2eighTZ4me Posted July 21, 2008 Share Posted July 21, 2008 I have the choice between using a MSA Stage 3 cam for my stroker setup (89mm bore w ported/polished MN47 head + 2mm head gasket) OR a Racer Brown cam that I just got in a head off E-bay. The Racer Brown cam (grind 341-R) has .500" lift both intake and exhaust, 1.5 Rocker arm Ratio .050" duration Intake and Exhaust = 242 .025" duration Intake and Exhaust = 266 Lobe Centerline (Intake) 105 Lobe Centerline (Exhaust) 111 Lobe separation 108.0 Advanced 3.0 Valve timing @ .050" lift (Intake open 16.0 BTC, close 46.0 ABC) Valve timing @ .050" lift (Exhaust open 52.0 BBC close 10.0 ATC) The MSA Stage 3 cam has less lift, but I don't know how they're calculating lobe separation, as it looks though Racer Brown does it at both .050" and .025" with different specs at each. I'm not an expert on any of this, so I'm hoping someone can make suggestions as to what would be best for my setup. I'll be running Mikuni 44's for induction. Car will be mostly AutoX and Track Days car with occasional street use. Quote Link to comment Share on other sites More sharing options...
naviathan Posted July 21, 2008 Share Posted July 21, 2008 I'd go with the Racer Brown cam. Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 21, 2008 Share Posted July 21, 2008 That racer brown cam is more equal to the MSA stage 4 cam (290/290 degrees duration and 0.495"). The racer brown cam (242/242 @ 0.050") should run well with 10.0 to 10.5:1 cr The MSA stage 3 (270/280 @ 0.050") cam should run well with 9.5 to 10:1 cr What compression ratio does your engine have? Quote Link to comment Share on other sites More sharing options...
ozconnection Posted July 22, 2008 Share Posted July 22, 2008 If you have the time and resources, why don't you try both cams? You'll be asking yourself forever "I wonder how the other cam will work with my engine combination?' otherwise. Put your car on the dyno for each cam and drive each one on your favourite piece of road and track. Then you'll have some idea of which cam is better suited to your driving style. Only YOU can decide this. Some guys will just tell you to use the biggest cam you can and for a dual purpose machine this might'nt be your best option. I read in a book once very famous to us Datsun guys, "Don't overcam your engine and don't break it either". Have fun!! Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted July 22, 2008 Author Share Posted July 22, 2008 It will be somewhere between 10:1 and 10.5:1 - it'd be great to have the luxury of being able to try both cams, but that's a load of work to change out a cam. I'd have to do rockers, lash pads, springs, retainers - I'd basically be doing a top end rebuild with the head on the car. I'll go with the Racer Brown. That's what I bought it for. Thanks for the replies guys! Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 22, 2008 Share Posted July 22, 2008 Looks like you need to run the racer brown cam due to high compression. What is the bore, stroke, head cc, and piston deck height? 10 to 10.5 is a pretty big range. You should be able to do a little math and get a closer estimate. Around 20 years ago, I ran a 240 degree Clifford Research cam in a daily driven 240z with a L28 block and 3.90 gear. I loved it! Came on really strong around 4000 rpm and pulled hard to 7000. It was a very fast street car, for the time period (new vettes only ran mid 14's in the mid 80's). However, I wouldn't do that again as a daily driver. Being older and wiser, I went with a quiet turbo setup. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted July 22, 2008 Author Share Posted July 22, 2008 Hey Pyro - thanks - it's tidbits like that (driveability vs. performance) that I"m looking at. As stated in the original post, it's a stroker (83mm) and 89mm bore. Maxima N47 head with Rusch Motorsports full race port job. Standard stroker deck height of +.6mm. The head is at my machine shop now having new seats cut in, and he's yet to cc the chamblers and give me a number. That's why I'm "best guessing" at this point. I DO have dished pistons and a 2mm HG, so that might drop things a wee bit. I dunno - just a W.A.G. at this point, based on other combinations I've seen others post. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 22, 2008 Share Posted July 22, 2008 Stage III is too small for your intended use. The Racer Brown cam is about right, maybe a bit on the small side. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted July 22, 2008 Author Share Posted July 22, 2008 Thank you Mr. Mortensen! Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 22, 2008 Share Posted July 22, 2008 compression should be around....10.6:1 516cc /cylinder 44.6cc for N47 12.7cc for 2mm head gasket -3.7cc for +0.6 deck height (516 + 44.6 +12.7 - 3.7)/(44.6 + 12.7 - 3.7) = 569.6/53.6= 10.6:1 Quote Link to comment Share on other sites More sharing options...
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