Offshoreonly.com - Help picking out a cam...

Offshoreonly.com (https://www.offshoreonly.com/forums/)

- General Q & A (https://www.offshoreonly.com/forums/general-q-20/)

- - Help picking out a cam... (https://www.offshoreonly.com/forums/general-q/341791-help-picking-out-cam.html)

You might want to find a spring that fits your locaters and retainers, if they make one.

Curious what the specs are on the 2 different cams

Crane 168731
Lift: .587''/.610''
Duration: 288°/298°

The current ZZ502 cam has.527 intake / .544 exhaust
Camshaft Duration (@.050 in.): 224° intake / 234° exhaust

This one HR-226/345-2S-12 IGOperating Range:2500-6000 RPMDuration Advertised:288° Intake / 298° ExhaustDuration @ .050'' Lift:226° Intake / 236° ExhaustValve Lift w/1.7 Rockers:.587'' Intake / .610'' Exhaust
I could be wrong but it doesn't look like it's worth changing.

Quote:

Originally Posted by GPM (Post 4615535)

The springs? That would be nice. I just had the heads gone through about 20 hours ago.

Just my opinion, the cam is only 2 degrees bigger so I doubt you'll be able to tell. Going from 110 to 112 lsa might idle slightly better, loose a little midrange and maybe pull another 100 rpm. The valves may hit the pistons with the higher lift.

Quote:

Originally Posted by ezstriper (Post 4489827)

can't help much on cam, but I ran a HP500 with a procharger for years, several carbs and EFI, last setup had to go down to a 750 from a 850 to keep from leaning out at WOT, thanks god for widebands. the air was being blown thru so quickly that would not pull fuel, the 750 worked perfectly

Your boosters weren't getting enough signal. Swapping to stepped boosters and playing with the bleeds should have fixed up the 850. That, and maybe a little drill bit work on the secondary metering plates..

MC

Yeah, you are tapdancing around essentially the same cams for the most part. Sure a little more lobe separation will help a touch, but if you don't have reversion problems I wouldn't bother changing them out. The procharger will definitely wake up the motor, but you definitely want to use a low pitch prop when pulling tubes to take the load off of your outdrive. Running a high pitched prop, and a supercharger while pulling tubes puts a lot more actual torque load on the drive components. Drop 6" of pitch, and you reduce the load on the components dramatically.
I blew up more Bravos than I care to think about. Old style, upgraded to newer cone clutches, billet caps and upgraded parts and pieces - each step made them a little stronger, but you simply won't find me recommending anything over 550hp with a Bravo. XR's are grenades as well. A lightweight boat, under 5600 rpm, cryo gears, billet cap, shower, maybe 650 hp for short bursts if you baby it elsewhere.

You guys who run 800hp on a Bravo, I gotta hand it to you.
You must be more Irish than I am (and I am Michael Collins by the way, with a stout dose of Irish bloodline...).

MC

Quote:

Originally Posted by GPM (Post 4615566)

I picked up the cam on a really good deal, and I am hedging against reversion issues as that cam is notorious for destroying marine engines with wet exhaust. I’ll degree the cam in and check PV clearance.

MC,
I’ve already canned the idea of any blowers as I’d rather boat than wrench. I should be well under 550hp and already use a smaller prop for whipping poor unsuspecting friends onto the beach ;).