around 200lb-ft from experience).. lol...

 

One point forgot to mention, the Gtech runs were don't with outside temp of 5C degree (41F). I think that can explain the fast time I got.

 

Eason, what's the part number or size of the K&N cone filter that fits the coupe. I want to get one and do some dyno runs and see what gains there are. I'll try it in different locations, the easy but hot air available in front and also using your drier hose technique. I wonder if the intake temps will stay consistant because of the more effecient intercooler or will it rise if mounted in a hot spot in the engine compartment. If the gains are significant I may be able to design a bracket for it and have ASP machine it.

 

No fight, honest :p just trying to pass on correct information for those that want it. I get a lot of good info here about things I don't know about, so I try to give back on topics I do know about.

 

Just plotted a graph on the acceleration between C230K under different mod.

 

This is one of those "me too" comments that really do nothing to help finding the truth. We have certain facts on the plate in front of us - why not use your brain and knowledge for that? Shaking your credentials may intimidate some, I guess, but this is Internet - you never know who is on the other end.

 

Buell, the cone filter that I got is part number RU-1480. I think I got this part number from eason, but he may have tried something different by now.

 

Thanks, I'll check and see if I can get it locally...

 

The biggest problem with it is that there is very little to clamp it onto and the tighter you make the hose clamp, the more it wants to slide off the end. I put wire ties around it to make sure it wouldn't fall into the belts, but it fell anyway and got caught in the fan the first night.

What I would do differentely is wire tie it onto the rubber hose that sits between the filter and the engine. It will hold tighter. Hopefully that will reduce vibrations too and keep it on there longer. Or else just go ahead and find a more permanent way of attaching it.

 

Before I spend too much time with it I'll dyno it to see if it's worth the effort to make a bracket for it. I know I get 3hp from the panel filter, if I can get more from the cone it may be worth the effort.

 

I have tried both RU-3590 and RU-1480, both works fine.

I am currently using the RU-1480 while my friend with the ASP pulley is using the RU-3590.

 

i did not know u dynoed your car with the K&N filter, did u compare it to the ITG and see if that gave any HP?

 

Most automobiles that have harmonic dampeners are tightened with lots of torque, I think the reasoning is because of the vibration that is being put on them, but I am not a auto mechanic so I really don't know, my field is large German printing presses

 

The ITG beat the K&N by 1 pony but we are doing more tests.

 

More tests would be good, 1hp is well within the variance of the dyno.

 

well as long as its the same or better then the K&N i am fine with that. As long as its not making us loose HP like people originally thought.

 

so if the key doesnt have anything to do with it and only the bolt is holding it in place then go ahead and remove the key and tighten it down. I DONT THINK SO!

Also since the pulley doesnt drive anything that has to be timed, then why do they use it. you should be able to just put the pulley on the shaft and tighten it down.
RIGHT?

I guess the timing pulley on my 91 integra, the one on the crank wasnt driven by the keyway. This was the only thing driving it. this pulley turned 2 camshafts and a waterpump off the timing belt. lets see, you add up 16 valves, high lift cams, 32 springs and your telling me a keyway is not strong enough. BULL****! you couldnt even turn the cams by hand.

 

Yup, do it all the time, currently the dyno cell next to me has a supercharged engine in it with the blower driven by a damper/pulley with a light pressfit and a bolt, but no key.

A key is often used in slip fit applications (such as the Benz) but it is not relied on to transmit all the power through it. If it was, you would see a lot of failures just like the one discussed here. The key/keyslot in the iron damper/hub would beat itself to death too. (it would just take longer)

Your timing pulley was behind a hub/pulley/damper on the end of the crank now wasn't it? And the whole thing was most likely sandwiched and held on with a bolt in the end of the crank.

When we modify an engine for cam timing development work, the key/keyway/ or dowel/dowel hole are modified by machining/filing/grinding or whatever we feel like doing at the time and the result is a large clearance allowing the cam to be moved, phasing verified, and retightened in place with the bolt . So now the only thing holding the cam in place is the cam retaining bolt and they don't move unless the bolt stretches or there is a serious design flaw in the valvetrain dynamics that needs correcting.

Obviously you know absolutely nothing about valvetrain dynamics or you would know that it doesn't take much power to spin a valvetrain once it's moving as there are springs pushing on the closing ramps while others are fighting the opening ramps and these forces offset each other. (although not necessarily evenly depending on engine design)

I have built spin fixtures for and conducted valvetrain dynamic testing when I worked for McLaren Engines http://www.mclarenperformance.com/se...nes-index.html
as well as other places during my 20+ years in this business.

What have you ever done? I think nothing. Maybe you tried to read a few books once? You should have paid attention in school instead of shooting spitwads at the teacher.

 

Ouch!

 

actually I am a manufacturer certified motorcycle mechanic, I have been certified by all major manufaturers, ( yamaha, suzuki, honda, kawasaki, ducati, seadoo) so yes i have built my fair share of engines. I do know a little bit about engines. THANK YOU. now to your prior statements yes the timing gear was behind the pulley, but the pulley had no where near 220 ft lbs of torque on it, I used around 80 or so. never had a problem. as for the pulley in question, the pulley was overtorqued and it most likely was cracked, which caused it failure. is what i am saying is that if the key way has nothing to do with anything on our engines then remove yours, tighten your pulley down and see what happens. go ahead try it MR. ENGINEER.