mystery exhaust cam

[dhen]

Hi everyone,

I was using a DE exhaust cam in my CA with adjustable cam gear advanced 8 degrees. It worked fine, but it seemed like a half-measure. Anyway, I ordered what I was told was a used CA18DET exhaust cam from the UK. It doesn't work like a JDM one and runs like crap with stock timing. I advanced the gear 8 degrees and it worked very well, but not perfectly on high boost. It feels like it needs to be advanced a couple of more degrees on the cam gear. In any case, it's not a US-spec DE cam.

I found this list of cam specs, but to be honest, I don't completely understand it.

another-de-intake-cam-in-det-thread-t541989.html

Is it possible to figure out what type of cam I have by advanced/retarding my cam gear. (I'm sure this is stock) I.e. if I advance it to 10 degrees and it works, I have X cam, etc?

If that's not possible, can I measure this cam to find out the specs? I understand a micrometer will tell me the lift, but what about specs like when the cam opens/closes/lobe angle?

Any ideas would be welcome. I'm curious to know what I have an more importantly how I could make it work.

Darian

[TheMAN]

it's been a while since I touched a CA motor internals... does the cams have any identification marks or codes on them?
to determine the valve timing, you will need a degree wheel... I also noticed that the list doesn't have the overlap specs, but that can be easily calculated using this formula:
degrees BTDC + degrees ATDC = overlap degrees

for newer engines that have VVT and have values in negative degrees BTDC or ATDC, do the same calculations, but remove the negative of the sum of the values

[dhen]

As far as I can tell, this cam has no special marking. I'll take a closer look at it when I take it out of the car.

So if I take it to a machinist and ask them to analyze it for timing, etc., can they do this even if they don't know the car?

Thanks,

Darian

[float_6969]

Working backwards to find cam specs will require the cam to be installed in the engine, a degree wheel, and a dial indicator gauge. Way more work than it's worth honestly. It would likely be less work to play with the cam timing until it runs well.