Cam choice mistake made

[Chuckcruzin1986]

I bought a 284 Schrick for my 2.5 M20. I am not happy with it, poor idle (I could have other issues but I think it is the cam), poor low end torque and not enough improvement at the top end to justify the losses (for my taste).

After a lot of thinking AND talking to Jim at Metric Mechanic I have decided the cam is to much for me so I will pull it and install the original stock cam!

What has happened (thanks Jim for the info) is that the total engine was not prepared for the cam.......not enough compression and CID....plus I miss the drivability of the stock cam which is 95% of my driving (3000 to 5000 rpm). Long story but we all make mistakes and this was a big one that I made so I will just move on and sell the cam.

Chuck

[dlmpsy]

Many people "overcam" a car, it happens once and you figure it out. You definately need one that operates best in the rpm range you plan to drive. No use having a cam for top end power when you spend most of your time in the lower to mid rpm ranges. Airflow needs to be increased with the higher rpm cams, intake/exhaust porting, maybe bigger valves, etc....

[z31maniac]

Sounds like you didn't do your research before you dropped your hard earned cash. Sucks, but I bet you won't do it again.

[Wh33lhop]

Hmm. How are your valve clearances? The 284/272, if ran with regular cam timing and stock "i" pistons, will cause the valves to actually graze the cylinders at TDC. Most who run this cam with a 2.5 either adjust valve lash to above spec or retard cam timing with an adjustable cam gear, because it will destroy your bearings if you don't (check out what happened to James Crivellone).

As far as I know the 284/272 actually increases low-end as well as screams on the high-end, although you won't be seeing the full potential of the cam with a stock bottom end.

[RobE30]

Hmm. How are your valve clearances? The 284/272, if ran with regular cam timing and stock "i" pistons, will cause the valves to actually graze the cylinders at TDC. Most who run this cam with a 2.5 either adjust valve lash to above spec or retard cam timing with an adjustable cam gear, because it will destroy your bearings if you don't (check out what happened to James Crivellone).

As far as I know the 284/272 actually increases low-end as well as screams on the high-end, although you won't be seeing the full potential of the cam with a stock bottom end.

Kind of OT but I am running this cam currently but so far haven't had any issues.... now I'm worried. Damnit

[Wh33lhop]

Well, it won't happen overnight. Just adjust your valve lash to something a good deal higher. What's the rocker arm ratio, 1.25mm on valve per 1mm on camshafts? Last I talked to nando he said he had .5mm too little valve clearance, so that translates to another .4mm or .016" of valve lash over stock. But don't quote me on that, PM nando for more info.

What have you noticed in terms of performance difference from a stock cam to give the OP some context?

[RobE30]

From my "butt dyno" it pulls great from 3000 and up. I'm currently running 17.5 injectors, k&n panel filter, ie shorty headers (planning out my own long tube headers), no cat and supersprint exhaust. The car is a little weak in the low rpms, but is completely acceptable for DD, even in stop and go. I can still pull from a stop in 2nd (3.73 rear) w/ no issues. I am running a 173 ecu w/ a stock chip (don't know what I wanna run, TMS, MarkD, Miller maf/ war etc). Hope that helps

[Danny]

How much do you want for the cam?

[nando]

I've had this cam for about 4 years now, had it in the stock engine for one year - idled great, pulled strong everywhere. cam clearance is an issue on the stock motor, but if you are having poor power and a shitty idle your issues are likely elsewhere. tthe 284/272 is meant to be a midly aggressive street cam, it's not "overcammed" by any stretch of the imagination.

[nando]

Kind of OT but I am running this cam currently but so far haven't had any issues.... now I'm worried. Damnit

measure the clearance of the intake valve at TDC. it's not hard, use a dial indicator, compress the valve spring until the valve touches the piston, and measure how far it travelled. if it's 1.5mm or more you're fine, 1.25mm you need to back off the valve lash a bit, less than that and your engine isn't long for this world..

[Philo]

Jim at Metric Mechanic

I use this guys cam. :)

[dark89e30]

You can't upgrade from a Schrick. There is a reason everybody copies them. It sounds like you have other issues as you should have no problem getting this cam to idle on a stock engine...

[nando]

I use this guys cam. :)

they are compromise cams. you get stock characteristics but you also don't gain as much performance.

[Chuckcruzin1986]

Stock cam back in........me happy

You can't upgrade from a Schrick. There is a reason everybody copies them. It sounds like you have other issues as you should have no problem getting this cam to idle on a stock engine...

Nice smooth idle, more low end torque. More fun to drive. What can I say...???

Chuck

[digger]

You can't upgrade from a Schrick. There is a reason everybody copies them. It sounds like you have other issues as you should have no problem getting this cam to idle on a stock engine...

depends on what you are after, catcam make some good cams