Thanks for the info, I guess I've been away from this sort of thing too long, new technologies are great! I'll have to check out those "new fangangled gadgets".

 

Who has some guidance on how to properly shim the springs? I would have just swapped them out without doing this, but in another thread they talked about this but didn't say how to do it. Kinda like the TV shows that say to do something during a project but never show you how.

 

I guess there are a few ways to look at shimming the springs. One group might say that you have to do it, others say it's not important, others say it might be a good idea but it's not required.

I know when I worked at TEA we measured every valve, and shimmed the springs accordingly to obtain equal spring pressure on them all. The primary reason that we did this was because most of the heads that we sent out had been machined for bigger springs. Since the heads had been cut you would need to shim the springs to account for any inconsistencies in your milling of the head.

If the head is stock though, think about it for a minute. The factor springs aren't shimmed so they are either all exactly the same and therefore don't need shims, or the factory didn't feel that it was worth the extra effort because it would all be within a reasonable spec.

As far as the actual process, you need an assorment of shims, a set of valve locks, one of the retainers you intend to use, and the locators you intend to use, if any. Then you will need a special micrometer designed for the purpose, you can get it from summit. You then take the head with the spring removed and place one of your locators. On top of this you put on your micrometer, then you put the retainer and locks on and tighten the micrometer. As you spin the micrometer it expands vertically. Turn the mic until you can't turn it anymore and then take the reading. Write this down on something and then move to the next spring. Do this for all 16 springs.

When you're finished you'll have a series of numbers, like 1.95, 1.90 inches, 2.00 inches, etc. Now you subtract off the desired install height, say for example you're shoot for 1.8 inches installed height to get the shim amount, IE:

Spring 1 - Measured 1.95 - 1.8 = .15
Spring 2 - Measured 1.90 - 1.8 = .10
Spring 3 - Measured 2.00 - 1.8 = .20

And so forth. Take the desired amount of shim, place them first, then the locator, then the spring, then the retainer and locks.

When you're done ALL of your springs will be set at the same 1.8" install height and thus should all provide equal pressure to the valves. Then another question becomes what is the desired install height? Good question, and it depends on your application. When I worked at TEA we would choose a spring based on the maximum lift needed, with a safety factor, the desired seat pressure, and the install height. The more you shim a spring, the more you are compressing it beforehand, and thus the less you can compress it in use before coil bind. You can get a higher seat pressure by shimming but you compromise maximum lift. Thus you have to choose a spring that can maintain the proper install height and sustain the lift before coil bind.

You can use another tool to measure coil bind and pressure for a given height, which might be available from summit.

 

Nathan, or anybody else; do you know anything about the roller rockers sold by GM performance? Here is a link to the info on them. http://www.superchevyperformance.com...s/12370839.asp

I am considering these along with new LT4 springs, retainers keepers etc..

 

Those are the same RRs I have. They are exactly what GM sells in the hotcam kit. They are no different from Crane Gold 1.6rrs (except color and the GM one have a little chevy emblem on em). Either GM has a contract with Crane or Vice Versa.

I wanted to use them cause I figured it would be the easiest install (being a factory GM part, etc) and I was right.

They are a full self aligning roller rocker also.

 

They're exactly the same as the crane golds but cheaper. There's no reason not to use them.

 

Do I have the regular stamped rockers on my LT1 (I haven't had the valve covers off yet)? It seems to me that this is quite possibly the best HP gain for the $$$$ spent!?? The article in "Vette" where they installed those CompCams Roller rockers on Mojo's car and that alone showed like 20hp gain sold me on the mod. (I think these are the same ones available on ebay http://cgi.ebay.com/ebaymotors/Comp-...52921336QQrdZ1 Is this a good price?) Does that sound reasonable? Again I will be swapping out springs, retainers, locks, seal etc. I am in the process of saving my nickles and dimes.

Will these Chevy roller rocker fit without modification to the covers or will I have to grind on them to make things fit? (see mention above about not having taken off the valve cover yet).

When I get my parts all assembled I will probably need some advice as to swapping this all out, so please bear with me. Remember I'm getting old (just turned 51 Thursday) and haven't done this sort of thing since I was in my early 20's.

 

Yes.

I had to remove the drip tabs on my '92 covers,
http://www.digitalcorvettes.com/phot...vecovers06.JPG
Your covers are different than mine, so I'm not sure. I went with the GMPP 1.6's and LT4 springs, I would recommend the upgrade.

 

I've been doing some more reading and I am wondering if I'll have to do some tuning to the computer after I get this done? Any body have answer? Denver, did you do the work yourself? You recommended the upgrade, did you buy the parts from Superior Chevy? Sure wish I had some one closer to help me out.

 

Just my 02 worth I run the Beehive comp cam springs pushrods and retainers.The 1.6 RR self aligning from comp cams .
I used the chevy gold self aligning 1.6 RR and switched to Comp Cams The LT4 springs gouged the under side of the chevy RR,when I hit it with a 100 shot of nitrous

 

Thanks, but no nitrous in my future. So I doubt I will have issues with the gouging. I just want a good running street machine.

 

I said that once also.I am older than you ,so I will never act my age
I love going fast ,It's just that the cops don't enjoy my passon with speed.

 

Just installing the 1.6rrs' did not affect my tune enough to warrant tuning and my '92 is SD (speed density) only. Your '94 MAF (mass air flow) is much better at adjusting for little changes like 1.6rrs. If you go Hot Cam and headers like I did then you looking at a re-tune.

Yes, I did the work myself, I've done all the work myself except for the tuning. I'm looking at trying that myself in the near future.
Yes, I got the RR's at Superior, I get alot of stuff down there, just 10min's down I 35 and there great guy's.
I would also recommend new valve seals, the LT4 springs come with there own shims, to install them you have to remove the seals, so you might as well reinstall new ones. I did not do this, then when I install the cam and headers a year later I found 2 exhaust seals leaking so I had to remove those springs and install new seal.
This fourm great source of info, but if you plan on doing all or some work your self get the helms service manual for the '94, http://www.helminc.com its worth every penny!!
Denver.

 

Ideally you would retune the car after any modification that you do. However if you don't have the capability to do that yourself in a cost effective manner, I'd suggest waiting until you do more serious mods to re-tune so that you'll get the best bang for your buck out of the tune.

 

Denver, I already have the Helms manuals (both the white and the red). BTW I have two daughter that live in the KC area, maybe we can meet up some time when I am there. Thanks for the info.

 

Yea, just drop me an e-mail, when and where. I can look at and talk about Corvette's all day.