Theory:Standard JDM CA18DET Cam specs: In lift - 7.8mmEx lift - 8.5mmIn duration - 240Ex duration - 248In opens - 0 BTDCIn closes - 60 ABDCIn center lobe angle - 120degEx opens - 64 BBDCEx closes - 4 ATDCEx center lobe angle - 120deg(Courtesy of Niscort)

I had read a lot about doing this, so I bit the bullet and picked up an exhaust cam. Following is a simple how to. All of this is covered in the FSM from EM-12 to EM-18, except for the setting for the new cam. Much of the theory on this is covered in detail here:http://www.sxoc.com/vbb/showthread.php?t=281511

A simple visual comparison of the two cams (crappy pics, but you can see the difference in lobe angle and duration).

Tools:-Metric socket set-2 medium crescent wrenches-Hex set-Socket for crank (I use a 1 1/16")-Small screwdriver-Something to tap in cam seals (I used a 1 3/4" exhaust adapter pipe from the parts store)

Supplies:-CA18DET exhaust cam-224052 Federal Mougl (or comparable) seals-Oil-Towels

Procedure:Step 1Remove the water pump pulley. Loosen the 4 10mm nuts on the fan/water pump. Loosen the 14mm lower alternator mount, 12mm alternator tension bracket bolts (1 on alternator, 1 on tensioner). Slide alternator to the right and slip off belt. Remove the 4 10mm nuts on water pump pulley and remove.

Step 2Remove upper timing cover. Remove the 5 6mm hex bolts and 4 10mm bolts that hold the upper timing cover on. Locations can be found in FSM. Remove 3 10mm bolts holding on CAS. Remove CAS, then timing cover.

Step 3Remove coil pack cover, valve covers, cam gears, and timing belt tensioner. I have hex hardware on my valve covers, but you need a phillips head screw driver for the 16 valve cover screws (8 each) and a 10mm socket for the 8 10mm bolts for the timing cover. Leave covers in place to avoid debris entering valvetrain as you continue to work.

Now, set the motor to TDC.

Loosen 13mm nut on tensioner. Loosen the tensioner by inserting 5mm hex into the hole provided on tensioner and swing counterclockwise to remove tension. Slip Timing belt out of the way. Remove the 13mm but on the tensioner and make sure and keep track of the Marcel spring underneath (looks like a wavey washer). Now, take a few towels and stuff them in the gaping maw to catch any debris or falling screws.

Now, remove the valve cover for the cam you are working with. Use a crescent wrench on the place provided on the cam to hold it in place as you remove the 4 12mm bolts holding the cam gear on. Repeat for other cam. Replace cover when done. Remove the cam gear backing plate via the 4 10mm screws. Pull off.

Step 4Removing the cam. Inspect the key for the CAS on each cam and use the one with a cleaner key on the exhaust side. The one in place on the exhaust side of my motor was fine, so I only removed the intake cam for the swap. Follow the diagram below for removing the cam.

Here is the cam removed. This would be a great time to change out lifters if your are making noises.

Keep caps in order. They are numbered to assist in reinstall. Here they are arranged, right to left for front to back.

Now, place the new cam in its new home, and replace cam caps in reverse of install.

Step 5Cam seals. Even though I only swapped one cam, I went ahead and replaced both seals.

Since I am not swapping exhaust side cam, I just removed the front cap entirely. You may need to use a small screwdriver to lightly pry the cap off. Remove the cam seal, and lightly coat the new one in some motor oil. Slip it on, making sure the inner ring seats. Tap into place with suitable diameter pipe or tool.Once seated, seal will be flush with the head.

Step 6Setting cams. As outlined in the article linked above, we need to advance the new intake cam 1 tooth if you do not have adjustible cam gears. If you do, reset the cam to 8* advanced.

Replace cam gear backing plate.

Double check that the crank is set to TDC (second mark from left). Use 2 crescent wrences on the cams to position them. Havng a friend helps. I painted the cam gear backing plate white at the timing marks, as well as the small divets in the cam gear where TDC should line up to assisit in visual. Replace cam gears and tensioner. Now, line up the cam gears. Here is the position of the intake cam. It sould be 1 tooth advanced (clockwise) from stock.

Rotate the enigne over with a wrench two full revolutions, making sure that the marks still line up. Button everything back up, reset CAS timing, and go.

Final ThoughtsI have not had a chance to go on a real test drive, so impressions will follow. I noticed that when resetting the CAS, the motor likes to idle be at ~17TDC now. Dunno. I'll play with it later. Any questions, comments or concerns ... I know you will just post.

thanx manghelpfull, straight foreward info is goodstiky?

Indeed. It was fairly simple considering I have changed lifters and cam seals before so I know the drill. Like I said, the entire process is covered in the FSM, but pics help. I will get some miles in her tomorrow to give a full report on the results.

Great write-up! I really appreciate this, since I might try this later. I'm a visual person, and the pictures help a lot.

On the sxoc page you linked, there is some debate about whether moving the timing 1 tooth is good enough or whether or not you need adjustable cam gears. Apparently one tooth adjusts it to 115 degrees, but it should be at 120.

Anyone have any experience with this?

Thanks,

Darian

I saw that as well. There is the info for modifying the cam gear by enlarging the holes. I did buy an extra gear in case I decide to attempt this. However, after driving it, she idles just fine (if a little lumpy) and pulls hard from anywhere in the rev range. I was actually shocked: a very noticable increase in performance.

Sounds good.

Sorry to ask so many questions, but did you tune for it? How much boost are you running?

Thanks,

Darian

Answering questions is the responsibility for the creator of a how to my friend. Ask away!

No special tune, but my car is chipped for KA24E MAF, with no boost/fuel or speed cuts. I run 1bar on a T25G. Like I said, she seems to like a little more timing now.

Hey, I was going to do something on this, but since I can't because my engine is effed, I will contribute to yours.

I was curious about the whole specs of the USDM CA16 cam deal, to see if the intake cam is actually the same as a DET exhaust cam. It is.

CA18DET intake cam:



CA16DE intake cam:



The base circle is 32mm for both, which would make the DET intake cam roughly 7.78mm lift, and the 16DE cam 8.5mm lift. Hope that cleared up any misconceptions anyone might have had.

Well boy howdy. I need to go look up the timing numbers for that cam. That would negate the need to get all goofy with the timing.

I love this cam. Motor seems much more responsive and revvable. Good stuff. Plus, it is just damn nice to have my CA back after 2 months without my baby.

I added this to the FAQ rico. Thanks for the writeup!

No prob Ryan. We all gotta give back.

Now I'm not 100% sure, but I don't think the CA16 intake cam needs any special timing. Not that I have specifically tried it, but I have accidentally tried it, and it ran like crap. I have always used the stock timing figures and the car runs like a top.

Its probably why my not having butterfly valves has not bothered me at all. I installed the cams at the same time I removed the valves, so I never got to try it any other way.

Interesting. It is easier to find CA18DET cams than it is CA16DE, but still, that means that all the tomfoolery with the timing is a non issue for those that can find the CA16 cam. Thanks Tim!

Man, my car pulls like a beast now. Love it. Best $75 and 2 hours I have spent on power mods. Next to the $2 Home Despot MBC I built.

Man I got my set of CA16 cams from a member here for free a few years back. Best $0 I have spent on my car for sure! Haha.

Oh and I forgot to add, the reason my pictures suck is because my digi caliper was low no battery and the display kept flashing, so I had to time the shutter for when the display was on. It sucked!

Well, it looks like I'm gonna be throwing the intake cam from my old CA16 into my CA18 when i do my rebuild And in the process of getting it out I can figure out what happened to make my motor go to hell... =[

There is a writeup on SXOC about the whole intake cam thing. The CA16DE intake cam still isn't perfect, IIRC, but it's only off like 2° or something very minor.

Yeah, you really need an adjustable gear, but its close enough to make some improvements over stock. Well worth my $0 investment.

so...questions

Stock ex cam + Adj (say tomei) cams on both cams = Idle issue resolved?

currently running NIStune, any fidgiding needed to the ECU for fuel?

what would timing be set with adj Cams?

sorry for bringing back the dead...i just saw it...thought id ask

This is where i found the best timing to be situated and this is using a dyno not the seat of your pants.Intake cam; (Each dash is 1 degree)

And the exhaust cam was 2 degrees retarded.

Whoa, you need to reset the opening point of your butterflies there. Either that or you're getting some weird boost spike.

Hello Gents,

I have just performed this mod to my car using the adjustable pulleys both on intake (5º advance) and exhaust (2º retard) and the car has a very low idle. Also my vacuum reading has gone from around 450In/hg to around 250In/hg.

What could be the issue? Any and all help would be great.

Thanks and best regards,

Korsou

It sounds like a cam is off a tooth. You have too much overlap.

Thanks Float,

I will check it again just in case but I think it was good. WIll keep all posted.

Could it be something else?

Hello again Float,

You got it right, myu exhaustr was a tooth off. Set it all straight but now my mm/Hg are around 380-400. Is this ok?

Thanks for the help

that sounds about right. It should be a little lower, as you do have more overlap than before.

just came across this again. And was wondering seeing how I have a spare engine sitting. Is it worth me doing this and should I use adjustable gears. Or should i just move the cam a tooth. Just Wondering if it's really worth the time and will it help when I put my sr t25 on

If the cost is $0, then I say go for it!

zil40 wrote:just came across this again. And was wondering seeing how I have a spare engine sitting. Is it worth me doing this and should I use adjustable gears. Or should i just move the cam a tooth. Just Wondering if it's really worth the time and will it help when I put my sr t25 on

I did this on a 4 port with just the tooth advance, and despite testimonies by others to the contrary, my car had zero noticable change in low-end, general behaviour, or anything at all. Sure, it cost me nothing (only time), but it has also brought me nothing. I know I'm not helping to decide, but this was my experience.