just checkin in, timing belt change finally.

[doctor z]

Hi all, been a while since being on the forum. NSX has been fantastic, I have only changed plugs and oil and coolant.
Right now I have it disassembled so I can change timing belt/water pump. Been at it part/time for about a week. No
hurry, reading up.Really, really appreciate every one who has contributed to this subject. I have done other belts, but
this one is critical, no room for error. With all of the knowledgeable contributors, I feel this will go pretty smooth.

 

[AcuraNSX]

Good Luck

Hi all, been a while since being on the forum. NSX has been fantastic, I have only changed plugs and oil and coolant.
Right now I have it disassembled so I can change timing belt/water pump. Been at it part/time for about a week. No
hurry, reading up.Really, really appreciate every one who has contributed to this subject. I have done other belts, but
this one is critical, no room for error. With all of the knowledgeable contributors, I feel this will go pretty smooth.

Congratulations! I am thinking of doing the timing belt too on my 91 NSX. Did you get the Harmonic Balancer (Crankshaft Pulley) bolt off? I am looking into buying/borrowing/renting the tool. Just need to get the tools together first before I get stripping her down.....btw, I am sure you have read by now like I have to change the Harmonic Balancer while doing the timing belt service....how about the shield? Doing it? Anyone chime in on anything else other than required gaskets, coolant, water pump....Good Luck and let us know how it goes!

 

[mwagner10702]

. . . btw, I am sure you have read by now like I have to change the Harmonic Balancer while doing the timing belt service....

While it is not necessary to replace the HB (or crank pulley) under normal use, some do recommend changing it if you track or auto-x your car. Since the crank pulley needs to come off during the TB replacement there is some logic to replacing it. While doing all of this I would recommend installing a harmonic balancer shield. Science of Speed sells the lightweight version from CedarRidge Fabrication as well as the ATI Super Damper pulley (expensive). You can also buy the shield directly from CedarRidge Fabrication. The OEM pulley is also available from SoS.

http://www.cedarridgefabrication.com/NSX_Motor

https://www.scienceofspeed.com/index.php/nsx/enpp/external-engine-components/cedar-ridge-fabrication-crankshaft-damper-pulley-shield-lightweight-version-nsx-1991-05.html

https://www.scienceofspeed.com/index.php/ati-super-damper-pulley-nsx-1991-05.html

https://www.scienceofspeed.com/index.php/genuine-honda-crankshaft-pulley.html

Finally, here is a great DIY from the Wiki on replacing the TB and WP. Note the recommendation to buy a high foot pound torque wrench. Maybe you have a friend who has one.

https://www.nsxprime.com/FAQ/DIY/timing-belt.pdf

I would also replace the timing belt tensioner while you are at it.

 

[doctor z]

I think the crankshaft pulley bolt will be removed tomorrow. My neighbor has a Milwaukee electric impact wrench. So my plan was, hold the crank with the holding tool, then, I bought one of those massive 19mm sockets that are supposed to hammer it off real nice. But the socket is so massive, it wont fit inside the holding tool. So after looking at videos, I think with an impact wrench there should be no need to hold the crank. I will put the spark plugs back in. And hope that works. Oh, all 4 pin punches fit right into place in the camshaft holder holes. (96 NSX 5-speed) It sounded like after reading up, that only 3 would actually fit. Of course they must be removed during crank shaft pulley bolt removal. And yes, I have just come to realize that a new crankshaft pulley is a wise idea, so I will order one. And luckily a tensioner came with the TB/WP. So I hope to report a successful pulley bolt removal tomorrow.
Thanks for your interest and input.

 

[doctor z]

The crankshaft pulley bolt came out without a hitch. We used the Milwaukee battery powered impact and the super heavy duty
Lisle thickwall impact socket. Did not hold the crankshaft, it budged about 3/8 of an inch, (backwards). I just turned it back to exactly
TDC, using the holding tool, in the harmonic balancer, by hand. I dont believe the cams budged when the crankshaft went backwards 3/8
of an inch, I think that was taken up with slack. All 4 pin punches dropped right back in the cams.
Oh, as a safety precaution I backed out the valve adjusting screws as in the Kentosh write-up.

 

[Larry Bastanza]

I think the crankshaft pulley bolt will be removed tomorrow. My neighbor has a Milwaukee electric impact wrench. So my plan was, hold the crank with the holding tool, then, I bought one of those massive 19mm sockets that are supposed to hammer it off real nice. But the socket is so massive, it wont fit inside the holding tool. So after looking at videos, I think with an impact wrench there should be no need to hold the crank. I will put the spark plugs back in. And hope that works. Oh, all 4 pin punches fit right into place in the camshaft holder holes. (96 NSX 5-speed) It sounded like after reading up, that only 3 would actually fit. Of course they must be removed during crank shaft pulley bolt removal. And yes, I have just come to realize that a new crankshaft pulley is a wise idea, so I will order one. And luckily a tensioner came with the TB/WP. So I hope to report a successful pulley bolt removal tomorrow.
Thanks for your interest and input.

The four punches will fit when at TDC #1 . When you install the timing belt you need to advance the rear exhaust cam a 1/2 tooth to get the belt to go on right, and that is when you will need to remove that punch from the rear exhaust cam to be able to advance it...... Once you get the new belt on the rear exhaust cam pulley, reposition the rear exhaust cam back to TDC, set belt tension, lock the tensioner down, recheck timing marks on all four cams, then remove all four punches, rotate the crankshaft two rotations carefully, then reinstall the punches, check timing marks again, to insure the cams are in place.

 

[goldNSX]

On modern cars it not a good idea to turn the engine in the wrong direction. But as the NSX has not an automatic tensioner the TB should not skip a tooth.

Hint: glue the rubber lines to the plastic covers so they don't fall accidentially off and hang around if the TB area. I saw one TB skipping a tooth due to a 'lost' rubber.

 

[doctor z]

Larry, thank-you, for detailed instructions. I will follow them to a T. I like the part about double checking. Getting excited about putting it together.
I just dabbed different color auto paint on 4 cams and crank. Cant wait to see all 3 colors of paint line back up again, after I transfer it to the belt.

Gold, Thats a great idea, clearance is minimal. Also I lost one just taking it apart. I will search some more and make dang sure it isnt near the timing belt.

 

[AcuraNSX]

excellent advice from GoldNSX and Larry of course. I am about to tackle mine this Spring. Great to keep learning new techniques and tricks

 

[Kaz-kzukNA1]

From your signature, looks like you have 96 model so the 4 pin punches will line up with the holes on the cam shaft. However, this won't be the case for the very early engine no. on 91 model at the front exh cam.

There is no guarantee that your existing timing is at the correct positon so personally, I won't rely on the paint markings.
Please note that once you start rotating the crank even for one turn, the paint markings won't line up again until you turn the engine for ages.

I always use the markings on the cam pulleys, drive pully, back plates and on the oil pump housing, just like on the workshop manual.
However, there was a mistake on the marking process on the backside (facing camshaft) of the rear exh cam pulley on certain range of eng no. that you can't rely on it.
Fortunately, the front side marking is fine so no big drama.

Still, if you dial-in the cam timing, you will notice that there are small variants in true TDC against these markings on each engines.

Timing markings won't line up against the ones on the cover plates, etc until you properly tension the TB but good enough to install the TB at the correct timing.

You can't make partial mistake such as the timing off by 1/5 tooth, 1/2 tooth, etc but instead, it will be always in the order of 1 tooth so just double check the timing like 10 times as you can easily spot it.

You can easily jump a tooth or two at the rear exh cam if the TB was loose (before properly tensioning it) and let the crank rotate anti-clockwise even for a tiny bit.
I have seen it on several engines that was serviced by the main dealers as well.

If not replaced before, you may want considering replacing the LMA while in there.

You can find lots of photos including the timing markings here; http://www.nsxcb.co.uk/blog.php?1811&blogcategoryid=51


Kaz

 

[doctor z]

Kaz, thank you for filling me in on details, also that link is sweet, I was able to see the timing marks on the front of the cams
then locate them on my engine. I was only looking at the back before. Now I realize what you mean about paint marks only lining up once,
I may have been confused with old V-8 engines, I think they just keep lining up.
Appreciate your help.
Joe

 

[AcuraNSX]

Kaz, thank you for filling me in on details, also that link is sweet, I was able to see the timing marks on the front of the cams
then locate them on my engine. I was only looking at the back before. Now I realize what you mean about paint marks only lining up once,
I may have been confused with old V-8 engines, I think they just keep lining up.
Appreciate your help.
Joe

Joe, which page is that pic(s) on? It is a 75+ page post....Thanks!

 

[doctor z]

Yes, Kaz has given us pages of photos and info huh. Best photo I saw was on page 55, also close-ups on 29.
and more, on, 20,27, and 35.

 

[AcuraNSX]

Thanks Joe...

Yes, Kaz has given us pages of photos and info huh. Best photo I saw was on page 55, also close-ups on 29.
and more, on, 20,27, and 35.

Thank You Joe....how's it going? Almost finished with the timing belt?

 

[doctor z]

Timing belt is on. A lot of reassembly to do now, and valve adjustment.
Should have it in a week or two. If my body can handle the contortions.

 

[doctor z]

OK, its done. Went for a quick test drive, everything feels good, and no leaks. I made a couple of rookie mistakes.
Instructions say un-bolt sway bar in order to reach that difficult, upper, rear, timing belt cover bolt. So I climbed
under and removed two bolts that hold that U-shaped sway bar bracket. Couldnt reach a thing, so I climbed over
the top of the engine from the drivers side, and struggled, and finally got it out, (dumb). So when it came time to
reassemble, I looked underneath again and noticed a really big sway bar mount right above the tiny thing I un-
bolted. This made it possible, not easy, but possible.
Also reversed the two washers that go on the A/C tension adjust pulley. Made a heck of a squeak till I figured
that out.
When installing the rear valve cover, the wiring that rests on top of it should be un-plugged. I struggled to get
the valve cover underneath it. Un-plugging and wiring them up out of the way would have been smarter.
Adjusting the exhaust valves without being able to see a thing seems impossible at first, but you really do
get a feel for it pretty quickly.
Thank you to our fine members who helped me recently, and previously, to get this job done. If anyone wants to
talk to me directly about this, PM me and I will give you my phone number.

 

[AcuraNSX]

OK, its done. Went for a quick test drive, everything feels good, and no leaks. I made a couple of rookie mistakes.
Instructions say un-bolt sway bar in order to reach that difficult, upper, rear, timing belt cover bolt. So I climbed
under and removed two bolts that hold that U-shaped sway bar bracket. Couldnt reach a thing, so I climbed over
the top of the engine from the drivers side, and struggled, and finally got it out, (dumb). So when it came time to
reassemble, I looked underneath again and noticed a really big sway bar mount right above the tiny thing I un-
bolted. This made it possible, not easy, but possible.
Also reversed the two washers that go on the A/C tension adjust pulley. Made a heck of a squeak till I figured
that out.
When installing the rear valve cover, the wiring that rests on top of it should be un-plugged. I struggled to get
the valve cover underneath it. Un-plugging and wiring them up out of the way would have been smarter.
Adjusting the exhaust valves without being able to see a thing seems impossible at first, but you really do
get a feel for it pretty quickly.
Thank you to our fine members who helped me recently, and previously, to get this job done. If anyone wants to
talk to me directly about this, PM me and I will give you my phone number.

Congratulations! I may take you up on your offer when I do my timing belt this Spring!

 

[goldNSX]

I've just ordered a heavy duty "Lisle 77080 19 mm Harmonic Balancer Socket for Honda", even though I have 3/4 sockets but I like the idea of having more options. Anyone used one of these so far?