5.3 to 6.0 curiosity (now video of knockin)

[4xcrazy]

Alright now,,, I've had a few to drink tonight, so bear with me please.

I've mentioned something about this in a previous thread, never really got a direct, for sure answer on it I think, hell I dunno at this point..

Anyways,,, the Avalanche currently has a 5.3 in it,,, it was recently rebuilt, well about 2.5 years ago anyways, close to 40k miles on it so far I'm guessing.

The, what I think is piston slap, in the cold, first start-up mornings, seems to be getting louder. Not liking this, something is obviously wrong and getting worse over time. We both make sure to let it warm up enough that we don't hear the slapping/tapping before we drive off on it, trying to be easy on it while it's still cold and whatnot, but it's bugging me. It DOES go away a short time after idling for about 5 minutes or so.

We're about to pick up an '83 2wd long bed from her dad, he's giving it to us, but it's going to be one of those projects that Tommy and I fix up, clean up and get in good shape for him when he turns 16 and crud..

Jenn and I were already talking awhile back about putting in a 6.0/4L80e for better towing capability and all around performance. She and I both agree this 5.3 seems to be a problematic engine at the moment.

We are considering pulling the 5.3/4L60e and setting it aside to have it completely gone through at a later date for the "Tommy Truck" project, and in the mean time, putting in a brand new 6.0/4L80e for our use in the Avy.

I could sworn I have read and or heard from people that the 6.0 was the same as the 5.3 aside from the piston size or stroke,,, one of them. Is this true and how difficult or what challenges am I going to run in to with trying to drop in a 6.0/4L80e in place of the 5.3/4L60e.

I know they put 6.0's in the GMC and Cadillac versions of this body style of truck, Tahoe/Suburban type, maybe not the Avy, which I think they did in the Caddy version, so it shouldn't seem to be TOO difficult.

Haven't done much research on it just yet, just thinking about it right now since I can't sleep.

I'll take some video of this thing starting in the morning so you can hear just what I am referring to. It's annoying..

 

[Babaganoosh]

5.3 and 6.0 are the same engine except the bore and stroke is different. The trans length might be different but they made a 2500 avalanche with the 4l80 so finding the correct mount might be tricky if the Silverado doesn't work. As far as tuning the ecm will need to be reflashed for the trans definitely you might get away with the engine parameters but if you are into the ecm just flash is for it as well.

They all piston slap so don't be scared.

 

[4xcrazy]

I've heard about the problematic piston slap. It just annoys me I guess because the only reason this engine was rebuilt was due to a camshaft/roller lifter roller failure. It had about 143k miles on it when this happened, and no slapping.

It originally didn't have the slapping problem, so I'm not sure what happened during the rebuild.

 

[Babaganoosh]

I agree with you 100% piston slap is annoying and the biggest let down of the ls engine.

 

[Stomis]

Piston slap should not be reoccurring with a properly done fresh rebuild. The piston slap comes from too sloppy of bore to piston specs from the factory. At first its fine but it rears its head when miles wear the engine in. A properly rebuilt motor with a proper bore job should alleviate this problem. Ive never heard of the LS's slap issue being form a rod to stroke or short piston skirt design or anything like that. So unfortunately I would say your machinist probably said screw it and honed the block rather than over boring it and ordering over sized pistons.


As said the 6.0 will slip right in place of the 5.3. Its the exact same scenario as replacing a 305 with a 350 or a 350 with a 383 etc. Yes the transmission is bigger but as you said the truck was offered with that and I really doubt they went out of the way to put a smaller trans tunnel in the 5.3s and a bigger one in the 6.0 trucks.

Where Im lost is the harness connectivity between the 4L60 and the 4L80 and I would really like to know for future knowledge. Does all the 4l60 plugs hook right up to the 4l80 no problem? I could have sworn the two had different gigantic plus that weren't interchangeable but Im not positive.

And obviously you'll need a reflash on the computer.

 

[Russell]

Not a difficult swap, but there is a bit more to consider than has been covered here yet:

1. Engine is a direct bolt in replacement as mentioned above.
2. The 4l80e will bolt right in as well. GM has done an excellent job of keeping the transmission mount in the same spot and with the same footprint since about 83.
3. Your transfer case will need a 32 spline input swapped in to work with the new 4l80e. A 4l60e has a 27 spline output.
4. You'll need a complete engine and transmission harness from a similar generation of truck (99-02 and 03-07). While the engine wiring remained relatively unchanged, the transmission wiring is not the same between a 60e and 80e. Make sure you grab the 6.0L / 4l80e PCM as well.
5. You'll need to have the PCM flashed with the correct VIN for your vehicle so the anti-theft will continue to work properly. It should otherwise interface nicely with the rest of your vehicle.

 

[riflerk20]

Where Im lost is the harness connectivity between the 4L60 and the 4L80 and I would really like to know for future knowledge. Does all the 4l60 plugs hook right up to the 4l80 no problem? I could have sworn the two had different gigantic plus that weren't interchangeable but Im not positive.

And obviously you'll need a reflash on the computer.[/quote]


this maybe
http://lsx4u.com/lstransmissions.html

 

[4xcrazy]

Not a difficult swap, but there is a bit more to consider than has been covered here yet:


3. Your transfer case will need a 32 spline input swapped in to work with the new 4l80e. A 4l60e has a 27 spline output.
.

'05 2wd truck.

 

[Blue85]

Yeah, the 4l60E and 4L80E use the same connector, but the pinout is different - could cause a lot of confusion if you didn't know. I don't know if a re-pin of the connector would solve it or if you have to get the whole harness from the 4L80E donor vehicle. You'd have to study the PCM and transmission harness to know for sure.

 

[rjfguitar]

Whats wrong with leaving the 4L60 in and just swapping to a 6L?

 

[4xcrazy]

The 4l60e thing was just an afterthought really, if I'm going to go through the troubles of installing a larger, more powerful engine, I figured a better power handling and more towing friendly transmission would probably be a good idea as well.

 

[NorCalAnthony]

Here’s a pretty good write up for the wiring from one of guys that did a 4l80e swap over at performancetrucks.com: http://www.performancetrucks.net/forums/gm-drivetrain-suspension-22/4l60e-4l80e-wiring-swap-413157/

Like Blue85 already said, they share the same connector so it’s fairly easy to just re-pin the connector either at the trans or at the PCM. You’ll still need to add a wire for the additional VSS though since the 4l60e uses one and the 4l80e uses two (input speed sensor and output speed sensor). Not hard to do but if you can get the new/donor wiring harness when you get the 6.0/4l80e, that’d definitely be the easiest way to go.

 

[4xcrazy]

OK, here we go.

Just tried to take this video, THIS time, it isn't doing it nearly as loud as it sometimes does, maybe I waited too late in the day for it. I'll try again tomorrow morning when it's a bit cooler and see how it does. BUT you can hear some tapping going on in there for a short time.

After watching this, it sounds like you can hear it more when I'm not in front of the engine, the mic on the phone apparently picks up the air going in the intake much better.

It went away pretty quickly this time, you can hear it if I were to step on the throttle and rev it a tad...

It's annoying..

Is the piston slap or do you think it's something else going on. I figured it to be the slap due to the fact it goes away within a couple of minutes of starting, once it starts warming up.

Also for anyone reading this that was looking for exhaust recommendations, this is a Flowmaster 40 series muffler

The one I'll be having swapped out soon due to the overly annoying drone at certain RPM's. I'll get a better video of that later though.