Cams+NPI Heads?

[SRT Handz]

can someone link me to said "Offset Retainers" i need to run CMS Stage 1 Cams.

So on a NPI motor, i can run CMS Stage one cams with the Retainers No Problem?

 

[1996mustangGT]

Here you go man,
http://www.cushmanmotorsports.com/index.php?main_page=product_info&cPath=11_229_230_1_6&products_id=1519

 

[SRT Handz]

anyone on this forum running comp cams XE268H on NPI Heads?

 

[SRT Handz]

TTT

anyone on this forum running comp cams XE268H on NPI Heads?

 

[DropTopPony]

TTT

anyone on this forum running comp cams XE268H on NPI Heads?

Those are NPI cams.

 

[DropTopPony]

i can see the use of an aftermarket cam for a set of PORTED npi heads but thats not what is being dicussed. i probably know about as much as you do about the 4.6 and which is why i dont care to own one

I wasn't trying to offend or say I'm more knowledgeable than you I apologize if I came off that way..

I run stock PI cams with my non pi head/piston setup and dont like them at all. It may be because i need a cam with more duration with my blower setup, but my next mod will be Crower stage II blower cams with upgraded springs/retainers

Which you will totally be able to do. The PI cams I had were not supercharger friendly at all. The duration isn't long enough on the exhaust side so you are losing some of your boost out of the exhaust before it gets a chance to close. Sorry that I took so long to find this thread. You can use an aftermarket cam that has over .500 lift in an NPI head without machining contrary to what a few people might tell you on here. In an NPI head, PTV contact isn't the major issue when installing a cam. The problem is that the valve springs have less room to compress in an NPI head than they do in a PI head. "Coil stack" is not something you want and with a higher lift cam, you are approaching it's limits. I did a lot of research and finally ended up taking my cam covers off and felt around with a feeler gauge just to find out how much space there was in between the coils. A stock PI cam has a .530 lift and that is what I originally had in my NPI heads without any problems. So how can there be a limit at .500 for an NPI head? I currently have CMS Stage 2.5 Blower cams that have are .536/.540 lift, 228/235 .050 duration, 114 LSA installed in my ported NPI heads. Yes, an NPI head can handle a .540 lift and still have some room left....not much though. I used Crower .060 offset retainers just to add a little insurance, but I am 100% sure that I could have gotten away without them.
As for degreeing a cam, some people say it's a must and some others don't even bother. The undisputable truth is that the cam has a keyway on it and can only go on one way. As long as you don't let your timing chains jump the gears to throw your timing off, than you are 99% degreed already. Sure, you can get the timing wheels, tear off the front of your engine and do it the "right way" as most everyone puts it, but if there are no machining issues with your cams (usually if you get them from a reputable company there won't be any issues) they are doing exactly what they are supposed to be doing because of the keyway and the already correct timing. Degree them if you want, but I think it's a waste of time if you did a good install and kept things lined up the way they should be. It's always smart to turn your motor over by hand just to make sure everything is not going to collide inside the cylinder anyway.

Did you notice much gain with the cams?? I'm still thinking about grabbing RICK FOCKS SVO charger, so I would be interested to know the gains you got with the cams

I run stock PI cams with my non pi head/piston setup and dont like them at all. It may be because i need a cam with more duration with my blower setup, but my next mod will be Crower stage II blower cams with upgraded springs/retainers

Which you will totally be able to do. The PI cams I had were not supercharger friendly at all. The duration isn't long enough on the exhaust side so you are losing some of your boost out of the exhaust before it gets a chance to close. Sorry that I took so long to find this thread. You can use an aftermarket cam that has over .500 lift in an NPI head without machining contrary to what a few people might tell you on here. In an NPI head, PTV contact isn't the major issue when installing a cam. The problem is that the valve springs have less room to compress in an NPI head than they do in a PI head. "Coil stack" is not something you want and with a higher lift cam, you are approaching it's limits. I did a lot of research and finally ended up taking my cam covers off and felt around with a feeler gauge just to find out how much space there was in between the coils. A stock PI cam has a .530 lift and that is what I originally had in my NPI heads without any problems. So how can there be a limit at .500 for an NPI head? I currently have CMS Stage 2.5 Blower cams that have are .536/.540 lift, 228/235 .050 duration, 114 LSA installed in my ported NPI heads. Yes, an NPI head can handle a .540 lift and still have some room left....not much though. I used Crower .060 offset retainers just to add a little insurance, but I am 100% sure that I could have gotten away without them.
As for degreeing a cam, some people say it's a must and some others don't even bother. The undisputable truth is that the cam has a keyway on it and can only go on one way. As long as you don't let your timing chains jump the gears to throw your timing off, than you are 99% degreed already. Sure, you can get the timing wheels, tear off the front of your engine and do it the "right way" as most everyone puts it, but if there are no machining issues with your cams (usually if you get them from a reputable company there won't be any issues) they are doing exactly what they are supposed to be doing because of the keyway and the already correct timing. Degree them if you want, but I think it's a waste of time if you did a good install and kept things lined up the way they should be. It's always smart to turn your motor over by hand just to make sure everything is not going to collide inside the cylinder anyway.

Only problem with installing the cams "straight up" and not degreeing is you are trusting they came perfectly set from the factory and this has been shown over and over that our cars are not perfectly set. I have seen some banks off by as much as 5-6 degrees from each other...one being 3-4 degrees advanced and the other 3 degree retarded. When they are working proberly they can pick up HP and have seen guys gain 10-12 rwhp just by degreeing them in. No sense in maybe leaving HP untapped especially if you just dropped $500+ for 25-30hp and you might have another 5-10 in the setup.

 

[9psi 98]

Well, if the guy picked up 10-12 hp just by degreeing them, then there is no way that they were degreed when they were installed. Otherwise, they wouldn't have known of the increase. Yes, degreeing your cams will help. I am not discounting that. My point is that you can install cams without tearing the front of the motor off and you will be able to run the engine without causing any problems. It's like installing a carb onto an engine. Yes, it will run straight out of the box, but will probably do better once it's "tweaked." Getting your cams degreed is important, but not the end of the world if you don't get it done immediately. I wouldn't believe it either if I hadn't done research on it and a cam swap myself.

 

[Petek]

Well, if the guy picked up 10-12 hp just by degreeing them, then there is no way that they were degreed when they were installed. Otherwise, they wouldn't have known of the increase. Yes, degreeing your cams will help. I am not discounting that. My point is that you can install cams without tearing the front of the motor off and you will be able to run the engine without causing any problems. It's like installing a carb onto an engine. Yes, it will run straight out of the box, but will probably do better once it's "tweaked." Getting your cams degreed is important, but not the end of the world if you don't get it done immediately. I wouldn't believe it either if I hadn't done research on it and a cam swap myself.

do it once and do it right. why go back and do it later when your already down their installing the cams?

 

[9psi 98]

you guys are right.

 

[SRT Handz]

Hey DropTopPony, can comp cams XE268H be installed straight up with stock springs and ect?

 

[DropTopPony]

Hey DropTopPony, can comp cams XE268H be installed straight up with stock springs and ect?

Yeah i'm pretty sure they can. I have never heard of anyone having issues with them. They however would not be much of an upgrade over stock PI cams so unless you are getting them real cheap i'd just do the stock PI's.