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Howdy folks! I'm a total n00b here, but I've got lots of experience building motocross four strokes and as a motorcycle mechanic. I know just enough about the LS family to get me in trouble.
I've got a 2006 GMC Savana 3500 with 315k miles on a 4.8 and I use it mostly to haul bikes. It's the perfect size vehicle for the job. But, I think it's time for some fixing. On startup, it makes about 20psi (indicated at the gauge on the dash) oil pressure, and sometimes it drops down to about 5 when you open the throttle. Once it warms up it idles between 20 and 30 psi, cruising on the highway it sits at 40 and I've seen as high as 65 psi at redline. From what I can tell, the issue(s) could be: bad/clogged lifters, split oil pickup O-ring, or I guess maybe a bad oil pump.
It also has made an ungodly metallic knocking sound on a few occasions, which I assume was a collapsed lifter, because it just went away, then drove and made power exactly as it had before.
It also has a p0304/p0306/p0300 code that I haven't been able to solve, but I have a hunch that its collapsing lifters ******* up the air flow. IDK, it's a guess.
I really am not 100% sure what's going on with the 4.8 and am hoping for some input here.
Tell me if I'm completely insane, but this is my loose plan: buy a jy/eBay 6.0, reseal it, swap it into the van, put the 4.8 on a stand, tear it down and inspect, reassemble with a new cam/lifters/pushrods/rockers/valve springs, whatever else is broken, get another trans, then swap that into my Volvo 245.
Should I trust a used 6.0 enough to run it as-is? Are there some basic mods/updates I should perform before installing? Is there a cam that would make a little more power but not destroy my fuel economy while hauling (at 80mph with the 4.8 its laughably bad; I'm WFO half the time on the highway, so I feel like a more aggressive cam might actually help my mpg)? And what would I need to tune things so the 6.0 runs right?
We have complete rebuild kits for both engines that work with stock bore or oversized for same price.
$679 each right now for Black Friday/Cyber Monday.
They include literally everything except cam, lifters, springs and pushrods.
Every bolt, seal, gasket, pistons, rings, oil pump and timing set plus LS Rebuild Manual included.
Great option for both your setups PLUS you can get flat top pistons and drop them in your 6.0 and raise the cr and have a fresh engine all around for another 300k miles!!
Thanks for that incredibly useful reply. I uh, specifically need all the **** your kit doesn't come with. [Edit: sorry for my tone, but jeez, first post on a new forum and the first reply is an ad that answers none of my questions. I mean, sure, $680 sounds like a great deal for a rebuild kit. I just don't know what parts I need, and this thread is about determining that.] [Edit 2: actually, $680 doesn't sound like a good deal when I've got no idea what components are in the kit and this one is $550 on eBay
Last edited by KCS; Nov 23, 2018 at 10:05 PM.
Reason: Non Sponsor Link Removed
Sigh... I get it, you've got a business to run and you're trying to make a buck. But man, this is my first thread on here, and you're just trying to hard-sell me on a ton of parts I probably don't need, without even specs or a link what you're talking about. I'm here to learn and make my plan, not because I can't figure out who sells parts. Coming from motorcycle racing, I'm also not the kind of person who's gonna rush off to buy some cheap pistons. I tend to look at the part manufacturer, the actual part specs, and similar parts before buying. There is already an enormous banner ad for your store at the top of the screen, so if you wanna come at me hard, at least bring the knowledge.
Anyway, the purpose of this thread is trying to figure out WHICH PARTS to buy and why. Also would be cool to have some idea of what is wrong with my 4.8, aside from a "bad lifters" hunch. I know, I'll see once I tear it down, but I'd guess other people have experienced this before.
If you have a specific parts recommendation, please, offer it up. Paste a link, I'll click it and read. I wish I could just blast this project with dollars, but that's not how it is. I'm trying to avoid replacing stuff unnecessarily here, and selecting parts that will work well for my specific applications.
Specifically:
A 6.0 cam package thats great for towing/hauling and includes lifters/pushrods/rockers/springs that work well with that cam, what kind of power I could expect, and what I should do to tune it. I don't really want to buy a JY motor and then shred it down to nothing to put pistons in it. In my experience, (with mostly four-stroke mx bikes) you either have to get lucky with clearance dropping a new piston into an old bore, or you have to actually measure the bores, and order the appropriately sized piston and ring packages.
A well-reasoned plan for my 4.8. If there is a really good reason to do pistons and bottom end bearings, I'd like to know what it is. If I can get away with stock parts that are still in spec, I'm most likely going to. I for-sure want to replace the cam/pushrods/lifters/rockers/springs on this one too. I'm also curious about the truck vs car intake manifolds (which one makes better power, will the car manifold fit on the truck heads) and possibly even getting a set of heads for it if that looks to be a good bang-for-buck buy.
You said you wanted a refresh. Everyones idea is different but we offer everything there from just gaskets and bolts to rering kits to full kits.
You said you wanted to reseal etc but then say you need everything that kit doesnt have?
Im not only laying out what we have but also the best way to be reliable and build power. You asked if you should trust a JY engine. I dont. Both personally and professionally. That is literally why we started offering these kits because i do it so often i wanted to make it available for everyone else and be able to customize it for their build. I use all of these parts myself so i know what they are and what they do and their quality.
You will get alot saying go forged etc etc and spend way more than you need to. Then you will have some say "i use jy engines all the time they are super reliable" which is right in their opinion but not likely what they experience. The lifters will nearly always make noise, they will nearly always burn oil or smoke or have odd noises or pcv issues.
It seemed like you had a budget for both of those and we are offerinf deals for black friday only that i thought i would bring up to not only save you some money, but also get everything you need from one place that doesn JUST sell parts but uses them nearly daily.
If i were doing a hard sell i would tell you to go forged. Instead i told you what to upgrade for the same price to make more power and be reliable easily.
I would look at getting a used motor, pull the old one, and put the new one in, and done.
The codes could be leaky valves, or valves not seating completely from being carboned up.
What trans do you?
Welcome to LS1Tech Sean. You’ve told us all that you’re a noob with the LS platform, yet your arguing what you think you need to rebuild your 4.8 or possibly a 6 liter, and it’s painfully obvious you don’t, with an extremely knowledgeable tech from a group of guys that go out of their way to help all of us. These guys will save you money. Arguments are welcome here, but please lose the attitude. If I were you I’d do a ton of research for what your trying to do, and then come back in and see what’s available.
Howdy folks! I'm a total n00b here, but I've got lots of experience building motocross four strokes and as a motorcycle mechanic. I know just enough about the LS family to get me in trouble.
I've got a 2006 GMC Savana 3500 with 315k miles on a 4.8 and I use it mostly to haul bikes. It's the perfect size vehicle for the job. But, I think it's time for some fixing. On startup, it makes about 20psi (indicated at the gauge on the dash) oil pressure, and sometimes it drops down to about 5 when you open the throttle. Once it warms up it idles between 20 and 30 psi, cruising on the highway it sits at 40 and I've seen as high as 65 psi at redline. From what I can tell, the issue(s) could be: bad/clogged lifters, split oil pickup O-ring, or I guess maybe a bad oil pump.
It also has made an ungodly metallic knocking sound on a few occasions, which I assume was a collapsed lifter, because it just went away, then drove and made power exactly as it had before.
It also has a p0304/p0306/p0300 code that I haven't been able to solve, but I have a hunch that its collapsing lifters ******* up the air flow. IDK, it's a guess.
I really am not 100% sure what's going on with the 4.8 and am hoping for some input here.
Tell me if I'm completely insane, but this is my loose plan: buy a jy/eBay 6.0, reseal it, swap it into the van, put the 4.8 on a stand, tear it down and inspect, reassemble with a new cam/lifters/pushrods/rockers/valve springs, whatever else is broken, get another trans, then swap that into my Volvo 245.
Should I trust a used 6.0 enough to run it as-is? Are there some basic mods/updates I should perform before installing? Is there a cam that would make a little more power but not destroy my fuel economy while hauling (at 80mph with the 4.8 its laughably bad; I'm WFO half the time on the highway, so I feel like a more aggressive cam might actually help my mpg)? And what would I need to tune things so the 6.0 runs right?
Dude,
Just get the 6.0, and put in a Truck-Cam, rings and bearings. The Power is better, and they are perfect in a big van.
I bought a 100k mi. JY 5.3, glad i rebuilt (refreshed) it after i tore it down, i would not want to have hopped it up and ran it. I rebuilt it with the WS6 kit, it comes with everything, the book, invaluable, the barbell, don't forget it. I added a TSP 212/218 cam from WS6, etc etc. If you do the 4.8 as is, your using over $1k worth of cam and valvetrain on 300k mi. on everything else, good luck. Confirm your reluctor specs before you buy a swap engine. At the machine shop they cleaned, magnafluxed, decked .003, cam bearings, three angle on heads, .003 off heads. I did all R&R, you'll need some special tools, currently have 8k mi. and rolling strong in a 210k mi. Tahoe i will put another 200k on. I am camming my 03 6.0 HD tow vehicle, going with a 216/220 114, (TSP from WS6 i bet). I did, will do, a mail order tune from my neighbors friend in Pa., if you don't know a tuner you need to find one, it is necessary to go to 6.0 from 4.8 and for most cam upgrades. 6.0's suck gas hauling/towing, esp. at 80. Truck intakes are designed for torque, keep it for the van. Lots of LS Volvo info. out there too. If all else fails, go forged.
I would look at getting a used motor, pull the old one, and put the new one in, and done.
The codes could be leaky valves, or valves not seating completely from being carboned up.
What trans do you?
Stampede.
It's a 2006 GMC Savana 3500, 4L80E is what they come with.
Do you mean, like leaky or carbon'd breather/pcv vent valves? Or literally valves?
I kinda doubt I've got leaky valves; the truck runs perfectly most of the time, but if it sits in bad stop and go traffic for 10 minutes plus, it often starts to do a shaking/shuddering/not firing on all cylinders thing. I think that is lifters collapsing. Sometimes it does it when cold too, and accelerating at part throttle for 3 seconds, then chopping throttle and repeating 2-3 times almost always makes it run right. I think its the lifters pumping up, but IDK. From what I've read, oil pressure fluctuation, some noise, and the shaking/shuddering thing point to lifters, but obviously I don't know.
Oh, and I should stress, it runs perfect, makes power and feels totally fine the rest of the time.
Welcome to LS1Tech Sean. You’ve told us all that you’re a noob with the LS platform, yet your arguing what you think you need to rebuild your 4.8 or possibly a 6 liter, and it’s painfully obvious you don’t, with an extremely knowledgeable tech from a group of guys that go out of their way to help all of us. These guys will save you money. Arguments are welcome here, but please lose the attitude. If I were you I’d do a ton of research for what your trying to do, and then come back in and see what’s available.
Lol, yeah, arguing for information.
Dude could have all the knowledge in the world but all he knows how to say is "buy a rebuild kit" when I ask for help picking a cam/lifters/pushrods/springs. I've been researching for a year, and I'm at the point where I know enough to know what I don't know, and that's why I'm asking some specific questions.
The only 2 people in here that know anything are 70velle and Ws6 store . Ws6 store answered your questions perfectly . You asked for a rebuild kit . They answered .. they even told you what was in it . Then you posted and Ebay link .. to some bullshit kit that uses cheap *** Ebay bearings and zero gaskete for only $100 less. If you're going to have an attitude towards a sponsor trying to help you. You need to go baxk.to 4 strokes and take your truck to a shop
It's a 2006 GMC Savana 3500, 4L80E is what they come with.
Do you mean, like leaky or carbon'd breather/pcv vent valves? Or literally valves?
I kinda doubt I've got leaky valves; the truck runs perfectly most of the time, but if it sits in bad stop and go traffic for 10 minutes plus, it often starts to do a shaking/shuddering/not firing on all cylinders thing. I think that is lifters collapsing. Sometimes it does it when cold too, and accelerating at part throttle for 3 seconds, then chopping throttle and repeating 2-3 times almost always makes it run right. I think its the lifters pumping up, but IDK. From what I've read, oil pressure fluctuation, some noise, and the shaking/shuddering thing point to lifters, but obviously I don't know.
Oh, and I should stress, it runs perfect, makes power and feels totally fine the rest of the time.
Sounds like it needs a serious decarbon treatment, the throttle body cleaned, the MAF cleaned, new plugs, new plug wires and probably some other maintenance items like new fuel filter, air filter, coolant flush etc.
Regarding "junkyard motors" there some risk. I bought one many years ago. It all looked good on the surface and basic inspection. Leaked it down before using it and two cylinders were bad. A friend pulled the heads and found a replacement piston in #7. He also found these oil drain back plug for the turbocharger that I missed. Anyway, it needed a full rebuild. It made a wonderful 383 LS1 stroker. Some folks have good luck with JY's. Buy your JY from somewhere reputable that offers a warranty unless you just feel lucky.
For the van with the 4.8, I'd look for a nice low mile 5.3 to swap in. The 5.3 will be a nice boost in power and more gas mileage friendly than the 6.0. Plus the 5.3's are usually less expensive than 6.0's.
Regarding, WS6 Store, they have helped many of us time after time. Their service is A+ and they are an outstanding vendor. Chevelle is A+ on knowledge and definitely knows his stuff. I'm honored when either WS6 or Chevelle respond to my threads. Playing nice & loosing the chip on the shoulder will definitely go a long way toward generating good will toward you and your questions. Otherwise, what Mavn said.
This is what i use in my 2 2500hd 6.0 trucks for towing and hauling
Texas speed stage 2 high lift. It doesnt make the most power out there and hardly has an idle but its perfect for what i do and what i need it to do.
You have to be realistic when getting a cam, whether it has a catchy name or not. What rpm range are you typically going to be using the engine in. A 4.8L lacks ALOT to be desired NA which is why most boost them, so if you are boosting, have that in mind.
6.0s are a different story but it all depends on the compression ratio there also and what heads you are going to use. I have an 07 nnbs 2500hd also i use the stage 3 tsp high lift 216/220. It had vvt and i ditched it. Just wasnt worth the hassle. Ive tried a bunch of cams in all of them and the tsp are the best when it comes to meeting my expectations.
I could use one of our signature cams like the high lift hot cam but like i said, youve gotta get a cam for the power and range you need, not want.
Most trucks will NEVER see above 3k really. So why get a larger cam that takes away your bottom end and towing capabilities? An rcsb is much lighter and normally not used for truck stuff as much so to speak to the range is a bit more broad and normally you can get away with using a larger cam there and never see an issue.
Id really depends on a few things but you have to be specific and not just ask for input otherwise everyone is going to throw something at the wall and see what sticks, and everyones idea of what is DD-able is different, sometimes way different. Ive seen no less than 10 cams on a few fb pages for sale because they weren't what they wanted.
Set a goal
Set a budget
Stick to them
My thoughts on cams are supported by alot and some have other ideas. Lift (to a certain extent) builds power. So does a narrower lsa, again to a certain extent. More lift on the same duration will also gain power and will gain rpm range as well. The adverse effects are nearly non existent within reason.
Here is a graph proving that. It also shows that bigger isnt always better
Thats the tsp low and high lift stage2 212/218 112lsa vs the stage3 216/220 112lsa. Theynare dynod on basically an L33 engine, so pretty much stock. And they are definitely not wrung out for max power. You can see the stage 2 high lift clearly wins above all. The springs are much quieter than the ls6 beehives also. They use a PAC 1219 on them.
Some of the parts etc are not necessary and youll spend extra money for no reason there also.
There is really too much info on the internet and you can read too much and go off in left field easy. Not all of it is right but not all of it is wrong either.
If you want more power in the mid range and top end a very nice aggressive sound and want to suppliment the bottom end and run a stock converter or small stall then this is a high lift hot cam install on an L33 with tsp headers in an 05 Z71
Also a friend got a junk yark engine. Pulled heads etc for a refresh. 3 valves looked like this
Both of those were unusable. He just wanted a clean up and quick lap. Not even 2 passes on the local machine shop valve grinder would clean them up.
One of the many reasons i am against running a used engine period if you are upgrading or not a dire emergency.
I dont care if you buy the parts from us, id rather someone have a good dependable engine vs just running one because its been done so many times.
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315k mile 4.8 "refresh" plan 
Anyway, it needed a full rebuild. It made a wonderful 383 LS1 stroker. Some folks have good luck with JY's. Buy your JY from somewhere reputable that offers a warranty unless you just feel lucky.
