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Car Forum / Honda Cars / April 20061991 timing belt question
hello, i am doing the head gasket on my 1991 civic. if there's any advice on this subject, feel free, but my real question is about timing. there seems to be a paradoxical aspect to replacing the timing belt. first of all, my crankshaft pulley has no markings. secondly, all the instructions i've seen requires the lower timing belt cover to be installed before you can use the indicators on it to adjust the position of the belt. however you cannot adjust the belt with the cover on. am i missing something? also, is there a more reliable way to find TDC than to stick something through the spark plug hole and watching for TDC? it seems so inaccurate... i suppose that's what the markings are for, but i've already pointed out the connundrum there. thanks! josh > hello, > [quoted text clipped - 12 lines] > inaccurate... i suppose that's what the markings are for, but i've > already pointed out the connundrum there. There's supposed to be two side marks on the cam shaft pully to make parallel with the surface of the top of the head with the word UP on top of the gear pully. > hello, > [quoted text clipped - 6 lines] > timing belt. > first of all, my crankshaft pulley has no markings. Does the pulley look anything like the following? http://www.norcalcrx.org/fig_6.jpg Mind you, though, I think you're confusing fine-tuning the ignition timing (which requires a timing light and using the marks in the photo above) with properly aligning the timing belt, crankshaft sprocket, and camshaft sprocket. Certainly if the timing belt isn't installed so that the camshaft and crankshaft are "in synch," you will have major problems fine tuning the ignition timing subsequently. So both involve timing, but they're different steps for tuning one's car. > secondly, all the > instructions i've seen requires the lower timing belt [quoted text clipped - 4 lines] > with the > cover on. am i missing something? I think you are missing something. What do you mean by "adjust the belt"? You want to ensure that the camshaft is "in synch" with the crankshaft. That's accomplished by making sure that the camshaft and crankshaft are fixed in the proper position when you install the timing belt. That's actually very tricky, unless you do the following: Prior to removing the old timing belt, mark with a Sharpie marker or "White-Out" teeth on the camshaft sprocket and their coinciding belt teeth. Do the same at the crankshaft sprocket. When you have the belt off, lay the new one next to it, and mark its teeth exactly as the old belt's teeth are marked. > also, is there a more reliable way to find TDC than to > stick something [quoted text clipped - 3 lines] > but i've > already pointed out the connundrum there. Are you using a manual? www.autozone.com has a free online manual for your 91 Civic. Otherwise, see above and Alan's comments. There is a square hole on top of tranny below the #4 spark plug. You will see a pointer. Turn your engine untill you see the letter "T", that's TDC. Same hole you use to adjust ignition timming. obviously i would have marked all this up, but i lost the factory "setting" when i did this the first time a while ago when i was still green. i think the belt that i had put on then was off by a tooth, so i'm more or less starting over this time. okay, i took a closer look at the crankshaft pulley and the marking are there, they were just obscured and had lost their paint. there is a series of three markings, which i think are ignition timing markings. there is one more marking, slightly clockwise of the three, which according to the auto zone online manual is the TDC mark. see figure 5 under the '91 engine section: http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1 4/13/29/0900823d80141329.jsp so, as you can see, in order to align the crankshaft pulley, you must have both the lower timing belt cover installed and the crankshaft pulley installed. both these items make it impossible to actually put on the timing belt. so all i can think of is that you must install the lower timing belt cover and the crankshaft pulley, align for TDC, remove those two items without disturbing the crankshaft, align the camshaft with the two lines on the sprocket on the same plane as the head (with UP up) and slip on the belt. is this right? i still need to look into William Burke's suggestion... thanks for your help. this is the best honda forum i've run across yet! > obviously i would have marked all this up, but i lost the > factory > "setting" when i did this the first time a while ago when > i was still > green. The price of Usenet posts is sometimes thinks aren't obvious to the reader. I understand where you're at now. :-) > i think the belt that i had put on then was off by a > tooth, so [quoted text clipped - 6 lines] > series of three markings, which i think are ignition > timing markings. Correct. > there is one more marking, slightly clockwise of the > three, which > according to the auto zone online manual is the TDC mark. Correct. > See figure 5 > under the '91 engine section: [quoted text clipped - 18 lines] > > is this right? Yes. Figure 5 above is exactly what's in the Service Manual as well. Autozone has mostly Chilton's and Haynes manual stuff, but occasionally exactly what's in the Factory Service manual is in these manuals, too. You just install everything loosely in order to get the crankshaft sprocket "in synch" with the camshaft sprocket. Then, yes, it all comes off again to get the belt on. I agree it's going to be a little tricky to get the belt on so the two shafts are as in synch as possible. I confess I bet it's darn easy to be off a TB tooth. I'd mark things at every attempt, to keep track. Being off a tooth will be obvious. Keep checking back to see if anyone has other ideas. I have done a whole whopping single TB change in my life but I researched the matter like mad and had a lot of help here. I did the white-out thing and it worked great. > i still need to look into William Burke's suggestion... > > thanks for your help. this is the best honda forum i've > run across yet! Yes, it's a good group. And we always agree on everything. ;-) See also the Concerto and CRX service manuals at http://www.honda.co.uk/car/owner/workshop.html . Sometimes the service manual is superior to the pretty much Chilton's manual at the autozone site. thanks so much. i'll revive the thread if i have any more questions. josh > You just install everything loosely in order to get the > crankshaft sprocket "in synch" with the camshaft sprocket. > Then, yes, it all comes off again to get the belt on. Why create extra work for yourself? With all the timing belts I've done over the years, I've never had to do that. Just set the crank so that keyway notch is as close to up as you can get it, put the belt and lower covers on, the cam should be aligned by the pulley markings, once you get the lower cover and crank pulley on fine tune the crank's position, then pull the belt up over the cam pulley, adjust the belt tension (there's an access hole in the lower cover), spin the engine over by hand a couple of revolutions and recheck the timing marks, and be done with it. There's no need to remove the lower cover once you get the new belt on, nor have I ever found it necessary to put marks on the belt or pulleys. I also usually recheck the ignition timing once the car warms up. If it was OK with the old belt, then it should be OK with new belt. A degree of difference might be attributable to belt stretch, but it'll be much worse if you've skipped a tooth. I usually find no change in the ignition timing if the belt was installed correctly. Eric > hello, > [quoted text clipped - 16 lines] > > josh ------------------------------------- Read this, and all the other stuff that surrounds it. http://www.tegger.com/hondafaq/crankbolt.html 'Curly' |
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