Defenistrator's L33 powered '90 GXL 8.8 IRS

[Defenistrator]

Guess I've got just enough stuff together to start my own build thread now.

I've got a white '90 n/a coupe that I bought from a friend a couple years back for only a couple hundred bucks.  Body is fairly straight though it could use a little work, the interior is unfortunately a mess that needs some sorting, and I was originally told the engine was bad.
Despite this I got it running, idling well and making decent power.  However after about 4000 miles it was getting sick.  Minor rupture in a coolant seal, and a couple components in the ecu had apparently fried making the injectors go wide open when trying to start it.  Got sick of it and decided on a v8 build!

After my mind was made up the engine came out... 

After not much luck trying to sell the engine whole some cool Australian bloke decided he'd like a few parts off this engine.  Despite it not running quite perfectly initially this originally considered "bad engine" had great looking internals for 146k miles.  The only real mechanical defect was a damaged coolant seal, the rest of it's rough running turned out to be electrical issues.  Selling the rotors, stationary gears, eccentric shaft and a few other bits has also helped a bit with the funding so far, I still have plenty of parts left and a good tranny to sell.

This forum has been an awesome help to me so far, after browsing all the threads and having some spare time, I decided to tackle the project of minimizing the wiring both under the hood and behind the dash.  This 1st picture shows the whole passenger side engine harness, and on the bottom is the newly reduced harness which contains only the cruise and wiper circuits.  I loved how I was able to do most of the wiring mods without taking the cutters to all but a couple wires.



Because my budget is not very big for the time being, I initially considered picking up an LM7 iron block 5.3 and doing a simple intake, cam & header swap.  Seemed easy enough to get me to the mid-300s power wise.  I was considering one of the Ebay deals through LKQ which would add up to around 600 shipped for mid 100k mileage wise.  Then I decided to give CraigsList a look...
And there I find a local listing for an L33 engine for a great price.  I did some quick research and was impressed.  It's a bit of a harder to find aluminum block 5.3 with 310 hp stock, 9.9-1 compression with a set of true LS6 heads bolted on!  Oh crap... the ad's 3 weeks old, I'm sure he sold it...  Sent him an email and I'll be damned, he still has it!
I finally got to pay the engin... err, him a visit today, it all checked out pretty well so I set down a deposit on it and will be picking it up later this week.
My Droid was acting up and took some crappy pics, but here's the mule.  Actually, the 1st picture is one he sent me via picture text... the rest from earlier today.



Just a confirmation these are 799 head castings, which are physically identical to the equipment on the LS6. (did a lot of searching on LS1tech, 799 and 243 castings are essentially identical)  I think the valvesprings are weaker truck units, but that is the only difference.


The guy I'm getting this from picked this engine off Ebay and was going to use it as a swap project for his 280z.  After restoring it though he decided he was plenty pleased with the reliability and power of the 6 and decided to keep it that way.  According to the VIN this engine is off an '06 GMC Sierra 4wd quad cab, and has somewhat over 100k miles.
I'm pretty excited to get this thing home now.  Add an ls6 intake, came and valvesprings and I essentially end up with a 5.3 liter version of the ls6 itself.
Unfortunately the engine does not have coil packs, accessories (I'd need ls1 brackets anyway) or a crank pulley.  Hopefully I can easily and cheaply remedy that.

[Defenistrator]

Got my engine home!! 

I'll start with the bad news 1st... the oil pan is cracked REALLY badly.  Probably from whatever wreck totaled the truck, but I still didn't notice it till I got home.  It's my understanding it doesn't matter anyway... gotta find the f-body pan.
My biggest concern so far has to be this smashed bolt hole on the front corner of the block.  From what I've gathered this hole is necessary for the alternator mount... What should I do?  Can I take it to someone with a TIG welder and have em add in a bunch of metal & grind it flat, then re-drill and tap?  I'd like to have that done without stripping this engine down to the bare block, because it looks like I won't have to!



Now onto the good news:  Other than that bolt boss & the pan this engine looks to be in EXCELLENT shape!  All I know about the mileage is it's supposed to be "somewhat above 100k"  but looking at it I'd really think it's less.  No oil sludge anywhere, the remaining oil was a nice light brown, and no trace of the dreaded "dex-cool mud" or any other deposits in the cooling system.

Here's a few pics of this partially disassembled, with no heavy cleaning done yet.  Check out the condition of the plugs (they were all identical) and the cylinder bores!  Other than a cleaning up and a possible ls6 cam swap I don't know if i really have to do anything else, what do you guys think?











I learned something new today:  I always thought the 5.3s needed different head gaskets, but looking at these I guess the L33 shares gaskets with the LS1?

[theantirotor]

why did you pull the heads off?

[Defenistrator]

Because I was unsure of the actual miles (somewhat over 100k is all I could get) and condition of this engine.  Easy enough to buy new head gaskets and bolts, and this gives me a chance to clean up all the carbon buildup in the chambers and intake ports, and at least remove the sharp edges on one corner of most of the intake ports.  Also probably going to be doing a cam swap anyway.  I've rebuilt about 5 engines in my past so I'm not too concerned, though admittedly this is my 1st LS engine.  Anything I need to watch out for while going through/reassembly?  I just got a couple new brass brushes and a plastic scraper, plan to clean it very carefully.

[spacevomit]

This is interesting, I'm considering it myself now. Any idea on how the block compares to a given LS series?

[Defenistrator]

From what I've gathered from doing a little reading on LS1tech, the engine block is superior to the old f-body ls1 blocks, and as far as anyone can tell it is essentially a smaller bore LS6 block.  It has the large cast-in breathing windows above the mains, and is missing that area that ls1 owners have to grind away to use an ls6 valley cover.  I do NOT believe it has the sodium-filled valves of the ls6, but the heads supposedly flow the same.  Also they stuck what's basically 4.8 pistons in the holes to bump compression up to 9.9-1

With the smaller bores, I wonder if this block would take to forced induction a little better than other aluminum block LS engines?  Though of course this would only be a benefit if you keep it 5.3.

[theantirotor]

799 heads are ls6 castings.  i dont know about valvetrain though.  my truck came with a 243 on one side and a 799 on the other.  lol

[Defenistrator]

as far as I can gather the valve SIZE is the same. I measured em out at 2.0 and 1.55, says the same for LS6, but the exhausts doesn't have the exotic sodium filled stems. 
interesting factoid I just found out too, the normal iron block 5.3's heads have only a 1.89" intake, but the exhaust is the same.  I am STILL trying to determine if the aluminum 5.3 can be bored safely to 5.7.  I have seen some people say it cannot, and others claim the sleeve OD is the same as the ls1 so it can, but I haven't found absolute proof to either argument yet.
I'm certainly leaving it 5.3 for now, but having built a few turbocharged engines in my history the increased piston choice & variety would be nice if I want to go that route eventually!

[finiata]

I hesitate to add this info but you guys can keep it to yourselves so everyone doesn't find out. 799 heads are essentially the same as 243's they are however different. The exhaust ports are improved/different and provide better exhaust scavenging. The L33 was originally a GM HO 327 design for a vette that got axed. Only the LS6 vettes got the lightweight valves, which is sad. I hadn?t considered how far you can bore an L33, hmmmm, this could be really interesting, also the l33 has better rods than the ls1/6.

[spacevomit]

I hesitate to add this info but you guys can keep it to yourselves so everyone doesn't find out. 799 heads are essentially the same as 243's they are however different. The exhaust ports are improved/different and provide better exhaust scavenging. The L33 was originally a GM HO 327 design for a vette that got axed. Only the LS6 vettes got the lightweight valves, which is sad. I hadn?t considered how far you can bore an L33, hmmmm, this could be really interesting, also the l33 has better rods than the ls1/6.

Dude...thank you!

[theantirotor]

I hesitate to add this info but you guys can keep it to yourselves so everyone doesn't find out. 799 heads are essentially the same as 243's they are however different. The exhaust ports are improved/different and provide better exhaust scavenging. The L33 was originally a GM HO 327 design for a vette that got axed. Only the LS6 vettes got the lightweight valves, which is sad. I hadn?t considered how far you can bore an L33, hmmmm, this could be really interesting, also the l33 has better rods than the ls1/6.

So you are saying GM would go ahead and use 2 heads that flow different on the same engine then?

Where does this information come from?

[Defenistrator]

From my understanding the 243 heads and 799 were dimensionally the same.  I have heard of several stories of both heads on the same engine so I believe that. 
Where do you get the info that L33 rods are different/better?  I had always figured all gen 3 rods of the ls1s stroke were the same.

[finiata]

I hesitate to add this info but you guys can keep it to yourselves so everyone doesn't find out. 799 heads are essentially the same as 243's they are however different. The exhaust ports are improved/different and provide better exhaust scavenging. The L33 was originally a GM HO 327 design for a vette that got axed. Only the LS6 vettes got the lightweight valves, which is sad. I hadn?t considered how far you can bore an L33, hmmmm, this could be really interesting, also the l33 has better rods than the ls1/6.

So you are saying GM would go ahead and use 2 heads that flow different on the same engine then?

Where does this information come from?

I'm not saying, I'm just saying. As far as what GM did I find it both odd and disconcerting truthfully. I?m not at liberty to say where I got it from and since I have no proof its probably better if I retract what I said. You know that show ?Hogans Heros?  I plead the Shultz

[theantirotor]

i know what you mean about not always being able to say where info comes from.  that can be frustrating.



i wouldnt put it past gm to do something like that, but i would hope not.

[Defenistrator]

Well, luckily for me, I have a matching set of heads.
Haven't done a crapload to the car recently as I've been low on both funds and time but I did pick up some interior parts out of an '87 TII.  I've also determined it must be damn near impossible to find dash components WITHOUT plastic as brittle as eggshells.  Despite my new dash being 10 times better, I still had to J-B weld a couple of areas on the main dash, and also turn signal and headlight switch housings, just to keep them in the bezel.
Also my interior will now be a funky grey/blue mixture for at least the time being, but at least it will be symmetrical and surprisingly the 2 colors look almost normal together.