Good luck with the build.

 

The two rear cylinders on these engines tend to run hotter than the other six.
This can cause destructive self detonation, which in turn damages the pistons and rings.

Now, you have a pressurized crankcase.

This is easily verified by removing the oil cap and seeing smoke coming out of it.
This can also cause your rear main seal to leak.

If you want to verify this, simply remove all your spark plugs
do a compression test and a leak down test.

Lay your spark plugs out in a sequence so that you know which cylinders they came from.

If the two rear cylinders have much oil on them, you know what happened.

In the meantime, I would not drive the car as more damage will occur to those cylinders.

—————————————————————————————————

You did not mention any modifications to your mass flow recovery system,
such as large intercooler, coolant tank in the trunk, etc.

These items are extremely important to ensure engine longevity
even if the engine is not modded when driven in hot climates.

And for those of you looking to improve horsepower, the cooler you can keep
that engine and IAT’s, the more horsepower you’re going to make!

Cheers

 

Running e85? Do you know anything of the tune like what AFR and timing was being commanded?

I would not just toss a BTR stage 2 cam. So many better options these days, especially if on e85. Couple guys to talk too would be @Lt1z here or Rick Crawford. Rick can get you a custom grind for you build.

 

Yes, the BTR cam‘s are getting a little old now.

Also, camshafts need to be matched to hp goals, cylinder heads, compression ratio
and finally engine rpm versus piston speed / piston CFM demand.

If the demand side exceeds the supply side, then peak horsepower will not be realized.

Cheers

 

We would be glad to get you setup with something appropriate for you build.

 

A rebuild on that block with the mileage would be fortunate. The cylinders are probably significantly out of round. You can't take more than .010 when machining them. crank probably good. Good luck!

 

These modified engines should use an iron block.

The easiest and most cost effective way to do so
is to go to the GM B15 LSX iron block.

This engine is guaranteed for 900 fwHP.

Now, cylinders stay round and one has ring seal.
Now, one also has a much improved oiling system.

Bore can now easily go to 4.185 inches with a power adder.
Without a power adder one can go to 4.250 inches.

Longer strokes can also be used with this block.

Since all one is doing with a supercharger is attempting to
make a small engine into a large engine.

One can now strategically build a larger engine and use lower boost.
This eliminates a lot of negative issues associated with a low efficiency blower, such as we use.

Cheers

 

The setup for the past 7 years has been very pleasant with the right amount of power and comfort with reliability for this daily driver.

Knowing a new build would be in the near future, some research on reputable shops who have skills on LS platforms in Orlando was done a couple years back. Conversations thus far have felt confident and transparent, more discussion on that later...

In regards to the BTR2 cam, it is an audio lopping profile that was a personal preference when listening to various clips online over the past few years. Not knocking science or perfectly balanced engineering, just a characteristic that is higher on the priority list than peak power.

Not wanting a wild setup where a tq stall needs to be addressed or obnoxious body shake is involved. Open to suggestions and video links lol!

2.5 Upper
9.1 Lower
B&B Test Pipes
Magnaflow X Pipe & Mufflers with DMH Cut-outs
Ported Supercharger & Snout
Airaid CAI
ZL1 Lid w/ Brick
Catch Can
Pennzoil Ultra Platinum Synthetic 5w30 w/ M1-113A Expanded Filter
Valve Cover Breather PVC
ID850 Injectors
NGK Iridium TR7IX Spark Plugs
Accel 9070C Extreme 9000 Ceramic Wires
Lingenfelter Varimax Intercooler Pump
Coolant Expansion Tank for SC
Green Belt
BMC Carbon Fiber Vented Heat Extraction Hood
BMC CF Splitter & Skirts
Double Drilled & Diamond Slotted Rotors w/ Hawk Performance Ceramic Brake Pads
Niche Verona 20" Concave 7 Point w/ Hankook Ventus v12 Evo 2
New OEM Struts all around
3 Camera Zenfox T3 Setup
Street Tuned with HPT
Dyno Nomad Max Power 576whp 579wtq
Best 1/4 128 mph 11.3 sec on street tires launched in second gear

 

Towed the V to the shop, decided to pull the bumper so the splitter won't be an issue.

 

Towed the V to the shop, decided to pull the bumper so the splitter won't be an issue.
View attachment 176684

Not pretty anymore…☹☹

 

Opportunity to repair bug damage now...which is a real eye sore.

And attend to those aging fog light housing units

 

The shop pulled my motor during Cadillac Attack here in Orlando Florida. They took some shots of the dirty block and bay.

The last fill of oil in order to start up and transit a short distance was overfilled a bit to much. Better then no oil 🛢

Quite a few leaks...the seals had minor leaks for the past few years

The overfill I assume overwhelmed the catch can and other manifold areas

It was never this dirty when cleaning up the TB and intake in the past

A few more captures

The spark plugs were new and tightened to spec, however it is recommended to snug them down guttentight...

Once the leak down and compression tests are completed, I'll post the results

Regardless, new water and oil pump for sure, LS9 head gaskets, poly motor mounts, trunnion kit, Stage 1 cam with chop...(keeping the low/mid TQ, instead of chasing HP max numbers)

 

To rebuild or turnkey this long block...
What is tariffing my mind right now!

600 HP/TQ using the parts that I have on a rebuild or get similar long block right now and slap my stuff on it. Daily doesn't need much more than stock.
However it will require the right sounding lope from that cam to make it feel right.

 

To rebuild or turnkey this long block...
What is tariffing my mind right now!

600 HP/TQ using the parts that I have on a rebuild or get similar long block right now and slap my stuff on it. Daily doesn't need much more than stock.
However it will require the right sounding lope from that cam to make it feel right.

One can either optimize the camshaft for HP, or the Exhaust Sound.

For sound one can simply open the exhaust valve (EVO) early during
the power stroke, or close it late (EVC) during the overlap period.

---------------------------------------------------------------------------

However, opening the exhaust valve early means you are going to waste energy
as you are now going to burn air and fuel (the mass charge) in the exhaust pipe.

And closing the exhaust valve late means you will allow incoming air and fuel (Mass Charge) to pass directly from the intake valve and exit out the exhaust valve, as you have increased the 'Overlap Triangle' period. This does also help cool the chamber, but also does hurt "Volumetric Efficiency (VE%)"

Also, when both the intake and exhaust valves are open together during the overlap period, engine vacuum tends to drop and can cause issues with such things as poor idle, car won't tractor at low engine rpm and power brakes can have an issue.

So, there is no 'Free Lunch Here'..

Cheers

 

Thanks man, loving the pros and cons you describe clearly.

The idea of picking up an ATK SP26 4G 408 built short block, putting the LSA cleaned up heads, throwing the cam in there, supercharge and the rest back together is definitely in the running for what I'm looking to do.

The current short block needs new rotating anyway, so the thought of selling off the block and getting a known built one decreases the machine shop and builder time. Options options

 

Settling on a built short block, cam kit, torque converter, and having a valve job on the LSA heads.

Side note:
As many of you dedicated enthusiasts understand; patience & realistic goal settings along with reflecting on the budget & timeline will be beneficial in the long run.

@Rubber Duck ... I love the suggestion of the B15 along with your passion to help share knowledge on this forum.

@Lt1z ... great conversation on PM, much appreciate your insight as well.

@Jayrolla ... your advice about working with the builder to set the goals on the cam; that is always a great idea. Thanks you for mentioning it.

@specialp ... Wildly agree with you on being "fortunate" reusing parts from the blown out LSA. My installer gave the facts, however has not sent me the pictures yet. More to come...

And thanks to others helping along this effort. As with all builds, my build won't be for everyone...so I'll try to be as transparent with what my goals are now as I'm locking in on the effort.

I write too much, so if you are reading this, please note I'm posting this way to reflect back on at some point. (I'll move along now and start posting the relevant topics!)

 

I write too much, so if you are reading this, please note I'm posting this way to reflect back on at some point. (I'll move along now and start posting the relevant topics!)

You can substitute about 1,000 words with one picture or so I’ve been told. 😉🤣🤣

I’m looking forward reading about… I mean seeing this come together! 🙌

 

Built short block:
ATK SP36-G4-B LS 408CI Stroker Short Block -29cc Dish Pistons 58 Tooth Boost/Nitrous Ready

CAM:
BTR PDS STAGE 4 CAMSHAFT V2

Torque converter:
Circle D - GM 258mm Pro Series 6L80E

Heads:
Installer has a machine shop to square and valve job the LSA heads. More on that later.

The short block will take about 8 weeks.

My goals on this daily driver are mild IMO.

Budget:
Near $20k

Power:
600-700 wheel with pump gas (no e85 or meth at this point)

Timeline:
Florida is getting hot, however I will not rush the installer/tuner...2025.

Personal Tweak:
Needs Chop... Tune friendly, forgiving if highway gas is dirty, puts a smile on my face.

To pull the motor was about $4k (with cleaning). Compression & leak down another $500.

I talked with folks at ATK, BTR, CIRCLE D and the conversation were aligned. This will be a build that should cover those requirements.

 

Built short block:
ATK SP36-G4-B LS 408CI Stroker Short Block -29cc Dish Pistons 58 Tooth Boost/Nitrous Ready

CAM:
BTR PDS STAGE 4 CAMSHAFT V2

Torque converter:
Circle D - GM 258mm Pro Series 6L80E

Heads:
Installer has a machine shop to square and valve job the LSA heads. More on that later.

The short block will take about 8 weeks.

My goals on this daily driver are mild IMO.

Budget:
Near $20k

Power:
600-700 wheel with pump gas (no e85 or meth at this point)

Timeline:
Florida is getting hot, however I will not rush the installer/tuner...2025.

Personal Tweak:
Needs Chop... Tune friendly, forgiving if highway gas is dirty, puts a smile on my face.

To pull the motor was about $4k (with cleaning). Compression & leak down another $500.

I talked with folks at ATK, BTR, CIRCLE D and the conversation were aligned. This will be a build that should cover those requirements.

I do not see anything related to additional cooling in your list.

As you generate more HP, one must be sure one can dissipate the additional heat.

As you spin the blower harder, one must also be sure they improve the mass charge
recovery system, especially when running on gasoline.

As we generate more horsepower or spin the blower faster, heat becomes your major enemy.
One then must manage that heat or possibly suffer losing the engine.


Cheers

 

Delayed PICs of the broken, oil went to low when cornering potentially...

The compression was low enough on a few chambers the piston fell into his hand

Making pretty colors the expensive way. Who is keeping score on this game?

Spin spin spin, bearings want to play too

Yup, broken stuff

Shedding weight

Jigsaw fun

Short block being built right about now...L96 408 Stroker

 

Nice job!

In Jest...
I have not seen one so completely ruined in several years now…☹☹

Good Luck!

 

After pulling the V to the garage, I turned it over for a minute to witness how oil pressure was still looking fine, idle sounded normal, no warning lights or alerts, no abnormal smells in the exhaust.

However, the cold motor ticking was already known, but the excessive smoke in the crankcase was not

She is old, needs something fresh!

 

174 days, that is how long it can take for a built short block in 2025.
In the shop on a pallet: SP36-G4-B!

Peeked in, looking good...not unwrapping until install time.

In the meantime, other V side projects have been underway.

Early morning wrenching...Florida sun does not play nice.

Lifted for months to avoid tire issues.
Pulling parts and repairing while accessable.

Pulled the old tint off, wet sand and polish

new tint Legend PPF

disconnect the cutouts and drop the exhaust

making way for ARH long tube to X

out with the Magna Flow

soon the connectors will be paired up to the ported and race valved heads

No axle back yet, just a test fit on the turn down

More later...not trying to rush a good thing.