JakeFusion

iTrader: (7)

For all the do-it-yourselvers, wouldn't it be great if cam clearance was available somewhere easy to find? I think the p-t-v clearance of cams is about as important as power or drivablity for the avgerage diy'er. I am a shadetree mechanic with limited but expanding skills. As such, I'd like to bolt on a head/cam combo, without flycutting.

I like the 230-234 duration cams, either F13 or F14, TSP 233/239, or G5X2/3, or the MTI Y1 with AFR 205s. The F13 and TSP 233 both seem to make incredibly strong torque numbers without losing a lot down low, or peaking obscenely high. I like LG's AFR package with Comp 921 Springs and having it milled .042" for 59cc yielding about an 11.4:1 CR. I'd like to have high compression for low-end and midrange power with the small port of the AFRs for the same reason. If I put a cam in, I want it to be cammed, and I want 50rwhp+ out of it. With that said, I have a couple of specific questions:

I have read before that the AFR offers .020" more clearance than either a stock or ported LS1 head, even with its 2.02 valve. So, if the AFR head is cut to .042" but starts with .020" more to work with, I've effectively only cut about .022" right? Outside of the T-Rex, the only cam I've been able to find p-t-v clearance on is the new TSP 233/239, which offers .100" clearance intake and exhaust with the stock heads. Since I'm not a math wiz, and I don't really understand how p-t-v is calculated, will the 233 clear the AFR's milled .042" if they effectively only shave off .022" clearance? That'd leave .078" by my calculations, and anything over .070" is realively safe, correct?

Also, does anyone know the p-t-v clearance of the F13 or F14, Y1, or G5X2/3 or any other 230-234ish cam?

It'd be great if we could get the most popular cams p-t-v clearance in this thread. Thanks guys for your time and Happy Holidays!

JakeFusion

iTrader: (7)

Also, at what point do you switch from a 7.40" Pushrod to a 7.35"? When you have effectively milled .020" or more? Or as little as .010"?

PREDATOR-Z

All the cams you are mentionning are designed to offer max effort on STOCK heads. The VE's were designed for the flow parameters and clearances of stock heads.

If you change heads and mill etc... my recomendation is to contact one of the sponsors and get a custom cam designed specifically for your choice of heads.

Mirek

Both good questions. But I am not certain that the AFR's provide .020 more clearance you might want to confirm that. I have seen AFR post two different numbers on that "additional clearance" amount and I do not think either was that much, closer to .015 if I recall.
In any event with any of the cams you mentioned you will need to check P/V and with AFR's cut to 59cc you will need to flycut. And make sure that the cam is installed 100% correctly most importantly. I tagged two valves with stock heads and a C1 cam so just image whats gonna happen if you ever miss a shift / float a valve with one of those bad oscars. I do not think the AFR valves are as light as the LS6's and I do not *think* the retainers are titanium so you will have "some" valvetrain mass to contend with as well. You don't need that much cam anymore with the AFR's cut down anyway,those days are over -- why chase 15 hp at 6800 rpm (unless your selling cams). Unless your building a strip car and then why not get the 225's if its a max effort w/ all the right complimentry parts (4:10's,etc)

ArKay99

iTrader: (1)

P/V clearance is more of an art, not a science. By that I mean there are so many variables that can affect it it is very hard to predict what it will be with non-stock components. There are variables like cam duration and phasing, valve operating height, head gasket thickness, and valve diameter, to name a few. You can get a good idea of wht you can expect from a stock configuration and then play with variables but to find your exact valve clearance you should always check. The other thing checking does is give feedback as to the integrity of the cam phasing. If you are off a tooth you will most certainly see it in you clearance. Another thing you should consider, although not necessary, is to degree your cam. It's not that hard to do these things, and Comp even shpis with directions on how to do them. It's a good learning experience and if done correctly will give max performance for the effort you put into it.

ArKay99

iTrader: (1)

As I remember, the 225's WILL require flycutting with any cam due the the 2.080 intake valve. At least that is wat was posted in the AFR 225 thread.

Mirek

True but he should be flycutting anyway. Keep in mind that the 62cc 225's are just heavily milled 72cc 225's and that is really why flycutting will be required (coupled with the 2.08 valves). I think I actually bubbled that unfortunate fact up in an earlier post. My point was if your gonna cam the hell out of it go big with the heads/gears too if your spending your time at 5,800 + rpm's. Spinmeisters like that are really the only reason for 225's over the 205's in the first place.

JakeFusion

iTrader: (7)

Well, I don't want to spin the hell out of the motor, and that's why I thought the F13 would be a good choice to get the most usable power out of the engine. Like I said, I want the high compression and the AFR 205s for the usable power both will produce in a street only car. I'm beginning to rethink things though, and might go with a 224-228 duration cam, but it seems a 230-234 gets the most out of the AFR 205s. I've also thought it'd be a good idea to call Futral or Comp and have a custom ground camshaft. I was just looking to see if anyone knew the specifics on any cams, especially since the TSP 233/239 produced big torque numbers and "seemed" to fit my choice of heads, and that got me to thinking.

There thing about buying a cam and then measuring is just that, I've already paid money for something that may or may not fit.

So, does anybody know the additional p-t-v of AFR heads? And what's the clearance of the Comp XER 224/228? It seems like these things should be made available for those who don't want to buy 15 cams and test them all out to see which one offers more clearance or power, unless you are Gomer.

ArKay99

iTrader: (1)

That I can tell you. Tony put a thread out to state that unmilled 205's have around .010"->.015" additional p/v clearance, as Mirek stated above. Here is what I came up with. I have AFR 205's on a 99 LS1. The pistons are 'out the hole' .004"-.005". I used a Cometic .040" mls gasket. The heads were milled .010". That combo gives me ~10.8:1 cr. I am using a Comp XE-R cam. 224/228 .581"/.588" 112 LSA on a 110 ICL. The cam when installed dot to dot was actually at 108 ICL. Intake valve clearance is .110" and exhaust clearance is .148". Due to the extra clearance I have I am going to have them milled another .020" and put the cam straight up, so I will be retarding it another 4 degrees. I should be around .086" intake and .120" exhaust using the same gasket and cr should be ~11.2:1.
The car put down 413rwhp with the above setup through 4:10's, cats, and mufflers on an M6, with heavy aftermarket Z06 chromies.

JakeFusion

iTrader: (7)

Awesome ArKay99! That's the kind of info I was looking for. Sounds like you have a strong setup with good street manners, and after the additional milling, it will be that much stronger.

Nate_Taufer

iTrader: (1)

62cc 225 AFR heads are not milled...thus why they are still waiting on releasing them...if they were just milled from 72 to 62 then they would already be released...they have a smaller combustion chamber fwiw mirek.

nate

Lvmyz28

iTrader: (1)

You can only get estimates as to where your car is going to be with all this information. You should never just bolt on a heads and cam package and expect it to work correctly. The only way you are going to find exactly what your PV clearance is, is by claying the pistons with the heads and cam installed. There are other methods of checking PV clearance, but Claying seems to be the best visual of what's going on inside the motor. You really only have to do one cylinder so it's not a big deal, however it can save you a lot of grief if the cam isn't exactly what it's supposed to be, or if you got thinner gaskets. Get a good estimate from the info provided, and then put it together and clay it. That way you'll know exactly what to do.