Installing timing belt

[Lucas03es]

So im installing my gates blue timing belt on my freshly rebuilt motor. I dont know if it matters, but it has 1mm oversized valves and bc 280 cams. I did the timing belt according to vfaq, but when I removed the tensioner pin and rotated the motor 6 times over, when I realigned the cam gears, the crank sprocket doesn't line up to the timing mark on the block. Its 1 maybe 2 teeth past the mark. I just dont know if this is supposed to be true TDC? I have the Jay racing tool kit as well. Thanks!

 

[bryanwheat]

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Huh.. odd.... looks kind of like each cam gear has two timing notches....

Short and simple - We make sure the dowel guide hole is pointed up (Up = 12:00 position looking at the driver side of the engine while facing the engine bay on the driver side of the car looking from the side, not the front) - (PS - AKA in the position the gear is in above) for a reason. That reason being - This is the CORRECT spot to set your mechanical timing. there is no "Cams are timed 180* out. It'll work just perfect! " median. Remove the belt - Do it right.

Those suggesting it will be fine - PM me when your engine detonates. I'd like to send you a .gif of me not giving a shit.

IF you turn the crank one full rotation than the marks will be lined up with the dowels straight up. There is no 180 out here. The cam's spin 180 degrees for every 360 degrees of the crankshaft. Why remove the belt when it is already in time. You accomplish the exact same thing either way. Go ahead and set it right, now rotate the crank 360 degrees and look at the dowels and the timing marks. The marks will be lined up and the dowels will point down.

 

[Jon91TSi]

Roger - I'll make note - Cam gears only have 1 timing mark each.

Apparently you only read what you want to read.. As I said... I was also remiss in thinking that perhaps he had a dab of white paint on the correct tang on the 3 o'clock and 9 o'clock of the cam gears as I'm used to doing with all the cars I work on.

The large mark is the only correct mark. The small mark means you screwed up, try again. I'm done here.

 

[Alan11]

Apparently you only read what you want to read.. As I said... I was also remiss in thinking that perhaps he had a dab of white paint on the correct tang on the 3 o'clock and 9 o'clock of the cam gears as I'm used to doing with all the cars I work on.

The large mark is the only correct mark. The small mark means you screwed up, try again. I'm done here.

It did had white paint. and the marks lined up correctly. I just cant recall and honestly didn't put attention to the dowel pins. The car fired right up and has no kind o surge or misfire.

 

[99gst_racer]

IF you turn the crank one full rotation than the marks will be lined up with the dowels straight up. There is no 180 out here. The cam's spin 180 degrees for every 360 degrees of the crankshaft. Why remove the belt when it is already in time. You accomplish the exact same thing either way. Go ahead and set it right, now rotate the crank 360 degrees and look at the dowels and the timing marks. The marks will be lined up and the dowels will point down.

Ignition would be 180* out. Pretty much the same thing as installing the CAS 180* out.

There's really no point in debating the wrong way anyway. Dowels go up. Always.

 

[bryanwheat]

Ignition would be 180* out. Pretty much the same thing as installing the CAS 180* out.

There's really no point in debating the wrong way anyway. Dowels go up. Always.

That would be solved by turning the cas 180 degrees. There is no need to take the belt off if it was installed with the dowels down. It is in time regardless. I am not saying that you should install the belt with the dowels pointed down, only saying that there is no need to take the belt off and re-do it.

 

[XiKeiyaZI]

That would be solved by turning the cas 180 degrees. There is no need to take the belt off if it was installed with the dowels down. It is in time regardless. I am not saying that you should install the belt with the dowels pointed down, only saying that there is no need to take the belt off and re-do it.

And that's suggesting that we do things incorrectly and fix them in a half-assed manner. Very very poor approach to things.

Do it right or don't do it at all.

 

[BogusSVO]

No not half assed, I see where bryanwheat is going with this,,

Pop the CAS out, rotate the engine over so all timing marks line up, including the cam dowels at the 12 O'clock postion, then install the CAS.

 

[XiKeiyaZI]

No not half assed, I see where bryanwheat is going with this,,

Pop the CAS out, rotate the engine over so all timing marks line up, including the cam dowels at the 12 O'clock postion, then install the CAS.

May I question - Since you are surely the last person I would question about machine work - in my experience with having the head off and rotating the cams, the valves are closed at 12:00 and 6:00, however certain ones are not sealed completely where as others are, and they tend to change which at 12:00 and 6:00. I will assume that this... excuse me, 'ghetto' way of resolving performing your timing job 180* out will correct the firing order to compensate for the valve vs tdc vs ignition?

If it'll work, it'll work. That being confirmed is just that. I just see it as 'incorrect'.

 

[bryanwheat]

May I question - Since you are surely the last person I would question about machine work - in my experience with having the head off and rotating the cams, the valves are closed at 12:00 and 6:00, however certain ones are not sealed completely where as others are, and they tend to change which at 12:00 and 6:00. I will assume that this... excuse me, 'ghetto' way of resolving performing your timing job 180* out will correct the firing order to compensate for the valve vs tdc vs ignition?

If it'll work, it'll work. That being confirmed is just that. I just see it as 'incorrect'.

I NEVER said that it was a good idea to set the timing like that. I guess you aren't understanding what is going on here. If you put the belt on accidentally and the dowels were pointed down, you can turn the crank one rotation and they will be pointing straight up, via, being in time. Every other time that the piston is at tdc the dowels will alternate where they are at from top to bottom. If you set the timing according do the factory service manual and turn the crank one revolution than the marks will be lined up, but the dowels will be pointing down. So because of this you should pull the belt off?

 

[XiKeiyaZI]

I NEVER said that it was a good idea to set the timing like that. I guess you aren't understanding what is going on here. If you put the belt on accidentally and the dowels were pointed down, you can turn the crank one rotation and they will be pointing straight up, via, being in time. Every other time that the piston is at tdc the dowels will alternate where they are at from top to bottom. If you set the timing according do the factory service manual and turn the crank one revolution than the marks will be lined up, but the dowels will be pointing down. So because of this you should pull the belt off?

If you set the timing with the Dowels up and then turn it a single revolution, you are not in the correct phase with your mechanical timing. In fact, your crank is going to be off. It takes 5-6 full revolutions to line the crank, Oil, balance shaft, and cams back up with the cam dowels up.

I don't recall any step in the procedure that people have been performing for.. what, 22 years now, that states to ever confirm timing with the way the cams align with the dowels down. You should start with them at 12:00 and end with them at 12:00. You don't go " Whoops, did it wrong. But if I turn the crank until the dowels are down and the Timing marks line up, I'm in time! "

Nope - 180* out. Incorrect. Do it again.

I'm not trying to bash you, argue with you, or piss fight with you. I'm just stating that this is negligent mechanic work. For something as important as your timing where it is not a desired 'request' but an imperative 'need' to be set correctly, you do it 100% right and by the book.

 

[bryanwheat]

If you set the timing with the Dowels up and then turn it a single revolution, you are not in the correct phase with your mechanical timing. In fact, your crank is going to be off. It takes 5-6 full revolutions to line the crank, Oil, balance shaft, and cams back up with the cam dowels up.

I don't recall any step in the procedure that people have been performing for.. what, 22 years now, that states to ever confirm timing with the way the cams align with the dowels down. You should start with them at 12:00 and end with them at 12:00. You don't go " Whoops, did it wrong. But if I turn the crank until the dowels are down and the Timing marks line up, I'm in time! "

Nope - 180* out. Incorrect. Do it again.

I'm not trying to bash you, argue with you, or piss fight with you. I'm just stating that this is negligent mechanic work. For something as important as your timing where it is not a desired 'request' but an imperative 'need' to be set correctly, you do it 100% right and by the book.

I never one time stated that this is how to set the timing. I only stated that it will be in time. The reason that you have to rotate it 6 times is to get the balance shafts lined up, not the cams. Every 2 revolutions of the crank will line up the crank and cam timing marks. If you accidentally installed the belt with the dowels down and than turned the engine over one revolution than the timing marks will line up to the CORRECT spot that they are supposed to. The balance shafts will also be in phase. If you can turn the crank to tdc, and the cams and balance shaft marks line up than why would you pull the belt off and re-do the timing? Again, stop accusing me of saying that this is how you should do a timing belt install, i never said that. It is in no way wrong, or shady. I've been installing these things for around 14 years, and have installed well over 100, i am well aware of the physics behind the timing belt.

 

[Calan]

If you put the belt on accidentally and the dowels were pointed down, you can turn the crank one rotation and they will be pointing straight up, via, being in time. Every other time that the piston is at tdc the dowels will alternate where they are at from top to bottom. If you set the timing according do the factory service manual and turn the crank one revolution than the marks will be lined up, but the dowels will be pointing down. So because of this you should pull the belt off?

Interesting. I've never thought about it like that.

Will it still work with the balance shafts? What is the turn ratio on the oil pump? (I can't remember to save my ass right now).

After a few dozen timing jobs....

That's the second or third time you've mentioned this. Why have you done a few dozen timing belt jobs in a year and a half? Did you open a shop?

Just curious.

 

[Colt4G63 also]

The balance shaft to oil pump sprocket is a 3:1 ratio.

Ps. A lot of this CAS turning jibberish sounds a little off. The CAS only goes onto the cam in one direction, so unless you took it off to do a timing belt, I don't see how it would ever need to be reversed.

Ps Ps. I only have two chicklets, and I have been doing this stuff professionally since the first DSM rolled off the assembly line. Maybe thats just because I'm an asshole.

 

[bryanwheat]

Interesting. I've never thought about it like that.

Will it still work with the balance shafts? What is the turn ratio on the oil pump? (I can't remember to save my ass right now).



That's the second or third time you've mentioned this. Why have you done a few dozen timing belt jobs in a year and a half? Did you open a shop?

Just curious.

The balance shafts marks will be 180 out technically if my math is right (too early in the morning) but still in phase to the crankshaft still. Again, i am in no way saying that it is the correct way to do it, if i found the balance shaft marks to be off i'd personally re-do it, i am just speaking in theory, it would be in time and run fine (as long as you adjust cas 180 degrees on a 1G). I more time, i am in no way telling anyone that you should do this at any time.

The balance shaft to oil pump sprocket is a 3:1 ratio.

Ps. A lot of this CAS turning jibberish sounds a little off. The CAS only goes onto the cam in one direction, so unless you took it off to do a timing belt, I don't see how it would ever need to be reversed.

Ps Ps. I only have two chicklets, and I have been doing this stuff professionally since the first DSM rolled off the assembly line. Maybe thats just because I'm an asshole.

The cam angle sensor can be installed with the shaft 180 degrees out. It will fit in either way, that is why there are the alignment marks on the cam angle sensor, so that you know the orientation when installing it with the engine at tdc.

 

[Calan]

Ps. A lot of this CAS turning jibberish sounds a little off. The CAS only goes onto the cam in one direction, so unless you took it off to do a timing belt, I don't see how it would ever need to be reversed.

I think there is some miscommunication going on here. Bryanwheat (Bryan?) isn't saying it's a good idea to install the cams with the dowels down. If I understand correctly, he's talking about a theoretical quick fix that wouldn't require pulling the belt, by simply throwing ignition timing off by 180* to line back up with the valve timing. I could see that as being pretty useful in some cases, even if it isn't ideal.

As for whether or not it would actually work, I have no idea and am too tired to think about it after being up all night crunching numbers. But it is interesting never the less.

 

[Colt4G63 also]

I never take the CAS off the head to change a timing belt, and the cam is what denotes what stroke the crank is on. If you reverse the CAS it will never run. The ignition timing would then become 180 out.

Unless you took the CAS off in the first place, and put it on backward, there would be no reason in the world, to ever take it off and reverse it regardless.

 

[Colt4G63 also]

So, the cams spin at a 2:1 ratio with the crank, right? One revolution of the crank (360*) is two revolutions of the camshafts (720*).

I didn't read past here. Have you guys been up all night?

360 degrees of the crank = 180 degrees of the cams.

 

[Calan]

I never take the CAS off the head to change a timing belt, and the cam is what denotes what stroke the crank is on. If you reverse the CAS it will never run. The ignition timing would then become 180 out.

Unless you took the CAS off in the first place, and put it on backward, there would be no reason in the world, to ever take it off and reverse it regardless.

Since we have a waste spark ignition system, the plugs are actually firing any time the piston is at TDC, so it shouldn't matter whether the CAS is 180* out or not...but it actually does.

The reason it matters is because the cylinder getting the waste spark is firing out of phase in relation to the cylinder that is on the power stroke, due the dwell time of the coil. In other words, there is a slight delay between the spark hitting cylinder #1, and the spark that hits cylinder #4 for example. So if you install the CAS 180* out, you have to adjust the base timing differently to compensate for it and keep the ECU in sync. If you don't, the plugs on the compression strokes will be firing slightly later than the ECU thinks they are.

You can actually see this effect if you hook up a timing light to a COP setup, and switch between the input to a coil and it's output. You'll see the timing mark on the crank pulley change by several degrees as you switch between the two wires.

Whether or not the car will run with the CAS 180* out depends on how close the mechanical timing is to the ignition timing. FWIW, my car will usually run with the CAS 180* out, but not very well.

I didn't read past here. Have you guys been up all night?.

I have...does it show?

 

[99gst_racer]

I didn't read past here. Have you guys been up all night?

360 degrees of the crank = 180 degrees of the cams.

HAHA, I re-read that first line, and quickly figured out my error.

For some reason, I always mix up the ratios between the camshafts and balance shafts.

 

[bryanwheat]

So, the cams spin at a 2:1 ratio with the crank, right? One revolution of the crank (360*) is two revolutions of the camshafts (720*). If you install the cams with the dowels down, then they are 180* away from where they should be. if you spin the crank 360*, then it spins the cams 720* and puts them right back where they were with the dowels down. If you want to move the cams 180* to get the dowels up, then you're only moving the crankshaft 90*, which means it's no longer in time.

I know it's early, and the coffee machine is broke, but am I missing something here?

The cams spin half as fast as the crank, not twice as fast. The crank has the smaller gear. If they spun twice as fast than the valves would open twice each rotation of the crank. Each valve opens every 2 rotations of the crankshaft.

As for the car running or not with the cas 180 out. Because it is a wasted spark system it could possible run, but the fuel will be pooling on the valves instead of being injected when the valve is open because it will be firing the injectors 180 degrees out from where they should be.

 

[Calan]

HAHA, I re-read that first line, and quickly figured out my error.

Damn... and here I was about to light you up.

Holy crap this thread is moving fast. I'm having to go back 3 posts every time I hit the submit button to get caught up.

 

[99gst_racer]

I know, I know. It's early.

Usually when I ask if I'm missing something, I am.

 

[XiKeiyaZI]

That's the second or third time you've mentioned this. Why have you done a few dozen timing belt jobs in a year and a half? Did you open a shop?

Just curious.

Wondering where you're pulling the 'Year and a Half' time ratio? - NOTE : (03-22-2010, 08:45 AM ) Oooh the first post of mine concerning a timing belt job on my 92 Non Turbo Eclipse Base Model, 4G37 - 4G63 Swap that I did in my carport without any prior knowledge to it. I see what you did there. Way to go out of your way.


As for owning a shop where one comes to bring their vehicle, drop off, sign a piece of paper, I head in, snap my gloves, perform a duty, and get paid on a weekly basis by distributing funds on and extracting my General Ledger to perform my book-keeping : No. I do not.

Now by performing work and research on my own vehicle, the vehicles of others who need help in my area, re-performing timing belt jobs out of need or concern that an oil droplet has deteriorated the integrity of the belt (IE being anal), and by that of helping those around me who need the assistance while performing a vital routine in upkeep : Then I guess you could say yes.

That is how I've performed, loosely, "A few dozen. "

Not once has a timing job I've done resulted in failure. So I'd say I'm at least 24-0.

The balance shaft to oil pump sprocket is a 3:1 ratio.

Ps. A lot of this CAS turning jibberish sounds a little off. The CAS only goes onto the cam in one direction, so unless you took it off to do a timing belt, I don't see how it would ever need to be reversed.

Ps Ps. I only have two chicklets, and I have been doing this stuff professionally since the first DSM rolled off the assembly line. Maybe thats just because I'm an asshole.

1 : It is 'off' as it's a 'work around' to correct one's mistake in an easy fashion instead of doing it right, which is why this sideways endorsement from others tossed in here and there is starting to irk me.

2 : I made the comment about chicklets based on the fact that they are now overseen by privileged individuals on the board, thus assessing that somehow, someone like me has been approved of three with zero negative counts - which goes to state that the input that I've given in situations like this has obviously not been incorrect. No hint towards "I'm better than anyone else" just moreso - "Stop telling people it's alright to goof your timing and then try to correct it by flipping your CAS 180* out. That's bad information."

I thought we were about doing things right here at Dsmtuners.com - Not screwing up your Mechanical timing and suggesting to not worry about it - "flip your CAS around, It should be alright but we're not sure. "

 

[99gst_racer]

I agree with bryanwheat that if a person accidently timed their engine with the dowels down, that they'd only have to turn the crank one rotation to get everything where it needs to be (provided balance shafts have been eliminated). Then, install the CAS as normal, and everything is timed perfectly.

I think we're all in agreeance that it's not recommended to install the cams upside down, or to do anything to compensate for it, but that it's a simple fix to correct it.

 

[Calan]

Agreed. It's actually a pretty cool thinking-outside-the-box idea.