How would you build the most dependable LS motor?

[Daaaanz67]

Interesting all the comments. Guess I got lucky on mine. Swapped oil pan for the conversion, knock sensors, intake gaskets. Motor had 59,000 miles.

[LH Lead-Foot]

Originally Posted by 72GreenMonster

Hey 77,

I was skeptical of how tired she was so i did the platiguage and they all checked out at about 002. Seeing enough convinced me to button that thing up and save time and money. Ordered a cam retainer, cleaned her up and hope to get started sooner than later. I am now siding with the fact they are pretty solid bottom ends and feel better going forward. Not to short cut anything but this was the sentiment i was hoping to verify. I know there's more of you out there that went that route. Hell swap can have many variants.

Will i get 100k less than a redo, probably but not my DD so no harm no foul the experience will be enough to do it again if needbe!! Everyone wins!
Thanks

I saw your post on the plastic-gauge measurements. I took a look on GM eSI using a 2003 GMT800 5.3L engine and scrolled down to specs. They show two for each rod or main bearing.
Rod clearance - Production = 0.0009" - 0.0025"
Rod clearance - Service = 0.0009" - 0.003
Main clearance - Production = 0.0008" - 0.0021"
Main clearance- Service = 0.0008" = 0.0025"

Yep, that's 3 zero's or 9 ten thousands = 25 thousands max production...
If your plastic-gauge sleeve shows 0.002" you are in the ball park.

Still don't know what year or size of "LS" you are working on, but I picked something generic. I see many post about NOT removing the rod or main caps to inspect, I do agree the ARP bolts as they are the best on the market and as always, your choice. But standing in the garage, looking at the bottom end of an engine I plan to run for the next ten years or more, then choosing not to measure the clearance of the rod and mains is the same as walking a mile for a "Camel" cigarette and get on smoke and not the whole carton.

I am confuse about the number of post indicating replacement of the knock sensors? Are people seeing these go bad? I asked my ex-coworker at the Cadillac dealer, he stretched his head and told me he thinks he had one go bad, but that was on a 1992 Buick Century in his 37 years at the dealer. We walked over the the Chevy heavy line-techs and asked the same question specifically on the "LS" engine...They both said no, never had on bad, but had bad wire plugs with bad terminal fit that are a goofy design as they are and have been for years.

I thought I would ask to find out, plus I got a lunch out of the deal.

[LH Lead-Foot]

Originally Posted by 72GreenMonster

Lead Foot,

Did get timing set and i took note of the heads and no resurfacing the valves rt? I was also tempted to decarbonize clean myself but i have new springs i needed i nstalling. Do i clean myself and buy a spring compressor?
I dont mind the elbow grease and the more i do feels good in the end.

Timing set is insurance depending on the mileage. It just that if I was stand there, I would look at the chain stretch and judge the slack. They are running metal gear teeth, not covered with a nylon cover found on GEN1s'.

As far as the valve condition and seat contact...if the exhaust and intake is off you can see the valves on both sides. Rotate the crank while on the stand, then look at all. These used hardened seats and the exhaust get the worst of it. Remember, the head bolts are torque to yield so the cost of good ARP bolt add up if you have head gasket set most come with / or without bolts...if you have not ordered yet. If you set this up with a starter, battery and on a solid stand, just do a compression test to find out a base reading. With 9.49:1 compression on an engine with 3.78" Bore / 3.62" stroke is near what they call a "Square Engine" called be engineering. This means a smooth running engine without need for a balance shaft. Your compression should be within 10% of each other. But if you can see a valve seat that has a rough spot, I would ask around for a machine shop to re-face the exhaust valves and seats. They will push you to buy other services but keep it on the low.
GM does not recommend re-facing the intake valve, but I am sure they are done every day. It just that good equipment, some metal dye or pushing blue, and good measuring tools, plus a good torque wrench and angle gauge, then take it to a machine shop that is will to work with you.
The width of the seat contact helps seal, but transfers heat back into the head. This is why the exhaust valve gets it hards. Too wide of contact, carbon can get trapped and not seal, too narrow contact and the valve will run hot. I am picky when it comes to valves and prefer Nu-Way tungsten carbide seat / valve cutters as it is easy to control and quicker to check seat contact pattern...but that's just me.

So, don't try it yourself unless your neighbor is a retired machinist. I have specs but need to know the year and engine size. It's nice to have the RPO code from the glove box lid, but little changes are expected. Like L59have a nylon coated skirt to run a little dry with E85 in the hole. The injectors are different as well because they have to spray more fuel for E85 (About 30% More) and have different numbers your tuner will need to set up your PCM.

Now valve springs are known to break from the OEM. Without pulling the head, buy a tool for air, screw into the plug hole, rotate engine until both valves are closed, then fill it with shop air. This allows you to pop the valve retainer, magnet to capture the keepers, but requires an over-head spring tool which is the cheapest of two choices. I have 2 over complete head for spring removal while one is set up for imports with small deep holes, the other for normal stuff. But I also have the on-engine spring compressor tool that grabs the spring near the bottom, it's off-set to fit the coils, but screw in by hand and works great. Don't forget valve stem seals as well at this point.

I still have "Clover" brand medium & fine small green cans of valve surface compound. it looks like fine ground stones in grease. You put your wooden stick on the valves face, some "Clover" brand valve surface compound on the valve then rotate between you hands like your trying to start a fire with a stick. This is how it was done during the 50's into the 60's when equipment was not near by. But I am old enough to have 4 grown children with 14 grandchildren...Oh yeh, I do.

[ls1nova71]

Originally Posted by LH Lead-Foot

I am confuse about the number of post indicating replacement of the knock sensors? Are people seeing these go bad? I asked my ex-coworker at the Cadillac dealer, he stretched his head and told me he thinks he had one go bad, but that was on a 1992 Buick Century in his 37 years at the dealer. We walked over the the Chevy heavy line-techs and asked the same question specifically on the "LS" engine...They both said no, never had on bad, but had bad wire plugs with bad terminal fit that are a goofy design as they are and have been for years.

I thought I would ask to find out, plus I got a lunch out of the deal.

I had one go bad because the hole it sat in filled up with water and rusted it up so that it looked like an artifact from the Titanic. It happens when the rubber caps get hard and no longer seal out water from engine washing, or in my case, the car has a 4 piece hood with a hinge down the middle so the engine gets wet every time it rains. I usually silicone the caps back in to keep it from happening again.

[LH Lead-Foot]

I believe there are holes in the back of the valley for water to drain out. Maybe I'm wrong, but I think they are there on both lower sides.
They must have plugged up. Either way, that will cause it to fail. Oh well, nothing is perfect.

Speaking of water, I have a new job to start today as I lost rear brakes coming home on a short drive, after I picked up garden seeds. One of the rear brake line on my 99 SUV, became subject to the salty-icebergs we carry around for 5 months of the year in Nebraska every year. Few things suck more than laying on a creeper looking at dark spots a light will not shine on with rust falling down everywhere. Oh the fun!

I have almost one of everything in my garden and give bags of it to the Firehouse "94" up the street. Every year as I have an abundance. Yep, jar spicy homemade pickles also.

I can order some 3/16" NiCop but wouldn't have until next Thursday but have doctors on Monday. I have all of the tools, but a trip to O'Rielly's for a stick already flared with two 10m X 1.0 ends will cost as much as a 25 ft. roll of NiCop.

Sometimes life is good, and sometimes, well!

I need a vehicle that is need something newer than a 99, 96 and 69 + 67.

[77c10bowtie]

they mostly fail because water gets in the holes they sit in and sits there rusting away the semsor and eventually shorting it out, alot of people fill the hole with silicone after changing them to avoid future problems. this was actually a major issue even when these engines were in the first few years of production, long before ls swapping became a thing. its a poor design

[StingRay]

Gen III LS knock sensors are when not if. The back foam dam under the intake holds water in. Water can get down in between the intake runners and be trapped. It leaks down into the well for the rear sensor. They rust and fail. If the vehicle never sees a wet road or an engine wash I guess they might last forever. Can't imagine which one engine in the world will be that miracle engine.