Cams

MadStang · Oct 1, 2010

Let me preface this by saying, I'm still learning about modulars and am just trying to build info on what I need.

I'm swapping in my custom grind cams in the next couple of months, and am wondering what I need or should upgrade while I've got everything off to swap in Cams. The car has 60k miles so things like the timing chain and tensioners will probably go out soon...

My plan is to swap the Cams in, the required valve spring upgrade, and since I have a Windsor block, installed Comp adjustable cam gears so I can degree the cams and make sure I have no PTV clearance issues.

Any other recommendations to look into?

Bullitt5339 · Oct 1, 2010

Do valve stem seals at the same time.

Ninety8stang · Oct 1, 2010

Bullitt5339 said:
Do valve stem seals at the same time.

definitely do valve stem seals if possible. Your timing components such as tensioners and crank gears should be okay to reuse. I would go ahead and replace the timing chains. I just purchased a set of Trickflows off of summit for pretty cheap and they look like a damn good part. Make sure you do your research and find a set of cams that isnt going to require valve releifs if you dont plan on pulling the heads off. Me and Duffy are running (degreed) Comp XE270's with a 234/238 duration at .550 lift. These cams degreed is about as radical as you can go without having piston notches so make sure when you are choosing a cam that you know will give you your valve clearance.

MadStang · Oct 1, 2010

Ninety8stang said:
Bullitt5339 said:

Do valve stem seals at the same time.

Click to expand...

definitely do valve stem seals if possible. Your timing components such as tensioners and crank gears should be okay to reuse. I would go ahead and replace the timing chains. I just purchased a set of Trickflows off of summit for pretty cheap and they look like a damn good part. Make sure you do your research and find a set of cams that isnt going to require valve releifs if you dont plan on pulling the heads off. Me and Duffy are running (degreed) Comp XE270's with a 234/238 duration at .550 lift. These cams degreed is about as radical as you can go without having piston notches so make sure when you are choosing a cam that you know will give you your valve clearance.

thanks for the info. as far as the cams go, I already have them, my engine builder made a custom grind for me, guaranteeing there will be no PTV issues when degreed. they are radical blower cams that are supposedly going to sound like "a popcorn machine at idle". Besides that he's helping me install them, if there is PTV issues he said he'd take care of it.

So timing chains and valve seals. Since my gears are press on (Windsor motor) the adjustable cam gears by comp are a good replacement yes?

PI96GT · Oct 1, 2010

you shouldnt have to worry bout PTV as much since you has a PI motor and the pistons have a deeper dish, ive heard nothing bad about the comp cam gears, i was going to get them when i did my comp 270's so i didnt have PTV, but since i already had the heads off i went ahead and had my pistons notched and just went with the stock cam gears for now.

Bullitt5339 · Oct 1, 2010

The dish has nothing to do with PTV clearance, since that's not where they make contact. They make contact around the rim of the piston, which is the same regardless of the cc of the dish. PTV is usually a result of duration in the 4.6, which coincidentally is what will give you the idle you're talking about.

A picture of where the valve notches should be:

http://www.modularheadshop.com/FAQ/images/notches.jpg

MadStang · Oct 1, 2010

duration is 292. and the LSA is a low number

Don't want to give away my cam specs though, wanna make sure I'm the first one with this grind!

I was guaranteed no piston to valve issues with this cam, so we don't need to worry about that!

Bullitt5339 · Oct 1, 2010

You don't have to worry about that. I'd rather go with a smaller duration cam with more LSA, that way I actually make useable horsepower.

MadStang · Oct 1, 2010

Bullitt5339 said:
You don't have to worry about that. I'd rather go with a smaller duration cam with more LSA, that way I actually make useable horsepower.

I'm putting a ported M112 on it, I'm not going to have a whole lot of useable tire grip if anything lmao.

Bullitt5339 · Oct 1, 2010

292 adv. duration cam would be around 244ish duration @ 50. By low seperation, I'm assuming you're talking about less than 108*.

You will have PTV contact with 244 duration/108*

Typically, the max you can run without piston notching is 235 duration/110 LSA installed on 110, or 225 installed at 108. Any more than that, and you will have PTV clearance without piston notches.

MadStang · Oct 1, 2010

Bullitt5339 said:
292 adv. duration cam would be around 244ish duration @ 50. By low seperation, I'm assuming you're talking about less than 108*.

You will have PTV contact with 244 duration/108*

Typically, the max you can run without piston notching is 235 duration/110 LSA installed on 110, or 225 installed at 108. Any more than that, and you will have PTV clearance without piston notches.

well we'll see what happens, but, anyway, point of this thread was to figure out what I should replace along with the cams, any other ideas??

duff daddy · Oct 1, 2010

I havnt worked on a windsor headed modular. As far as what you should replace, look at the chains see how they look. If you get a/m cams why cant you use bolt on cam gears? If you use them, yo ucan use stock romeo gears then grind the keyways and save your self from the hassle of the adjustables.

Check the tensioners and chains, if you want to be anal then repalce them. Im using my stock guides which have 130k just because I know they are good and not work the slightest.

duff daddy · Oct 1, 2010

oh and as far as your LSA when you feel like telling let me know if you have anything near me. 108 but the rest of teh specs are the money maker...
Duration Lift @ valve Centerline LSA
NATURALLY ASPIRATED 250/248 540/540 106/110 108

MadStang · Oct 1, 2010

Duff Daddy said:
I havnt worked on a windsor headed modular. As far as what you should replace, look at the chains see how they look. If you get a/m cams why cant you use bolt on cam gears? If you use them, yo ucan use stock romeo gears then grind the keyways and save your self from the hassle of the adjustables.

Check the tensioners and chains, if you want to be anal then repalce them. Im using my stock guides which have 130k just because I know they are good and not work the slightest.

I'd rather just go with the adjustables honestly. I'm looking for parts to just upgrade while I'm in there and that's something I've been looking at.

I'll probably end up replacing the chains, I'll check the tensioners.

I've got blower cams not n/a cams duffy

duff daddy · Oct 1, 2010

reguardless. and The thing about the adjustables, i have seen ALOT of peole have issues with them failing, good luck.

Bullitt5339 · Oct 2, 2010

I go with the adjustable lower, and then grind the keyways on the gear as well. He will have to use Romeo style gears and bolts with aftermarket cams, there's no other way to do it.

And here's the specs on my cams, nothing special, they're in a bunch of fast cars. I have pretty much no PTV clearance, .008, and was expecting to have to replace valves.:

.560/.575 lift, 225/235 .050" duration, 108 LSA

Lift isn't a problem in the PI engine, it's the duration and intalled intake centerline that'll get you in trouble.

Duff, your cam's specs look like something I'd have run on ported NPI heads a few years ago. :thumbsup: