Guest Anonymous Posted May 2, 2001 Share Posted May 2, 2001 Hello, two questions for anybody who might know.. ok first being the 288 im building is gonna be a screamer im hoping for about a 6500 to 7k redline. questions concerning valvetrain.. should i be running a solid cam or can i sneak by with a hydraulic? especially considering the high strung nature im trying to create for this motor. also pertaining to solids: what is required to maintain a solid lifter cam? ok second question pertains to rockers. im thinking im gonna use roller rockers, is this going to be possible, and also looking through my PAW catalog i noticed the ratios of 1.5 and 1.6. iunderstand the greater ratio would basically make it seem as if a larger cam were actualy in it. but question being is the 1.6 ratio used on the street? and if so what are the advantages of it over just running a bigger cam? thanks DAN Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 2, 2001 Share Posted May 2, 2001 Let me say this first - I like solid cams. I like not having those lifters squishing up. I also like the sound of the solid lifters, although they play havok with knock sensors! I've read that for stuff much beyond 6500 rpm on a SBC, hydraulics (even the anti-pumpup ones) still tend to pump up and promote valve float. Solid lifters obviously don't do this. Street solid cams have gentle ramps that make it easy on the parts and the valve seats. Sure, you need to adjust them every 10K miles or so (that's probably every couple of years for me), and stiffer parts like 7/16" studs and probably rocker arm stud girdles are a good idea for valve train stability and keeping the adjustments in check. My car had nothing over the valve covers and removing them takes about a minute each if I take my time. I think the maintenance aspect is negligible. I think that if you want to rev in this range, solids are the way to go. Comp Cams just came out with a mechanical (solid) flat tappet version of their Xtreme grinds. I'm looking to upgrade to that from my Magnum solid cam this Winter. As far as rocker ratios, the stuff I've read says to get the cam you need and used standard ratios. I see larger ratios as a band-aid to getting the lift and duration needed. Valve train geometry is trickier with non-stock ratios. Of course, if you want to buy a standard cam, but want more exhaust lift and duration, using larger ratio rockers on the exhaust side of a cam with the same duration and lift for both intake and exhaust is a proven method that works. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted May 2, 2001 Share Posted May 2, 2001 I've never used a Solid Roller nor a Hyd.Roller so I can only go by what I've read. The Solid Rollers do require maintenance checks (Setting Lash) but that is completely dependent on the driver's right foot; a mile engine may never need the resetting of the lash once ite properly been set; totally dependent upon the driver's right foot! Now, if your build is a monster motor that see's the outer limits on a regular basis-then setting the lash will be a weekly/monthly thing. Further, the Solid Roller's allow an engine to usually rev @ 1000rpm's higher than Hyd.Cams. Because of this extra 'umph' the cam offers-their materials are also a little costly; the books I've read say if you're gonna use a Solid Roller not to skimp on parts. Buy the best or the extra pressures placed upon your valvetrain will come to an early demise. In other words; buy hardened valves, titanium keepers, maybe even a rev kit which could imclude a stud girdle for the valves & springs for the lifters/pushrods in the valley area. If you plan on pushing it to the 6500rpm level/make sure things are not going to twist/flex to the point of breaking something. Of course anytime someone consistantly pushes the outer limits you can expect to break something along the way; kind of goes w/the territory. Just my .02c's worth. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 2, 2001 Share Posted May 2, 2001 I tend to agree with Pete on the rocker ratio's. I may experiment with it because its cheap, and I can get a tad more lift without getting into the internals (something I'm not doing at this time), a few more ponies for 60-70 bucks seems ok for an hour or so project. That said, if I had built an engine, I would just get the cam to do the job and not fool with the rockers ratios. You can put in the cam that has the lift and duration you want, so unless the cam manufacturer recommends a different ratio, then its not necessary. (some setups do, I was involved in a buildup of a Ford FE 428, and it required a slightly different ratio for the Edelbrock performer RPM setup on that engine.) Safest bet is to just contact the cam manufacturer for suggestions on what rocker ratio to use for their setup. Regards, Lone Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted May 3, 2001 Share Posted May 3, 2001 You can use a solid or hydraulic cam for your desires/solid will be a fair bit cheaper as you won't need a rev kit that you would with a hydraulic to see 7k with strong power. Nothing wrong with using non 1.5 rockers, just work it into your overall lift ahead of time so you know your springs have the room to accomodate whatever lift you decide on. Pete's referencing old single pattern cams mostly (v. few single patterns today...) and grinds have come a long way since 60's factory single grinds so step to a newer dual pattern cam that will match up with your heads/intake/exhaust plans. The only reason I mix rockers on my mill is I run a ZZ4 roller cam (it was $50 new)and that cam was designed around the rather lazy exhaust port of L98 heads(old vette/new ZZ4) so has a wide split pattern that my mill didn't have to accomodate with better flowing heads so I bumped up the intake. A proven dyno combo among Lt1 Impalas good for ~320hp/320tq at the wheels with appropriate fuel/breathing support. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted May 3, 2001 Share Posted May 3, 2001 Ross, Is that ZZ4 in your Z? If so-what trans are you running & how well does your Z hook, what rear gears & tire sizes are you running? Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted May 3, 2001 Share Posted May 3, 2001 quote: Originally posted by Kevin Shasteen: Ross, Is that ZZ4 in your Z? If so-what trans are you running & how well does your Z hook, what rear gears & tire sizes are you running? Kevin, (Yea,Still an Inliner) Kevin here's my setup: 1998 4 bolt 350 full roller shortblock edelbrock rpm heads/victor jr/performer carb -stewart water pump -ZZ4 cam, comp cam springs/pushrods/keepers etc -1.6 Gold race on intake/1.52 Chromolies on exhaust Trans is 700R4, diff 3.7LSD. Car hooks VERY well IMO, 1st is sorta useless with the engines flat powerband right off idle...WOT but driver control makes it sane A nice blast is scratching solidly 1st/2nd/3rd on shifts. Maybe I'll do some Gtech runs before this EFI install. Tires were SZ50's (still my favourite!) 225/50/16's for past few years with fine manners and last year has been 245/45/16's AVS sports for street and A032R Advans for track (and some street ). It would hook better with softer springs/shocks but then the high speed track stuff would suffer which I live for AIR, my rear springs are 350 ftlb and 5ways set at 2 for street (1 didnt' control rebound enough) and autox with 3 fine for roadracing. Up front I don't recall spring rates offhand but similar and shocks at 1 for street/2 autox/3 roadrace. Some experienced drivers/instructors (I'm quite green at this aspect) commented last summer the spring/shock combo is ideal and the car is very neutral in cornering. I know it 'rails' v. smoothly now in comparison to the pre coilover/tokico setup so I'm pleased. Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 3, 2001 Share Posted May 3, 2001 Ross is right about me talking about people mixing ratios on an engine for the use of single pattern cams. But also remember that the newer heads for the SBC flow so well on the exhaust side that single pattern cams begin to make sense again. I have a few year old magazine article (can't remember the mag - I'll dig it up tonight) that compared similar hyd and solid flat tappet and hyd and solid roller cams on the same engine. What I found interesting was that the solid flat tappet cam (an old design no less) did very well when compared to the hyd roller in terms of average power and torque over 3 bands. THe writer went on to say that if an engine wasn't already set up for rollers, he'd go with a solid flat tappet in alot of cases. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted May 3, 2001 Share Posted May 3, 2001 Ross, sounds like a nice tight set up; sorry 283z...didnt mean to get your thread off track. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted May 3, 2001 Share Posted May 3, 2001 quote: Originally posted by pparaska: But also remember that the newer heads for the SBC flow so well on the exhaust side that single pattern cams begin to make sense again. OK, but it'd take some convincing for me to come full circle..these fully ported Lt1's (ie. fine flowing heads) have tried many cams and they're still on dual pattern typically, not a wide splay but dual nonetheless. Even if total lift is identical they've staggered duration, (and removing cats doesn't change these results much) , just GM's offerings below but one local guy has a box full of dyno slips on a highly mod'd NA LT1 and I only recall discussion of duals http://www.sallee-chevrolet.com/Cam_Specs/GMPP_Small_Block.html Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 4, 2001 Share Posted May 4, 2001 BTW, that article on the different types of cams was in the August 1999 Car Craft magazine. [ May 04, 2001: Message edited by: pparaska ] Quote Link to comment Share on other sites More sharing options...
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