Xe278ah cams install issues?

Bullitt5339 said:

It's a combination of centerline and duration that's the problem, not the lift.

The 270's and CMS stage 2 cams are borderline safe, and must be degreed in, or you're taking the chance of PTV contact. Some that have been degreed in have had less than .005 PTV clearance, which is crazy.

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.005 clearance is more than crazy, thats asking to destroy your engine. They are measuring this when it is cold, not @ running temps and besides metal expanding when heated it also stretches @ higher rpm's, you might think that the rods stay the same length when the engine is running but you would be wrong!!!! They stretch and contract, think of the loads it under. To move that piston @ 6000 rpm's that piston and rod must go up and down in less than .01 second. Just the force of stopping the pistons movement must be tremendous, now think about the force of the explosion (combustion) that propels the piston crank n rods up and down in under .01 seconds and this is complicated by the timing chain which even if new will stretch @ high rpm's and someone thought it a good idea to have less than a human hair's gap between the piston and the valve. When I used to build race engines or blue-printed an engine I would NEVER have less than .020 and that is on a race engine that will be worked on every few laps/ rounds/ races........

I will take ANY BETS that if this person EVER misses a shift or over revs the engine there WILL BE a MARK (@ the very least) on the piston where the valve hit it......... and wouldn't doubt it if the valve is bent.........

HiTech Stage 2's or MHS Stage 2's are probably about as safe as they get while still being fairly aggressive.

Just remember, an aggressive cam on the street is not really a whole lot of fun when cruising in traffic. I know everyone wants the noise, but trust me, it's not worth going too big and not enjoying driving it everyday.

To notch the pistons requires you to take the heads off, put clay over the top, mark where contact is made, and then take a notching tool and cut into the pistons to make room. I'm not doing all that, I ordered new aftermarket intake valves to use with my VT Stage 2's. They have a thinner profile than the huge stock valve, and will give me the clearance I need to run these cams safely.:bigthumbsup

Yep, those are it......

Here's a clip from Youtube of them.

http://www.youtube.com/watch?v=PY7HEJarbQ0

And here's the VT/CMS Stage 2's that I have. But I recommend them only with piston reliefs or aftermarket intake valves.

http://www.youtube.com/watch?v=aqxjDgEbCBs

modularheadshop has them, they're $249 for the valves, and then figure about $600-800 in labor to have the heads removed, reconditioned and reinstalled.

To be honest with you, the performance difference between the VT and Hitech cams on stock heads sways towards the Hitechs. I would go with them for the simple fact that I can bolt them in, set the timing and make 300rwhp with all the other bolt ons.