Pwebbz28

iTrader: (31)

Big springs are possible but you must use longer valves to get the install height right. You can just go cutting on the spring pocket or you will get into the runner.

My cam is .720 lift and the motor made around 750 on pump gas N/A. No water pushing. Using a felpro gasket

Gen414

iTrader: (38)

Yes, Possible, but ALOT more work than you are suggesting. A .720 lift cam is one thing, and easier to do...but when you are pushing .800, it is a whole nother ballgame. You can't just use a longer valve. Rockers need to be shimmed up, and then when you do that, it pushes rockers into valve cover rail, and that has to be clearanced, AND THEN you still have jacked up vavletrain geometry cause the further you push the rockers up, the closer it becomes to the valve, and then the sweep on teh rocker arm gets into a poor contact situation. Looking at using recessed retainers (to drop valve back down some) as well, and more.

Gen414

iTrader: (38)

yeah, there will be more to follow, and TRY to get some pics to show you guys what is going on. The thing is, now I MIGHT sell my top end to avoid all this work. I mean, I do have it for sale, but, if it doesn't then will keep it and make it work. But there is the other catch....My pistons. Shortblock is together, but if I sale my heads, does not look like I can use my Wiseco Pistons, as the valve spacing is unique to the L92 I talked with Richard (again, at WCCH) and he said for to call Brian Nutter @ Wiseco and make sure that I can't. So, if I can't reuse my Pistons, then I AM gonna make this work, as I am not gonna eat cost of pistons as well
I am hoping that people read this and learn from my hard knocks

So, again, up to low.700 lift the L92 is OK, but when you get into big springs/pressure to handle a cam nearing .800 and more lift, THAT is where the problem arises. So, more to follow

TT632

iTrader: (3)

+1. You can't put a big spring in there with a small pocket and no material to work with. The flow goes flat(stock) at over .600 anyway, so it probably isn't the right head to be using with a large race cam.

Gen414

iTrader: (38)

What we did is took a stock casting, flowed it up to .700, and got 316 @ .600 320 @ .650 and if I remember correctly it was 321 @ .700. Then I had another set (have 2 sets) of heads get worked over, and we have yet to flow them as we found out about this problem, so?????? I guess we'll see, as I currently do not have anyone (trying to sell the setup) interested in my heads and such, so looks like i will be keeping them, and make 'em work, maybe.

NemeSS

iTrader: (127)

i say run em'

JBrady

Just a thought.

Would it be helpful to use the "rev kit" design of an extra set of springs between the lifters and the underside of the head? This reduces the total reciprocating mass that must be controlled and therefore reduces the spring strength needed at the valve.

Gen414

iTrader: (38)

You know, now THAT is something I have not thought about. I have never run the "rev kit" nor had any personal experience with them, but is something to run by some people I wonder if it would help in terms of reducing the spring needed "up top". Hmmmmmmmm, interesting.

Gen414

iTrader: (38)

Ya know, for the sake of doing something that no one else is doing, THAT is the tempting part. I have never been one to follow the herd so to speak. BUT, at the same time, I am not one to **** away money for teh sake of not trying to follow that herd either. so....

That is why I put my stuff up for sale. If I can sell it for basically what I have in it, then no biggie. But, if I can't (and does not look promising) I'll run it. What I need to do is find out about this "new" idea that has been brought before me (teh "rev kit" from above, thanks JBrady) I know the Rev Kit has been out for some time, but just something I have not thought about (gotta love this site )

But, if I can help other's out, by trying something different, and as long as I don't have to shoot myself in teh foot to do it, then I am all for that as well.

So, I need to talk to my machine shop and get an idea of how much time/money is gonna be involved in setting the heads up RIGHT!

Also, what I need to do is flow the heads, and see the flows #'s @ .700-.800 and if they stall, then I can back teh cam down some and let it eat. BUT, getting ahead of myself. So, onna give the heads another day or so to sale, and if not, then I will go forward with "project too much cam for my wimpy *** L92 heads" and report back and maybe we can learn something....or maybe not

cutlass_455

iTrader: (2)

HOT ROD magazine has a write up in the current issue about a rev kit they tried in an older engine, I think it was an old MOPAR motor, but I cant remember. Decent info and pics. Maybe check it out.

All this trouble with the L92 head not being able to take that big lift sure sounds like a good excuse for an aftermarket company to make an L92 type head or their own.

Gen414

iTrader: (38)

yeah, and see here is where I have already run into some problems, and i could not figur eout WHY on earth no one was running these heads (hence me starting this thread a couple months back)

1st problem:
at the time, NO ONE made adj rockers for teh heads, except Jesel ($2000) and Yella Terra (hold down bolt was SMALL, and not capable of handling any spring pressure) T7D, who I found out much later, made them, and was alot cheaper than the Jesel (I paid $1200 for my T&D's) THAT was an ordeal in itself, and almost made me get rid of the heads in teh 1st place, but, I stayed with them.
2nd problem
again, at the time, NO ONE made an intake for it, other than the GMPP (and currently Edelbrock only offers the Vic jr, but not the Super Vic) and since I am running a carb, that was another problem But, I continued on.
3rd problem
Current one. Can't handle a big valve spring.

OK, so when i was told that, I was like son of a gun, how much do I have to go through to run this freakin head! Since I already had rockers ($1200 worth) I needed to see which OTHER head fit my rockers. You guys guess yet? Yeah, NADA!! No other head shares this rocker. So, called T&D to see if they could take them back. Told me yes, IF I bought something else from them. OK, no problem.
SO, at this point, I COULD sell my heads, exchange out my rockers for another set of T&D's, buy another set of heads, BUT, MY PISTONS!!!! Yeah, since this head is unique to itself (valve spacing) I could be screwed there as well. So, I got to call Brian Nutter over at Wiseco and see whats up.

OR, I could run a smaller cam, be done with it and just eat the cost of this cam I already have.

Or, continue on, make the heads work, and see if I can't help people or pave a way for others. And since I have no real offers on my setup, THAT is what it looks like I am doing. I am heading to my machine shop tomorrow (was hoping today but nope) talk to them about teh rev kit, and my other options.

But, you are right though, NO ONE makes really anything for this head, and this head's potential is very impressive to say the least, IF it was built to handle the rigors of a serious motor. I still can't believe the intake selection is limited, and more people are not coming out with stuff for it. I mean, I know WHY on a few reasons, but you would THINK that is where the aftermarket would come in

Robin L

I am amazed at the lengths that you are going to run this head. It's really not suited for what you are trying to do.

It is a value for what it flows but it really is only good in a mild application. This head is made by the thousands and is meant to be a production part.

Given the horsepower you are making I would have thought that you would have gone to an aftermarket head a long time ago. All the limitations that you are describing have been there since the start. We identified them a long time ago.

As a street head cam choice is critical. You can make decent power and mid range torque with the proper cam. The probelm is that if most builders can't figure it out on the first try they blame the heads. I have seen the results myself and you should also very soon.

I give you an A for effort on trying to make these work on your application. Do yourself a favor and get a set of all out race heads. Sure the castings are not less than 200 but in the long run you will have less headaches.

Robin

Gen414

iTrader: (38)

Well Robin, you obviously don't know much about me, but even I amaze myself sometimes at teh lengths I will go to figure somethign out (or in this case, make something work).
And no, no one identified the problem to ME, so who you are refering to is?? But does not matter anyway, since it was not me.
Yeah, I know it is a production head, and made by the thousands, did you think I did not know that or something?
Am I blaming the heads? Or anyone? Maybe you got this all wrong (sounds like you do) For the sake of time, will try and make it short for ya:

Has this been frustrating? Sure. Is ANY build that is NOT stock, frustrating at times? Sure. Whether it be back order on a crank, or wait list at your machine shop, or lifter problems, or LSX block failures at certain power levels, or whatever, anytime you are doing a "one off build" so to speak, you run into problems (and you should know this as well as anyone) and I see this as NO DIFFERENCE to me in what i am doing. I come from the Ford camp (hence the Fox body this motor is going in) and over the last couple years, kept reading about the LS series motors and all their potential. Read an article here and there, decided to build one for myself. Why not, was bored of teh same old SBF stuff.
Saw the specs on teh L92 head. Big intake runner. Big valve. Good #'s out of the box. Saw teh price, and was like are you kidding me?!?!?!?!? So, picked up a set. In the beginning, was gonna be a street motor. Then as we (as hardcore guys have a tendency to do) progressed, though..hmmmmm, let's up the ante some. More compression, yeah! More Cam, yeah! More Cubes, yeah! More cam again, yeah! So, going along the while, and come to the problems listed above. So what. Problems occur with ANY BUILD of this sort Again, frustrating? yeah. Big deal. I'll get over it. You (anyone) tell me I CAN'T do something, I tell you I CAN.
Thing is, if I didn't share this with anyone, maybe they run into the same problem. Maybe they read this, and THEN they can make up thier mind if they want to go through with the head ache. Sure, easy way out. Stop. Drop. And buy another set of heads Then buy another set of pistons. Break the shortblock back down. Balance the motor again. Put shortblock together again. yeah, that's not a hassle either (nor less expensive)
Again, I am not pissed at GM. Hell, I thank them! This is still a killer head, and I can't believe it is on a production vehicle. Does it have it's faults? yeah, so what. What head is perfect? Ain't one. Am I asking a bit much of a production head? Sure. Oh well. SHOULD I have gotten a more race oriented head to begin with? Honestly, yeah. But, I didn't, and looks like I am just gonna have to "make due".
And besides, I DID ask (that is what this thread is titled) a LONG time ago, and guess what, for all the info that was shared, I got NO concrete answer from anyone (including yourself) on why I shouldn't run thi shead. I don't blame anyone, as they either did not know teh answer. Did not see my thread. Or, just did not want to respond. I don't care, it's cool. Like I said, maybe I am helping someone now with this thread. And if I can do that, cool.
Tell ya what. I'll finish the build with these heads, report back on what you have to do to make 'em work, and see if I can't frustrate MYSELF some more

Richard@WCCH

iTrader: (3)

Manley makes a 1.50" dual spring that will easily handle the lift. The part number is 221456-16. It's small diameter should clear your rockers. You can remachine some LS7 valves down to the L92 diameters and step cut the spring pads. I'm pretty sure you'll be able to get a 2.10" installed height with that combo. Then you'll need to deal with spacing up the rocker stand and clearancing the interior of the valve cover area to gain some rocker clearance. It'll be a bunch of work but I'm pretty sure it'll go. Keep us updated on your progress.
Your next big battle is going to be getting the heads to produce linear flow up to .800" lift. The combustion chamber shape is going to be a big problem here.

Good luck sir!

Richard

Old SStroker

Listen to Richard!

Jon

Robin L

Well you may have taken my response the wrong way. First you answered your own questions with your observations.
Many others have tried and have similar roadblocks as you.

If that is what you want I say more power to you. I know that most of the hard core parts people won't make parts for these heads because of the their limits. Many good street parts but not the all out stuff.

There are some heavy hitters making 1000+ horsepower. No doubt about it. Also some very good advice by others here. When we looked at heads for several builds we felt the limits would hurt the program in the long run. The LS7 head in addition to some of the same issues as the L92 has a limit on the amount of lift before you see turbulance. At .750" they hit the wall of the combustion chamber. Great for a street head but not if we wanted anything over .800" lift.

Anyway good luck with your build.

I am still amazed.....




Robin

TT632

iTrader: (3)

I was having problems getting the Rev kit to work with the heads and block. Clearance was not within the specified range listed in the Rev kit, so we did not use it. I'm wondering if everyone is having issues with the Rev kit. It would have been helpful using a rev kit, but it wasn't absolutely needed in the street strip application I was building.

If your looking at building a heavy 9.9 street strip vehicle with bottle or boost, these heads stock can get you there. If your looking for a max effort head they don't really fit the bill.

Gen414

iTrader: (38)

Thanks again Richard! Ever since our conversation the other day, you gave me a whole new outlook on you. Guys around this site always talk about how good you are, and this and that, but actually talking with you and you taken the time that you did with me without me spending a dime goes a LONG way in showing your true colors! THANKS!! Once I get this figured out one way or the other, there will be a day (maybe sooner than later ) you have my business. I wouldn't consider choosing anyone else, so, again, THANKS!!

Gen414

iTrader: (38)

I guess you could say I did take it wrong way. How I took it was some harsh critiscm from you. If you didn't mean that, sorry for me taking that way.
And me answering my own questions wth my observations...well, I guess I really didnt have any questions, more than observations or comments.

As mentioned, I spoke with Richard and he informed me of the problems I was gonna run into (And i spoke with Richard after my machine shop had told me what they ran into, so I wanted a 2nd opinion, and knowing that Richard gets high remarks around here, he was the 1st and only person I called to verify) I DID send a PM to a "friend" here on the site, that has run a pretty stout cam (in the low-mid .700's lift on teh '92) and see what he did, but that was it.

You know, again, I kow I am trying to make something work, that in the long run is not gonna produce the results I want, I now know that. BUT, it was a matter of me starting out with these heads because I was building a more street friendly motor, and then it was a "well, why NOT add more cubes and compression and cam?".
AND, IF I had $$$$$Big Money$$$$$$, I WOULD probaly buy a set of All Pro's right now, and be done with it But, teh fact is, I am looking at it as, I am CLOSE to this motor being done with hardly any more money...shortblock is together, intake is ready, carb is ready, clutch, tranny...and I can (if I wanted to) right now, plop a smaller cam in, and call it done. Fire it up, dyno it. Put it in the car, and go have some fun.

Thanks to ALL of those that have contributed to this thread, good, bad, neutral, whatever. Thanks. I hope that there are (is) someone that reads this and learns from the hardknocks I am going through with this head. Maybe most of you guys already knew, I didn't. Been stuck over at Ford for so long, what can I say This thread I can say is far from over, as we still need an ending, and till that motor is in the car, we don't have one. So, stay tuned.

Gen414

iTrader: (38)

no, no, not at all. Just a REAL serious street car, that will actually spend more time on the track, but will see the street (hence teh 6 speed). I knew when I bought the heads (as well as now) that these were never intended to be THE head to go make a million HP with. Yeah, I knew that. And those are not my intentions with this motor. We get a "little" crazy with teh cam selection? Yeah, little. But oh well.
Hey Richard, thanks again for the info, BUT, I already have $600 worth of valves. That is ANOTHER reason why I have been hesitant to just give this up, because of teh money I have in parts already.

I did try and sell the parts to see if I get could close to my money back here on teh site, but no serious offers. I THINK what we are gonna do, is drop a smaller cam in, put the motor together, "get my money's worth" and go from there. Don't hold me to that though, as I am not 100% on that.....