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Guys lets put our heads together and come up with a fool proof way to set up TDC when doing timing belts etc. To many post even on the first page with timing belts off a tooth or 2.
Im thinking its easy to get the crank set it the cam thats the problem. Maybe a way to line up and jam the cam pulley so when you put the belt on there no chance of slipping etc.
I am thinking something thats easy anyone could make with a print of it.
wp
I didn't have a problem with my cam moving. My problem was that the crank would move, and for some odd reason the teeth didn't exactly line up. Thus, I could not set the crank to exactly TDC, it is off a bit.
I have done it twice. The easiest way I know of getting TDC set right is to line up the cam before you remove the belt. Line up the TDC mark and pointer (timing marks) AFTER you remove the belt. After doing that it started and was timed right on the first try.
;good point, it is pretty hard to deal with the cam , trying to turn it without breaking or loossening the cam gear bolt.Quote:
Originally Posted by DBMaster
I think one of the biggest problems people are having is finding the TDC mark for their particular vehicle. The book says white mark, I fiind it to be the -T- mark, etc.. If there was a mark on the crank pulley and something to reference it too, maybe it could be simpler.
Yeah, the markings are a bit confusing. I have always used the "T" mark that is stamped into the index plate as TDC. I also have a white mark and red mark. When I apply vacuum to the distributor it advances nicely from the T mark to the red mark - which I assume to be the 15DBTDC that I am supposed to achieve. It's worked for me for 19 years so I guess that's just testimonial evidence.
i think where people get confused is the cam gear.
i find that my Chilton's book doesn't clearly define where to line it up.
i always use a straight edge set on the top side of the valve cover bolts. you would actually go an additional 1/8" past the bottom of the straight edge for the thickness of the nut.
the center of the nut is tdc on the head.
for the ones that do not know...
for every 1 revolution of the crank the cam turns 2 revolutions.
so if you use the way i explained you still have to verify tdc on the fly wheel because you have a 50% chance of being 180 degrees out.
i wounder if i explained it clearly enough?
It's the other way around. 1 crank revolution is ½ a cam revolution, eg. 1 cam revolution is 2 crank revolutions.Quote:
Originally Posted by 89turbo'ed
So as long as the crank is set at TDC the crank will always be in the correct position.
And always put on a timing belt in the opposite direction of the engines normal rotation direction. And start at the crank finishing at the belt tensioner and waterpump.
duhh!
wtf was i thinking. not enough coffee i guess.
thanks for correcting me.:)
hehe you're welcome
The Woodroy key on the crankshaft is aligned with the UP mark on the cam gear when the crankshaft is at TDC.
Hell, I just get the "UP" mark stamped on the cam gear as close as possible to lining up with a valve cover stud - more or less vertical in relation to the engine. That's always been close enough to get the timing set right. This does not have to be 100% precise.
"the center of the nut is tdc on the head."
Yes, this is the way I line the cam gear up as well.
Back to the whole point of the thread---- changing the timing belt and keeping the cam stationary shouldn't be an easy task to begin with. Only smart and well trained people should attempt changing their own timing belts. Don't get me wrong, this website is all about learning and etc. But a 16 year old kid that's never owned a car or worked on a car, should not attempt this procedure (CAH comes to my mind).
Trial and error only makes you better at it. I've only changed my timing belt 3 times, and It's always taken a little TLC to keep it lined up after putting the timing belt on. Thus, practice makes perfect. No tool is required to keep it from moving, just wisdom and many times of doing it.
Guys it not about lining up the marks its about keeping it lined up when getting the belt on. Any one can line it up in my experience that cam aways ends up moving a little and then its off a tooth.
Im thinking of a tool to jam the cam from moving once its lined up. The crank is easy to jam with a screw driver in the ring gear and the compressions holds it some too.
And not to pick on any on here but 4 of you have had your timing belts off a tooth or more and had to do it more then once to get it correct which im reveling in the irony.
wp
Its not as hard as you make it come out to be. Simply line it up, slip on the timing belt and its done. Just don't move the gears at all, and it will stay lined up.
:tongue: pshh im 18 fool :P and have worked on many cars :tongue:Quote:
Originally Posted by BITESIZE
a) marking the belt itself is no good on these motors. Volvo actually tells you to do that on there old inline 4 cyls (ah the 80's) It sure changed on me when I tried it to make it easier to adjust valves.
b) I timed up my motor last month after putting on the ACG, using number four cam marks up and TDC on the crank, came out perfect. That was a result of the cam gear not being snug to begin with and it slipped, and I didn't want to damage the cam by trying to turn it with hand tools.
c) The t belt tensioner really is different compared to other OHC cars like dodge 2.2, or ford 2.3, or toyota 1.6, or volvo , eg the tension really doesnt need to be fiddle with much other than turning the motor over to move the belt three or so teeth, this pulls it up against the belt taking the little bit of slack out. Those other cars, you can get the belt too tight because there is too much adjustment and people seldom use any measuring tools on them. These Hondas just have a little light spring tension on them. You can set the belt without even taking off the lower cover and crank pulley as long as the belt is installed already. These belts are pretty tight even without snugging the tensioner although I wouldnt run one like that too long. just tighten the hold down on the tensioner when it is set.
So, yes you can make a tool to hold the cam gear still, it would have to be installed on the back side of it. Something like a huge leaf spring type U bolt with two adjustable feet perches (with hollow round tubing and set screw bolts) that would rest on the inside valley of the head below the gear . If I had autocad or some other diagram software I would show what I mean, A20A1 used to do that here, great way to get the idea across.
Never had a problem with the 89, but boy did I make a mess of the '93. It's that double timing belt, balance shaft nonsense. Tried doing it without the manual and it ended up being a tow to the shop and a $900 bill. Oh God what a disaster.
:Owned:
I changed mine the first two times. When the third time came around I let somebody else do it because I have found a very good Honda mechanic in town. I guess I just didn't feel like doing it again. I still do almost everything else except when a lift and heavy equipment is required. Maybe that's a sign of middle age.
Quote:
Originally Posted by thegreatdane
do your timing belts this way and you wont have so much trouble.
If you find it hard to keep the belt fixed on the crank sprocket while putting it on you can use a clamp or some other sort of tool to keep the belt fixed to the crank sprocket.
I seen this a while back if ever;Quote:
Originally Posted by Dr_Snooz
http://www.store.partsdinosaur.com/product266.html
wp
Found this for Acura's
David Teichholtz in alt.autos.acura noted that "On my wife's 1993 Integra there are holes in the camshafts and the front journals in through which small drill bits can be inserted so as to stop the camshaft from spinning. This essentially makes the job about 300% easier."
http://timingbelt.soben.com/
wp
dunno if anyones mensioned it but on the b20a theres a hole drilled thru the cam, and also on the 1st camshaft holder downer thingee that holds the cam seal by the pulley you can stock a nail down the hole and into each cam to hold it in place. works for me every time. and you get perfect results
Bump to the top.
I like the dowl pin idea just need a simple jig made up and the right place to do it.
wp
I have replaced the timing belt a few times and what I have learned is that alignment is not that complicated, but the real problem is keeping the alignment when installing the belt.
The two things you need are ATTENTION TO DETAIL, and PATIENCE.
One thing it should be clear: there must be NO BELT SLACK on the side facing the front of the car. If you think of it, since the A20 rotates counter-clockwise, any slack there would disturb the valve timing. Once you get that right, finishing assembly is not a big issue.
Something I ALWAYS do is after tightening the belt tensioner, is removing all spark plugs and then install the crank pulley and rotate the engine BY HAND (COUNTER-CLOCKWISE) to check and double-check the timing. If everything is right - I would normally rotate the crank 4-6 laps (that gives 2-3 times to check timing) and if everything is right I will re-install the other parts and drive the car.
Why so anal with the double and triple check? I saw a destroyed engine because of a broken timing belt. Though ours are apparently not interference designs, I do not want to be stranded on a road because of cutting corners. Better spent another half hour checking than two hours on the side of the road.
I bet unless a DIY commits himself with getting the job right no matter what, he should leave it to a "mechanic". But that is my 2 cents, so take them with a grain of salt (or two)
Any idea if the B20A is interference? I had mine sorta running at an estimated 60 degrees advanced because my reman flywheel had a nonsense mark on it. both cams and distributor (and consequently firing order) were wack fuck and it still sort of ran.:flash:
