AEM Cam Gear Install

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(Yes, the bolt is not in, I forgot to put the bolt in for the picture.  It's in now though!)


General disclaimer:  What you do to your car following this article is your responsibility.  Don't come to me if you ruin something while attempting this install.

Overview:  It has been dyno proven that using adjustable cam gears can yield us ~10rwhp.  I only installed the exhaust cam gear because that's where most of the HP gains will be obtained from.  Some say the intake side isn't worth doing, (most do it to look pretty) and the gains are very minimal.  The timing belt is covered all the time so I didn't feeling like shelling the extra dough for looks.

Objective:  This technical article will provide the installer with the proper information and procedures to install a single or a pair of adjustable cam gears on their twin (or single) turbo Supra.

Tools:  Socket set, socket extensions, 10mm, 15mm, 22mm box end wrench, electric screwdriver with extension for 10mm socket,  5mm (I think) allen wrench, wood blocks for the rear tires, jack and jack stands, a bucket, some shop rags, pliers, flat tip screwdriver, loctite (I used 271), and possibly some other tools I didn't list.

Time:  From start to finish, a good solid 2 1/2 hours.  Second time around...maybe 1 1/2 hours TOPS. :)

Let's start this badboy!  Before you actually start, I suggest you read this article at least 10 times to understand what you're going to be doing.  (Or until you can do each procedure while half-ass asleep. :)


1.  Disconnect the battery cables and remove the battery, set aside.  Remove the battery clamp, set aside.  Using a 10mm box end wrench, remove the 3 10mm bolts holding the battery tray down.  Set battery clamp and 3 10mm bolts in tray, set aside next to battery.  Make sure it's up against the wall so someone doesn't trip over it.

2.  If applicable, disconnect the center piece of your strut brace, set aside so it won't get scratched and damaged...the best spot would be the hatch.

3.  Remove the 10 allen head bolts on the spark plug cover, so it won't get scratched and damaged, once again, the hatch is a safe place.  Take a small baggie and place the 10 bolts inside and place on your bench or in the hatch.   All the stuff placed in the hatch won't be touched until reassembly.  Since that spot is choice location, it would be very difficult to really lose anything while attempting this install.

4.  Take your pliers and squeeze the clamp on the radiator hose on the radiator flange.  Slide the clamp back a good 5-6 inches.  ***Make sure your engine is COLD or you have waited long enough to bring the coolant temperatures down!***  Take some rags and place them under the flange to catch most of the coolant that doesn't make it into the cup.  Take your cup and place it under the radiator hose, pull (wiggle) the radiator hose off and aim it into the cup.  You can tip the hose down allowing coolant to run out into the cup.  Do this a few times to get most of the coolant out.  Repeat for the other end of the radiator hose.  You will want to stuff some clean shop rags into the opening to each end to soak up any more coolant that flows out.

5.  This is where you need the jack and jack stands.   Put the wood blocks behind the rear tires to keep your car from rolling away.   Lift up the front end of the car and place jackstands under each allocated location for jackstands.  Place jack aside to prevent a trip hazard.  Make sure everything is secured at this point before crawling under the front of the car.

6.  Take your electric screwdriver and use your 10mm socket and lay under the front end of the car and remove the plastic "Engine Under Cover."

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  Place the bolts in a baggie and place the screws in a separate baggie, then place both baggies in a single baggie and stash in the hatch to prevent them from growing legs and walking away.   Removing the plastic cover will do the following:  a.  Provide access to the bottom mounts of the radiator, access to the removable harness for the stock electric fans, and access to the bottom clip of the fan shroud b.  provide access to the timing belt tensioner.

7.  You want to remove the harness attached to the fan shroud.  You do this by unbolting the 2 10mm bolts holding the fan shroud to the radiator.  Just place the bolts back into where they came from once you back them out enough to remove the shroud.  Then you go underneath the car and  unbolt the 3 10mm bolts holding the bottom of the shroud on.  While you're down there, disconnect the harness/plug going to the temp probe (I think it's a temp probe), disconnect the 2 plugs for the electric fans, and using a flat tip screwdriver, from the top of the shroud, push in the tabs to the stock zip tie holding the harness to the shroud.   For the 3 10mm bolts, you should just be able to leave them bolted in while removing the shroud.  The part where the shroud attaches is open and the bolt "clamps" the shroud bottom down.  Unclip the bottom half of the shroud, it's pretty straight forward and should be obvious, remove the 2 clips and swing out the bottom half.   Remove the fan shroud and set aside.

8.  Take your allen wrench (5mm) and remove the timing belt cover.  There are 3 bolts holding it on(STEP #5 in the next scan).  Take the 3 bolts and place them in a baggie and put them aside.

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Upper radiator hose and timing belt cover.

9.  See here, under STEP #6, LOOSEN and DO NOT remove the drive belt tensioner.  I think it's a 12mm socket.

10.  Look at following diagram before going any further.

Steps 7a & 7b
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Complete steps 7a and 7b.  At this point, you want to take note of the little punch marks and paint on your stock cam gears.  They will be pointing at the notches that are indicated behind the cam gears.  You want to take a ruler and a permanent marker and mark on the belt (make the line above the 'ridge' of the [either cam gear will work, I'm focused on the exhaust side for this install, but can be applied to both for installing a pair of cam gears] cam gear) of exact position the stock cam gear was located in.

When the crank is at 0 the cam gears should each look like this, if the crank is at 0 and the cam gears are not, then turn the crank another 360 revolution till all match up:
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11.  Remove the intake plumbing going to the throttle body, this should give up some free working space.  Take a 22mm open end wrench and a 22mm socket and place the wrench on the crank pulley bolt and place the 22mm socket on the cam gear bolt.  ALWAYS remember to turn clockwise on the crank pulley bolt.  But don't turn the crank pulley here!  Use it to keep the cam gear bolt from moving.  Carefully loosen the cam gear bolt, but do not remove, yet.

12.  Take a 12mm socket with extension and go underneath the car.  Look up to the right and you should see the alternator right above the sway bar.  Behind that, locate the timing belt tensioner. 

STEP #8a.
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LOOSEN the 2 bolts, but DO NOT REMOVE them!  This should give you enough slack in the timing belt to remove and reinstall the timing belt over the new cam gear.

13.  By now, you should have enough slack to easily remove the timing belt.  BE VERY CAREFUL HERE!!!  You don't want to bump the cam gears or the crank pulley or you could seriously throw your timing off!   Carefully back the cam gear bolt back out and set aside.  Note:  I think on pre97's, you need to order a new cam bolt as it has a smaller washer.  Mohd told me about the new bolt and so I ordered just to make sure, I found out that I didn't need to use the new one, because it was exactly the same as the stock cam gear bolt.  (On my 97TT)  No biggie, I used the new one anyway.  You will notice behind the bolt there is a pin that is offset.  See tip below.

Tip 1:  Try NOT to move the belt position on the other cam gears teeth.  Have a buddy place his/her hand on top to keep the belt from budging.  Take your new cam gear and slide it partially onto the cam flange at an angle, then take the timing belt and it should slide and fit on the cam gear exactly like how the stock cam gear was removed and should be in the same exact position the stock gear was in.  It should look something like this if you've made it this far.  See tip 2 below.

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Tip 2:  Remember the line you drew on the timing belt to mark the location where the stock cam gear indentation was?...well, with the cam gear installed exactly in the first Tip, take some touch up paint/white out and mark on the new cam gear ridge exactly where the line falls on...this can be used for future reference if the cam gear is ever taken off and reinstalled.

14.  At this point, you're halfway through the install...take a step back and to the side and this is what the front part of the engine bay should look like this,

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15.  Take a break at this point...the rest is reassembly, but you should pay attention to the torque values.

16.  Enjoy your break?  The next few steps will be quick as at this point you will probably know exactly what to do.  I will point out some important areas.

17.  Install the new cam gear bolt.  Place the 22mm open end wrench back on the crank pulley and use that to keep the belts from moving and torque the cam gear bolt to 59 ft.lbs..

18.  Using a standard allen wrench, loosen the cam gears adjustable bolts.   On exhaust gear, retard -3, on intake gear, advance 1.  On AEM cam gears, it's recommend to use Loctite thread locker to prevent the bolts from loosening.  After placing the Loctite, torque them puppies down!  Make sure you don't move your settings or you will lose the  performance benefit of the cam gears!   Double check and triple check this. 

19.  You should go under the car and torque the timing belt tensioner to 20 ft.lbs., come back up  and then tighten the drive belt tensioner to 15 ft.lbs..

20.  Re-Install the timing belt cover.

21.  Re-Install the fan shroud, re-install the bottom half of the shroud with the 2 clips, plug in the harness back into the shroud, plug the temperature probe plug back in, plug both fan plugs in and tighten down the 3 10mm bolts...careful, it's plastic remember?!

22.a  Re-Install the plastic engine under cover.

22.b  Lower the car back onto it's tires.   Remove wooden blocks.

23.  Re-Install the upper half of the radiator fan shroud via the 2 10mm bolts.

24.  Re-Install the radiator hose and move the clamps back over the flanges.

25.  Re-Install the intake plumbing at the throttle body.

26.  Re-Install battery tray, battery and battery clamp.

27.  Double check and triple check everything up to this point.  You should be able to fire the car after you install the battery.   Don't put the spark plug cover back on yet, make sure all your tools are out of the way and everything of kosher.

28.  If everything is OK at this point, reinstall your spark plug cover and your strut brace and be on your way!


Questions? Comments?  Email me

Thanks to Nick P. for his pics and his cam tech info off of his old tech page for the addition to this install.

Source Links:  Timing Belt Replacement