What numbers/specs do you look for in a set of valve springs? To match up to a CC xfi 280, what specs do you look for in springs?

 

Im sure the answer is beyond my knowledge, but a good starting point would be helpful. Things like inside dia, outter dia, height... Thanks guys.

 

I'm no expert but my advice would be to just call the comp cams and see what they recommend to handle added lift of the new camshaft.

 

I always come off jerky, but here it goes. Comp Cams is the most hit-or-miss company around. Sometimes the guy knows alot, sometimes he's a moron. I've seen some real out of line recommendations for springs from camshaft manufacturers. Comp has a hard on for beehives and I'm sure that's what they'd recommend. I personally do not like them.

Springs for a XFI280. Many things must be considered. Are you running 1.5/1.6/1.7 rockers? Obviously the lobe design is rather aggressive, so running a single spring with 90lbs on the seat that meets the lift requirement is not the way to go. The valve train mass, max lift, RPM requirements/sustainability, lobe design, installed height, installed height pressure [seat pressure], coil bind clearance, etc must all be taken into consideration.

Cheap valve springs typically do not last long, meaning maintaining the pressures they originally had. One thing you must calculate is what the seat pressure is at the installed height you are using. Stock LT1 installed height typically varies from 1.740 to 1.780 I have my latest exact figures laying around somewhere, but that's close. If a spring is rated 135lbs @ 1.800, then it would be greater at 1.750 because it's compressed more.

I by no means know everything about spring selection, but using something that is proven is always a good route. I personally have never liked beehives. Some folks never have any problem with them, others have real bad luck. I've seen patriot gold, and patriot gold extremes hold up well on aggressive HR camshafts. I've used the Crane 10308-1 kit with good results, that was on a Magnum lobed CC306.

I know I've read lots of valve train guides around the internet. Typically found on camshaft/valve train company's websites. Take everything you learn from them and try to apply that to what you need.

Valve springs could be a 50 page thread...search around lots of talk on it on the web.

Not sure if that helps, but it's the best I've got this time in the morning, lol.

-Dustin-

 

The XFI lobes were designed specifically with the benefits of beehives and 1.6s in mind so guys have had a hard time controlling them with similar pressure duals.
Comp's rpm ranges are also apparently based on long runner gen 1 stuff and often 800rpm lower than the cam will see in an LT1 with decent heads so depending on how much overkill they had in their spring recommendation to begin with it may or may not work.

There are a lot of spring brands but fairly few actual manufacturers.
I would guess Comp specs a 918 what I would do is look up the specs than go to a company like PAC and try and find something just a little heavier, they have a LOT more options for springs than Comp.

 

I used the Comp cams 918 beehives with the XFI 280 for three years, but at the end of this year I could start to tell they were getting weak after 6k RPM's. If I had to use the beehives again I would go with PAC next time.

 

Thanks guys. Yeah, Caprice you have mentioned the inaccuracy of comps recommendations(along with a few other members that have said the same). Will most likely look at the Pacs since they seem to be highlhy recommended.

 

Thank you for correcting me and from possibly saving me from some trouble when I'm building mine up. The reason I said that was because from what I have read and been told is that yes they don't do really good with cam specs but that they do good with the valvetrain components. I guess I have been given bad advice and thanks for the correction

By the way you didn't come off as a jerk.