The UD pulley did not break your chain. Get it balanced if you think its an issue. A vibration from an out of balance pulley pales in comparison to the added tug from the 100hp you added. The exact same pulley you have has been on countless builds without issue. Your builder chose a stock chain for the build and that was what caused your issue.

 

Hmm does anyone know why they switched from the 3 bolt set up in '05-'06 to a 1 bolt set up in '07 and then back again for '08+? I know nothing about nothing but is this at all related? What year/set ups are the breakages?

 

That may be so, but people are using the stock chains on stroker applications(although new stock chains) and so forth and making much more power/tq than me. I think there is more to it than just saying it was just my chain. I feel it was a combination of things and I am not risking it on the next go around.

Hell, these damn LS7's are kicking the crap out of everything with bolt on's and cam's and I have yet to heard of a timing chain failure. Their damper setup will definitely be used in the new setup if it will work.

 

It's not the vibration from an imbalanced underdrive pulley. It's the natural frequency of the spring/mass system. If the natural frequency of spring mass system (rotating group) coincides with an operating range of the engine all heck can break loose. If the natural frequency and the driving frequency are the same then the normal oscillations become uncontrolled. The rotating group is made of steel and thus does not have a lot of dampening. If you twist it and let go of it it will oscillate back and forth at its natural frequency. Changing any part of either the mass or the spring rate will change this natural frequency.

 

Statistics arent made from non-failures, they are failures counted up and those stock chain strokers can have an issue in the future. The one main constant in the builds is that they all had after market cams....why not delete that part? ARE THOSE STROKERS RUNNING AN UD PULLEY??? Please let me have a link to threads showing the build stats because I doubt they dont have an UD pulley. Another factor, just becuase some guy runs around with a motor with insufficient P/V clearance because he didt want to fly-cut doenst mean its ok becuase he didnt have a failure yet.

I'm of course being sarchastic and trying to get you to see that you have so many variables. I had your same pulley, heads, cam, and mine didnt break with the stock chain so why doesnt my set up with the UD pulley let you know the combo works? Because you are counting failures. I now run the IWIS chain (katech) in all my builds.

You had a bad chain and bashing the UD pulley when they are on countless motors without issue makes no sense. They are used all the time with big power builds and the key words are big power. the chain is tugged at harder with more power. The stock chain is for stock power. If you think the stock chain doesnt break with the stock dampner and stock power you better talk to a few GM repair shops. The stock chain isnt that good even on stock engines.

The correlation here is that stock dampners are present with stock chains and stock power. You are latching onto something to feel better about the likely cuase of your failure and it isnt the UD pulley as proven by countless cars running them with no issue. The stock chain is your issue.

The chain and its damper inside has changed on the LS2 and LS3 and there was no such issue in the LS1 and 6. Same crank and UD pulleys on the LS6's and no issues. Now you have a break and you think its the UD pulley when the chain changed. There are very few stock pulley modded engines running around to show the results from no UD pulley. I suppose we need a stock pulley car to have a chain failure to prove this one and the GM dealerships have them now so go ask.

Also: lets keep in mind thast the vast majority of breaks are never reported due to tuner love. No one admits these things when the tuner promises to help you out. The home wrencher doesnt want to admit he had a failure for fear of embarrassment.

 

Just a thought, the ATI superdamper is a better alternative for exactly this type of crank harmonic suppression. It would be foolish to think that such a damper which is clearly superior to the UD pulleys we have been using and even the stock pulley (probably the worst balanced of all pullies) would be able to save a weak stock chain from failing with higher power levels.

More power requires a stronger chain.

I dont see how a poorly balanced stock balancer is better for a stock chain. I would pay the 50 bucks to spin both of them and see which is better balanced. If someone thinks the stock is better balanced I have to disagree.

 

The LS2 was/is a common upgrade for the LS1/6 guys. There are a lot of high horsepower LS1/6 engines out there with "our" stock chain. Why isn't it seen as a big issue with them?

Does anyone know why the change in '07 and then back again in '08?

 

First off, I am not bashing the ASP UD pulley. It works for many many setups perfectly fine. However, there is theory out there about aftermarket UD pulleys and a roll they may play in these kind of failures. Can it be proven? No. Is there enough smoke for me to say "why even run the .01% more risk an UD pulley may add to me breaking a chain again"? You bet.

A new chain will be going into the new setup. It will either be the Katech piece or this one http://www.lingenfelter.com/store/cly9-3153al.html

 

Besides the chain, what else are you doing different this time around? Is your motor having to be rebuilt? Is Vengeance taking any responsibility for re-installing your stock chain?

 

^ Honestly, I don't see this as Vengeance's fault. My stock setup had 7k miles on it when we did the cam. Who would have thought to replace the timing chain with those few of miles? It never even crossed mine or their mind's.

I am not too sure as of yet. I am going to find the best balancer I can, an LS7 style chain guide, and the best damn chain money can buy. Not sure what else will change as I am unsure of the damage done.

 

We are not talking balance, we are talking damping. I truly feel that the stock balancer was engineered with the correct elastomerically mounted mass for damping a stock assembly. I don't think an ASP has the correct mass. Can the ASP work without destroying an engine? certainly. Would I put it on my motor so that I could have 25% reduction as opposed to the safe 10% reduction that an ATI would give? No. What is the difference in HP between 25% and 10% maybe 3 or 4.

 

So with all that's been said here, what chain and gear set is the best aftermarket one available for the LS3 motor? Double roller or not?

 

1- Its the same crank on the LS2 and Ls3 as is seen on the LS1/6 which has not got these rash of breaks. The system/model you speak of is no different in the two engines so there is obviously something different in the current situation and doesnt support your position.

2-Strokers use a variety of different cranks from different manufacturers so this frequency you speak of is not a constant. The total runs a wide range and the UD pullies arent making or breaking the bank here since there are engines running them without issue all the time. The engines failing arent using a C5r chain since according to Katech, there hasnt been a failure yet with that chain even when used with UD pullies.

 

Using an UD pulley there has been no failures when coupled with the IWIS chain according to Katech.

There is no smoke indicating why your chain broke other than it was a stock chain which in engine building 101, is a bad idea.

Lastly, the theory you speak of is not a theory, its a correlation based on non-sense. "The engine had an UD pulley so thats why the chain broke." The C5 and its massive use of the UD pullies have long ago proved they run without issue. Same crank, same pulley, different chains. The difference is the chain.

C5R chains dont break, stock ones do in modded applications. Power breaks chains.

 

There has been no reported issue with timing chains on the LS1 and LS6 which use the exact same crank and UD pullies for the last 10 years.

 

FWIW, this gentleman broke a stock chain and then a C5R chain no less than 3k miles later on his Lingenfelter 402 with them performing all of the work, including the engine build.

http://forums.corvetteforum.com/c6-t...ter-403-a.html

I still think there is more to this than just chain strength. This gentleman was a bigtime road racer. He said he never had this issue with his Lingenfelther 383 in his old C5.

 

Now this is a good question to shed some light on the real issue. Double rollers are better and the C5R chains are better. Prestretched chains that are made with stronger materials are avaialable but there are issues.

The double rollers dont fit right. If you mount one you will see they dont fit the way they do in a LS6. The chain sits further back because it wont clear the timing sensor in the cover. This puts the center of mass of the double roller gear off center to make it fit.

The alternative of using a stronger single is still available. The difference between single and double rollers is also in question. I have noted that the vast majority of all chain breaks is not at the link, its at the pin. Having 3 links is therefore not an advantage if the pin is where is going to break. The pin on a double roller is longer but not thicker so if it breaks at the flatened edge it does nothing to have a longer pin holding 3 links together.

The LS6 uses a double roller that is centered with its moment of inertia. The double roller of the LS2+ doenst fit right. The LS7 cant use a double roller.

 

And that means the UD pulley broke the chain? Did the 383 have an UD pulley (yes)? If it did then your data point just went south. Or did we just jump from 'UD pulley breaks chains' to the 'C5R chain breaks too'? You just supplied two situations with a UD pulley and one never broke but we look at the one that did. This has been my point for a long time when tuners say that hollow stem valves dont break in normal use , yet there has never been (never) a head breaking off of a stainless one peice valve. When I posted there was a significant event to watch I was attacked becuase it shut down sales of cam only installs. Everyone running the hollow stems loves them and attacked me and the guys with the failures was like you: its very significant. To them it was significant becuase they were the holder of the hot potato. My position remained that you never have a failure with a stainless one piece valve so use them exclusively and not have to worry if the spring went out of spec as it got older. I dont knwo what your position will yield. No UD pulley and a C5R chain results in what 9rwhp less and a chain less likely to break....sounds safer.

I have been at Ramp Chevy and my friend Brad pointed out that he has had 100% stock LS2 engines break a chain and thats with the stock balancer.

All moving parts have a failure rate....all parts, all manufacturers, no exceptions. Statistics are to show the significance of how often an event happens. I'd say that the one in a million break isnt statistically significant and Katech was the source of the info about the reliability of the C5R chain.

I am not arguing some chains dont have failures, they do. I'm just saying the UD pulley has nothing to do with it because the same pulley and same crank has countless sucessful installs with no chain failures shows the correlation to be false. UD pullies dont break chains becuase they didnt on the LS1 and LS6 to any great degree when coupled with a good chain. The chain is the variable and the C5 double rollers dont fit this motor.

In the end dont mod if you cant handle a failure (not directed at you or your reaction to your failure) because all engines and parts will fail.....all of them. Its a question of use and age.

I want you want to use a stock balancer and I would like the next 5000 engines to use them so we can get a statiscially significant data point to prove the chains will still break. Power breaks chanis and the power levels of the Ls2 and LS3 are far higher than the LS1 and LS6.

 

Spin, you aren't understanding me man. I am not saying the UDP is what broke the timing chain. I am saying a combination of things broke it and the UDP may have had a hand in it. I just got off the phone with Katech and the gentleman agreed that my UDP could have contributed to some funky harmonics. The fact that my chain broke at 3500rpm points to 3 positions:

1. I had a weak chain
2. I had a bad harmonic at that rpm that finally did my chain in
3. 1 + 2.


I think we can all agree that I wasn't floating the valves at that rpm. My rev limiter for the first 5k miles of cam'ed use was at 6600rpm. It wasn't until the last 3k miles that I bumped it to 6800rpm. As I said before, my valvesprings will be tested for open and seat pressures, but I "expect" them to check out ok. If they don't, then that would be a huge relief as I would have something definite to lean towards.

I understand what you are saying, but I think you are taking what I have typed the wrong way and are running with it. I feel an ATI UDP will probably find its way onto my car after speaking with Katech and the test regime they went through to approve it for use on their cars.

 

See this is the problem. These failures are too scarce and with too many variables to determin exactly what the cause is. I don't believe it is purely an issue of chain strength. Like I posted, LS1/6 guys have used the LS2 chain as an upgrade. There are also countless other cars making big power with the stock chain. Do cam specs have anything to do with it? Do we know exactly what valvetrain upgrades were done on these failures? There has to be a constant about all these failures other than just using the stock chain.