Jump to content

What if timing belt is changed without being TDC


forevermemorable

Recommended Posts

I changed my timing belt and water pump and I might have set my crank shaft and cam shaft with my timing marks and not the TDC mark, before I took off the old timing belt. I also put the new timing belt on (without moving the crank shaft and cam shaft) and tried to start the car, but it wouldn't turn over...new battery and starter sounds just fine...car will not turn over.


I have read that the crank shaft and cam shaft need to be placed at TDC when changing a timing belt...my question is...why? Does it really matter where they are located when changing a timing belt? Isn't really the problem come if either the crank shaft or cam shaft move while installing timing belt? I don't see the logic in having everything set at TDC...there is nothing special with how the timing belt is put on and logically you would receive the same results whether the crank and cam are on TDC or not. It seems the issue is, "DON'T MOVE THE CRANK OR CAM WHEN PUTTING THE NEW TIMING BELT ON." It all comes down to gears and the timing belt being fitted to fit into the grooves...and the groves will line up and the gears still look the same whether or not the crank and cam are set up at TDC.


I look at it really logical here...lets say I replaced my timing belt 180 degrees opposite of TDC and I removed my old timing belt (WITHOUT moving the crank or cam one bit) and I place my new timing belt on...in the exact same position, matter, belt lines up perfectly with teeth, etc. What variables have changed?

Link to comment
Share on other sites

Okay, you seem to know the answer or it's staring you in the face and you still don't see it.

 

The point of setting it to TDC before you start is to cut down on the work of setting it to TDC before you install the timing belt.

 

Yes, you should be fine if nothing moved.

 

Something moved because it won't start, and that's your proof something moved. That or you forgot to connect something.

 

Check to see if everything is at TDC, if not the remove thebelt aand try again. If all is kosher then find what you forgot to connect.

Link to comment
Share on other sites

In reality even if you are off one tooth it will still try to start or might even start but will run like crud. If it isn't trying to start at all there might be something more significant than the gears being slightly off.

Link to comment
Share on other sites

Okay, I have spent several hours taking pictures and Photoshopping my results. I am posting 3 different collages of pictures, because it takes my crankshaft 2 revolutions to complete one cycle. The first two sets of collages is the TDC white mark. The third collage of photos is another mark on the crankshaft, which I am not sure what it is, but I am attaching it here.


Collage2.jpg


Collage4.jpg


Collage1.jpg



Information.jpg

Edited by forevermemorable
Link to comment
Share on other sites

Looks like your timing is just a bit off. The cam is retarded just a bit when the crankshaft is at TDC. By how much exactly is hard to tell but it might be 3 or 4 teeth by the look of the photo. It is by however many teeth between that bottom mark and its correct position when the crank is at TDC, cf your second photo.

Edited by James Matteu
Link to comment
Share on other sites

Okay...next step is to get the timing back. Should the first thing I do is put the cam shaft at TDC with the TDC marks on the cam shaft, as seen in my picture #2 (of course with the alignment of the TDC in the correct places (in line with the engine block, as the book says) and the 3rd line aligned where I said it should be aligned (shown in the second picture). Should I start there and than remove everything to get the timing belt off AND THEN align the crankshaft with the TDC white mark?

Edited by forevermemorable
Link to comment
Share on other sites

Put it like you have in photo #2.

 

Then take the timing belt off, put all the marks where they're supposed to be: cam and crank. Then reinstall the belt and give the motor a few turns by hand. Bring it back to TDC and make sure all the marks still line up. Then you're good.

 

Edit: if the marks are off after afew turns, it means you had too much slack in the belt. Reinstall like I described above and this time double check the tension.

Edited by James Matteu
Link to comment
Share on other sites

Put it like you have in photo #2.

 

Then take the timing belt off, put all the marks where they're supposed to be: cam and crank. Then reinstall the belt and give the motor a few turns by hand. Bring it back to TDC and make sure all the marks still line up. Then you're good.

 

Edit: if the marks are off after afew turns, it means you had too much slack in the belt. Reinstall like I described above and this time double check the tension.

 

Thanks for responding James. Here is something I thought of...what if the cam and crank both shifted (even just a little bit), when I originally put this timing belt on...this would mean putting the crank or cam at TDC would be faulty, because I would not know if it was an accurate reading; unless I go by judging where cylinder #1 piston is at (highest stroke up, means TDC). Well, now that I think of it, looking at my picture #2, it shows cylinder/piston #1 at the top most position; whereas the crankshaft white TDC line is in line with line of sight mark AND it shows that the cam is off just a bit.

 

Okay, Lets start with picture #2...my next step is to remove timing belt. After that, I rotate cam just a tad to line up TDC marks with engine block and the last line aligned up with the place it should be (as shown in picture #2). I read somewhere about some type of valve spring whereas something needs to be held down tight while this process is performed. I am not sure if this is true or not. Anyways, would the next step be to loosen tensioner? Next, follow re-installation of timing belt by putting belt around cam first, then crankshaft, then tensioner, and finally waterpump. After which, then tighten tensioner? Finally, rotate the engine a few times counter-clockwise ofcourse (for my engine) and see if the timing lines up. Please correct me anywhere in the procedure or add anything you think is important.

Edited by forevermemorable
Link to comment
Share on other sites

Let me ask this...getting the crankshaft bolt off was probably the most difficult bolt I have ever had to remove...no air tool could get it off and it took sheer force with a pipe extender and jumping on with all dear might, to get it loose. Than, trying to get the lower timing belt casing off was more difficult than that, because there is very limited space in which to remove it. I think the whole process takes 4 hours. Since we are just talking about the timing belt and cam shaft here...couldn't I just place the crank at TDC with the white mark (which it is currently at), loosen the tensioner, slip the timing belt off the cam, adjust the cam to be at its TDC marks, slip timing belt back on, rotate crank a couple of times to see if all TDC marks line up, and if all TDC marks line up, then finally tightening tensioner bolt. Here are some new pictures...and would you believe I have discovered the "UP" on my cam...whoever put the white mark on the cam, covered it up...I had to scratch through it to see if it was there.



UP.jpgTimingBelt.jpg

Edited by forevermemorable
Link to comment
Share on other sites

Since we are just talking about the timing belt and cam shaft here...couldn't I just place the crank at TDC with the white mark (which it is currently at), loosen the tensioner, slip the timing belt off the cam, adjust the cam to be at its TDC marks, slip timing belt back on, rotate crank a couple of times to see if all TDC marks line up,...

Yes.

Link to comment
Share on other sites


Success!


At first, I loosened tensioner, removed belt, adjusted cam just a little bit to get it to TDC, put belt back on, then rotate crank several rotations; however, the cam got off again (because I did not tighten tensioner back up).


Going at it again, I get crank to TDC, tensioner is already loose, I remove belt, adjust cam just a little bit to TDC, tighten tensioner, rotate crank several times and TDC lines all match up. I turn on the car and it starts! Sweeeeeeet! Of course, I will adjust the timing with my timing light, just for good measure.


I have one question though...how close should the TDC marks on the cam be with the engine block? Its hard to tell with just looking at the indent TDC lines. I mean, I see that the word "UP" is sure enough in the "UP" position, but how accurate are we talking about here that my cam needs to be to TDC? Are we talking about within 1 centimeter...within a millimeter? Yes my car started up (after a good 8 months of sitting)...I just want to make sure my valves don't get destroyed, all because my cam is just a millimeter or two off (which is so hard to tell).


I actually discovered in my Chilton, that in my #2 picture where I said, "This line is suppose to be aligned here" is actually wrong. With my particular engine (D15B7), I do not line it with that...I align the TDC marks with the cylinder head upper surface and make sure the "UP" is in fact "UP." The results of that third indent line that I made the mistake of saying where it should be aligned, is actually slightly off to the left of that pointy line on the plastic casing...it also shows it slightly off in my Chilton (for my particular engine). However, for the D15B6 engine, you need to align it with that plastic casing line. Never the less, I am pretty sure the blasted thing is close as I can get it.


Correction.jpgCorrectionTDC.jpg


I got everything put back together, but I have noticed the car runs hot. I am not sure if it ran that hot before. I mean the distributor, radiator, radiator hose is not just hot, but VERY HOT. Maybe its been too long since I had this car running. And yes, my temperature gauge shows normal operating temperatures and my radiator fan comes on.


One last thing, I hear a very faint slow squeaky noise coming from my engine...not sure what to make of that.

Edited by forevermemorable
Link to comment
Share on other sites

Sounds like you forgot how hot the car runs, it's been 8 months. But keep an eye on that temp gauge and remember never to operate the motor when the temp exceeds 3/4 (I'm helping a guy cope with the results of repeatedly driving with the temp gauge pegged out: warped head).

 

Check the tension of all your belts; then make sure the power steering, A/C, and alternator spin freely.

 

 

 

It's been my experience that those marks in your pictures are close enough. I've tried to get all marks dead on and it always seems like there's one tooth on the timing belt that gets in the way.

 

My guess is that honda toyota gm acura etc would have a more precise way of setting the cam and crank had it been necessary to get it dead on.

 

The only timing related component with the ability to make fine adjustments (from the factory) on your vintage* of Honda is the distributor. *After '95 there is no fine adjustment since OBD-2a uses a "floating" timing advance and a non-aadjustable distributor.

Edited by James Matteu
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

Terms of Use | Privacy Policy | Guidelines
We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.