420A Timing Belt Questions

[MeteorBurn]

Hello everyone,
I was wondering about a few things I read in the VFAQ's article on changing the timing belt on a non turbo engine (1998 eclipse RS).

At the part when it says "Move crankshaft to 1/2 notch before TDC" after aligning the camshaft timing marks and setting the crankshaft sprocket to TDC, why is that? What's the issue with just leaving it at TDC?

Thanks in advance.

 

[Vegas Smith]

I don't own a 2gnt nor have I read the vfaq you referenced but sometimes when you release the belt tensioner at the end it can cause the gears to rotate a 1/2 cm or so. It may be accounting for that little jump that happens when the belt tightens so that it jumps into perfect alignment. I'm not certain of this though.

 

[josh408]

I don't own a 2gnt nor have I read the vfaq you referenced but sometimes when you release the belt tensioner at the end it can cause the gears to rotate a 1/2 cm or so. It may be accounting for that little jump that happens when the belt tightens so that it jumps into perfect alignment. I'm not certain of this though.

You are correct sir. After you let it set for a bit and then rotate everything to make sure everything still lines up you'll notice that the timing will fall into place. The only time I don't do the half a notch trick is when I'm using the cam gear alignment tool. I'll just keep the alignment tool in place and pull the grenade pin on the tensioner and leave it like that so it tightens all the slack with out moving anything.

 

[Zero6391]

if u put the belt on with everything lined up at TDC then u will see slack on both sides of the belt, however if u leave the crank slighty before TDC then when u put the belt on then u can rotate it so it puts all the slack on the side of the tensioner and will make everything nice and snug

 

[MeteorBurn]

Cool, thanks for the replies guys.

 

[MeteorBurn]

Alright, I did something that was not too smart. While trying to keep the left camshaft sprocket from turning to remove the bolt, it ended up moving counter clockwise a bit (maybe 1/4 revolution). Any chance I damaged my valves? I'm feeling pretty stupid right now. It was really an accident, I was just fumbling around because I didn't get the special tool that holds it in place, and I can't find any good place to wedge a bar so that it stops turning.

Any help would be really appreciated! My timing belt and all the pulleys are already off, and I got the right camshaft sprocket off. It's just this one that's giving me a lot of trouble.

 

[XiholdtrueX]

I believe as long as you did not run the engine like that or slam the crank hard as hell I doubt you did any damage. To bend some valves you usually have to hit it hard or be drving and the piston slaps in to it.

 

[1990TSIAWDTALON]

I would bet you are ok. A leakdown test would tell you. Get some zipties and ziptie the belt to the cam gears in 2 or 3 different places, worked for me until I got the correct tools to hold them.

 

[XiholdtrueX]

I have also used those black binder clips used for papers to hold timing belts before as well.

 

[MeteorBurn]

Well, my water pump was toast so I just finished replacing it now. I have two new camshaft seals, but I'm a bit nervous about installing them. The old ones aren't leaking, but I'd rather not cut corners and leave them in. The right seal looks easy to get in/out, but for the left seal the space is limited because it's so close to the shock tower. Should I replace them? Is there a good way to get the left one out/in?

 

[MeteorBurn]

Any idea whether I should change them or not? When do they usually fail?

 

[Zero6391]

my vote is to change them now because youll have to remove the cams and retime the belt again if u have to change out leaky seals next month, they are easy to replace. the less you have to mess with the timing belt the better

 

[MeteorBurn]

Thanks for the reply. Have you changed them before? I have a special tool kit for installing/removing them, just want to make sure it's not a tricky job or anything.

Also just noticed that your two cars have gundam 00 names. Cool, that show was awesome.

 

[XiholdtrueX]

I would do it now also, do it right the first time and avoid a oil leak that could foul the tb later on down the line. Never done them before

 

[MeteorBurn]

So now, I'm aligning the camshaft timing marks before I put the new timing belt on (420a engine). I'm using a long straightedge and aligning it with the center of each bolt, and checking the timing marks to see if they are aligned with the straight edge. Basically, I've got the timing marks aligned, but maybe not aligned with the center line. Anybody know of a better way to do this? How important is the center line? I'm thinking that they are most aligned when the distance between the notches is the smallest.

 

[Zero6391]

very important, itll mean the difference between a running engine a busted up motor trust me, these 420a motors are real picky about timing alignments I actually installed my timing belt 8 times in one day cuz I couldn't get it to line up but I finally got it. get some zipties and then attach the belt to one cam shaft then rotate them to line up together then ziptie the other sprocket and now your done up top then u want to route the belt down the front and around the water pump and now all that leaves is the tensioner pulley. so with the cams up top aligned and held in place you can wrap it around the crank sprocket and then rotate it the half notch and then put tension on the tensioner pulley. I believe its 20 ft lbs and then pull the grenade pin and then let the tensioner tighten up then rotate the crank a few times and make sure it all still lines up and then your done. a lot easier with two people but it can be done by yourself... if you were closer I would go help

 

[MeteorBurn]

Thanks for the reply. I'm trying to get the car back to a family member while they use my car, so it's getting a bit annoying, and eventually I'm gonna need my car back. I got the camshaft timing marks good, and then I moved the crankshaft sprocket to 1/2 notch. I then routed the belt from the camshaft (they were already clipped on as you recommended) down around everything, then around the crankshaft sprocket. I turned it back to TDC to take up the slack, and everything was nice and good. Here's my issue; I went to put the tensioner on, and while applying torque so that I could bolt on the tensioner, both the camshaft sprockets and the crankshaft sprocket moved together by a very small amount. Is that okay, considering before the tensioner was put on, all the marks were fine? If they all moved together, shouldn't after 2 revolutions (stopping at TDC at the end of the 2nd revolution), the marks should be good? I imagine the alignments should all be good to go as long as they moved together.

 

[Zero6391]

if they all lined up good after the 2 revolutions then your good and if you don't feel any binds while rotating the crank by hand then I say your fine to fire it up! but if its off more then 1/2 a notch then I would say redo the timing belt, cuz if its off too much itll bend valves in the head

 

[MeteorBurn]

This is driving me crazy. I get the camshaft marks good, I move the crankshaft back to TDC to get rid of the slack, and everything's fine. When I apply torque to the tensioner pulley, it moves the camshaft sprocket. After two revolutions, the camshaft marks are not good. I've done it 4 times already and I keep getting the same results. Is it normal for the tensioner to move the camshaft when it's being torqued? I just can't seem to get the tensioner to stop screwing the marks up. I haven't read anywhere about this problem, looks like it's just me!

 

[Vegas Smith]

This is driving me crazy. I get the camshaft marks good, I move the crankshaft back to TDC to get rid of the slack, and everything's fine. When I apply torque to the tensioner pulley, it moves the camshaft sprocket. After two revolutions, the camshaft marks are not good. I've done it 4 times already and I keep getting the same results. Is it normal for the tensioner to move the camshaft when it's being torqued? I just can't seem to get the tensioner to stop screwing the marks up. I haven't read anywhere about this problem, looks like it's just me!

Whoa, why are the cam gears not tied down with a clamp or zip-tie? When tied down, they won't move at all and you can then manipulate the rest of the system.

 

[Zero6391]

remember when I said I did my belt 8 times in one day? that's why. another tip is to note how much the belt moves when u apply the tensioner and then adjust the cams off that much so when u apply tension it will move it back into place. sometimes the timing belt goes on right the first time and then others itll take try after try after try till u get it. really tests your pacience but whatever u do don't force it into position or else youll bend the valves on the head

 

[MeteorBurn]

I'll keep trying, but when you say the cam gears need to be tied down, do you mean to each other? I've been clamping the belt with binder clips to each camshaft sprocket, but that's it. If the tensioner tugs the belt its moves both of them in opposing directions.

 

[Vegas Smith]

Hmm, unless I'm confused...it should be very difficult to rotate the cam gears. They shouldn't be rotating very easily.

 

[Zero6391]

before u put tension on the belt have someone get a box wrench and rotate the intake cam towards the firewall to keep the cams in a appropriate position and then u can go under the car and rotate the crank to have that point line up and make sure all the belt slack is on the side of the tensioner. and with your friend still holding the cams in position apply the tension to the tensioner pulley and then pull the grenade pin

 

[Zero6391]

https://www.google.com/url?sa=t&sou...pbuiqf3dXGiotJi6A&sig2=LQmasvssTnXnNmXH-9rv7A

https://www.google.com/url?sa=t&sou...m5-gfebaDX6dINxEw&sig2=8e2HSMtY0iRqsSzAT4XcoA

give these a try, im a visual learner so its easier to see then to read