I've never been a believer of camshafts not because I think they're funny, only because I own an auto car. To make it worse - I'm driving a 3-speed auto. So anything that affects my low end is generally a bad thing for me since my gear ratios are ridiculously tall.
What does that mean? It means camshafts are for people who want to improve their mid to highend power. Or so I thought. I've tested a few cars with similar configurations as my own car and they all have fantastic oomph across the whole powerband (almost all) and the car was no less drivable as my own car when driving like a tortoise on a road. Reading about it at howstuffworks.com made it even clearer on how cams work (fantastic pictorial descriptions!)
That got me itching - should I get a cam installed? My evil friends all replied : Oh hell yes!
(What are friends for if not to poison you into modifying your car?)
After some surveying, I opted for what I call the "Hellokitty" camshaft. A mild 260 degree intake and 288 degree exhaust billet cam. Feedback for this cam was it worked wonders for the mid to high powerband and it didn't mess with your idling too much like the "Thundercat" 292 high cams. Too much overlap between intake and exhaust gases will need some A/F tuning which can only be done with management (piggyback or standalone) otherwise you'll have some really rough idling or it won't idle at all and just die off everytime you lift off the accelerator.
Anyway, since my car is only a single overhead cam engine, it was relatively simple to remove the cam.
First things first, battery comes out. Safety first! Next remove the whole airbox assembly right to the manifold. Then the rocker cover (or valve cover / cam cover / whatever you call it) comes off.
In my case, the ignition coil was in the way so that had to come out too.
Remove the bolts clamping down on the camshaft. Since I was changing my cam-pulley as well, that had to come out as well.
Gently turn and slide the cam shaft out. You have to be extremely patient to do this and brute force should never be used if it's stuck.
Once the stock camshaft is out, lube the new cam first. It makes it easier to install. Notice Drexchan (my installer for the cam shaft and pulley) is not wearing any gloves. Why? Gloves has hair and/or may introduce foreign objects into the exposed cylinder head. We wouldn't want any dirt or hair mixing in with the oil do we?
Gently slide and turn the new cam in. Be extra careful with the camshaft oil seal! You may need to take out the oil seal for the new cam to sit properly on the seal. If you're skilled enough like Drexchan, you should be able to twist it into the oil seal without problems.
Refit all the bolts back into the original locations. To tighten the bolts, start from inside/middle and work your way outwards to ensure equal pressure on the camshaft. Best to use a torque wrench to ensure you get the best and even torque is used to lock down the bolts. Once done install the new cam pulley.
At this point you can re-tune your tappets if you're not using a hydraulic lifter setup. Since mine is old school manual tappet adjustment, I had mine re-adjusted just to compensate for any differences between my original tappet gap difference and now since over time the clearances might change.
The cam pulley was retarded -4 degrees initially and it was found that the powerband was way too high. Changed that to -2 degrees and it worked better. From 0 to 4000rpm the rev was normal but after that the RPM meter moved drastically faster and the car surged forward quite satisfactorily. Happy but at 4k RPM, for an automatic that was somewhat dissapointing.
I experimented using a higher octane petrol with my next fuel fill and surprisingly this worked much better. 2.5k RPM all the way to 6k RPM the oomph was there! After a discussion with Drexchan on my findings, he figures the overlap between the intake valve and exhaust valve opening somewhat decreases the octane in the cylinder making it harder to burn. Switching to a higher octane petrol offset that loss and translated into power.
A week and a half later I'm still experimenting with different setups, mainly tappet adjustment, octane boosters mixed with RON95 (I'm a cheapass ok?), cost vs benefits, etc. Will share my findings as my experiments complete themselves.
Until then, I highly recommend camshafts to anyone who doesn't have one. I'm pretty much sure it'll help your acceleration or improve your overtaking prowess. And the rawwwrrr the Hellokitty cam gives me when I hit the powerband is priceless!
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