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**geoffinbc** · 10-25-2005, 04:48 PM

That is pretty insane. You would need to clay check it I think. Hard to say if anyone here has measured the max alowable lift. I know the heads wont do it stock. But they could be made to... Then you have to worry about touching pistons.

**94Camaro** · 10-25-2005, 05:23 PM

yea im figuring on needing new springs...but i wanna make sure that putting this cam in isnt going to make the valves kiss the pistons..that wouldnt be good.

**Guest** · 10-25-2005, 10:30 PM

No, you'd probably need longer valves, not just better springs.

You'll probably find that the retainer hits the valve seal long before you reach max lift.

**smilinguy99** · 10-26-2005, 01:28 AM

The comment about longer valves for higher lifts is correct. However, there is another limitation of these heads that would prevent that. There are two valves, an intake and an exhaust, that close toward one another. When a cylindrical spring of 1.460" diameter is put on these two stock-length valves the retainers have .030" clearance between them. This is OK as long as your lift doesn't exceed the .550" range.

The only other (easy) way to get longer valves to work here is to use conical springs, but this is not practical because conical springs can't give you the pressure you need to move the valve that much, that fast.

The other ways I've been able to think of right now are pretty impractical and I'd just as soon keep them to myself for now.

Bottom line, currently these heads have a lift limitation and the cam in question is right up against it.

sg99

**94Camaro** · 10-26-2005, 12:47 PM

well. thats fine -- what im concerned with is:

will the cam in question run in the engine without bending/breaking anything?

112/107/248/258/.533/.543 (with the 1.6 rollers that come with the aluminum heads)

and in addendum: can you get adjustable rocker arms, or USE adjustable rocker arms on the aluminum heads. i ask because this cam requires adjustment... so i need to know.

**smilinguy99** · 10-26-2005, 02:23 PM

Originally posted by 94Camaro

well. thats fine -- what im concerned with is:

will the cam in question run in the engine without bending/breaking anything?

112/107/248/258/.533/.543 (with the 1.6 rollers that come with the aluminum heads)

and in addendum: can you get adjustable rocker arms, or USE adjustable rocker arms on the aluminum heads. i ask because this cam requires adjustment... so i need to know.

Well, from 2000 miles away there is no way to tell if this cam will create physical conflicts. What you will need to do--that is, what every engine builder needs to do--is check piston to valve clearance. There are various ways to do this and you can do your homework and discover them on your own. If there is P/V conflict you will need to have the pistons flycut for valve pockets. Of course, that assumes you have enough material in the pistons for cutting clearance. You will also have to check for clearance elsewhere as well. Every moving part in the valvetrain needs to be checked throughout its full range of motion for clearance with all the parts around it.

One thing I would be cautious about is the .543" lift figure you give. This is likely to be with a 1.5:1 rocker. With the 1.6:1 rocker you mentioned, the lift will increase to .579". This will certainly be too much lift for the length of the valve in these heads and will most certainly bend and break things without some clearance work being done and without some careful part selection.

What you have seemed to ignore from other posts is that this cam may not even work in this engine. The heads are lift-limited due to the length of the valve. The valve length is limited due to retainer-to-retainer clearance issues between an intake and an exhaust valve that close toward one another. Higher ratio rockers will aggravate this problem. There is a possible coil bind issue as well.

All of these clearance questions are for you to answer in your garage or workshop. Each engine is unique. New parts--especially moving parts--create clearance issues all over the place. It is your job to find them. You may end up spending a few hundred bucks on parts to try out until you find something satisfactory.

About the rocker arms, yes there are rocker arms you can use. Look around this site and you'll find lots of information about Crane rockers and what is needed to put them in your engine.

**smilinguy99** · 10-26-2005, 03:03 PM

Here's the first part you can try out:

Crower 68501
1.475" OD
538#/in. rate.
204# seat at 1.850"
525# open at 1.250"

It is a spring with plenty of tension, but it may not physically fit in the head. There is likely to be a very close clearance (probably around .015") between the intake and exhaust retainers mentioned earlier. Any clearance is good clearance though.

Might need to sink the spring pockets a bit. Check around this site for some cutaway pix of the heads to see if there is sufficient material for this. If you can't find the pix, cut apart an extra head.

You'll also have to get a couple of valves cut with square grooves as well. Get them in stock length and put the grooves about .300" down from the top. Try various retainers and shims to get the right spring heights.

Get a couple of those springs, a pair of retainers with keepers and two valves and start checkin'. That should cost about $150 right there. But if you find something that works it'll be worth it.

As an alternate try the Crower 68380X2 spring.
1.460" OD
456#/in. rate.
173# seat @ 1.850"
446# open@ 1.250"

Twice the retainer-to-retainer clearance here.

**TurboZ24** · 10-26-2005, 04:00 PM

I run .62"/.60" lift, but also run iron heads, not the aluminum, so no splayed valves. As for piston clearance, I have no issues, but I also run 8.0:1 static compression also and the iron heads have twice the combustion volume of the aluminum ones. As for those springs, I run one of those you listed also, but you need spring cups for them, you need too machine the spring seat, etc and I'm not even sure the aluminum heads would be sufficiently strong too resist damage from springs that large.

The issue with the springs and valve lift is usually going too be bind height, so you need too check the listed bind height of the spring and make sure with the rockers you choose too use, that you would still be at least .05" away from bind height on the spring.

Another question is what type of cam is this? Flat tappet? roller? etc? The style of cam also dictates the springs you can use and if it's a flat tappet, the maximum spring pressure you can safely use and not smoke the cam/lifters.

**94Camaro** · 10-27-2005, 12:27 PM

Originally posted by smilinguy99

Originally posted by 94Camaro

well. thats fine -- what im concerned with is:

will the cam in question run in the engine without bending/breaking anything?

112/107/248/258/.533/.543 (with the 1.6 rollers that come with the aluminum heads)

and in addendum: can you get adjustable rocker arms, or USE adjustable rocker arms on the aluminum heads. i ask because this cam requires adjustment... so i need to know.

Well, from 2000 miles away there is no way to tell if this cam will create physical conflicts. What you will need to do--that is, what every engine builder needs to do--is check piston to valve clearance. There are various ways to do this and you can do your homework and discover them on your own. If there is P/V conflict you will need to have the pistons flycut for valve pockets. Of course, that assumes you have enough material in the pistons for cutting clearance. You will also have to check for clearance elsewhere as well. Every moving part in the valvetrain needs to be checked throughout its full range of motion for clearance with all the parts around it.

One thing I would be cautious about is the .543" lift figure you give. This is likely to be with a 1.5:1 rocker. With the 1.6:1 rocker you mentioned, the lift will increase to .579". This will certainly be too much lift for the length of the valve in these heads and will most certainly bend and break things without some clearance work being done and without some careful part selection.

What you have seemed to ignore from other posts is that this cam may not even work in this engine. The heads are lift-limited due to the length of the valve. The valve length is limited due to retainer-to-retainer clearance issues between an intake and an exhaust valve that close toward one another. Higher ratio rockers will aggravate this problem. There is a possible coil bind issue as well.

All of these clearance questions are for you to answer in your garage or workshop. Each engine is unique. New parts--especially moving parts--create clearance issues all over the place. It is your job to find them. You may end up spending a few hundred bucks on parts to try out until you find something satisfactory.

About the rocker arms, yes there are rocker arms you can use. Look around this site and you'll find lots of information about Crane rockers and what is needed to put them in your engine.

no. the specs i gave are with the 1.6 rocker arm ratio on teh 3x00 heads.
the stock specs are:

248/258 duration (in/ex)
and .500/.520 lift (in/ex)

with 1.5 ratio rocker arms.

i converted it to 1.6 cause thats what i have. sorry for any confusion.

so by what you said i should ignore your post and read what others said up there, and from the looks of things this cam is just before what would be the lift limit due to valve length. as for the whole "2000 mile away" comment.

i come to this board to get advice and information from people who have more experience with these parts than i do. i posted in the hopes that maybe someone knows the maximum lift i can do with a cam using the aluminum heads, not get a smart-ass remark from someone that doesn't know and feels that in order to make people think he knows a lot, he'll throw around a smart attitude.

If you dont have any information to contribute then dont bother posting in my thread.

thanks to everyone that actually had something to say that was worth saying.

**94Camaro** · 10-27-2005, 12:33 PM

[edit: double post -- fixed problem ]

**xonelith** · 10-27-2005, 01:03 PM

Originally posted by 94Camaro

i come to this board to get advice and information from people who have more experience with these parts than i do. i posted in the hopes that maybe someone knows the maximum lift i can do with a cam using the aluminum heads, not get a smart-ass remark from someone that doesn't know and feels that in order to make people think he knows a lot, he'll throw around a smart attitude.

If you dont have any information to contribute then dont bother posting in my thread.

thanks to everyone that actually had something to say that was worth saying.

I suggest you go to a site like FullThrottleV6.com for getting questions answered. You get alot of responses to threads, like the ones you have gotten, from this site. There are alot of opinions on this site (as with many other sites) and many are very narrow minded. You have to weed through the BS.

I come here, cuz there is some really good info and a few knowledgable people, but I wouldn't post too many questions

FullThrottlev6 has alot of camaro's there too

Good luck!

**smilinguy99** · 10-27-2005, 03:18 PM

Originally posted by 94Camaro

so by what you said i should ignore your post and read what others said up there, and from the looks of things this cam is just before what would be the lift limit due to valve length. as for the whole "2000 mile away" comment.

i come to this board to get advice and information from people who have more experience with these parts than i do. i posted in the hopes that maybe someone knows the maximum lift i can do with a cam using the aluminum heads, not get a smart-ass remark from someone that doesn't know and feels that in order to make people think he knows a lot, he'll throw around a smart attitude.

If you dont have any information to contribute then dont bother posting in my thread.

As far as me being a smart ass, yes I was and I apologize.

Coming to this board for information is not a bad idea. There is lots of info contained here. You may have noticed there is no FAQ on this site. If there was, some of your questions would no doubt be answered there.

There is however a SEARCH function on this board and it performs much the same function as an FAQ. I use it a lot. Many of my questions are answered without posting at all.

As far as having nothing to contribute, well I suppose if we sat down over a couple of beers and had a chat you'd get a better idea of what I actually do know. I'm not going to beat my chest too much here.

Suffice it to say, for a few years now I've been fitting parts, measuring, designing and machining unique parts for these heads and puzzling over their limitations. Every few weeks I come up with a new and often strange idea about how to get around this problem. I don't really like any of them yet. Someday it will be solved.

In my first post I tried to be helpful and caution you about the aluminum head's current lift limitation. I said, "Bottom line, currently these heads have a lift limitation and the cam in question is right up against it. "

I could not be more specific because there are a number of factors that would affect the final fit. For instance, TheRaven said, "You'll probably find that the retainer hits the valve seal long before you reach max lift." This is perfectly consistent with my own work with this head. This is the heart of the limitation.

This limitation is affected by the choice of retainers and keepers, the location of the keeper groove, how far the valve head is sunk in the seat, the depth of the spring seat, the thickness of the spring cup, the type of valve seal and whether or not the spring seat can even be cut very deep.

When I first began looking into this limitation I was trying to determine the maximum lift with stock-length valves. It turns out it was in the .525" to .560" area depending upon which parts were tried. Hence my original "bottom line" comment.

There are a lot of questions that come to this board where the answer is, quite rightly, it depends.

When you are talking about camshafts above certain lift levels, there are always going to be issues. .550" lift? In some larger engines that's no big deal. In this motor the combustion chambers are rather small and the valves are close to the deck so it might be a big deal and you will have to plan accordingly. You may have to flycut the pistons. You may have to think about a smaller cam. The more radical the lift, the more vague the answer.

Regardless what someone on one of these boards (including myself) say about whether something will work or not, you will be left with the bent parts if they are wrong and therefore it is incumbent upon you to check all clearances.

You're right out there at the edge with this cam. That's great, but you are probably going to have to juggle a lot of parts and do some machining to make it all work. If you make it work and especially if it doesn't, let us all know.

**bszopi** · 10-27-2005, 06:16 PM

I personally will back sg99 up on this 100%. I feel he provided you with probably some of the best recommendations, even if he didn't state it in the best way. You could listen to several people on here (or on any other site) and will get mixed responses. If you go with someone who says "sure it'll work" and then you bend your valvetrain, who are you going to blame? The guy who said it would work, or yourself for not testing everything to make sure it would work.

**94Camaro** · 10-27-2005, 07:29 PM

Originally posted by smilinguy99

There is however a SEARCH function on this board and it performs much the same function as an FAQ. I use it a lot. Many of my questions are answered without posting at all.

yup. i know this. i spent 30 minutes doing different search terms to try and find what i was looking for. i couldnt.

Originally posted by smilinguy99

As far as having nothing to contribute, well I suppose if we sat down over a couple of beers and had a chat you'd get a better idea of what I actually do know. I'm not going to beat my chest too much here.

Suffice it to say, for a few years now I've been fitting parts, measuring, designing and machining unique parts for these heads and puzzling over their limitations. Every few weeks I come up with a new and often strange idea about how to get around this problem. I don't really like any of them yet. Someday it will be solved.

In my first post I tried to be helpful and caution you about the aluminum head's current lift limitation. I said, "Bottom line, currently these heads have a lift limitation and the cam in question is right up against it. "

I could not be more specific because there are a number of factors that would affect the final fit. For instance, TheRaven said, "You'll probably find that the retainer hits the valve seal long before you reach max lift." This is perfectly consistent with my own work with this head. This is the heart of the limitation.

This limitation is affected by the choice of retainers and keepers, the location of the keeper groove, how far the valve head is sunk in the seat, the depth of the spring seat, the thickness of the spring cup, the type of valve seal and whether or not the spring seat can even be cut very deep.

When I first began looking into this limitation I was trying to determine the maximum lift with stock-length valves. It turns out it was in the .525" to .560" area depending upon which parts were tried. Hence my original "bottom line" comment.

There are a lot of questions that come to this board where the answer is, quite rightly, it depends.

When you are talking about camshafts above certain lift levels, there are always going to be issues. .550" lift? In some larger engines that's no big deal. In this motor the combustion chambers are rather small and the valves are close to the deck so it might be a big deal and you will have to plan accordingly. You may have to flycut the pistons. You may have to think about a smaller cam. The more radical the lift, the more vague the answer.

Regardless what someone on one of these boards (including myself) say about whether something will work or not, you will be left with the bent parts if they are wrong and therefore it is incumbent upon you to check all clearances.

You're right out there at the edge with this cam. That's great, but you are probably going to have to juggle a lot of parts and do some machining to make it all work. If you make it work and especially if it doesn't, let us all know.

heres the thing for everyone reading this who thinks im a flaming asshole...heres the deal:

I know that I'm going to have to test this someway. I've gotten a lot of good answers from here but you guys aren't seeing the kind of answers I was looking for. Since I really cant see it any other way, let me be more specific:

I am getting a cam, the specs are 112/107/248/258/.500/.520 with 1.5 ratio rocker arms.

at 1.6, that will put lift around .533/.543.

I need to know:

1. Does anyone know one way or the other if this will not work in a 3x00 engine. im not asking if i have to test it -- has anyone actually used a cam this large with the canted valve Gen III Aluminum heads with 1.6 roller rockers?

2. If the answer to #1 is no, and mind you this is in regards to one of the answers I got above, would this be too much cam for the aluminum heads? (and mind you when i ask this I am wondering if the springs will break the heads from the pressure.)

I am guessing, in the interest of peace and harmony and all that good crap, that I'm going to have to be more descriptive in my questions in the future and explain to everyone that i have searched every time i post because you guys are so used to dealing with noob's who don't know the first thing about using a message board, and not with a web developer who sets these things up on a regular basis.

Thank you for any info you have given.

-R

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