Death is a Knockin

[cebra]

The truck is my daily driver, I have put about 15K miles on the swap and I got a knock developing. It is a 4.8L I got from a junkyard for $900. I will continue to drive until it blows up but I would like to upgrade to a 5.3L, I was looking at the 385hp 5.3L upgraded motor for $3.2K and just a stock 5.3L for $2.2K from Autozone (Summit is similar price). I am curious whether I can turn my 4.8L in as a core on the 5.3L...the 385hp crate motor doesn't have a core. I don't hot dog my truck at all but I am concerned that my NV3500 trans may not be able to handle the 385hp for long. Opinions on what to go with?

[cornerstone]

Well that sucks! On the bright side all the main work is done and this swap should go a lot easier than the last one. Do you presume there will be any programming issues with the next motor?

What is the HP and TQ rating for the cheaper LS? Is it re manufactured or all new components?

It'd be hard for me to pass up on 385 ponies for 3200 bucks. You said you don't hot dog the truck, so I wouldn't worry about the transmission.

Hoping others chime in here too.

[mongocanfly]

There may be lots of differences in the wiring harness and ecm...
If your not a hotdogger then why 385hp?...a bone stock, under 300hp 5.3, is good power..

[ls1nova71]

If swapping a gen3 4.8 with a gen3 5.3, then there will be no wiring differences at all. There will be tune issues that should be fixed though. It will run with the old tune, probably even pretty good, but wont be optimum. That said, I'm always leary of auto part store remans.... At work, we have used NAPA a few times and they never last, also they only warranty the original engine, so once it blows, the next one they give you has no warranty at all, a lot of incentive for them to make a decent product..... Just saying, check everything out before you buy. Personally, I would find a good machine shop and have one rebuilt. Talk to the hot rodders in your area, they will know who's good. A good core shouldn't be hard to find for cheap these days.

[cebra]

Yeah, thinking stock 5.3L would be fine for me but if I can't use my 4.8L as a core then it makes the 385hp more enticing but the trans is only rated for 300 so I may feel like I need to baby the 385hp even though I drive like a grandma anyways. Good info on the parts store remans, I'd do a Summit reman but you have to pay to ship your core back which I wouldn't do so it is $350 more than parts stores but if the Summit ones are better I would go with that. A rebuild would be great but it is my only vehicle so I was kind of hoping to pull and replace the motor over a weekend so I didn't waste a bunch of money on renting a car. How long do rebuilds generally take? Do you pull the motor and drop it off? That could be a challenge to as I was going to pull the motor in an abandoned parking lot (don't have a garage either). I have 3 computers (from sending them to different tuners to try and find someone capable of turning the fans on...took 5 tunes I think to get that to work) so getting a tune is not a base tune isn't an issue and I would do that ahead of time so I can drive it as soon as its dropped in.

[cebra]

Side note, I am not really mad about the engine having issues. The 4.8L is a bit under powered especially now that it is losing oil pressure and I would like to have something rebuilt and more reliable since it is my daily driver/only vehicle anyways.

[cebra]

I could do another junkyard motor but that makes me sick to go through all that work and it may be another 6 months before I replace it since I run 30K miles per year in the truck. I would like to put something super reliable in I know that I can get at least 100K miles out of.

[ls1nova71]

What I meant was buy another junkyard long block, or Craigslist, facebook matketplace ect., drop it off at a machine shop, then when you pick it up, it will be ready to install. Depends on how busy the shop is, but a week or so minimum I would guess for them to go through it. Once you had it back, swapping long blocks could be done in a day if you got up early and hit it hard.

[cebra]

Originally Posted by ls1nova71

What I meant was buy another junkyard long block, or Craigslist, facebook matketplace ect., drop it off at a machine shop, then when you pick it up, it will be ready to install. Depends on how busy the shop is, but a week or so minimum I would guess for them to go through it. Once you had it back, swapping long blocks could be done in a day if you got up early and hit it hard.

I did not even think of that, that is exactly what I should do. Thanks. I have a buddy with a scrapyard that has a dozen or so LS engines of unknown condition so I could pick one up for cheap. What would I expect to pay to get a 5.3 long block machined/assembled with a mild cam and upgraded valvetrain do you think?

[57taskforce]

A lot of that depends on the condition of the motor being rebuilt... ridges in the cylinders vs clean cylinders that only require a hone, crank that is grooved vs crank that only needs polished, etc... cam will set you back 3-400 minimum + the proper springs. Id definitely suggest trunnion upgrades for the rockers and good lifters if your gonna cam it. A cam swap can easily be 1,000 with the cam, springs, quality lifters, and trunnions. When it comes to building an engine right, obviously cheaper isn’t usually good. For quality parts and assuming you need cylinders bored and crank only polished, heads fully built, with a cam swap you could easily be 4-5k for a complete overhaul with quality work and components.

I don’t do LS builds for a living, but I do build engines for a living.

[MDPotter]

Sorry to hear it's having issues already. For you, I would suggest buying a 5.3 off eBay. I would say look for a low mileage (less than 100k), but it's getting hard to find Gen 3's with less mileage. When you get it, do some disassembly to find out what kind of shape it's in. I am by no means an engine expert, but you can start by pulling the valve covers and see how things look, and pulling the spark plugs so you can shine a flashlight in the cylinders and see how the pistons look. You can go deeper and ultimately end up at the machine shop to have the block freshened up with cam bearings, crankshaft bearings, and hone (bore if needed). From there, you can replace timing set, rod bearings, pistons and rings, and replace all the gaskets associated with the engine. Also have to replace head bolts as they are stretch bolts.

It is a bit of a risk buying a salvage engine because you don't know the history, but since you already have a running engine you have some time to either buy a salvage engine and swap it out or rebuild it.

If you're seriously interested in a rebuild, I would recommend buying a book about it. I read this one and learned a lot: https://www.amazon.com/How-Rebuild-L.../dp/193249460X

[Killer Bee]

1. toss the 4.8
2. buy the cheapest 5.3 core available
3. gm crate 5.3 w/ 36mos 100k mile warranty FTW

if you're certain you'll be completely satisfied with stock OE performance, there's absolutely no need to re-engineer the wheel..

odds of success are exponentially higher with the OE that has manufactures thousands of these rather than any local shop..

good luck!

[cebra]

GM Crate 5.3L is $6-7K, that is way beyond what I want to put into the truck as it was meant to be a $20K build but I am sitting at $35K now (ouch). $4-5K for a rebuild is pretty dang expensive too when you can buy a ATK rebuild from Summit for $2,500 or roll the dice on a junkyard motor for $1,500. I hate to do that again but i could do that 3 times and still come out ahead. I didn't realize rebuilds were so expensive.

[MDPotter]

I think you just had bad luck with your 4.8. Most of these engines go well above 200k if they've been well maintained and not abused. My company buys only 1/2 and 3/4 ton GMC's and they've all ran for a LONG time, but very few had engine issues prior to 150k. I would look for a low mileage 5.3 on eBay or a local salvage yard (less than 120k miles), then inspect it and if it looks okay on the surface swap it out and keep going. Then in your free time you can use your 4.8 core and rebuild it at whatever pace you want and eventually put it back in. The difference between a 4.8 and 5.3 is stroke and pistons, so you can turn your 4.8 into a 5.3.

[cebra]

That is probably what I will do, drop a JY 5.3L in it and by the time that is cooked I should have my own house/garage and can rebuild the 4.8L.

[prodjay10]

Buy a junk yard 5,3 and use it till it takes a sh**, then rebuild it.

Is it ticking or knocking? Oil pressure could be the pump or pickup tube oring which would cause ticking.

[cebra]

Originally Posted by prodjay10

Buy a junk yard 5,3 and use it till it takes a sh**, then rebuild it.

Is it ticking or knocking? Oil pressure could be the pump or pickup tube oring which would cause ticking.

It is more of a knock, I have not driven the vehicle in a while due to quarantine. I put a new pickup tube in it (replaced stock pan with GM muscle car pan). It started at about 40psi at idle and after about 15K miles it has gradually went down to about 30psi.

[cebra]

I also have an issue where my throwout bearing is dragging on my pressure plate so I need to resolve that when I put a new motor in. I will try to order a shorter one from a later model silverado (02-06) and see if that works since I am running a 2000 AT engine but I may have to shim the trans away from the motor a bit.

[Killer Bee]

Originally Posted by cebra

GM Crate 5.3L is $6-7K, that is way beyond what I want to put into the truck as it was meant to be a $20K build but I am sitting at $35K now (ouch). $4-5K for a rebuild is pretty dang expensive too when you can buy a ATK rebuild from Summit for $2,500 or roll the dice on a junkyard motor for $1,500. I hate to do that again but i could do that 3 times and still come out ahead. I didn't realize rebuilds were so expensive.

well you shouldn't punish your engine budget because you overspent on paint, wheels, lowering or wherever you overspent already..

you think you feel jilted now, wait until you sink all that time and money into another kitbash engine project and back here in 2-3 years going through the same thing..

for a $35k investment, I recommend rethinking the focus of the budget.. I'm not a psychologist but I have dried a lot of tears.. good luck!

[aknovaman]

I fail to understand why anyone would rebuild a LSx engine, much less a 4.8L. There are literally thousands of them in salvage yards for around $500 all day long. Most local u-wrench-it sells them for about $200 fully dressed. Kansas City Muncie salvage has them for $140 with $30 core charge. LKQ has 150K mile engines for $750. Most places if reputable, have a 30 day warranty too. There are tons of them on car-part.com for $600 local to OP. Just my opinion.

[Killer Bee]

^ same reason some of us will spend $2-300 for a factory alternator vs o'Reilly's $39 lifetime warranty chicom special.. lack of longterm reliability, wasted time and expense towing breakdowns home, and repeated rework just flat gets old..

I get 100-200k miles on oe factory components and rightfully should expect similar from those oe replacements.. brakes, water pumps, etc..

component systems like engines and transmissions removed from unknown salvaged vehicles comes with risks..

my point to the op is in reference to a $35k+ build.. I recommend against the starving college student approach..

I went through it too when I was younger, but then I had a lot more time than money, and not much more responsibilities than getting myself to work.. nowadays most adults have little time for tinkering everytime they leave the driveway..

I'm not knocking the budget minded, especially where it has hard limits.. but I didn't perceive this project falling into that category..

some get lucky but I have been called on many times to bail out a lot of victims of bad decisions, some even after my own advice..

and typically the ones seeking advice are the ones that will later need help.. not knocking the OP whatsoever, just trying to share a little sound advice or at least food for thought