What valve springs should I use ??
#31
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Location: NY-NC
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On the crane cams website, under frequantly asked questions, at the heading below, "reasons and causes for cam failures" I wanted to post that topic, as it states spring pressures for Hyd. roller, street performance BBC's.. Yes, it does not say boat, but I build my mild boat engines as basicly street car performance style, of course with some exceptions. But come on, a low rpm, well thought BBC is very comparable, whether its a car, boat, or ?? The bottom line is HP-TQ at the right rpm, with reliability. Although, some boat engine builders would like to think there is a black art to building offshore engines, the none racing performance offshore engines are some of the lowest stressed BBC's I have ever built, but again, I'm comparing exp. I have gained from trying to keep very high stressed applications together, such as blown gas-alky, injected nitro drag-boats. Although very different, agreed, I have learned a few things along the way that correspond with the basic mechanics and design of engines & componets regardless of what it is, from the dyno or actual implement its going in. The last page I wanted to post was from the Competition products, inc. website. If you go under valve springs, and then Isky, you will see the 8005's with the specs. That is where I buy my springs from, and probalbly have over 50-engines out there with hyd. rollers and that exact spring. Also, my Rimac tester, verifys the numbers listed from comp. products, dead on. Thats it, sorry for all the BS.
#32
Charter Member #40
Charter Member
I am no cam wizard but I can tell ya I tried running a Tool Room Sp that went in new around 250 at the seat, with .720 lift on a solid roller. That was the ticket I guess for 7500 running but it was not good on lifter life. Switched to an Isky Plus which has I believe a tool room outter and a lesser inner spring and they go in around 200, end up around 185 or so after dyno and life has been good. My experience with the pressure drop after break-in is almost 10%. There are some builders suggesting that you want 180# or so with a hyd roller. I think I would look at that a little closer for a boat app.
#34
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Wow all this back n forth and no one even said the Fountain word.
#37
VIP Member
Thread Starter
WOW !!! I would have never guessed valve spring choice would be such a hot topic. Thanks for the input guys. I will start researching the part numbers offered.
Thanks,
Smitty
Thanks,
Smitty
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