Need help after 1.8 rocker install
03-21-2003, 08:32 AM
#1
Staging Lane
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Need help after 1.8 rocker install I had installed crane 1.8 rockers recently and I have a drop off of 10 rwhp after 6000 rpm through 6600. Before I had the rockers installed at 6000 rpm through 6600 it would level off at 355 rwhp and go straight across with no drop off.
Now it goes from 353 rwhp 6000 to 342 rwhp at 6100 and stays there until 6600 rpm. Any suggestions?
BTW: the rockers picked up 10-15 rwhp from 3000-5600 so my car is quicker but it scares me that I may have problem that needs attention now before something major screws up.
Now it goes from 353 rwhp 6000 to 342 rwhp at 6100 and stays there until 6600 rpm. Any suggestions?
BTW: the rockers picked up 10-15 rwhp from 3000-5600 so my car is quicker but it scares me that I may have problem that needs attention now before something major screws up.
03-21-2003, 08:58 AM
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Re: Need help after 1.8 rocker install One possibility that always occurs to me when high-RPM power drops off is a cat overtemp condition. When the cats get too hot the PCM will add fuel to cool them off, which lowers the A/F ratio.
Did you use a wideband O2 sensor for your dyno pulls? If so, what did your A/F ratio look like above 5500 RPMs?
Did you use a wideband O2 sensor for your dyno pulls? If so, what did your A/F ratio look like above 5500 RPMs?
03-21-2003, 09:24 AM
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Re: Need help after 1.8 rocker install Thanks Hitmanss for the try. Someone told me it maybe valve flutter. Something about the springs not having enough compression? I am running CC918 springs.
03-21-2003, 09:56 AM
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Re: Need help after 1.8 rocker install The pushrods came with the kit, and I had someone install them for me. As far as valvetrain noise, no it actually got quiter than it was before the install.
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03-21-2003, 10:08 AM
#8
Re: Need help after 1.8 rocker install If you followed crane's 2 turns after taking up the slack the lifters are probably pumping up. It really should be 1/2 to 3/4 turn after you take up the slack. Most likely it is valve float, I am just about to try some crane 1.8s and I have the same cam you do and 918 springs.
03-21-2003, 10:13 AM
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Re: Need help after 1.8 rocker install What do I need to do to fix Valve float? Can the 918's on it now be adjusted or do I need them to adjust the rockers?
03-21-2003, 10:23 AM
#10
Re: Need help after 1.8 rocker install Find out if they did the two turn thing, if they did re-adjust them. My springs at stock height (1.800) are at 120lbs on the seat which may not be enough. You can shim the springs up but if I have float problems with the 1.8s and 918s I will probably switch to the 987 dual springs since my seats are already machined for them.
People have used the same cam and 1.8s with 941 springs so I would think the 918s should be enough - cant tell until you try it though..
BTW, detonation will look a lot like valve float on the dyno, its hard to tell sometimes. If you have LS1edit you can back off the timing a few degrees and see what happens.
<small>[ March 21, 2003, 10:31 AM: Message edited by: kp ]</small>
People have used the same cam and 1.8s with 941 springs so I would think the 918s should be enough - cant tell until you try it though..
BTW, detonation will look a lot like valve float on the dyno, its hard to tell sometimes. If you have LS1edit you can back off the timing a few degrees and see what happens.
<small>[ March 21, 2003, 10:31 AM: Message edited by: kp ]</small>