CAS install, TDC question

[AWDPetmitsu]

When installing/ replacing the CAS on a 1G, does the #1 cylinder need to be at TDC on the compression stroke or just at TDC?

 

[LiquidX]

Put #1 cylinder to TDC and install CAS with the notches pointing to the dot. Use a timing light to adjust.

 

[AWDPetmitsu]

So it doesn't matter whether or not cylinder 1 is on the compression stroke or not? As long as it's at tdc?

 

[Boostdriven]

It does make a difference, you can have your CAS 180* out. You need to make sure that #1 piston is on compression stroke, you can tell this by looking at the marks on your cam sprockets. They should line up as if you were installing a timing belt and only then you can install the CAS with the marks lining up on it.

 

[chaclark83]

Install at tdc with timing marks aligned, which means yes compression stroke. It will run either way though but inj timing will be off.

 

[Devilsfutbol17]

How important is installing the CAS at TDC? I've never followed any procedure when installing my CAS on my galant and I never had an issue. I noticed on my girl's 2g that there is a difference in that piece that attaches to the cam shaft, but I don't remember seeing any markings on my 1g CAS.

 

[Boostdriven]

I have never installed one 180* out so I can't tell you if it will run or not but I know there are marks on the sensor so there must be a reason for them. Here is a picture I found online showing those marks and how they should line up. In the picture is says crank angle sensor but on 1Gs CAS does both crank and cam.

 

[AWDPetmitsu]

In addition to checking the timing marks on the cam sprockets, do I also have to check the alignment of the timing marks on the crankshaft sprocket and oil pump sprocket to verify #1 cyl is at TDC on its compression stroke as opposed to being at TDC on its exhaust stroke?

 

[chaclark83]

If your timing marks are lined up with the can dowels pointing up its at tdc on compression stroke. Then line the marks up on the cas and install.

 

[LiquidX]

It's just easier to have the timing marks aligned at the cams when doing the cas install. It does not need to be installed without the motor in time since the cas can only be installed correctly or 180* out.

If it runs like complete crap or doesn't run then try rotating the cas arm and try again.

Don't forget to set your ignition timing with a light bulb then.

 

[AWDPetmitsu]

If your timing marks are lined up with the can dowels pointing up its at tdc on compression stroke. Then line the marks up on the cas and install.

Ok, I replaced the CAS, but there was something strange. I had the dowel pins at 12 o' clock and the cam sprockets timing marks lined up and the crank pulley mark at the "T". When I took out the old CAS, the punch mark and notch on it were not aligned. They were 180° opposite of each other. They would only be aligned when the cam sprocket dowel pins were at the 6 o'clock position and opposing cam marks aligned. So confused!!

 

[LiquidX]

Then your cas was put in 180* out if your mechanical timing is set properly. Just rotate the arm to match up the notch and dot and re install.

 

[AWDPetmitsu]

I installed the new CAS the same way the old CAS came out. marks on the CAS aligned and cam sprocket dowel pins at 6 o'clock and it runs fine. I figured it ran fine like that so I should put it back like that, but I'm still baffled as to why the dowel pins are at 6 o'clock.

The cam sprockets can only be installed one way, correct? They can't be installed 180° opposite, correct?

 

[LiquidX]

That's correct if they are stock cams. Aftermarket cams may have multiple dowel holes (like fidanza having Evo holes).

I would get your timing to TDC with all marks lined up and put the cas alignment in proper.

 

[chaclark83]

Yes do it proper. It will run slightly different 180 out but just listening to it run you won't be able to tell a difference. The problem is that you're injectors are firing 180 out and the gas is just pooling at the valve waiting for it to open and that doesn't do well for proper atomization. It will run and you may not be able to tell a difference but its there. Install your cars proper and be done.

 

[AWDPetmitsu]

Hmmm... I can't understand why the original CAS would have been installed 180° out. I bought the car brand new and to my knowledge, the CAS has never been touched.

I've read many posts here about people's engine not running because their CAS is 180° out, but you're saying that it will run 180° out and run so smooth that you can't tell there's something wrong.

I might redo it and flip the CAS plate 180°.

 

[xxNocturnalxx]

I have installed one 180* out during some trouble shooting and I did not notice a difference, not saying there wouldn't be one though.

 

[AWDPetmitsu]

I have installed one 180* out during some trouble shooting and I did not notice a difference, not saying there wouldn't be one though.

Thanks for your input. I just gleaned over the shop manual and read this:

1. INSTALLATION OF CRANK ANGLE SENSOR
(1) Locate the dowel pin on the sprocket side of the intake
camshaft at top.
(2) Align the punch mark on the crank angle sensor housing
with the notch in plate.
NOTE
The crank angle sensor can be installed even when the
punch mark is positioned opposite the notch; however,
the position results in incorrect fuel injection and
ignition timings.
(3) Install the crank angle sensor on the cylinder head.

Sounds like LiquidX and chaclark83 are right.
I'm going to have to redo the CAS install with the dowel pins at 12 o'clock.

 

[chaclark83]

That is correct but the ignition timing being 180 out doesn't matter if its 180 out unless you're tuning etc, and need to identify a cylinder. Our cars use a waste spark ignition.

 

[LiquidX]

You don't need to set it to TDC to re do the cas. Just unbolt it and rotate it half way around and re install. Just do the ignition timing with a light afterwards.

 

[AWDPetmitsu]

OK, so I redid my CAS install and flipped the plate 180°, aligning the marks and installed it with the dowel pins at 12 o'clock. If there is any difference, it's imperceptible, as chaclark83 said. It runs exactly the same, but I'm sure the injector and spark timing is different now. One thing that I did notice is that it doesn't seem to crank as long before it turns over when starting, which makes sense.

 

[xxNocturnalxx]

So all is well or are you still having some issues?

 

[AWDPetmitsu]

Yes, all is well and all was well before too. I just wanted to update and say that I can't tell any difference in the way it runs with the CAS plate installed in either position. I'm sure there is a difference so I reinstalled it the correct way.