Advance Cam Timing by One Tooth

I've heard a lot of talk about advancing the cam timing for more low-end power at the expense of a little high-end power. It's also said to grant a little better mileage, so I thought I might tackle this project and see how well it truly holds up to the claims.

First things first, we need to decide on how we're going to advance the cam. There are three methods, installing an adjustable cam gear, using cam keys, or rotating the cam in relation to the engine and using the teeth on the gear and timing belt as a guide. The third option is what we'll be using as it's the easiest, not to mention free. The down side is that you can only adjust the cam by teeth instead of degrees, in our case one tooth is equal to 9° of adjustment. All engines are slightly different and for maximum benefit, the cam would need to be more accurately adjusted but for free and easy, this is the way to go.

Like all projects that involve the timing of anything, the first step is to remove the timing cover. For those that have never removed the timing cover, there is a single bolt on the side of the cover, where it attaches to the lower timing cover. On top, there are two nuts, one in the front and one in back of the valve cover. Once you remove all three, the timing cover can be taken off by pulling straight up; if there is any resistance, slightly rotating and moving the cover around while still pulling, will pull it right up.

This is what you should be looking at with the timing cover off. Our first move from this point is to rotate the engine until the cam is in alignment position. Simply take a large ratchet with an 18mm socket (sizes may vary) and rotate the engine by turning it on the large cam bolt. The torque on the cam-bolt will rotate the engine without loosening the bolt. You will know the engine is in alignment when the very small hole in the cam gear aligns with the gasket knub on the valve cover, and the small arrow pointing outwards on one of the larger holes, aligns with the seam between the valve cover and head (this arrow is really meant to align with the top of the cam towers, but the seam is at the same height).

Now that the cam is aligned, we want to mark the rotor position and the cam and timing belt's position with each other. Should anything go wrong, this will allow us to reset everything back to factory and start over again.

We are now ready to start our actual work. First we'll have to remove the cam gear bolt so we can remove the cam gear, but if your remember, it's on tight enough to be able to turn the engine without actually loosening the bolt. This is where you'll need either a pin spanner or something (in my case, a very large screwdriver) that you can cram through one of the holes in the cam gear, and wedge against the rest of the engine. Loosen the bolt by turning it towards the firewall (counter-clockwise).

With the cam bolt out, you can now remove the cam gear. It's unlikely to come off by just pulling on it, but I managed to remove it by wiggling it back and forth while pulling back. Once I could get a flat-blade screwdriver between the cam and the cam gear, I used that to help pry the cam gear off. Be careful once you do remove the gear, as you do not want to let anything slip; try to keep the belt and gear tensioned so nothing slips and the ignition timing doesn't change.

While keeping the timing belt tensioned in one hand, carefully take the cam gear and partially reinstall it (push it partly back on, just enough to stay on) and advance the cam gear one notch (turn it clockwise, or towards the front of the car). Since the cam is no longer attached to the crank by the belt, this can be done by hand. Once the cam is advanced, pull the cam gear back off and put it back in the belt, making sure to align the mark you made on the gear, one tooth ahead of the mark on the belt.

You can now reinstall the cam gear, simply push it all the way back onto the cam and reinstall the cam gear bolt. You may have noticed that my method is slightly different than the methods given by others, but I've noticed that this is by far the easiest way. You cannot simply slide the belt off, adjust the cam and slide the belt back on, as the tension of the belt will do nothing but work against you. Instead, by removing the actual gear and belt together, only taking the gear out of the belt to adjust the cam, you can use the gear to keep the tension on the belt.

With the cam gear and belt reinstalled, double check to make sure the rotor is still in its original position and that the cam gear has been advanced one tooth in relation to the belt. If the rotor has changed position, you will need to realign the engine to the rotor's original position and realign the cam. If the cam gear is not advanced one tooth but the rotor is still aligned, you will simply need to realign the cam. If everything checks out however, go ahead and start the engine. Everything should appear normal, but the car should have slightly better throttle response.

If the car runs really rough, double check to make sure that the timing is indeed correct. If there is nothing wrong but the engine contiued to run rough, check to make sure that you haven't broken any vacuum lines. Although my car is lucky that the vacuum lines have remained like new over the years, they become brittle and break easily on most cars and several large vacuum lines run directly next to where you are working.

If the car will not start at all and only cranks, make sure you have reinstalled the ignition cap. I made this mistake when I first tried to start the car. It is unlikely that a no start will be caused by a mistake in the timing as even when far off target, the car will at least try to start. Also, make sure to double check that you have the coil wire away from the cam gear, as I also made this mistake and ended up eating through the protective loom around the wire. My only consolation is that the gear didn't hurt the wire itself and cut the loom at the exact spot I was planning on cutting it anyways, so it would fit better into the timing cover's coil wire slot.

Please keep in mind that the results you are about to read may be completely skewed because of some already existing problems and your results may be completely different, that said, here is the results of the cam advancement.

You will completely loose the high-end; the engine will powerwise, stall out above 5000rpm and will have trouble accelerating above 4000rpm; 4500rpm is right around where you will slowly accelerate, but not at any appreciable speed. The low-end however will be considerably improved, my results showed a 0-45mph time of 4 seconds but there is an almost instant slowing beyond that point. It took a full 20 seconds to reach 60mph. The top-speed of the vehicle has been reduced from 105+ to just over 60mph. I was unable to even reach freeway speeds. To make it all worse, the engine runs exceedingly hot after any sort of spirited driving and the car has to be shutoff to cool-down. I've double-checked everything and the only thing changed from before is just the cam timing.

Forget this mod, it is everything you don't want. I'm sure that a few degrees advancement would work wonders, but a full tooth (9°) is far too much. Get an adjustable cam gear or cam keys and don't waste your time here.

A few things to keep in mind when comparing your results against mine. Due to various reasons, my engine already does not make the power others make in the high-end, so any additional high-end power loss ends up being more noticable on my vehicle. This is in addition to my torque converter being permanently stuck in lock-up and having a low stall speed (1500rpm), which means any improvement in throttle response and power from a stop is severely limited, although accerelation and throttle response from a rolling start is actually helped. You should expect to see at least slightly better performance results than I've seen.

If you have any comments, suggestions or questions, just throw an email my way: Justin Brimm.

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