what's the proper ARP part #for a LT4 wet sump harmonic balancer/crank pulley?!

Schroeder · 07-15-2022, 07:53 PM

I pulled the crank pulley of a 2019 ZL1 LT4 engine. These are torque to yield bolts. ARP said 234-2504, but this is 30mm longer than the bolt that came off the engine. It won't work. Amazon has 234-2503 listed, and I ordered it too. Its package doesn't list the Lt4 as proper application though. The package lists ls1. What's the right answer here? I don't want to install the wrong bolt and be told I can't get my my money back. I have two bolts different places have listed as the right part, but they're different.

Also, the flywheel bolts ARP listed are 234-2801. They're 5mm or so longer than the ones that came off the engine; granted it's an auto Lt4 that had a flex plate on it. The crank shafts don't have a different rear flange on them so they?

Evansa22 · 07-15-2022, 10:24 PM

This is what I used, the 2504 says ls7 and lt1 but I believe it's too long for our application.

swisstyphoon · 07-16-2022, 02:09 AM

Use a new OEM Crank/balancer bolt. I have heard about too many ARP balancer bolts coming loose! If you install an ATI balancer, the LT4 bolt is too long, then you would need the LS bolt, which is shorter.

Evansa22 · 07-16-2022, 10:33 AM

If your using stock balancer then by all means go for the stock tty crank bolt. If you use an ATI balancer ,you'll need the arp bolt or have to modify the stock bolt to get it to fit.

Schroeder · 07-17-2022, 05:47 AM

Quote:

Originally Posted by Evansa22

This is what I used, the 2504 says ls7 and lt1 but I believe it's too long for our application.

Yes. I have the 234-2503 too. It's the same length as stock. I will be using an ATI balancer. It's one reason I opted for the ARP bolt because I don't want to mess with turning down the stock bolt's large flange. Arp's 234-2504 definitely is too long, and it sounds like others have figured this out.

Does anyone have any input on the flex plate bolts? This was an auto engine now being paired with a T56 magnum 6-spd, and the ARP flywheel bolts are 3-5mm longer than the GM flex plate bolts that silver sport transmission sent me to make the flywheel to the engine before I decided to get these ARP bolts 234-2801. Perhaps the flywheel is slightly thicker than the flex plate, and that's the reason for the added length. I have the bellhousing and trans mounted now, and I can't see if the bolts are sticking out too far. It'd be great if someone could confirm the ARP part number 234-2801 for the flywheel bolts before my return window runs out (which will be before I take the bellhousing and trans off again.

swisstyphoon · 07-17-2022, 06:11 AM

This is the bolt you need for the ATI balancer on the LT4 wet sump.
12557840
https://store.vengeanceracing.net/gm...ncer-bolt.html

I have no idea which Flywheel bolts?

07-15-2022, 07:53 PM	#1
Schroeder Drives: 77 Pontiac Trans Am Join Date: Jun 2021 Location: NW, Ohio Posts: 7	what's the proper ARP part #for a LT4 wet sump harmonic balancer/crank pulley?! I pulled the crank pulley of a 2019 ZL1 LT4 engine. These are torque to yield bolts. ARP said 234-2504, but this is 30mm longer than the bolt that came off the engine. It won't work. Amazon has 234-2503 listed, and I ordered it too. Its package doesn't list the Lt4 as proper application though. The package lists ls1. What's the right answer here? I don't want to install the wrong bolt and be told I can't get my my money back. I have two bolts different places have listed as the right part, but they're different. Also, the flywheel bolts ARP listed are 234-2801. They're 5mm or so longer than the ones that came off the engine; granted it's an auto Lt4 that had a flex plate on it. The crank shafts don't have a different rear flange on them so they?

07-15-2022, 10:24 PM	#2
Evansa22 Drives: 2018 HBM ZLE Join Date: Aug 2017 Location: In the garage Posts: 891	This is what I used, the 2504 says ls7 and lt1 but I believe it's too long for our application. Attached Images

07-16-2022, 02:09 AM	#3
swisstyphoon Former GM Technician Drives: 2018 ZL1 A10, 06 Silverado Duramax Join Date: Sep 2009 Location: Switzerland Posts: 405	Use a new OEM Crank/balancer bolt. I have heard about too many ARP balancer bolts coming loose! If you install an ATI balancer, the LT4 bolt is too long, then you would need the LS bolt, which is shorter. __________________ 2018 Camaro ZL1 A10 Rotofab Big Gulp, Nick Williams 103, Magnuson 2650, 9.17" (14%) lower, 90mm upper, Vengeance Racing Heads (LME) Cam Package (Cammotion Stage 1), Johnson Lifters, DSX dual intank pump, Lingenfelter high flow check valve, Motion Raceworks Flex Fuel adapter, LPE Big Bore Hpfp, XDI 30% Injectors, BBK shorty headers, Custom 2.75" down pipes, Gesi Gen2 high flow cats, MM catch can. 2006 Silverado Duramax Diesel MPI Compound Turbo 40% over Injectors Efi Live DSP5 Tuning Follow me on Instagram: SwissZL1

07-17-2022, 06:11 AM	#6
swisstyphoon Former GM Technician Drives: 2018 ZL1 A10, 06 Silverado Duramax Join Date: Sep 2009 Location: Switzerland Posts: 405	This is the bolt you need for the ATI balancer on the LT4 wet sump. 12557840 https://store.vengeanceracing.net/gm...ncer-bolt.html I have no idea which Flywheel bolts? __________________ 2018 Camaro ZL1 A10 Rotofab Big Gulp, Nick Williams 103, Magnuson 2650, 9.17" (14%) lower, 90mm upper, Vengeance Racing Heads (LME) Cam Package (Cammotion Stage 1), Johnson Lifters, DSX dual intank pump, Lingenfelter high flow check valve, Motion Raceworks Flex Fuel adapter, LPE Big Bore Hpfp, XDI 30% Injectors, BBK shorty headers, Custom 2.75" down pipes, Gesi Gen2 high flow cats, MM catch can. 2006 Silverado Duramax Diesel MPI Compound Turbo 40% over Injectors Efi Live DSP5 Tuning Follow me on Instagram: SwissZL1

07-16-2022, 10:33 AM	#4
Evansa22 Drives: 2018 HBM ZLE Join Date: Aug 2017 Location: In the garage Posts: 891	If your using stock balancer then by all means go for the stock tty crank bolt. If you use an ATI balancer ,you'll need the arp bolt or have to modify the stock bolt to get it to fit.

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