need cam advice bad

[ROUSH1]

i have a problem i have a 2002 roush stg 1 4.6l sohc 5-speed with 4.10s, cai, off-road h pipe, spintech exhaust, and im currently also installing a 100 wet shot.

i just bought a set of new comp cams from a friend for the car i have bought new cam gears and the bee hive springs. well the cams didnt come in the box and i have no way of knowing what side is which so i called comp for some cam help and now some a**hole at comp is telling me that i will have piston to valve clearance problems and will have to have the pistons milled to fit for the valves here are the specs

comp extreme energy cams
duration 242/246
lift 550/550

is that a to agressive cam, or will it work because the guy at comp wouldnt say anything but it wont work, you have a 50% chance bye. but if you go to their site it says nothing about any clearance problems. please help if you can.

http://www.compperformancegroupstores.com/store/merchant.mvc?

 

[ROUSH1]

please help i am supposed to be getting these installed tomorrow, any advice, could they possibly cut or machine the stem of the valve so it wouldnt push so far down? clueless

 

[forum155pl]

i dont know how to read all the specs.. but you cant machine valve stems so they will have a smaller opening... the only way i know that you can run an agressive cam is to mill the pistons.. and in some cases you can run a thicker head gasket.. but that also changes compression..


now that prolly didnt help much did it? i would listen to the guy and comp when he says that they wont work with your shortblock.. maybe call back and talk to a differant guy ?? i dunno..

 

['01 Steed]

Use a degree wheel when installing them. Also known as "degreeing" the cams. This is a must for the cam specs you have given. The lift and duration alone aren't the problem. The cams orientation in your engine is what you have to check.

You can go to the MD board and read a write up on it in the General Tech forum.

You don't need to mill your pistons. That guy is smoking crack! There are plenty of people running XE278's with no reliefs in their slugs.

 

[ROUSH1]

i dont know what to do any one want to buy a new set of cams 300.00 shipped to your door.

 

['01 Steed]

You should prolly go with a smaller/less aggressive cam, or get a nice set of heads and longtubes to go along with them.

Put 'em in the classifieds. Someone will trade you for them, I'm sure.

 

[LaserRed01GT]

Yes, the guy at Comp is right, you will have PTV contact with that cam. I have had PTV with smaller cams. Call MPH or VT and they will tell you the same. That and the lift and duration combined will also bind the springs if they are stock. These 2 valve motors have a .0153" crown(piston) to deck clearance which is fairly tight for a factory setup. The exhaust valve might BARELY clear, but the intake valve definitely won't clear the piston.

You will have to flycut the piston or go with a little smaller cam. That's a really big cam for a stock 281" shortblock.

 

['01 Steed]

Cometic head gaskets?

 

[ROUSH1]

^^^ what is that?

 

[the98stang]

Cosmetic head gaskets are metal I think, or different material than the stock HG's.

From what it sounds like you won't be able to use those cam's. That is a HUGE duration/lift for a baby 4.6L . Just sell them and get some VT Stage 2's. Your car will love those with the juice. However, I wouldn't run that combo with your stock block. It won't last long.

 

[Stan Weiss]

A thicker head gasket will give you more Valve To Piston clearance. There is a couple of problems with this solution. One it will lower your CR and the cams you want to use should have higher than stock CR. The second is they increase piston to head clearance and will reduce the squish velocity of the air fuel mixture, not something you want to do in a N/A engine.
http://www.cometic.com/

 

[ROUSH1]

if any one knows who could possibly need these cams ill let them go for 275.00 shipped or trade for something of equal price. thanks all of you for your help and knowledge

 

[LaserRed01GT]

A thicker head gasket will give you more Valve To Piston clearance. There is a couple of problems with this solution. One it will lower your CR and the cams you want to use should have higher than stock CR. The second is they increase piston to head clearance and will reduce the squish velocity of the air fuel mixture, not something you want to do in a N/A engine.
http://www.cometic.com/

Exact-a-mundo!

if any one knows who could possibly need these cams ill let them go for 275.00 shipped or trade for something of equal price. thanks all of you for your help and knowledge

Are the cams new? If they are in good shape, I could probably use them. Shoot me a PM when you get a chance. Thanks. BTW, I have chingles of stuff to trade.