Do any of you that have higher duration Shrick, or whatever brand, cams have any issue with the rockers? Any idle issues, or loose of vac?
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I had a 292 deg custom grind in my 2.7 Alpina B3. It had a very rough idle but I would say had no power advantage over the original cam. I don't know what the original was and I no longer have it.
Together with all my other mods (bigger throttle body, 733 AFM, branches, aluminium flywheel, piggy back computer) the car pulled like crazy from low rpm and fizzled out after 5,500 rpm.
I did break a rocker arm once at 7,200 rpm.
Soon I will be building a 3.1 stoker M20 with a 304 deg Schrick cam. Not sure if the cam will work nicely but there is only one way to find out. Schrick claims the cam works best between 5,000 and 7,000 rpm.
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I've had a 304 Schrick for a year before I swapped. VERY lopey cam, horrible unburnt fuel smell at idle, and IMO the power band is too high, peaking around 7k rpm, where the intake manifold starts choking the engine. So all in all, I say if you're not going ITBs and getting rockers that can 'rock' 7500rpm all day, then a 304 cam is totally useless.
FYI my cam was in conjunction with high-comp pistons (10.8CR), m30 AFM, 2.7 stroke, piggyback, adj cam gear, and headers (Among other things, but the rest are too tedious to list and not that relevant).This is your M20 on steroids:
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Originally posted by kylebes1 View PostDo any of you that have higher duration Shrick, or whatever brand, cams have any issue with the rockers? Any idle issues, or loose of vac?
You'll lose vacuum too... no way around that with an agressive cam.
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I've enjoyed my last month with my 283 Catcams camshaft. Lopey idle, dunno about loss of vacuum, but have no brake issues at idle. Pulls strong from about 3500rpm all the way to the current stock 6250rpm redline. I do believe it runs a bit rich, but I'll see how much things change with my markD chip that's in the mail, and once I hit a dyno and get an a/f reading. Oh yeah, the headers might change things too.Your signature picture has been removed since it contained the Photobucket "upgrade your account" image.
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Oh sorry I forgot to add, YES almost total loss of vacuum around idle, enough to cause a few near-collisions at first when I wasn't used to (or expecting) it. Just remember to rev a bit before trying to use the brakes, if you've been coasting at idle. Otherwise no brakes :DThis is your M20 on steroids:
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Originally posted by MrK View PostI've had a 304 Schrick for a year before I swapped. VERY lopey cam, horrible unburnt fuel smell at idle, and IMO the power band is too high, peaking around 7k rpm, where the intake manifold starts choking the engine. So all in all, I say if you're not going ITBs and getting rockers that can 'rock' 7500rpm all day, then a 304 cam is totally useless.
FYI my cam was in conjunction with high-comp pistons (10.8CR), m30 AFM, 2.7 stroke, piggyback, adj cam gear, and headers (Among other things, but the rest are too tedious to list and not that relevant).
I would like to ask a few questions.
Did you have to rework the valve reliefs in the pistons to accomodate the high lift and how much could you adjust the cam ?
At what rpm did the power band kick in ?
How much power did the engine make ?
Would it be a good track cam or would you often be out of the power band when coming out of a corner ?
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Originally posted by Andreas View PostHi MrK
I would like to ask a few questions.
Did you have to rework the valve reliefs in the pistons to accomodate the high lift and how much could you adjust the cam ?
At what rpm did the power band kick in ?
How much power did the engine make ?
Would it be a good track cam or would you often be out of the power band when coming out of a corner ?
I'd say the power band kicked in around 4800rpm.
I'm not sure how much power the cam added, but the engine overall was pushing decent hp... I'd say a little above 200 at the crank after some tuning.
I suppose it would only be a good track cam IF the track was fast, and if you had ITBs to make use of the higher power band.
Hope that helped.This is your M20 on steroids:
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Originally posted by MrK View PostYes I had to rework the valve reliefs, and I just adjusted the cam back to the point where the marks on the head and block align (stock), because after I shaved the block, the marks weren't aligned.
I'd say the power band kicked in around 4800rpm.
I'm not sure how much power the cam added, but the engine overall was pushing decent hp... I'd say a little above 200 at the crank after some tuning.
I suppose it would only be a good track cam IF the track was fast, and if you had ITBs to make use of the higher power band.
Hope that helped.
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Originally posted by SA E30 View PostI would say if the power band was around 4800rpm... seems 2 me like it wouldnt be such a great camshaft for the tracks in SA
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