tyjova

Hello,

I've spent a mind numbing amount of time reading through threads here, but was hoping to get some info/confirmation from the pros on the direction I'm going on my rebuild to make sure I'm going about it the right way.

I'm currently working on a rebuild of a Gen III 5.3 out of a 2004 GMC Yukon, that I am going to be swapping into a Toyota Land Cruiser to replace the very tired and very slow original motor. I have the 5.3 down to the block now and will be taking it off to the machine shop this week to get cleaned up and checked. I don't have a firm number on milage but I believe the motor had about 250K on it. I'm starting now to collect the necessary rebuild parts and the immense amount of research involved in that. I just ordered a new set of cam bearings, the front and rear bores measured at 2.34 in. My overall goals with this build are to upgrade and replace the worn out parts for things that are maybe a bit stronger, a little more powerful, but in reality the V8 in a stock form is already going to feel like a rocket ship compared to the toyota I6 so I'm not really trying to go super crazy with things. My questions as I work through some of the more complicating parts are:

Cam
-This is going to be a 4 wheeling sort of vehicle so low end torque is needed, definitely not going to be doing any drag strip stuff or anything. However it is going to spend a fair amount of time "daily driving" too, and also on fairly long road trips for camping and things like that, maybe a bit of towing here and ther. It seems like the standard recommendation for things like that is the stage 1 truck cam, does that sound right?

Valves and springs
-I'm seeing LS6 as the common suggestion here. I don't see any real issues with the stock valves, are these something that are suggested to replace at the same time too? Will the LS6 work with the original valves? I'm assuming I'd just be looking to get stock size?

Rockers and push rods
-The original rockers look to be in fine shape so I'd like to keep those if possible, but there were a few rods that were for sure worn out so I'll swap those out. I'm assuming I can just get a new set at the same size as stock? Or this is going to depend on the particular aftermarket cam as well

Pistons ands rods
-piston rods are in good shape so I wasn't planning on changing anything there. The pistons themselves are pretty beat though so those are going to be replaced. They are press fit so that makes things a little more frustrating but no big deal. Those I will wait on until I get the block back from getting honed to make sure I can still get a set at the stock size.


Sorry for the blast of information and questions, it's one of those things where I just want to be totally sure i'm getting all the proper stuff so that I either don't have to take it all back apart again and/or don't completely destroy the motor. I really appreciate any info you can share!

Che70velle

iTrader: (6)

If your set on caming the engine, the stage 1 truck cams are as big as I would go personally.
Ls6 springs are the general go-to for a mild cam build. They are ridiculously reliable and will work with most any small cam. Stock valves are fine, just have the machine shop do a complete head re-do and valve job.
Factory rockers are recommended. Push rod length will have to be measured. Variables include how much heads were milled, and how much was milled off block deck to true it, along with the new cams base circle diameter.
Pistons…you’ll need to go ahead and get a set, so that the shop can final hone to the pistons measurements. Any shop worth a poot will want to do it this way. I’d plan on an overbore of .020 myself, and go ahead and hit up Summit for a new set with pins and rings. Remember they are press fit when ordering. Rods can be re-used no problem.
Shop can order your gasket and seal kit for you. Have them press in the cam bearings for you. It will save you headache later.
Sounds like a cool project and overlander. I LOVE that kind of stuff, as camping is my absolute favorite thing to do. I have a nice Roam roof top tent that stays on my Silverado just for my weekends away. Keep us posted here, and feel free to ask any more questions that you need to. Welcome to LS1TECH.

slowride

iTrader: (3)

On a high mileage unit I can see an oversized piston for sure. 5.3 block has room for days to open up and get a nice straight cylinder. Depending on price one could even oversize it to 5.7 stock bore. I agree on all the stuff above, stock cam or small truck cam, maybe look at a later truck intake for a bit more power with the same driveability. Heads need valve job possibly new valves and guides checked with the miles it has. Check out the ws6store for a kit to suite your needs.

tyjova

This is exactly what I have been looking for, thank you so much!! I've done my fair share of auto work and feel plenty confident in this job, it's just the insane amount of different variables and set up possibilities that have had my head swimming lately, especially with many builds being geared more towards squeezing every HP possible, turbos, etc.

So sounds like I'll get those LS6 springs, easy enough. I by no means am absolutely set on needing a new cam, it's just one of those things that since I have the thing completely apart I may as well replace as many "wear" items as I can. The original cam doesn't look all that bad, but I guess I sort of assumed it was a worthwhile upgrade while I was in there. Though if it doesn't make a ton of sense to upgrade the cam for something that's not necessarily aimed for high HP, I'm more than happy to save the money on that one.

Next then I'll take the block in for machining and the valve job, but I'll get those pistons first it sounds like. Seems like sort of a chicken and egg situation with boring cylinders to the size of a piston, or buying pistons to the size of the bore. Sorry for what I'm sure is a dumb question, but that .020 overbore is going to lead me to a size at 3.800in correct? Something along the lines of these? https://www.summitracing.com/parts/s...make/chevrolet


Thanks again so much for the info! It's definitely an exciting project that will be fun once it's all completed. The original toyota motor is at 330K and while I'm sure with some rebuilding of that it would last another 300K, I'm ready for a bit more power. As it stands now, it's one of those things with the pedal to the floor at 40mph trying to make it up steeper inclined roads and that's just getting old. Getting the 5.3 together is probably the easier part of the entire project to be honest, but one step at a time!

slowride

iTrader: (3)

Many companies can get you set up in a simple rebuild kit with hypereutectic piston oversizes, rebuild kits etc. WS6store, Summit etc etc.

tyjova

True, this may be a good option for sure. More than anything I'm trying to figure out the best path forward to build something that's strong, reliable, etc, and nothing crazy so that would probably work best vs a lot of parts that are geared towards crazy power.

LS1 TJ

I have a LS6/4L60E in my 98 Wrangler. LS6 cam and springs. Stock rockers. Engine was fairly low miles. 45K when I bought it. Maybe 65K now. It's a summer time cruiser. Did the swap about 15 years ago and it's been bullet proof. Maybe a rocker trunnion upgrade? I would add new/better push rods in case you want to add a bigger cam in the future.

gnx7

iTrader: (28)

I'm guessing this is a toy and not a daily driver? I would look for a stock running 6.0 or alum/iron 5.3 that doesn't need to be rebuilt from a totaled truck. You should calculate machining/parts/assembly costs before giving the green light on the rebuild.
You could overbore that 5.3 and make it a 5.7 though...

There are thousands of running 5.3 and 6.0's for sale on FB marketplace (LS engines parts for sale/trade group) that could provide life for many many years to come etc. A 6.0 will give about 50 ft/lbs of torque pretty much everywhere in the powerband over a 5.3.
or shop here from the largest directory of junkyards in the country.
https://www.car-part.com/

You would be almost better off just buying a totaled complete truck and pull the engine/trans yourself confirming it runs. 4L60e has a nice deep 1st gear for off-roading.

Here is my old turbo LX450 LandCruiser. It was a fun truck.... awful gas mileage.
https://forum.ih8mud.com/threads/lx4...er-rig.292261/

Where are you located? used engines in the mid west and east coast are a lot cheaper than West Coast that is for sure.
What year is your LandCruiser?

Che70velle

iTrader: (6)

Those pistons won’t work. The pin height (compression height) is wrong. Those are intended for a 6.125” rod. Your factory rods are 6.098”. As mentioned above, buying an entire kit will save you money. I’ve bought several engine kits from WS6Store. They are a sponsor here. Call them and tell them what your trying to do. They are extremely helpful and will get you the right parts at a great price.

tyjova

Good call! Looking at WS6Store I'm seeing a pretty comprehensive kit that has just about everything. Seems like getting with them and ordering that kit is the way to go since it will all be together other than a few things like springs, push rods, etc. Thanks so much!