tsidrift1

iTrader: (46)

Ok guys, I bought a set of the gsc high rev valve springs and retainers. I was up at Boostin a few weeks ago, and it likes like I was getting valve float. Gsc std beehive springs on s2's at 40psi is a no go I guess lol.

So I got the springs on their way, as well as the EuroXport valve spring compressor.

My head has had a valve job done. It was just when the car jumped time. So I bought some std size ferrea valves and supertech bronze guides and the machine shop put them in.

Here is my main question, from what I can tell, their are no shims under my seats of any of the springs now. I have read, that if the head has had any work, its important to measure your spring height and add shims if necessary.

How exactly do you measure the spring height. Is it as simple as using a digital caliper and just measuring the spring from the seat to the bottom of the retainers? Do you measure the spring with the valve open, or measure with the valve closed, or both? Is any of this a must for the springs install?

Please explain a little bit if anyone knows lol.

Thanks

EvoDan2004

iTrader: (94)

my guess would be from the seat to the top of the valve stem. i would assume the seat on all 16 would be the same. but if the valve is up on its seat then my guess is the valve stem would be higher from the valve spring seat. make sense or did i just make you dumber?

that is so odd i was just on GSC's website doing some homework for a winter freshen up and noticed they have different springs tagged with different RPM ranges.

tsidrift1

iTrader: (46)

Yea, I have been emailing Travis at GSC back and forth today. It wasnt really that I was over revving the std beehives, but more of just running too much boost with the s2 cams.

Upon reading further tonight, it looks like the valve spring height I want to measure is the installed spring with the valve closed. The spring height is just the spring, so bottom of the spring to the top of the spring, once installed. So I want to get that measurement to 1.55" according to GSC's website.

My next guess, is where do I get shims for an evo head. I looked on jegs, and they have shims, but I dont know the I.D. and O.D. that I need for the shims. I also dont know the thickness, guess, I will just have to wait till this weekend. Seems I will have to install every spring, measure, then get the appropriate shims for the valve springs that need them, if any.

michaelrc51

iTrader: (37)

If I were you I would try a few and see if there are any that are different than they should be. I ended up going from the Supertech duals to GSC 5041 springs and there weren't any shims under the Supertechs nor did the GSC set require any and the seat pressure was right on what GSC said, I think it was 105.
This was on a Buschur Stage 3 head, ended up having to pull the head off and have a race engine shop pull out the spring locators (spring seats). They wouldn't come off even using needle nose vice grips, the machine shop had to weld a rod onto them and use a slide hammer to get them off!

If you have any questions call GSC, they are great to deal with even if you aren't an engine builder.

tsidrift1

iTrader: (46)

Thanks man. According to GSC site, the spring height needs to be at 1.55" on the intake and 1.30" on the exhaust side. The caliper I have wont fit into the head right now, but I havnt taken cams out or anything yet lol. Might have to just man up and buy the actual tool for measuring the spring height.

BogusSVO

iTrader: (1)

Spring height is measured from the spring pad in the head to the underside of the spring retainer.

The measurements that GSC has posted are for untouched stock heads and what you should find or be close too.

Good chance that you will need shims, and the factory spring locators.

The installed height, closed seat pressure can be adjusted to fit your needs, but the over the nose pressure needs to be checked.

Also if you install the spring "tight" to gain seat pressure, that spring height has to be checked at full lift to make sure you do not hit coil bind.

Next, the proper tool for measuring spring heights in an import is not made and readily available, but is made by the shop.

The twist ones that you will find at Jegs, summit are for domestic OHV and is too large an OD to fit in an import head.

The shims come in 3 thicknesses, .015, .030 and .060.
If you can not get them from a supporting vendor, let me know and I can get you some.

If the shop that did the install of the guides and valves did not install a shim under the spring when they did that head ( that would be valve job 2?) I would bet your springs are installed loose, by as much as .020-.030 so that would drop your 85lbs @ 1.550 by 6-10lbs of seat pressure

So your 85lbs is now 75lbs then subtract boost pressure, the back of the intake valve is appox 1 sq inch, so 75lbs is now 35lbs left to control valve motion.

tsidrift1

iTrader: (46)

Thanks a lot man. I was waiting for you to post up, as ive seen you post in so many threads on here and dsmtuners about head work lol.

I get the springs tomorrow. I have a digital caliper that I was hoping would work, but it might be too big to get in there and measure correctly. The only shims ive seen for sale are from some vendors that sell Tomei shims, they come in packs of 8, and in only three increments, .2mm, .3mm. and .5mm.

I did not see any shims from the machine shop. I really wouldnt expect them to shim them as its just a local machine shop, they do good work, but mainly specialize in big motor apps. Even if they did shim them, I would imagine they would be incorrect, as they would have looked up the specs for stock evo 9 springs and I have the gsc beehives in there now.

I get the tool from the eurotools tonight, so I am gonna pull the springs out, maybe then I will see some shims, maybe not lol.

jason42003

iTrader: (18)

So my question is are shims necessary if you are just replacing the springs and cams cuz all the threads I've read didn't mention anything about shims. I'm not a big fan of doing the same job multiple times so I would rather have all the information before I begin the job. I currently have supertech single springs and was looking at upgrading to map's ultimate duty beehives with titanium retainers when I replace the cams with kelford 272s.

tsidrift1

iTrader: (46)

Shims usually are only used if the head isnt in its original state. For example, my head has had some valve work, so shims may be needed to meet the correct spring height.

jason42003

iTrader: (18)

Ok thank you mine had some valve work done when it was built but I'm jus gonna assume since it's running right now and I haven't broken anything I 8k miles if it needed shims they're good. Thanks for clarifying.

tsidrift1

iTrader: (46)

Mine runs fine too. But I was getting valve float on the dyno.

tsidrift1

iTrader: (46)

Ive modified my vernier caliper to measure the spring height. I am a little confuse, GSC shows spring height should be around 1.56" for their std beehive, my springs are measuring 1.73". Is that possible my spring height could be that off?

Edit: I was reading the damn caliper wrong lol

tsidrift1

iTrader: (46)

Also, when you measure the spring height, am I just doing this wrong?

Do I need a tool, that applies the 86lbs of pressure to the spring, then measure the spring height, which should be at roughly 1.56".

jason42003

iTrader: (18)

And what does valve float feel like or was it something you were seeing on the dyno charts? Def following this one for when I dig into my head this spring.

jason42003

iTrader: (18)

Not sure if this will help but this is what lunati outlines as the procedure for their springs and they are a quality name in sbc applications.
http://www.lunatipower.com/Tech/Valv...pringTech.aspx