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Cam Replacement Options? Misfire


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I have a 15 Yukon Denali (6.2) with a magnuson supercharger and about 100k miles. I have been chasing a Cylinder 5 misfire for a while now. It’s very odd because it only misfires at idle, off idle it runs perfectly. We’ve gone through all of the usual suspects: plug/wire/coil, injector, spring, pushrod, nada. So at this point the only thing left is a bad lifter and/or damaged cam lobe.... unless someone has a different suggestion??

 

So, if I really HAVE to replace the cam I’m curious what others are going with. Above all else, I don’t want to sacrifice drivability. In the LS world, doing an LS9 cam on supercharged applications gave good results and drivability. Is that a thing for the LTs? Can I just toss an LT4 cam in? I did some searching but didn’t see a lot of cam talk in this forum. Open to ideas and suggestions.

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nah stage 3 on a 6.2 is fine. Especially with a blower. You are upgrading all the lifters and valve springs anyways just don't be a cheapskate and buy eBay junk.

 

If you are too nervous for a stage three get a stage 2. I am just hear to tell you that a stage 3 would not sacrifice drivability in a larger cube engine. The rule of thumb for these "stages" is that all of them are based off of a 5.3. The stage 2 on a 5.3 is like a stage 1 on a 6.0 or larger. Stage 3 is a stage 2 and so on. 

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You'll want to get with brian tooley and brain storm to come up with a cam that's easy on the valve train. Likely a cam motion cam core. This will ultimately give you what your looking for. He will go over your current engine spec and provide you a solution. He's been in this cam design game for a couple decades

 

https://briantooleyracing.com/

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1 hour ago, shakenfake said:

nah stage 3 on a 6.2 is fine. Especially with a blower. You are upgrading all the lifters and valve springs anyways just don't be a cheapskate and buy eBay junk.

 

If you are too nervous for a stage three get a stage 2. I am just hear to tell you that a stage 3 would not sacrifice drivability in a larger cube engine. The rule of thumb for these "stages" is that all of them are based off of a 5.3. The stage 2 on a 5.3 is like a stage 1 on a 6.0 or larger. Stage 3 is a stage 2 and so on. 

is it more lift or just longer duration on those cams vs oem cam?

 

like PMoore states in his video, the LT5 makes like 750hp with the same lift as the oem  5.3 cam, so its probaly all durration for durability

Edited by pokismoki
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longer duration and more lift. stock cams are normally .500 but the low lift aftermarket normally is about .550. I'd have to take a look at the stock cam. 

 

Saying that though .550 is pretty easy on valve springs and a lot of stock springs can handle it. LS6 springs are cheap and good to use. 

Lift doesn't define durability as long as you have the valvetrain to match. :D

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after you get the cam and valvetrail installed, the two biggest issues you will wrestle with is feeding fuel and then stopping the high powered Pig.

 

I just did a trans tune and activated Power enrichment and that was getting the truck to the point of overwhelming the brakes. i really cant drive it in the city stop and go.

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Feeding fuel isn't that big of a problem with only a cam. Especially if he is already SC'd I can imagine that he has injectors plentiful enough as well as the fuel pump to go along with it. On a stock engine of his vintage it is not an issue at all, back in the NBS days yeah you probably needed some 8.1L injectors but not really anymore.

 

I suggest you change your brakes or your driving style. PE and a trans tune is not going to overwhelm them lol. I'm on a stock 1999 brake system with my cammed LQ4. The stock brakes suck ass but they aren't any worse lol

 

What do you drive?

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20 hours ago, shakenfake said:

Feeding fuel isn't that big of a problem with only a cam. Especially if he is already SC'd I can imagine that he has injectors plentiful enough as well as the fuel pump to go along with it. On a stock engine of his vintage it is not an issue at all, back in the NBS days yeah you probably needed some 8.1L injectors but not really anymore.

 

I suggest you change your brakes or your driving style. PE and a trans tune is not going to overwhelm them lol. I'm on a stock 1999 brake system with my cammed LQ4. The stock brakes suck ass but they aren't any worse lol

 

What do you drive?

2016 k2 LT 1500, the problem with our trucks brakes is they are overly front biased, truck potentially has lots of braking power if it used the rear rotors correctly

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Have you pulled the valve covers and check the valve springs.  L86 I known for breaking valve springs!!!!  I speack from experiance. 

 

 

But If you want a good cam.  I have had a TSP 5.3 stage 2 218/226 32% over in my L86 for almost 30K miles now.  The plan was to be boosted by now but.  I just haven't pulled the trigger.  To many other toys.  It runs hard for a full bolt-on NA truck.

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