I checked my receipt from Vengeance racing today when the pulley was installed. It was an ASP 25% underdrive pulley. Thought I would let everyone know. Funny thing is that the guy that does my work on the car locally has installed several ASP pulleys and has never experienced a chain failure, even with the same chain that I was running. I guess that's just my hard luck.

 

I guess that the best thing for me to do is to go back to the stock pulley. This sure hurts since I was at 491RWHP and was installing electric cutouts to try to see that magical 500RWHP. I guess the 346 at 500 will elud me now. It is not important enough to sacrifice breaking parts to do it. I guess I should have tried to do it with a vehicle that has a solid rear axle versus trying to do it with this CTSV drivetrain. I probably could have done it with a different car. Oh well, it is what it is.

 

i heard the stock one is 13 lbs., summit was 11.5, powerbond/slp was like 10 and asp was slightly less then 10.

 

It is no more than a 10 RWHP loss. I can't afford to run it, when my shortblock and a fine set of heads are at risk. That amount of horsepower is just not worth it to me. If I were in racing class than 5 RWHP were to make the difference between winning and losing, it would be different.

 

SO are we just saying its just ASP or all underdrive pulleys?? I have a Summit underdrive pulley on my car that has 107XXX miles. I'm sure that I broke or jumped time on my 01 Camaro. I will have more info tomorrow when I have it all apart.

 

Is this happening to M6 cars only? How many people with auto's have had this problem?

 

With great respect to all whom posted (and there are some notable, knowledgeable posters in this thread), and no, I have ZERO affiliation with ASP (would be good to have them chime in actually), I think it may be "fuzzy logic" to suddenly condemn ASP pulleys, claiming they are the "smoking gun" to cam chain failures..

Point #1 - I would put money on this - for every 100 ASP pulley sold, 3 Powerbond's and 2 ATI's are sold. Just on sheer volume, and considering ASP is by far the most popular aftermarket pulley (or was until very recently), it makes sense that *most* motors suffering cam chain failures will occur with an ASP pulley installed because *most* cars running aftermarket cams used in a performance situation have an ASP pulley installed.

Point #2 - I am not discounting the importance of a properly designed dampener, however.. The stock dampener has an aluminum hub / center, and is around as light as one of the lightest aftermarket pullies (ASP). Yes, I understand there is much more to this than shear weight, I am sure ATI can explain the complexities in great detail, and I know they are vast. Still, just look at racing motors that basically eliminate any sort of crank-mounted dampener. Yes, race motors have parts swapped all the time, and that brings me to the next point.

Point #3 - Making the logic jump that employing race-bred parts (whether it be a timing chain, dampener, valve springs or anything else for that matter) results in a "bullet-proof" build when subjecting said parts to the same conditions experienced by a racing team (say, road race track car (like the 04 Z06 mentioned in this thread) but without the aggressive (impractical for most of us) component replacement schedule.. Think about it - I have no proof (Jason does), but do you really think the GM team manager saves a few bucks by leaving in that super expensive - heavy duty "bullet proof" TC between rebuilds (which happen in hundreds of miles, not tens of thousands)? Its apples to oranges folks.. Saying "GM racing has never had a failure with XYZ TC" is like saying "my African Elephant repellant works great; haven't seen one in my back yard yet"..

Bottom line IMHO..

When it comes to timing chain reliability / survivability, I would think the order of importance is as follows;

1. Use - driving style and type - road racing / constant wrapping up to redline / downshifting for hours at a time is certainly harder on components than 1/4 mile runs and street driving.

2. Valve springs - if they float and valve meets piston, that creates way more load than a timing chain was designed to handle.

3. TC quality - obviously of major importance.

4. TC dampener - I am kicking myself for not installing one when I did my cam swap, but to be fair I would have had to tap the block.. And now it appears GM stopped making them, so 2 strikes for me. I have a background / understanding of chain harmonics / dynamics, and I can say with some confidence that a TC dampener is a GREAT idea, hence they are on newer GM designs from the factory, and we all know they do only what is absolutely necessary ($$).

5. Crank dampener - I am sure the size, type and design does play a factor in ALL aspects of bottom end reliability, but it is my understanding an improperly designed dampener has greater impact on crank / bearing longevity than being the likely cause of TC failures.

 

Powerbond definitely heavier than stock Y-body pulley (F-body pulley may be different). The PB unit is steel throughout, not an aluminum center like an ASP. Aaron's post claims the ASP is lighter than stock, but I swear I recall the ASP being just a bit heavier, or maybe it was just a bit lighter.. Construction-wise it would make sense the ASP is a bit lighter than stock. Too many years ago. (and lots of hard miles / track days on ASP + LS2 chain - knock on wood)

 

I would also say that although you may be right about the 100:1 ASP/ATI thing...I would say that ratio is MUCH lower in racing applications.

Somebody that's going to race their car hard and competitively is not going to throw the "cheap" stuff on. I'd say the ratio may be in the single digits as far as that goes. And absolutely NO reports of a motor with a ATI balancer snapping a chain.

Just playing Devils Advocate.

 

Do yourself a favor and replace all your pushrods and springs anyways.

 

Here is an (apparent) ATI - involved failure.. I am sure it will be blamed on the underdrive percentage. Enjoy.

http://forums.corvetteforum.com/c5-t...n-pistons.html

 

I would like to see the chain. From the pictures, only the exhaust valves hit which seems strange. It is no secret that ATI doesn't recommend the 25% UD. Not absolutely blaming it, but the combination of small balancer and stock LS6 timing chain (weak) isn't a good combination.

 

Im pretty sure the ASP pulleys are 5lbs lighter than the factory one. Its on the weight reduction list.

 

i agree with dan the man, i hate to see the widespread bashing that will follow all the "i can almost guarantee you it was the pulleys fault" post. if you cant 100% prove it...

 

Can you show ANY proof that all of the failures with ASP are NOT contributeable to the damper design? I didn't think so.....

Let me guess, all coincidence...…

 

Katech's are on sale, 20% off till the end of the month. Just bought one today paid $111.95 plus shipping

 

What some people don't realize is that the ASP is not a dampener, its simply a pulley. Also, as long as you have the same spring on every valve, the timing chain will see pretty much the same load.

 

can you show any proof???i didn't think so.....my point is every thread i read from you is labeling asp for these failures, even though you say it in a round about way. and im starting to notice that others are following your advice with no proof of what you are saying is true. i never said they were or werent responsible but until you have proof dont bash what could be a completely innocent company.

 

Sorry to hear it man.. I cringe everytime I see a thread titled like yours. Thanks for sharing though.

 

Well, ATI does recommends 10% max. Now why they offer the 25% if they don't recommend it I have no ******* clue...