Need Help Bad - Timing screwed up after WP/TB Install.

pgilliam1

pgilliam1

Experienced Member
Joined
16 October 2008
Messages
1,869
Location
St. Louis
I've done timing belts on other cars but I hosed this one. After I put the new belt on I turned the crank before I tightened the tensioner (I know now the manual says not to do this) and it skipped a tooth or 2 and I didn't know it. I put the thing back together and it ran like it was on 3 cylinders. I cut it off promptly and disassembled it again. The rear intake/exhaust cam pulleys were off about 2 teeth but the fronts looked OK. I reset the rears to the TDC marks and all looked good ( the crank was at TDC - the front and rear cam pulleys were aligned and I had all 4 pins in the camshafts). I torqued the tensioner and turned the crank. It all looked good but after about 3 turns of the crank now it looks like I'm 180 degrees out because the blue mark on the crank pulley is at the top when the cam pulleys are at #1 TDC on the front. Now I think I'm starting to feel valves hitting the cyliders when I slowly rotate the engine and I have never felt that before. I could sure use some advice right about now - LarryB or any real mechanics out there? Feel free to call me collect 636-458-1166 or email me direct at [email protected].
Thanks - Pat
 
If you turn the crank 3 rotations, it would be 180 out from the cam marks, as the crank turns 2x faster than the cam. I would like to hope you are being cautious about the valves making contact with the pistons, but will let others like Larry chime in.

Miner
 
LOL I've been there on another car and I know how you feel. I've hit a piston after jumping time when turning the crank by hand and agonized over whether I might have bent a valve or two. Turns out it was OK, but there is a lot of leverage involved. You're probably fine if you didn't gorilla the thing. Good thing you tried turning it by hand first. Take a deep breath. You'll get through this, one way or another.

Miner's right. If you turned the crank 3 times the front cams shouldn't be @ TDC. Something's not quite making sense there.
 
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I could have turned the crank more than 3 times before. Now - with the belt removed I released all pressure on all cams (there's a sweet spot where each of them relax). I was able to turn the crank without any resistance. So I realigned the cam pulleys and crank to TDC and reinstalled the belt. Everything seems OK. I loosened all the valves and they all seem OK but 1. The exhaust valve on the number 3 cylinder. After I loosened the 10mm retaining nut I can't seem to turn the adjusting bolt with a screwdriver. Does anyone know if that means it's bent?
What an ordeal this is. In trying to save a grand, I probably damaged the engine in a car that I've dreamed of owning and it's possibly going to cost me 5 times what I might have saved. This is what is meant when saying "I learned the hard way." :redface:
 
I don't see how a bent valve would cause the screw to not turn. The adjusting screw is separate from the valve and threads into the rocker arm. If the valve was bent it would be bent below the guide (in the combustion chamber).
 
I think you are panicking a bit, there was no point in messing with the valves at this point. You're just adding more things to worry about: stop it.

Re-index the cams and crank, set the belt and give it another spin. After two spins it should line up and be properly indexed. It is very easy to get the rear exhaust cam off by a tooth or two....which is very hard to see.

Once you get everything lined up and it stays indexed when you hand turn the crank.

If you bent a valve it will show up in a vacuum reading or a compression test.

good luck


drew
 
I have the belt on and after hand turning the crank everything seems to align properly with no resistance. I will continue the reassembly and start her up tomorrow. I just got this feeling in my gut that I've screwed something up. Thanks for the replies/help, at this point it's very much appreciated.
 
pgilliam1 said:
I've done timing belts on other cars but I hosed this one. After I put the new belt on I turned the crank before I tightened the tensioner (I know now the manual says not to do this) and it skipped a tooth or 2 and I didn't know it. I put the thing back together and it ran like it was on 3 cylinders. I cut it off promptly and disassembled it again. The rear intake/exhaust cam pulleys were off about 2 teeth but the fronts looked OK. I reset the rears to the TDC marks and all looked good ( the crank was at TDC - the front and rear cam pulleys were aligned and I had all 4 pins in the camshafts). I torqued the tensioner and turned the crank. It all looked good but after about 3 turns of the crank now it looks like I'm 180 degrees out because the blue mark on the crank pulley is at the top when the cam pulleys are at #1 TDC on the front. Now I think I'm starting to feel valves hitting the cyliders when I slowly rotate the engine and I have never felt that before. I could sure use some advice right about now - LarryB or any real mechanics out there? Feel free to call me collect 636-458-1166 or email me direct at [email protected].
Thanks - Pat
Click to expand...

I really doubt you bent any valves while hand turning the crank and the belt jumping 2 teeth. I think you are ok and you are just over worrying about things. The valves are pretty strong and will take alot of force to bend them.
A running motor hitting the valve will bend it. You turning the crank by hand slowly wont.

Like others said. 3 turns on the crank, the cams wont be lined up.


what I do on t belt installs is.

Before I take the old belt off. I hand crank it to TDC and make sure ALL the pulleys are ALIGNED to their corresponding marks. Then I use touch up paint and paint 1 tooth on ALL pulleys (including balance shaft (if applicable) and oil pumps (if applicable) etc) and then mark 2 the teeth on the belt that coincide with the pulley tooth.

I transfer the marks on the old belt to the new belt and and install the new belt. I use zip ties and zip tie the timing belt to the cam sprockets to hold the belt in place while I install the rest of the belt.

With this method, its a little longer but I have never had to remove and re install the new belt for being out a tooth or 1/2 tooth after doing the tensioning sequence and then rotated the crank x amount times. Really helps me sleep at night when I do a t belt on an interference fit engine knowing the new belt is on the exact same place where the old belt came off.
 
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NCC-1701D said:
I really doubt you bent any valves while hand turning the crank and the belt jumping 2 teeth. I think you are ok and you are just over worrying about things. The valves are pretty strong and will take alot of force to bend them.
A running motor hitting the valve will bend it. You turning the crank by hand slowly wont.

Like others said. 3 turns on the crank, the cams wont be lined up.


what I do on t belt installs is.

Before I take the old belt off. I hand crank it to TDC and make sure ALL the pulleys are ALIGNED to their corresponding marks. Then I use touch up paint and paint 1 tooth on ALL pulleys (including balance shaft (if applicable) and oil pumps (if applicable) etc) and then mark 2 the teeth on the belt that coincide with the pulley tooth.

I transfer the marks on the old belt to the new belt and and install the new belt. I use zip ties and zip tie the timing belt to the cam sprockets to hold the belt in place while I install the rest of the belt.

With this method, its a little longer but I have never had to remove and re install the new belt for being out a tooth or 1/2 tooth after doing the tensioning sequence and then rotated the crank x amount times. Really helps me sleep at night when I do a t belt on an interference fit engine knowing the new belt is on the exact same place where the old belt came off.
Click to expand...

Oh man , here comes Ed with his mechanics for dummies ...

But all kidding aside if you follow his instructions (a) - I will laugh at you AND (b) your timing belt will be on correctly

Problem is you now need to start from scratch and time the thing by putting all th pins in and turning the crank pulley to TDC , just double and triple check everything and turn the motor through at least two full revolutions by hand - SLOWLY -

And I have seen someone bend valves turning a motor by hand , they are super thin (5mm) and you can bend it by hand.
 
NCC-1701D said:
I really doubt you bent any valves while hand turning the crank and the belt jumping 2 teeth. I think you are ok and you are just over worrying about things. The valves are pretty strong and will take alot of force to bend them.
A running motor hitting the valve will bend it. You turning the crank by hand slowly wont.

Like others said. 3 turns on the crank, the cams wont be lined up.


what I do on t belt installs is.

Before I take the old belt off. I hand crank it to TDC and make sure ALL the pulleys are ALIGNED to their corresponding marks. Then I use touch up paint and paint 1 tooth on ALL pulleys (including balance shaft (if applicable) and oil pumps (if applicable) etc) and then mark 2 the teeth on the belt that coincide with the pulley tooth.

I transfer the marks on the old belt to the new belt and and install the new belt. I use zip ties and zip tie the timing belt to the cam sprockets to hold the belt in place while I install the rest of the belt.

With this method, its a little longer but I have never had to remove and re install the new belt for being out a tooth or 1/2 tooth after doing the tensioning sequence and then rotated the crank x amount times. Really helps me sleep at night when I do a t belt on an interference fit engine knowing the new belt is on the exact same place where the old belt came off.
Click to expand...

Did you zip tie all the cam sprockets including the rear exhaust cam?

Would you still need to advance the rear exhaust cam half of a tooth to get the belt on and retard it back or this is not necessary?
 
nis350 said:
Did you zip tie all the cam sprockets including the rear exhaust cam?

Would you still need to advance the rear exhaust cam half of a tooth to get the belt on and retard it back or this is not necessary?
Click to expand...


I paint mark 1 tooth on the cams/crank sprocket and paint mark 2 teeth on the timing to my painted cams/crank tooth before I remove the old belt. I then transfer those marks on the old timing belt to the new one. You can move the cam sprockets anywhere you need to move them to get the belt on. Because all the marks will correspond to how it was before you removed the old belt.

I zip tie the new timing belt to the cam sprockets.
The zip ties really help hold the belt in place to the proper tooth on the cam sprocket when you are trying to put the belt on. The belt won't accidently jump or slip off on you without you knowing it.

Back in the day when I use to work on cars for living. I use to just rip the off belt off and then line up the pulleys. for cars with 1 cam sprocket. It was easy to get them bang on. 2 cam sprockets with balance shafts it was probably a 75% success rate on getting everything lined up on the first try. With 4 cam sprockets, I was probably at 25% success rate getting it the first try.

The first car I ever did a t belt on with quad cams was a 1990-300zx...It took me so many tries of setting "1 tooth back" etc to get it all lined up. Next time I had quad cam 300zx. I did my painted tooth to t belt method and I was bang on the first time and every time after that to the point now that I do it no matter how easy the job is.

http://www.nsxprime.com/forums/attachment.php?attachmentid=38309&d=1196056616

that is a pic of my old timing belt. that should make more sense if anyone didn't understand what I wrote
 
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ALL IS WELL! I want to thank drew, daedalus and NC-1701D for telling me to quit panicing and focus - I was too full of emotion and I needed that. I also want to give a big SHOUT-OUT to LarryB, whom through all my tribulation proved the saying, "A friend in need - is a friend indeed!" And KUDOS to all those that maintain this website. Prime and it's members have helped me enjoy this car more than I otherwise would have.
All is well - That ends well.
Thanks Again,
Pat
 
pgilliam1 said:
I've had 2 - going back for more - Oh Happy Days! I would have lost confidence without you my friend - Thanks Again!

Pat
Click to expand...

So, does this mean "WE" will be drinking beers in Toronto in September at NSXPO2009??

Regards,
LarryB
 

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