Just curious about VS Cam - Page 2 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 02-27-2006, 03:17 PM   #11
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Quote:
Originally Posted by McGrath
#90 LS6
Installed load is 90 pounds at 1.800", 115 pounds at 1.720", and 300 pounds at 1.230".

#105
Installed load is 105 pounds at 1.800", 127 pounds at 1.720", and 293 pounds at 1.200".

So you can see the LS6 spring starts to catch up fast and then surpass the #105 spring. I would go with the #105 if you do decide to go with the VS.

My point had more to do with cost. You can get some perfectly good used, low mile LS6 springs for a fraction of the cost of the CompCams springs. The difference in pressure at 1.230" seems pretty negligible to me, though I'm no professional by any means. In my case, I got a full V8 set of springs for 1/5 the cost of new Comp springs, and they can certainly be had for $50 or $60 on Ebay or forum marketplaces.

I'm not saying you guys are wrong, but I still think the LS6 springs are a viable option. Just some food for thought. The sum of parts for a cam swap can get fairly pricey, so it'* good to explore cost-saving avenues.
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Old 02-27-2006, 05:16 PM   #12
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Here'* my $.02. Since your car has 105k on it, you would want to change basically your whole valvetrain. You'll want a new chain, 105lb. springs, modded retainers, probably valve seals while your at it. Plus if you get a cam install kit you would get a dampner with it which you definately want. You'll also want to get your shift points and limiter changed, so while you're at it you might as well get the misfire code deleted because on some cars the VS does set the light.

However, the XP cam is just as streetable as the VS cam, at idle you can hardly tell the difference (personally I can't tell the difference, but some can I guess?) and the XP will make more power. Both cams cost the same money, yet the XP makes more power and is just as streetable, which seems like an obvious decision which to chose IMO. And since you'd have to get your PCM changed for shiftpoints and limiter anyways, it wouldn't take anything to get the PO300 deleted.

My dad gained 19whp with the XP cam over what his GTP had with 1.9 rockers and thats without dropping a pulley size and with basically no tuning, all we did was turn the mini-afc 1.0 down to get the 02'* in the 950'* instead of over 1000.

Shawn
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Old 02-27-2006, 05:26 PM   #13
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Quote:
Originally Posted by dbtk2
Here'* my $.02. Since your car has 105k on it, you would want to change basically your whole valvetrain.
That'* what I figured.

Looks like a lot of work. I don't want crazy power from an XP. I just want something mild, so the VS looked nice. I use this car to travel everywhere and want something that'* not going to kill my trans quickly ... plus I couldn't afford a heavy duty built trans right now.

Rockers sound more feasible the more I read this stuff.
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Old 02-27-2006, 05:30 PM   #14
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All said and done a cam swap would cost you ~$600 if you do it yourself. Thats not including the PCM work though. I was just looking this stuff up the other day because I want to put a GT2 cam in my 203k mile GP, so obviously I was looking into replacing the entire valvetrain.

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Old 02-27-2006, 06:11 PM   #15
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My recommendation is to use the 105# springs. The spring pressure at the nose is more important than the other end of the travel.

Any valve spring, with the exception of coated springs, will loose 10% to 15% of its tension due to heat. So, if you buy used springs from Ebay, and you do not check the springs on a tester, you do not know what spring rate you are installing on your cylinder heads. That is why is good to have a spring tester handy or take the heads to a shop that have one, so the springs can be shimmed to the appropriate installed rate/pressure.
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Old 02-27-2006, 06:18 PM   #16
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Quote:
Originally Posted by ssei1995
Any valve spring, with the exception of coated springs, will loose 10% to 15% of its tension due to heat.
Ok, but wouldn't that happen to a new spring after installing it on your own vehicle and heat cycling it? You might install it brand new with a certain seat pressure, but it would end up 10% to 15% weaker once you used it in the car. What'* the difference if you buy some springs that have already been pre-worn? They're still going to be stronger than stock, which will guard against valve float. Can you explain this a little better?
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Old 02-27-2006, 08:04 PM   #17
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If your near Toledo,OH I'l give your car a case learn (didnt look where you were from) via PT-possibly shift points.

But yeah defienately change lifters, springs, valve seals, and retainers. You can get a good set of lifters from Ed Morad (I got a 04 set from him-cheap).

Viton valve seals will give you a hair more clearance also.
With the VS you be ok with unmod'd retainers and 105'*, but if you go S1x get the mod'd retainers and viton valve seal. The S1x has chewed up some valve seals on completely stock valvetrains. I didnt have that issue, because I used mod'd retainers and viton'*.
Also go with the 105'*, the 90lbrs cause false KR on some cars.

And it is hit/miss with 90lbrs on 97 heads(I have 2 97s). One car will seat fine and the other wont.

But good luck!
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Old 02-27-2006, 08:37 PM   #18
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Like I said, the number on the initial installed pressure and the spring rate area the most critical factors for any high performance/racing application. Therefore, there is a big difference when the spring looses pressure due to cycling and heat soak. There is another big factor in place: spring material; there are springs made from cheap spring steel all the way to exotic Titanium. Good brand name springs are made of better materials than the OEM springs therefore the loss will be less than OEM and they will last longer and be more consistent.
For example, some of the best valve springs in the market by brand are PSI, Isky Tool Room, K-Motion, Manley and a few others.
...and...Yes...weak springs at high RPM will cause KR.
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