InfernalVortex

iTrader: (4)

Im trying to figure out if I can get this done without machinework... Put a decent roller cam in my Vortec heads. I have a quick question but I feel like explaining my story. Skip to the end to get to the meat of it.

Looking at doing an XR276 cam if I have the money, or going with an LT4 hotcam if I need something cheaper and more available.

XR276 lifts are .507/.510
Hotcam is gonna be right around .500 lift intake and exhaust

Currently the heads are tolerating .468 lift on the intake and .475 on the exhaust. (1.52 rockers throw off the factory numbers of the xe262 cam I have. )



Anyone know what kind of valve seals these are? My machine shop set up these heads for me a while back when I was in a money pinch, so Im not sure what exactly was done to them. What I do know is that my guideplates, screw in studs, springs, and 1.60 exhaust valves from my $600 set of new junk heads were moved over.


I have 1.25 inch single springs, so Im thinking I can run some LS3 yellow beehive springs pn 12499224. They're only $70 new. Those are good for .550 lift, far below what my cams can do. The beehive retainers from comp I can use with them are going to afford me the retainer/guide clearance I need. I just dont know exactly how much. I hear ".550" lift thrown around alot, so the retainers I am guessing are .070-.100 inches shorter than regular retainers. I'll have to buy and measure and compare to what I have when the time comes, but I am thinking it should give me at least another .050 inches of leeway, but I'll verify that before running them.

These are the retainers Im thinking I will run. I believe they are correct. But Im not sure: http://www.summitracing.com/parts/CCA-787-16/

The question I have is due to using my old 1.60 exhaust valves from my scam heads, I have NO idea what the valve stem diameter is. I also am not sure what the valve stem diameter is of my 1.94 inch intake valves. They could/should be Vortec stock 11/32's. The exhaust valves I just have no idea. They may be 11/32's, or they may be 3/8s.

Do beehive retainers use normal, regular locks? Or do they use beehive specific locks? If beehive specific, is it going to be hard for me to source them in potentially different sizes?

sofakingdom

iTrader: (1)

Your valves should be 11/32" (.34375").

Those seals look like the ones that come in FelPro head sets, for some other motors (notably Northstar, among those that I've actually paid attention to). Probably perfectly OK.

AFAIK the beehive retainers take the same locks as any others. WHich means, you can even get them in a +.050" version, to add even more insurance of clearance. You'll just have to stack up more shims under the springs. Just look up in Comp's catalog what they call for, for going with those retainers; last time I dealt with it I seem to recall it was just the usual suspects.

I'd STRONGLY recommend getting rid of the stock exh valves. Even just some cheeeep replacement semi-performance ones would be an improvement. "Best" all-around street valves are probably the Manley ... these right here. http://www.summitracing.com/parts/MAN-10765-8/ If the int valves are stock, I'd recommend changing those too. You can lap them both in by hand easily enough; just make sure you use some fine lapping compound, aka "Clover"; DO NOT use the Permatex stuff in the aisle at AutoZone, it is like gravel instead of grit.

IMO the XR276 would be the better choice.

TreeFiddy

It would be a good investment to get a dial vernier and a spring micrometer, if you don't have them already. If you are keeping the current valves, measure the stem both at the guide and the locks.

Don't know if this is normally the case or not with sbc valves, but it confused me a little: Last year doing my cam swap, I measured my exh valves at 3/8 where they went thru the guides, but still took 11/32 locks - the tips were narrower. The intakes were 11/32 the whole length. Meant I had to get bigger seals for the exh.

skinny z

Since your exhaust valves are 1.6" from a previous mod, they're no longer stock and it's a guess if they're performance oriented or not. Stock Vortec 1.5" came with a back cut and the seats were cut with three angles. In fact the factory valve job on both intake and exhaust is what helped the Vortecs perform as well as they did (in the low to mid lift range) as well as the excellent LT1 styled intake port. Often second time around valve jobs take away some of the Vortecs potential if the machinist doesn't pay attention to the what GM decided in the first place.
You say your spring pockets haven't been cut (as was discussed in another thread) so the Beehives are an excellent choice. I know for a fact the Comp version can be installed with NO machine work. I used a generic keeper with my 26918 springs and 787 retainers. Crane 99095. Not 100% certain (no time to look it up) but I'm reasonably sure it's a one size fits all scenario.
The XE276HR with 1.6 rr fits with room to spare and has seen 7 grand with no ill effects (other than scaring the crap out of me).

InfernalVortex

iTrader: (4)

These were the valves out of my original heads:



Note that the intake valves had no margin left. That's why my machine shop told me not to use them. My exhaust valves had plenty of margin on them, and they have a few of those performance things done to them. I forget all the names, but they're narrower around the valve head and swirl polished etc, they seemed like a nice improvement over stock to me, but at the time I was in kind of a money pinch and a time pinch to get the car rolling again, so I didnt pay as close attention to some things as I should have.




Are there any downsides to running +.050 locks? Are they a strength/reliability compromise? They dont seem to cost any more...

And since I've had 3 or 4 different sources corroborating the "beehive retainers use normal locks" sentiment now, that's a bit of a relief. I figure I can reuse what I have with no problem, so even if I have some bizarro mismatched valve stem diameters, I already have the locks for them, and all of my retainers are visibly identical, so they're probably all the same part number.

I'd consider replacing the valves but Im not sure how much benefit I'd really see. To my untrained eye my exhaust valves are probably fine. My intakes are, I think, just standard OEM fare. But if Im going through the expense of a roller cam swap, Im not too excited to pay for new valves and a new valve job.

Also thanks for the advice about the vernier and the spring micrometer. I've got a vernier, just not good way to get to the valve stem with everything together. Logistical issues with apartment living unfortunately get in the way. The spring micrometer is going on the list when the time comes.

Would you consider the exhaust valves in the above picture okay? With my baby cam it still managed to pull a 101.8mph in untuned carb straight out of the box form while I was still trying to figure out how to drive a stick. I got a 14.5@101.8mph in a 3550lb car. I think that's pretty good (the trap speed, not the ET, lol), honestly, especially given how much better it's running now that I've gotten better at playing with the Holleys.

Im trying to do this without pulling the heads. The head gaskets are fine so I'd rather not pull the heads if not necessary. I get superstitious when it comes to removing things that are working okay. And valves are so expensive. Maybe if I get lucky and have the money I'll ahead and pull the heads and put some nice intake valves in there, assuming my exh valves are okay.

Thanks again for all the input. All of it is noted, definitely encouraging to hear that most of these affordable solutions are still viable. How much room do you have between your retainers and guides? You're using 1.6RR's with the xr276, how much of a margin do you have for clearance? I hear people say .050 is a good safety margin, do you still have that?

You do mean the XR276, right? Got any sound clips of the idle?

skinny z

I've never seen a stock Vortec valve with a reduced stem or swirl polish but then I haven't seen everything.
Reading up before I posted I read that they came with back cut exhaust valves however the original exhaust valve I have in my hand at this moment has no visible 2nd angle. I can't see an additional angle from your posted pictures either. I'm not sure what to make of that.
Considering you already have a functional valve job (correct?) then your attention comes down to the springs that'll work with the cam you want.
Comp26918 specs are as follows priced at 185 bucks.
OD: Top 1.075" Bottom 1.310"
ID: Top .650" Bottom .885"
Seat Pressure: 125 lbs @ 1.800''
Open Pressure: 367 lbs @ 1.150''
Coil Bind: 1.100"
Spring Rate: 372 lbs/in
Like I mentioned earlier, they'll handle anything you might want to throw at them. I'm not sure of the LS3 spring you had posted. If the specs are similar and the price cheaper, then that seems a logical choice.

skinny z

http://www.carcraft.com/techarticles...ade/index.html

InfernalVortex

iTrader: (4)

Im confused about why you're confused. The stock vortec exhaust valves are not what I have... ? You seem to be comparing it to a stock valve, and it's not a stock valve, that's why it's different? I must be missing something obvious or I didnt explain myself very well. Sorry.

Also, these are the specs on the LS3 spring:

Seat pressure: 90 lbs. @ 1.8 in.,
Open pressure: 295 lbs @ 1.250 in.
Coil bind height: 1.085 inches
.570 max lift.

I hear from the LS1 boards from googling that it's not really recommended to go past .550. But I dont think there's much of anything I could do the Vortecs to make them handle .550 without machinework. They're not as strong as the 26918, but they're 1/3 the price.

The XR276 recommends the Comp 986 spring which is as follows:
Seat pressure: 132lbs @1.750''
Open pressure: 293lbs @1.250''
Coil bind: 1.150''

The open pressure is the same, the seat pressure is a little less wtih the LS3 springs, but the LS3 springs are at a taller installed height, which is probably what I will use given my reservations about retainer/guide clearance. It's the closed pressure which causes problems with valve float from what i understand. SkinnyZ, how high do you rev your xr276? How high does the power band go?

skinny z

It makes sense now. I thought the valve in the bottom picture was an intake valve not an exhaust. My confusion but I get it now.
To answer some of your questions (even if they're not all directed at me).
I like the looks of the exhaust valve in the pic. My understanding is that just about anything you can do to the exhaust port (short of mangling a valve or porting job) is a good thing. I like the undercut stem however I don't see a back cut on the valve face. That's an improvement that makes a measurable difference.
Coil bind clearence with my cam and 1.6 rr is .100". Lots of room.
Keep in mind that using 1.6 rr will mean having to enlarge the push rod holes in the heads. Push rod binding along with the guide plates is the result otherwise.
I see that the Comp Cams upgrade for the LS3 IS the 26918 spring so I suppose if the OEM LS3 spring will fit then it workable.
My concern, as you suggest is the weak seat pressure. That's were valve bounce, rather than float, comes into play. Something you don't want.
I mean the XR276HR cam.
http://www.compcams.com/Company/CC/c...?csid=159&sb=0
I shift at 6000-6300 on the 1-2, and slightly less than 6000 on the 2-3 with a 700R4 trans. Although I haven't done a drag strip comparison, I think I might be a little quicker if I shift a little sooner. From my chassis dyno results and those of other engine dynos, shows peak power in the 5500-5700 range and peak torque in or around 4000 rpm.





RWHP numbers notwithstanding, that same car went 12.77 @ 106 mph the next day. So much for dyno values.

InfernalVortex

iTrader: (4)

Looks like I'll be getting the 26918s if I can afford it. if I can afford the extra $100 or so for the comp springs I'll run the LS3 springs. If they suck I'll switch over to the comps later.

One more question... roller lifters.

Will I see any benefit with going to a solid roller? Or are those strictly for mega-high RPM cars? The solid rollers are usually a little cheaper (Not a significant amount) so I could go either way budget-wise. I know you have to reset lash on a solid lifter on a regular basis, kind of a pain in the ***, but nothing I cant handle.

skinny z

As I mentioned before, I have no direct experience with the LS3 springs. I CAN comment on the stock Vortec springs though. One missed shift and I went past 6500. Result. One bent exhaust valve. That was with a flat tappet hydraulic that was along the lines of 224 degrees/.480" lift. Beware.
Personally from the standpoint of MY rpm limit, lift and duration numbers and the fact I like to drive my vehicle as much as possible rather than do maintenance, I see no benefit to a solid roller over the hydraulic.

JekyllandHyde

iTrader: (3)

I'm running the comp cams 26918 beehives with my Trickflow 195s. They take standard locks, but make sure to check your retainer to valve seal clearance to make sure you get no binding there. The spring may take the added lift, but if the retainer smacks into the valve guide seal, you're going to get bent parts. I'm running 1.6 roller rockers with my cam that comes out to .555 lift. I needed to run 10* locks because comp cams didn't have .050 offset locks in 7*. I had to run the offset locks to get my spring installed height closer to 1.800. Without the offset locks, I was getting installed heights of ~1.7200 to 1.7300.

InfernalVortex

iTrader: (4)

I gave up on a roller cam, it's just SO expensive. Over $1000 for the conversion. I'd rather go Gen III than spend that kind of money...

But I am going with a cam in the .490 lift range. The extra .050 from the beehive retainers should get me into a safe clearance zone. If not, I'll be doing what you did and getting the 10 degree locks. I didnt know they didnt make 7 degree offset locks, good info.






Also.... I read something about getting locators put in to make these springs work... Is that necessary? I read that running beehives without locators will lead to the end of the world, and then I've read that the vortec spring pocket acts as its own locator because the center area is so large.

skinny z

Locators are not needed. The Beehive spring is the same od and id as the stock Vortec spring. The guide boss acts as a register.
I've put over 50 000 miles on mine with no ill effects. It will be interesting to see if they have maintained their pressures over the years.

clean92rs

iTrader: (1)

i have just read about these beehive springs and was courious if these would go good with the voodoo 268 cam? didnt mean to hi-jack your thread. but as i am gonna be running vortecs as well.

InfernalVortex

iTrader: (4)

If you're talking about the 60103LK, the Lunati guys told me the LS3 springs would be fine, but it's such an aggressive cam Im not sure it will be good enough. The Comp beehives will work just fine though. Just looka t the specs on Lunati's suggested spring, and try to get close to the same seat and open pressures with a beehive spring. The LS3 springs are pretty close, though.

clean92rs

iTrader: (1)

yea, i have a hard time understanding that kind of stuff. lol. i just want a mild 355 using vortec heads. and i keep getting stuck on the cam and piston dish size. i keep hearing about the xe268 cam but i have also read alot about valve train chatter.