L99 Cam, selecting???

[thebrainhart]

Luckily those (yes plural) weren't my engines. From their posts, the cam bolt was still super tight, well within the specs.

I'm going to a 3 bolt setup because there is literally a zero percent chance of the pin shearing, and the cost is very little.
(I am getting rid of VVT, so my cost is a little more, also doing a C5R chain, and LS7 tensioner).

There are several performance shops who will not sell a single bolt cam due to the possibility of this happening.

[Jason7]

alright alright my arm has been twisted! 3 bolt it is...!

JASON

[Bay Area SS]

Originally Posted by Jason7

Gotcha, well thanks for all the information and time Andy. I was obviously pursuaded into thinking that sticking with a single bolt would be ok, but looks like my mind is leaning towards the safer side..

JASON

yup Im thinkin the same. I think Andy knows his shit

[mlee]

Mast Motorsports has a great lineup of VVT cams too... 3600 seems way too high for what your dad needs. I have a large cam and 3200 stall is perfect...

[cam-]

I bet whoever installed that cam in those pics re-used the stock one time use torque to yield bolt and thats why it failed. Either that or it wasnt installed properly.

EVERY single new GM truck V8 has VVT now and you dont hear of these failures and its not like they dont get beat on. Heck just about every guy I know with a 6.2L truck is tuned and has shift points around 6500 and thats pushing a 5500lb tank along. Blaming the single bolt is really just plain DUMB.

How many bolts hold your damper on your engines there? How many bolts hold your rocker arms on? How many... you get the idea.

VVT is a good thing it just takes someone with know how to make it work properly.

[Andy@Livernois]

Originally Posted by cam-

I bet whoever installed that cam in those pics re-used the stock one time use torque to yield bolt and thats why it failed. Either that or it wasnt installed properly.

EVERY single new GM truck V8 has VVT now and you dont hear of these failures and its not like they dont get beat on. Heck just about every guy I know with a 6.2L truck is tuned and has shift points around 6500 and thats pushing a 5500lb tank along. Blaming the single bolt is really just plain DUMB.

How many bolts hold your damper on your engines there? How many bolts hold your rocker arms on? How many... you get the idea.

VVT is a good thing it just takes someone with know how to make it work properly.

this is totally incorrect though. remember, a balancer has press and over 200 ft lbs, however, they do fly off sometimes. corvettes were famous for this. My father in-law had a balancer come off on a bone stock c6. it happens.

not only that, we are talking about higher than stock spring pressures in addition to this. that is a big dynamic change. also, we are talking about less than .500 lift compared to over .600 lift.

You have to compare apples to apples. Like I said, tell that to ever SBF guy that has ever had a cam pin fail. Could the bolt have been reused and caused the issue? maybe, however, how do you explain the pin sheering off? that is not usually the failure you see with that type of issue. On the other hand, Why would you chance it? its not worth it. what are you saving in the long run? why defend a single bolt? again. almost zero chance of failure with a 3-bolt, but its possible with a single bolt. why go the route with the possible failure when 40-50 dollars can prevent it???

[cam-]

Originally Posted by Andy@Livernois

this is totally incorrect though. remember, a balancer has press and over 200 ft lbs, however, they do fly off sometimes. corvettes were famous for this. My father in-law had a balancer come off on a bone stock c6. it happens.

not only that, we are talking about higher than stock spring pressures in addition to this. that is a big dynamic change. also, we are talking about less than .500 lift compared to over .600 lift.

You have to compare apples to apples. Like I said, tell that to ever SBF guy that has ever had a cam pin fail. Could the bolt have been reused and caused the issue? maybe, however, how do you explain the pin sheering off? that is not usually the failure you see with that type of issue. On the other hand, Why would you chance it? its not worth it. what are you saving in the long run? why defend a single bolt? again. almost zero chance of failure with a 3-bolt, but its possible with a single bolt. why go the route with the possible failure when 40-50 dollars can prevent it???

While I will agree there are failures of all types in all things mechanical I think you missed my point. Its not that the single bolt cam is a known problem and the above pics illustrate to me what i mentioned in the previous post which is likely either using expired parts or faulty installation. The human effect. If Ford has problems with their designs thats a shame and not surprising being Ford crap but that doesnt mean GMC will have the same problems with theirs and unless you can show some proof of frequent factory GM single cam bolt failures either modified or stock? Then I think this point is moot.

As for why the pins fail? Pins dont fail... Improperly fastened bolts or improper fasteners ( as in re-used torque to yield bolts ) fail and when they do the only thing left holding the load is the pin and then surely they fail but its not as if GM cam bolt pins or flywheel pins just fail. The pin on the cam is only there to ensure alignment anyways its not meant to bear load. So apples to apples or excuses to excuses here what are we talking about? Faulty parts or faulty install? If its faulty parts then wheres the service bulletin or the facotryt recall? Last I heard there wasnt EITHER for the single bolt cams with GMC.

Now whats really the issue and all this three bolt cam swap garbage aside like it or lump it the MOST POWER that can be had out of a N/A LS3/L99 is by utilizing VVT and to do so yes you use a single bolt/valve and NO they are not prone to breaking but YES they are much more challenging to design cams for and especially TUNE.

So long story short if you or your shop inst up to the task of designing/tuning/building a VVT cam engine thats fine but please dont thrash on whats alreay a proven winner. Remember VVT might be new to Camaros in 2010 but its been around in trucks since 2007 and we've been modding them since and aside from tune issues and figuring out how it works which now we have down? There have been no such single bolt failures rampant amongst us modders.

Good luck with your three bolt static cam builds

[ADIO SS]

Originally Posted by jrhaus76

make sure its a 3 bolt cam. PERIOD.

You should have elaborated that also requires a L99 to LS3 conversion running about $5k (labor incld). Then depending on the 'spirit of the cam' he may need to shop for a torque converter.

My opinon here is unless you are going to track the car - stay with the stock torque convertor - better street manners. You can still get nice lopes...

As for VVT - can be cammed but within reason.

[siriusdish]

Hummmm, why not the 3600??? Guy I talked to @ TSP said he would go with the 3600 over the 3200. He takes it to the track a lot.

[kaler]

Originally Posted by ADIO SS

You should have elaborated that also requires a L99 to LS3 conversion running about $5k (labor incld). Then depending on the 'spirit of the cam' he may need to shop for a torque converter.

My opinon here is unless you are going to track the car - stay with the stock torque convertor - better street manners. You can still get nice lopes...

As for VVT - can be cammed but within reason.

Just curious what a VVT cam with in reason would be?

[NipTuckTaxi]

I chose the L99-LS3 Conversion with a mild cam package.
Factory torque converter.
yet to install, but assured it will drive well and be very fast without blowing the tires off.

[Andy@Livernois]

Originally Posted by cam-

So long story short if you or your shop inst up to the task of designing/tuning/building a VVT cam engine thats fine but please dont thrash on whats alreay a proven winner. Remember VVT might be new to Camaros in 2010 but its been around in trucks since 2007 and we've been modding them since and aside from tune issues and figuring out how it works which now we have down? There have been no such single bolt failures rampant amongst us modders.

Good luck with your three bolt static cam builds

Our shop is different than almost every shop out there. We have been in the OEM industry for over 65 years. We dont look at VVT as an evil thing, we look at it as a system with trade offs, one of which is in its current form, it shouldn't be used with larger cams and higher spring pressures. I will say that, Yes, two IDENTICAL camshaft profiles, one with VVT and one without, the VVT will make more power. However, when you run VVT you limit how good of a spring you can run, which limits you on cam lobe design, which limits you on choice, which... you get the idea. As of today, we would never recommend one to a customer because we look at long term durability. not just a handful of cars that have been good for 5 or 10k miles. I would argue that the reason you don't see failures in VVT cam pins is because it's not a solid, mechanical link, it is Dampened by a spring, and oil. Because of this, and the fact that you aren't running valve springs with over 400# open pressure, is why you aren't seeing pins fail.

We have made these types of arguments on vehicle systems before. I remember when the G8 came out and other shops called us fools for not embracing DOD technology with cams. Then guess what? people had stock lifters with stock cams start failing, they started seeing excessive cam bearing wear, and the people with aftermarket cams had it worse. VVT has many of the same drawbacks. Like I have posted on this board at least a dozen times. YES you can make more power with VVT, however, but we would gladly trade 5-10 hp to ensure the durability of our customer's engine. Please answer me this, if it's such a good system, why does every cam manufacturer, and most tuners that utilize it suggest limiters with the phaser just like they do with a Ford VVT system? If it's so good you should be able to ensure proper PTV without such silly things as a phaser limiter. Also, let me know in 50k miles how well that oil pressure dependent system hold up as bearing clearance starts to free up and pressure drops. Trust me, these things fail in stock applications. We have access to engineering data most people wouldn't. We know the design limitations, we know the proven and documented failure points.

Also, a single dowel pin with a single bolt does not matter how tight you make the bolt. That bolt is there to keep the sprocket on, the dowel is there to take the rotational load, the way you make it seem is that the bolt is there to keep it from moving. The only exception would be if the sprocket were pressfit onto the camshaft, but even then the dowel would be the piece that helps ensure the pressfit did its job, just like a crank keyway does. By your logic this should also mean that there is never a need to double key a crankshaft either. You can't seriously believe that my example isn't valid because it's a ford cam, and that's the problem, right? I used that example because it's been a battle for them for over 50 years.

Bottom line, increased load equals increased stress equals increased chance of a single load point failing. Our choice has nothing to do with the fear of technology. We work on technology and platforms that aren't even out in the market place yet. Because of this we know which systems to embrace, which ones that can be improved upon, and which ones to flat out get rid of.

[Unobtainium]

This is a great discussion. Thanks to the Livernois folks who tell it like it is.
It's so strange how in the V8 applications its a boon, and yet in the 4cyl world, its a leap forward. It's a real bear to tune on my Acura, but is so worth it. Seems like there is more work needed on the V8's to make it worthwhile.
I saw how it can make a difference on my car, as even with the 26hp less, and through an auto tranny, it made the same or better low-midrange as a manual car with the same mod.That is about 30whp or so.
The failures that have happened on the Camaro do raise doubts for me.
The AFM has to go, as it seems to make no real mileage difference for me.
If I put it in Manual and paddle it for a whole trip, or put it in D, still gets the same km's from a tank.
I really wanted to buy TSP's L99 stg 3 stuff for now, but I would have to change it later if I wanted to get more serious.
Lots to think about.