crankshaft pulley bolt ... scary indeed ... loud pop ... wow

[myhui]

How many times should that nut turn before it's loose enough to be turned by a 12" ratchet? I have mine pop loose on the first try, using breaker bar with 24" extension with 1/2" socket, crank stabilized by special tool connected to another breaker bar going to the floor. That first time the nut probably turned about 90 degrees. So I tried again, and got another loud pop. But still, the nut doesn't seem to be getting any looser.

I'm not using a hoist, so I can't do those tricks where you lower the car slowly and use weight of car to turn the nut. I already soaked it with penetrating oil a few days ago, and soaked it again before starting to work on it.

Really funny question now: should I be turning the nut counter-clockwise ?

Why does this thing have to be so tight anyway? I just don't see the need.

 

[angus]

hahahaah ! you've obviously never had i crank pulley come off your car at 8000 rpm!!! yes it needs to be tight - as tight as they say or tighter,and yes it's a bitch! keep turning lefty-loosy , dont worry the threads are tough you wont break/strip them too easy

 

[ftuhy]

The specified bolt torque is 181 lb-ft. That's beyond the range of most 1/2" torque wrenches. I don't know if your tool set is Snap-On or K-Mart, so its possible you cracked the socket. A WAG: that snapping sound you hear could be a cracked socket "skipping" to the next postion under high torque.
Per Gary Kentosh's article on changing the timing belt, loosening torque could approach 250 lb-ft.

Look at your 19mm socket closely for a fine crack. If possible, use a 6 point rather than a 12 point socket - less chance of rounding the bolt or the socket "skipping" at the high torque. A 19mm impact socket might be a good choice.

Hope that helps.

Frank
'96 NSX-T red/tan

PS I'm getting ready to change my timing belt this year, and so have been reading up. The only thing that intimidated me in the whole procedure was loosening & re-tightening the pulley bolt. I'm getting ready to order the special pulley holder as well as a 3/4" torque wrench. (Harbor Freight has the torque wrench for $70: # 808-7VGA. Its 50 to 300 ft-lb at 4% accuracy; it will probably wear out quickly. But then again, I'll use it once every 5 or 10 years, so who cares.)

I'm even more anal with the NSX than I've been with my Corvettes, so no bolt goes back on the car without the use of a torque wrench, and "Never-Seize" on every bolt. That crank pulley bolt sure calls for a torque wrench, especially with those fun visits to 8000 rpm.

 

[myhui]

The bolt came off on the third try. Pictures enclosed. The bolt did turn on each "pop". The noise comes from the snap-back of the tools. The extension and breaker bar combination rotated 60 degrees before anything would budge. I only use 6 point sockets, all Made In USA, Craftsman brand. The Craftsman aluminum jack has a two section handle with quick release in the middle, perfect for this application. Per the manual, engine was raised up 5 degrees to free up more space for removing those timing belt covers. Note use of cement blocks with steel plate on top to support car, while front wheels are on the ground. This is a lot more stable than jack stands, and also keeps the car low for easier access.

I thank a Prime member who gave me the tip of using the jack's handle for added leverage on the breaker bar.

Does anyone have a tip on how to re-align the transmission mount so the bolt will go in smoothly? I can use a mirror and visually check for best alignment while someone else adjusts engine height on the jack.

I'm getting ready to order the special pulley holder as well as a 3/4" torque wrench. (Harbor Freight has the torque wrench for $70: # 808-7VGA. Its 50 to 300 ft-lb at 4% accuracy; it will probably wear out quickly. But then again, I'll use it once every 5 or 10 years, so who cares.)

Here is a nice Snap-on Torque Wrench that's reasonably priced and has 1% accuracy. They make a whole range of models, so browse around.

 

[Zennsx]

The bolt came off on the third try. Pictures enclosed. The bolt did turn on each "pop". The noise comes from the snap-back of the tools. The extension and breaker bar combination rotated 60 degrees before anything would budge. I only use 6 point sockets, all Made In USA, Craftsman brand. The Craftsman aluminum jack has a two section handle with quick release in the middle, perfect for this application. Per the manual, engine was raised up 5 degrees to free up more space for removing those timing belt covers. Note use of cement blocks with steel plate on top to support car, while front wheels are on the ground. This is a lot more stable than jack stands, and also keeps the car low for easier access.

I thank a Prime member who gave me the tip of using the jack's handle for added leverage on the breaker bar.

Does anyone have a tip on how to re-align the transmission mount so the bolt will go in smoothly? I can use a mirror and visually check for best alignment while someone else adjusts engine height on the jack.

Here is a nice Snap-on Torque Wrench that's reasonably priced and has 1% accuracy. They make a whole range of models, so browse around.

Reasonably priced for who?? Donald Trump?

 

[ftuhy]

Glad to hear the "pop" was the tools. I'll keep that in mind when I do my timing belt.

Frank

PS - Most of my tools are Craftsman, too. In over 40 years, I've broken only 2 sockets. They are hard to beat for the money.

 

[myhui]

Reasonably priced for who?? Donald Trump?

This is the second lowest priced unit in that product family: http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=76640&group_ID=19917&store=snapon-store&dir=catalog

$323.50 list. 5 to 100 ft. lbs., 3/8" drive. Accuracy (Fixed Head Models) 2%CW, 3% CCW.

For super-heavy torque, the manual method is best: just put a few bricks in a sack, measure extension length, weigh bricks, and bounce the bricks on that lever until it won't budge anymore. It's quite accurate too. That's also the way farmers measure all kinds of produce in open-air markets in Hong Kong, even now. Notice I already have bricks in my garage ... I do plan ahead.

 

[sahtt]

Sounds like you have it figured out.

I have several tools solely for timing belt jobs. One of my favorites, though it is quite crude, is a snap-on chain wrench. It takes a little finesse but I use it to get off cam pulley's etc. as well.

The NSX crank pulley is actually about the norm as far as 'difficulty' is concerned. Many cars require near 400lbs to get the pulley off, usually the mid 200's is spec for tightening it.

I had a hard time finding a 'do it all' torque wrench with the capacity I wanted, well over 300lbs of tq. I tried some high end stuff but no matter what they broke at about the same rate. The gear inside the wrench would shear/shatter after a few TB jobs unless I was very careful.

Now I just use a 90$ from Lowes. I've replaced it 3-4 times, but it's a no-questions-asked lifetime warranty and it's about 4 minutes away so no big deal.

I went through 2 torque wrenches in one afternoon when I did 2 TB jobs on Lexus LS400's and a couple brake jobs; I always tighten every nut to spec, even the lug nuts on a stock civic.

 

[myhui]

I had a hard time finding a 'do it all' torque wrench with the capacity I wanted, well over 300lbs of tq. I tried some high end stuff but no matter what they broke at about the same rate. The gear inside the wrench would shear/shatter after a few TB jobs unless I was very careful.

The pdf file in the FAQ on timing belt replacement also specified a torque wrench for removing the bolt, and I think that's a mistake. A breaker bar is what you're supposed to use to loosen the bolt. You never use a torque wrench to loosen anything, unless you want to measure the removal torque. In this case, that piece of information is not that useful, and it can be closely approximated by manual measurements without a torque wrench.

A breaker bar is designed to take abuse, and I'm sure my Craftsman unit won't break at well over 300 ft-lbs. Coupled with an extension, it's capable of loosening anything.

But back to my original question of why this bolt does not need to be so tight at all. This is the part of the car that's made of the strongest steel, since it's part of the crankshaft, so the material is completely capable of taking this torque, and that's why it's specified to that level. The crankshaft and timing belt pulleys both use a key to align with the crankshaft, so they are impossible to put out of alignment by a loose bolt unless the whole thing flies off. And you don't need that torque to prevent it from flying off.

Imagine the nightmare scenario: the bolt breaks before coming loose, and you can't drill it out. Then you'd have to do the mother of all engine refreshes by replacing the crankshaft. Curiously, that never crossed my mind until a few days later after I got the bolt out cleanly.

 

[stacy'snsx]

Imagine the nightmare scenario: the bolt breaks before coming loose, and you can't drill it out. Then you'd have to do the mother of all engine refreshes by replacing the crankshaft. Curiously, that never crossed my mind until a few days later after I got the bolt out cleanly.

This was my biggest worry !!!!
I just removed mine 10 minutes ago,Thank-goodness !
This thing was on TIGHT !
But all is well now.
Thanks to NSX prime again for all the info.

Stacy

 

[myhui]

I just removed mine 10 minutes ago,Thank-goodness !

Did you use a breaker bar or a torque wrench for removing the bolt?

Did you send your car to SoS to install the Gruppe M?

 

[stacy'snsx]

Did you use a breaker bar or a torque wrench for removing the bolt?

Did you send your car to SoS to install the Gruppe M?

Yeah, I had SOS put the motor,tranny and Gruppe M in.
But that is in another thread.
Here is the link
http://www.nsxprime.com/forums/showthread.php?p=726406#post726406

I ended up talking to Devin(@ AEM) and he suggested what I already was planning,3/4" impact gun.
One hit with the trigger and it came off,no problems at all.
It is amazing that when something is torqued to spec how much extra is needed to break it loose.
Anyway,all went well and onward and upward(HP that is).

Stacy

 

[UberNSX]

Imagine the nightmare scenario: the bolt breaks before coming loose, and you can't drill it out. Then you'd have to do the mother of all engine refreshes by replacing the crankshaft. Curiously, that never crossed my mind until a few days later after I got the bolt out cleanly.

Well that thought started crossing my mind after shearing a 3/4" to 1/2" drive impact-rated reducer with a 5.5 foot cheater.

It started getting more strident after a 3/4" impact rated at 950 ft/lb, with a 20 gallon tank behind it, didn't budge the bolt.

This is after being soaked every day for a week with PB Blaster.

Next step is full 3/4" drive breaker/extension/socket. I guess. I got nothing else. But that nightmare still concerns me and I'm hesitating because of that.

Here's a question: has anyone heard of a crank pulley bolt shearing on a 3.0 or 3.2? I've heard of plenty snapping on the 2.2 but there's a lot more 2.2 out there.

 

[myhui]

Did you try using an impact wrench? I have a CP-8750.

http://www.amazon.com/Chicago-Pneumatic-Electric-Impact-CP-8750/dp/B0002JMBNI

Just give it a 30 second blast 100 times over 10 days and it might break lose.

 

[ftuhy]

When I did my timing belt, I used a 3/4" torque wrench (approx. 3' long), set to about 300 lb-ft to loosen the bolt. (I did that so I knew I was not going beyond the rating of the torque wrench.) All extensions, etc were 3/4", with a 6-point socket. I needed two 3/4" extensions. Only having one long 3/4" extension, I tried using a long 1/2" extension (50+ year old Craftsman). The 1/2" extension began to twist (but was undamaged), so I borrowed another 3/4" extension.

It made one frighteningly loud crack/pop when the bolt broke loose. But, after that first 1/8 to 1/4 turn, I could have removed the bolt with a 3/8" drive ratchet. In any case, I didn't hit the 300 lb-ft seeting on the torque wrench when the bolt came loose. However, it was still way more force than it took to re-tighten the bolt (approx 180 lb-ft, if I remember correctly)

Note that if you use a 12 point socket (especially an inexpensive one), the socket itself could flex and jump on the bolt head, making a loud popping sound but still not loosen the bolt.

I don't recall reading about or talking to anyone who had sheared the crank bolt on an NSX. But, I still have to say that removing that bolt was the step that concerned me the most in the whole TB process.

A 3/4" impact wrench with a 6-point socket appears to be the most popular solution for you from what I have read in this thread.

Oh, if you get the bolt off and are doing the timing belt, check out my photo from my '96 of where all the cover bolts are hiding -- http://www.nsxprime.com/photopost/data/500/medium/Timing_belt_cover_bolts.jpg

 

[UberNSX]

The pdf file in the FAQ on timing belt replacement also specified a torque wrench for removing the bolt, and I think that's a mistake. A breaker bar is what you're supposed to use to loosen the bolt. You never use a torque wrench to loosen anything, unless you want to measure the removal torque. In this case, that piece of information is not that useful, and it can be closely approximated by manual measurements without a torque wrench.

A breaker bar is designed to take abuse, and I'm sure my Craftsman unit won't break at well over 300 ft-lbs. Coupled with an extension, it's capable of loosening anything.

+1 (or in English, I second that opinion)

All extensions, etc were 3/4", with a 6-point socket. I needed two 3/4" extensions. Only having one long 3/4" extension, I tried using a long 1/2" extension (50+ year old Craftsman). The 1/2" extension began to twist (but was undamaged), so I borrowed another 3/4" extension.

I'm pretty close to that setup, with just a single 16" 3/4 drive extension. The only thing I don't have, to go full 3/4 drive all the way through, is a 3/4 x 19mm socket that is thin enough to fit through the center of the crank pulley holder tool. I'm looking for one of those. Closest I've come up with is a 3/4 x 3/4 thin-wall deep-well impact socket that would need to be ordered. (19mm = .748 inches... close enough!)

I don't recall reading about or talking to anyone who had sheared the crank bolt on an NSX. But, I still have to say that removing that bolt was the step that concerned me the most in the whole TB process.

I'm just hoping it's because those bolts are really strong and not because of the statistics of there being not many NSX out there. I wonder if Larry B or Barnman have ever seen that happen?

Did you try using an impact wrench? I have a CP-8750. Just give it a 30 second blast 100 times over 10 days and it might break lose.

A 3/4" impact wrench with a 6-point socket appears to be the most popular solution for you from what I have read in this thread.

The impact I've been using throws three times the torque of the CP, actually. But the lack of success even after changing over from 1/4 to 3/8 NPT (we're going on two weeks of beating on it, with a HUGE 3/4 impact gun and a HUGE tank) indicates a change in strategery may be in order

I'm adding your photo to my scrapbook, ftuhy, thanks! I've seen it before but didn't print it out along with the .pdf guide, and then lost track.

 

[UberNSX]

Yay, bolt off. I think the #1 problem is lost force, caused by many factors (tool flex, joint flex, etc). Once I had full 3/4 drive and a single extension, the thing popped right off. Putting 600 ft/lb and losing half or more to flexion isn't getting that bolt off. Everything need to be tight and solid even more than big and beefy, IMO.

Oh, and the noise wasn't that bad either.

I'll throw this out there for anyone out there tackling the job and buying tools. I figure if you start from scratch and get everything, you'll be a little over $100, and you'll be ready for next time.

1) Powerbuilt 45mm crank pulley holder, [eBay.com ~$25 shipped] (part #648818)
This is the #1 key to the whole operation, as has been stated.

2) McMaster-Carr 3/4 drive, 3/4" 6-point thin-wall deep-well socket [mcmaster.com ~$22 shipped] (part #5552A161)
This is the #2 key, chiefly because the 1-3/8" OD of the socket is a nice snug fit into the 1-3/8" plus a couple pubimeters ID of the above tool, which almost eliminates lost torque due to angling of the socket/extension.

3) Pittsburgh 3/4" quick-release breaker bar [Harbor Fright B&M, i got it for ~$15 after sale and 20% coupon] (part #98270)
Don't need a Snap-On here, it's 3/4 drive.

4) Masterhand 3/4" extension 16" [Tractor Supply B&M, ~$15, find a coupon if you can] (part #3835200)
Again, who cares brand it's 3/4 drive. 16" easily clears wheel well.

5) Big long 1" ID steel cheater pipe for breaker, I got at Home Despot for ~$10

6) 2 1/2 foot 1" ID pipe for the pulley tool. Way too much flex using the 1/2 breaker on it. If your jack doesn't have it, hit HD for that too, or just get one long one from there and trim a piece off. I think a 10 footer is less than $20.

Then just use the jackstand-fulcrum method like has been described 100 times before. Presto, timing-belt-chango.

 

[ralph cerbone]

+1 (or in English, I second that opinion)



I'm pretty close to that setup, with just a single 16" 3/4 drive extension. The only thing I don't have, to go full 3/4 drive all the way through, is a 3/4 x 19mm socket that is thin enough to fit through the center of the crank pulley holder tool. I'm looking for one of those. Closest I've come up with is a 3/4 x 3/4 thin-wall deep-well impact socket that would need to be ordered. (19mm = .748 inches... close enough!)



I'm just hoping it's because those bolts are really strong and not because of the statistics of there being not many NSX out there. I wonder if Larry B or Barnman have ever seen that happen?




The impact I've been using throws three times the torque of the CP, actually. But the lack of success even after changing over from 1/4 to 3/8 NPT (we're going on two weeks of beating on it, with a HUGE 3/4 impact gun and a HUGE tank) indicates a change in strategery may be in order

I'm adding your photo to my scrapbook, ftuhy, thanks! I've seen it before but didn't print it out along with the .pdf guide, and then lost track.

your starving the gun even with a 3/8 fitting ,you must increase the total volume , my gun uses a 1/2 npt fitting,1/2 hose at about 120 psi , then it wings the bolt right out( i use two home owner compressors unioned into one 1/2 hose ) my gun is 50 yrs old and still kicking ass

 

[UberNSX]

your starving the gun even with a 3/8 fitting ,you must increase the total volume , my gun uses a 1/2 npt fitting,1/2 hose at about 120 psi , then it wings the bolt right out( i use two home owner compressors unioned into one 1/2 hose ) my gun is 50 yrs old and still kicking ass

Moar toolz! Now I can has excuse to upgrade :biggrin: