Lesson learned - GMT900 Regret, GMT800 Reset

[DateNight]

Awesome crew cab!

As far as the gmt800-900 debate…
I have a 400, 800, 900 in the drive way.

I like them all, they all have there little quirks but our 900 has been great and at almost 200k miles it’s been nearly maintenance free other than a battery and brakes. The interior is cheaper in the 900s vs the 800s of the comparable trim levels, but has held up nicely and still looks as good as it did brand new.

 

[Tonimus]

Here’s the cup holder addition I bought from @all4oldchevys. Best $45 I’ve spent in quite some time.

 

[AuroraGirl]

Willing to bet money I don't have, that less 4.8L engines will survive vs however many 5.3L vs however many 6.0L.
Hopefully the 4.8L blocks that say "4.8L-5.3L-6.0L" (all three displacements) on their front passenger side survive, and get bored out to 6.0L.

wdym?

 

[Marky Dissod]

What do I mean?

The 4.8L V8s all lived harder lives; I don't think as many of them were made as the 5.3L, and I don't think as many 4.8L will still be around as 5.3L V8s.
However, some 4.8L and some 5.3L V8s were made with blocks that say
"4.8L-5.3L-6.0L"
(all three displacements) on their front passenger side. These blocks were designed to withstand being bored out as far as 4.000".
My hope is that many 4.8L V8s will find new life as 6.0L V8s, or whatever stroke ...

 

[stutaeng]

What do I mean?

The 4.8L V8s all lived harder lives; I don't think as many of them were made as the 5.3L, and I don't think as many 4.8L will still be around as 5.3L V8s.
However, some 4.8L and some 5.3L V8s were made with blocks that say
"4.8L-5.3L-6.0L"
(all three displacements) on their front passenger side. These blocks were designed to withstand being bored out as far as 4.000".
My hope is that many 4.8L V8s will find new life as 6.0L V8s, or whatever stroke ...

Huh?

How did you figure the 4.8 lived harder lives? [Monkey thinking emoji]

There's simply less 4.8s because they were only offered on the 1500 pickups (along with the 4.3 and 5.3) and Tahoes (along the 5.3). The Suburbans didn't come with the 4.8. Although the 4.8 were used on the 2500 Express Vans (along with the 6.0). So fewer models offered with the 4.8 = fewer production numbers.

In my observations and experience, the pickups tend to be used for work trucks more often vs the SUVs, so those engines usually get more abuse and neglect than the SUV/soccer Mom/family haulers. Express Vans are probably the MOST abused and neglected because they are almost always used as work vans. Very few passenger vans out there in comparison.

Those 4.8 5.3 6.0 blocks are not common at all anymore, unfortunately. They were only made for the first year or two. A 4.8/5.3 block bored out to 5.7 LS1 specs is doable though. Basically you can create an iron block LS1 with factory internals.

But there's plenty of aftermarket companies making LS blocks these days...

...speaking of which, did you guys see this series of the LS vs Coyote? Those engines are insane!

 

[Marky Dissod]

How did you figure the 4.8L V8s lived harder lives?

If a 4.8L & a 5.3L are doing the same amount of labor, even if the 4.8L has equal gearing as the 5.3L,
the 4.8L would be under a higher relative load vs the 5.3L to accomplish the same amount of 'work' as measured from the outside.
The 4.8L in the above example would spend less time in 4th, and more time in Power Enrichment compared to the 5.3L.
OR
Page 4-59 of my owner's manual:
A 2WD Tahoe with 4.8L & 3.73, and a 2WD Tahoe with 5.3L & 3.42, have the same Max Trailer Weight, 6,800lb, & the same GCWR, 12,000lb.
Page 4-60:
A 4WD Tahoe with 4.8L & 4.10, and a 4WD Tahoe with 5.3L & 3.73, have the same Max Trailer Weight, 7,600lb, & the same GCWR, 13,000lb.

Fate forfend there be any 4.8L paired to 3.23 ...

 

[AuroraGirl]

What do I mean?

The 4.8L V8s all lived harder lives; I don't think as many of them were made as the 5.3L, and I don't think as many 4.8L will still be around as 5.3L V8s.
However, some 4.8L and some 5.3L V8s were made with blocks that say
"4.8L-5.3L-6.0L"
(all three displacements) on their front passenger side. These blocks were designed to withstand being bored out as far as 4.000".
My hope is that many 4.8L V8s will find new life as 6.0L V8s, or whatever stroke ...

isnt the 6.0 block materially larger by a small amount to accomodate the bore diameter and also extend the bellhousing pattern by a small amount ?

 

[Marky Dissod]

isnt the 6.0 block materially larger by a small amount to accommodate the bore diameter and also extend the bellhousing pattern by a small amount?

4.8L 5.3L 5.7L 6.0L 6.2L & 7.0L pretty much all take up the same external physical space.
Although the 6.0Ls that mate to the 4L80E do have a different bellhousing bolt pattern, they take up the same amount of space as the 6.0Ls that mate to the 4L60E.

 

[stutaeng]

The "LS" bellhousing bolt patterns are all the same. A 4L80e will bolt up to a 4.8 or 5.3 as well. GM used a spacer on the LS engines flexplate to account for the shorter crank vs the SBC/BBC. The only exception was that first year 6.0 LS with the "long crank" (was also the first and only year of the cast iron heads). On that one, you can only mate it to a 4L80e, not a 4L60e, unless you get a special unique torque converter designed for it.

This thread discusses that in detail: https://ls1tech.com/forums/automati...xplates-converters-transmissions-spacers.html

 

[stutaeng]

If a 4.8L & a 5.3L are doing the same amount of labor, even if the 4.8L has equal gearing as the 5.3L,
the 4.8L would be under a higher relative load vs the 5.3L to accomplish the same amount of 'work' as measured from the outside.
The 4.8L in the above example would spend less time in 4th, and more time in Power Enrichment compared to the 5.3L.
OR
Page 4-59 of my owner's manual:
A 2WD Tahoe with 4.8L & 3.73, and a 2WD Tahoe with 5.3L & 3.42, have the same Max Trailer Weight, 6,800lb, & the same GCWR, 12,000lb.
Page 4-60:
A 4WD Tahoe with 4.8L & 4.10, and a 4WD Tahoe with 5.3L & 3.73, have the same Max Trailer Weight, 7,600lb, & the same GCWR, 13,000lb.

Fate forfend there be any 4.8L paired to 3.23 ...

I understand what you are saying. Yes, but that's too general of statement.

I think the general idea is: for 2 engines to be making the same amount of work, the smaller one if working harder (and wearing faster), right?

That's complicated because even if both engines are in the same family, they are not identical. In the 4.8 and the 5.3 case, the block is the same, so that doesn't matter. The rotating assemblies are what's different, with the 4.8 having a shorter stroke and different piston (but same bore). So the 4.8 will be obviously smaller, so it will be spinning at a higher RPM to make the same power. However, that doesn't necessarily mean it's going to be wearing faster. Piston design is pretty complicated, and you can actually design a piston with the same, or even less stresses than another piston for the same forces. This article discusses piston design in general terms: https://www.jepistons.com/je-auto-b...6jJJOCEQsyMOfmF4XmhFi6I4V-yuned6n7zPu447ERZwE

On the contrary, I speculate that a higher spinning (within a margin, of course) gas engine may actually live longer because it will have more lubrication and better materials on the newer engines vs the old engines. This isn't discussed much, but the other end of the spectrum is "lugging" a gas engine and the damage that causes to main/rod bearings because the low RPM (for the higher load):


Interesting fact: GM used Finite Element Analysis (FEA) on the LS engine design, back in the early 90s according Will Handzel on his book called "How to Build High-Performance LS1/LS6 V-8s". That was the early use of FEA on computers as far as I know.

 

[Marky Dissod]

On the contrary, I speculate that a higher spinning (within a margin, of course) gas engine may actually live longer,
because it will have more lubrication and better materials on the newer engines vs the old engines.
This isn't discussed much, but the other end of the spectrum is "lugging" a gas engine and the damage that causes to main/rod bearings,
because the low RPM (for the higher load):

Aside:
there's a thread about short -lived L87s that does not seem to understand what you're getting at here.

I'd grant that a 4.8L with 4.10 will likely live an easier / longer life than one with less advantageous gearing, precisely for the reasons you cite.

 

[99Sierra2500]

This discussion reminds me of Little Deuce Coupe by Beach Boys "She's milled and ported, stroked and bored." 5.3 is a stroked 4.8, and the 6.0 is stroked, and bored.

 

[stutaeng]

And I forgot how we managed to derail this thread once again...

Classic us! LOL

 

[AuroraGirl]

The "LS" bellhousing bolt patterns are all the same. A 4L80e will bolt up to a 4.8 or 5.3 as well. GM used a spacer on the LS engines flexplate to account for the shorter crank vs the SBC/BBC. The only exception was that first year 6.0 LS with the "long crank" (was also the first and only year of the cast iron heads). On that one, you can only mate it to a 4L80e, not a 4L60e, unless you get a special unique torque converter designed for it.

This thread discusses that in detail: https://ls1tech.com/forums/automati...xplates-converters-transmissions-spacers.html

the LS4 does not have a bellhousing like the rest, it uses the metric bellhousing (FWD 60 degree V6, like the 3800 and 3400 etc. 2.8l v6, et al) Youd need a rwd 4l60e for a 3800 to make it rwd or adapt

 

[Tonimus]

the LS4 does not have a bellhousing like the rest, it uses the metric bellhousing (FWD 60 degree V6, like the 3800 and 3400 etc. 2.8l v6, et al) Youd need a rwd 4l60e for a 3800 to make it rwd or adapt

Actually, the 3800/3.8l is a 90 degree, but uses the 60 degree bellhousing. Ultimately not a huge distinction, but we're swapping a 3.4L into a '76 MG Midget because of the smaller footprint of the 60 degree vs the 90 degree.

 

[AuroraGirl]

Nice!

Actually, the 3800/3.8l is a 90 degree, but uses the 60 degree bellhousing. Ultimately not a huge distinction, but we're swapping a 3.4L into a '76 MG Midget because of the smaller footprint of the 60 degree vs the 90 degree.

And yes good point. I knew the bell housing was 60 degree but yes good catch there.

The 3.4 isn’t bad but.. why? At least get a tunnel ran going like some grand ams. Good for like 3hp

 

[Tonimus]

Nice!

And yes good point. I knew the bell housing was 60 degree but yes good catch there.

The 3.4 isn’t bad but.. why? At least get a tunnel ran going like some grand ams. Good for like 3hp

There’s no space for a 90°. And the MG had like 40hp stock and it’s impossible to get parts for. 3.4 with a T5 will make a pretty good swap, I think. Lots of parts availability and “easy” to use factory fuel injection.

 

[Marky Dissod]

There’s no space for a 90°. And the MG had like 40hp stock and it’s impossible to get parts for.
3.4L with a T5 will make a pretty good swap, I think. Lots of parts availability and “easy” to use factory fuel injection.

By that very same logic, a 3.9L LZ9 or LGD would be even better.

 

[AuroraGirl]

There’s no space for a 90°. And the MG had like 40hp stock and it’s impossible to get parts for. 3.4 with a T5 will make a pretty good swap, I think. Lots of parts availability and “easy” to use factory fuel injection.

I meant more like what lead the choice for that specifically, modern fuel injection and decent aftermarket for all the replacement parts, not r maybe you have niche experience with performance on them etc
Maybe the t5 was your first part ybut it wanted then it was a matter of what will go in front of it dimensionally that’s found in junkyards and plentiful

 

[Tonimus]

It was a combination of factors. One of which being there’s actually some swap support for MGs with Gen I 60° swaps. Also sourced a running donor ‘94 Camaro for a good price. Lots of factors, but really it boils down to we wanted to and it’ll be fun.