How To Get 500+ More RPM, Without Changing Cam |
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How To Get 500+ More RPM, Without Changing Cam |
motorvated |
Jan 15 2019, 05:50 PM
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#1
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Member Group: Members Posts: 281 Joined: 13-February 13 From: Colorado Member No.: 15,519 Region Association: Rocky Mountains |
2.0 Liter Four. Doing a top end refresh and not planning on splitting the cases or changing the cam. Would stiffer valve springs and beefier pushrods get me there. I'm a little confused when looking at aftermarket springs, as the European Motorworks Single HD springs are rated at 135 psi seat pressure, and stock springs are rated at about 175 psi. Also thinking that chromoly pushrods set at zero clearance cold don't let the valves open fully when hot due to the lower expansion of the pushrod, plus they are a lot heavier than aluminum pushrods. So what can I use to get those elusive extra 500+ rpm? My old stock 1.8 floated valves up near 6,000, which wasn't bad, but I'd like a little more with the 2.0 liter. I'm racing the car in Vintage. Any suggestions.
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Dave_Darling |
Jan 16 2019, 03:03 PM
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#2
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914 Idiot Group: Members Posts: 14,991 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
To remove the lifters, use a magnet. You'll have to remove the pushrod tubes and pushrods first, of course.
You cannot change the cam without completely tearing down the case. You might or might not be able to re-use the main bearings and such, but that just screams "false economy". Splitting the case is pretty easy. Except for the first time or two, because everyone misses one or two of the through-bolts. Like the one hidden behind the flywheel. Or the lower one on the front of the motor that often gets caked over with gunk. It the case doesn't come apart relatively easily, check for bolts you have missed. Because everyone does at some point. --DD |
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