SteveDoten

Crank pulley, for the past 15 years this has been a dramatic subject

SAVE $$$$, SAVE TIME, KEEP THE Corvette in the game

WOBBLE, WOBBLE, WOBBLE.......
NOTE: OEM GM crank pulleys have an aluminum inner with steel outer/rubber or elastomer separates the two parts
VERY COMMON FAIL ITEM IN THE LS CARS/C5
1. Before you remove the stock crank pulley, inspect it for wobble(out of round/radial/axial runout), with the engine running at idle, very common for the outer steel pulley to 'shift'
WEIGHTS......
1b. GM may have installed weights on the OEM pulley to zero balance the pulley or with internal balance(consult GM tech data, topic has been covered) if you do replace the OEM pulley with another new GM pulley, you should index and transfer the wieghts(again, consult GM tech data for details)
1c. I have never had an issue replacing the OEM pulley with an ATI, Powerbond, etc., but it's good to index and be aware of the details

BOLT REMOVAL

1. Kent Moore flywheel tool attached to block(mounts in place of starter)
1a. Lesser way, trans in gear with wheels on ground
1b. Auto? I wouldn't test the parking pawl strength
1c. IR2135Ti impact gun will remove any LS crank bolt in seconds

INSPECT BOLT

1. red loctite? somewhere has been here, GM does not use loctite on bolt, you will see the orange sealant under the head of bolt
2. threads, look OK? TAKE NOTE: how LITTLE of the threads actually penetrate into crank

PULLEY REMOVAL

1. Index mark the pulley; scribe/white paint, something, even if don't re-use the same pulley, INDEX everything just in case
2. MEASURE the crank snout to crank pulley face depth, WRITE IT DOWN. Compare to OEM spec. Now you have the OEM spec and a reference for installation
3. Keep the measurement for step 2 somewhere safe; heck, write it in sharpie on the front cover or on the alum. cradle of the car
4. USE the Kent Moore LS crank pulley removal tool or the OTC 6667 removal tool, I've used the OTC tool countless times with success

PULLEY INSPECTION

1. IF you decide to reuse the steel/aluminum/elastomer wobble wonder pay close attention to the rubber/elastomer between the outer/inner pulley, wobble, wobble, wobble
2. Inspect the Crank pulley SNOUT, the grey OEM 'national' seals often 'eat' into the snout................OIL LEAK is result

PULLEY INSTALL

1. Measure the crank snout OD vs. the pulley ID, compare to GM tech data for acceptable limits, only a few thou here for the interference fit
2. USE Kent Moore LS pulley install tool or the infamous "HAWK crank install" tool
3. You will feel/see the pulley get within an 1/8" of the seated position, if the motor is in the car, simply compare the AC belt ribs to the AC idler pulleys for depth location(you don't want to go too far, but I'm hoping the effort required on the pulley install tool will keep you aware)
3a. USE old bolt to Torque to 240ft/lbs and comply with step 4.
4. MEASURE snout depth to pulley face, compare to GM tech data(the A/C belt is a ballpark method), MEASUREMENT is the correct procedure
5. Replace old bolt with new GM bolt, torque to 37ft/lbs and then turn 140 degrees
6. You have already complied with step #4, but why not eyeball or see how the A/C belt will line up? this is just another step to see if you are in alignment(quite a few pulleys available in the aftermarket)

SteveDoten

RECAP/NOTES:

TOOLS REQUIRED:
Kent Moore LS Flywheel holder($40-60)
OTC 6667 pulley removal tool OR Kent Moore pulley removal tool
Hawk LS pulley install tool OR KM equiv.

INSPECT PULLEY:
grooved on pulley snout? the inner crank pulley is aluminum, it can groove from a prior improper front cover install or from time/wear(I do NOT have the EXACT answer here), I have seen them bad at 15k miles and good at 100k miles

REPLACE FRONT CRANK SEAL/FRONT COVER SEAL AND USE NEW GM BOLT OR ARP BOLT:
1. New crank seals are available for about $10-15, the newer style is black in color(started OEM in 2005?), Every crank seal I have removed from a C5 that is OEM is the grey 'NATIONAL' seal (will update pn)
1a. New front engine cover seals now have the black silicone seal vs orange, also use RTV in bottom corners
2. New GM crank bolts are $4
3. ARP bolts are about $30-40, get correct tech data from ARP on torque

GM TECH DATA: HUGE, always base your Corvette maintenance off of the tech data and follow torque specs(if OEM application)

SteveDoten

OIL PUMP, mine as well cover that also.........

1. I always replace the OIL PUMP with a GM LS6 or LS4 pump and use a new blue GM O-ring
(port and shimming of spring is another topic)

2. OIL PUMP, remove the old pump, remove the 10mm bolts that retain the front cover, inspect for FOD(foreign object damage), note the pump gears, dot faces outward

3. O-RING, this is a major issue, if you try to 'push' or force the tube into the pump, the Oring is going to FAIL
3a. have pump loose on block, Oring installed on pickup tube and install, lube Oring with engine oil or petrolatum(pet)

TIMING CHAIN

1. LS2/3/7 GM OEM replacement at minimum, about $40
2. (better) Katech IWIS C5R Racing chain, about $150
3. double roller, another topic

SteveDoten

Please PM or call 860-989-8972 if I missed something, I would like to add the pics of crank pulley to crank depth from the manual

I'll add the pinning 'how to' soon, I have pinning kits here in stock ready for shipment

All supercharger cars will have the crank pinned, why not do this on any crank pulley install?

lucky131969

Attached.

SteveDoten

Thanks Lucky, that depth measurement is rarely discussed on the forums; Again, I'd like to point out in my original post......the AC pulley to crank pulley is only to 'ballpark' the installation, correct measurement using a dial caliper with the above range will provide accurate results

Attention to detail and following tech data with a sense of urgency.........These are the words of Air Force Leadership

Knowledge/correct information/experience is the foundation for any proper Corvette repair

_r2h

Curious, how does one measure the accurately? Tools needed, method to use said tool?

madmatt9471

Nice job Steve!

Thanks,Matt

leadfoot4

Vernier calipers. One edge of the caliper frame against the damper face, the sliding part against the face of the crank.

2MFFZo6

good intel thanks.............

SteveDoten

this info is not optional when doing the crank pulley swap

I'm going to update and combine a few of my other threads

No need for people damaging LS motors on repair/cam swaps

double timing chain with the spacer flipped on the output bore side? another potential issue that could happen.

lionelhutz

Good info. I always find applying a little heat to the pulley makes it slide on so much easier. 200* in the oven for about 20 minutes works well.


1a. For me, trying it that way but running out room to swing the wrench before the bolt started moving was when I knew for certain those cheaper BMW driveshaft couplers were absolutely no good!

1b. The parking pawl won't hold the engine from turning. You need to lock the flywheel on an automatic.

SteveDoten

Heat; I don't do it, I the Air Force has me engrained with "by the book", unless one of my go to people/heavy hitters (Don Kinder, Bret Bradbury, Nick@ARH, Rodney@RPM(TJ and Jeremy also), Andy and Jesse@A&A, Mike Sedor) tell me otherwise............I'm following the GM tech data to the "T".

1a. BMW couplers, too much time involved VERSUS the labor on "lesser" couplers, always better to do it ONCE.

1b. Parking pawl, although many have done the A4 cars with the wheels on the ground; The Kent Moore flywheel locking tool works perfect everytime

SteveDoten

If anything is unclear I can help

lionelhutz

Heat - This can't be the first time you've read about this? Don't go too hot so the heat isn't anything more than the balancer would be subjected to when the engine is at operating temperatures. You should try it because it makes life so much easier. The balancer slides right on using the old stock bolt to finish seating it. Yes, I just posted that too. The balancer slides on so far that the stock bolt is just needed to seat it the last bit. Using the stock bolt is fine as long as you're not stupid about it. I have seen others post use up to 350* but I don't feel comfortable going above the engine operating temperature.

On small-blocks with the keyway, a little heat usually lets me seat the balancer without even using the bolt or an install tool at all. Line it up and give it a good push and it seats with a nice clunk. However, the LS engine balancer being a tighter intereference fit without the keyway stops it from going all the way.

The auto trans has no solid connection between the engine flywheel and the parking pawl or the output shaft. Can you explain how having the wheels on the ground or the engine in gear could possibly hold the engine from rotating????

Level8Drummer

Anybody know the proper GM Spec for crankshaft snout Outer Diameter?

Everybody references it, but nobody lists it...

Thanks

Level8Drummer

vettenuts

I have my actual measured numbers for the crank and the ATI damper, unfortunately after 20 minutes of looking I can't find them. I know the ATI is very specific on the amount of interference fit and mine fell within the specifications.

SaberD

III. Balancer Installation:
A. Inspect the crankshaft for burrs, nicks, etc and file to clean up. Using a stone or file,
create a slight radius on crankshaft end to break the sharp edge
B. Anti‐seize lubricant is highly recommended for the crankshaft hub prior to installation.
C. Press fit of the hub to the crankshaft is vital to transfer harmonics to the damper
assembly. The recommended press fit for the LSx engine is .0007” ‐ .0009”. For non‐OEM
cranks, the crank must be checked with micrometers and the hub with a dial bore gauge to
verify fit. Most OEM cranks are held to +/‐ .0002” while most aftermarket cranks are held to
+/‐ .0005”. Hub bores are tight to accommodate aftermarket cranks and most hubs will require
honing. DO NOT HONE ALUMINUM HUBS. See special instructions for dampers with
aluminum hubs