A little background, they were listed on here and corvette forums as rebuilt 1k miles ago, advertised as good for .525 lift but he said the springs will except .600. After I spoke to the seller he double checked and said the heads are only good to .470 but the springs are def .600. I just got them yesterday ,, pulled an intake valve and here is what I got.. the retainer to guide with seal removed is .790 .... the seals are umbrella style with orings but there rock hard and clearish, w/o the oring there is .525 or so from retainer to seal. Is there a different seal that will allow me to get closer to .550 lift or can I grind the seat ledge? Also the guides have grooves in them? Is this normal or were these knurled? Finally I cant find a part # on the springs, how can I verify there god till atleast .550? thanks alot guys heres some pics, If you see anything in the pics that you can give me insight on, Im not familiar with machining or head rebuilding techniques so I dont know what was done correct or incorrect,please lmk.




notice the huge space between the top of seal and guide

 

few more pics

 

Although you're looking at the distance from the bottom of the retainer to the top of the guide/seal, which is good, there are so many other factors involved when setting up heads.

I'd ditch the umbrella seals and put some positive lock seals on. How much lift is allowed depends more on the springs. With those single springs, I doubt they can reach your goal of .550" lift. You need to know what the installed height is.

Doing a quick search through a Comp Cams catalog for a camshaft around .550" lift, they recommend the 986 double spring. Recommended installed height is 1.800. Coil bind is 1.150". Allowing for .060" clearance at full lift, these springs will allow up to .590" lift.

Since the majority of performance SBC valvetrains use the 1.800" installed height, compress your springs in a vise until the coils bind and measure the thickness. Add .060" to get the maximum allowable lift and subtract it from the installed height to see how much lift the cam can give the springs. Typical single spring install height is 1.700"

You can always reposition the installed height with retainers that sit higher on the valve stem then compensate for the extra installed height distance by using more shims under the springs to bring it back to 1.800". The higher sitting retainer will add more clearance between the retainer and valve guide.

A typical factory style single valve spring w/dampener is Comp Cams 981. It has an installed height of 1.700" and coil bind is 1.150". These springs allow a maximum safe lift of .490". You'll cause a lot of damage if you try to use something like these with a .550" lift camshaft.

What specific camshaft you intend to use will determine what valve springs to use. I hate seeing heads sold fully assembled. Springs will rarely be what the camshaft requires.

 

Guides look to have been knurled and honed. Not a bad thing if the valves are right and tight, but not the best either.

 

The valves arent tight, I have a pair of 601s that are knurled and have no miles and the valves are tight with no play, the valves wont stay in place by themselves on these 113s,, theyll slide down guide. Also Im running a 258hr12 with 1.6 GMPP rockers which will have @ .520 lift

 

Knurled guides often wear out again quickly. Sounds like that's what happened to those heads, if they're loose an floppy like you say. Having them slide easily is no big deal, but if you can wiggle the stem and feel it clunk back and forth with the valve held about 1/2" off it's seat, they're in need of replacement.

Your spring cups are what's killing your retainer-to-seal clearance. Not sure why they have that metal cylinder in the middle (probably to center them on the guide boss) but that's what's contacting the skirt on the bottom of your seals and greatly diminishing your clearance. You need different spring cups to fix that problem whether you stick with umbrella seals or go with positive-style seals.

The only part of the seal that should be diminishing your retainer to guide clearance is the thickness of the part that touches the valve stem- NOT the entire height of the seal.

You NEED something to prevent the springs from directly contacting the aluminum heads (which they will chew up very quickly in a running engine) but that particular design is causing you problems with your seals. Fortunately, aftermarket cups and shims come in a dizzying array of ID/OD sizes.

 

Is that what that is. I don't recall ever seeing something like that. After looking at the pictures again, I can see the umbrella seal doesn't sit all the way down over the guide because of those cups.

This is what you should be using to locate the spring on the head. Shims are then used to get the proper install height.

http://www.jegs.com/i/Comp+Cams/249/4704-16/10002/-1

 

I think I can grind the spring seats and mic. them to equal heights,,, I put the springs in a vice and they didnt get close till 1.045" but still had a tad bit more... am I doing something wrong? There installed at 1.7 from the shim to the top of the spring and 1.74 from the spring seat and they are 1.25dia. If Im doing the bind test correct thatll give me .595" of lift. I pulled the intake out from the seat .5" and there is a little bit of wiggle, does this mean the guides need to be replaced? Also the valve seats look new but they may just be really clean, not sure how to tell. Once these go on I dont want to have to remov them for at least 50k miles so I rather do it all now than in 5k miles. Thanks again for all of the help.

 

Throw the single springs out and buy new ones recommended by your camshaft. Those are a factory stock spring size with that tiny 1.25" OD. They probably have a maximum lift potential of about .400". Better single springs have an OD of around 1.45".

You can't "grind" the spring seats. They can only be cut with a proper cutter and only if the head manufacturer recommends cutting the seats. There isn't a lot of metal between the spring seat and the runners or coolant passages. Most head manufacturers say not to cut the seats deeper.

Take the heads to a proper machine shop and have them built, checked etc to your engine specifications.

 

I think he means grind the spring seat inserts. ie. not the pocket in the head, but the steel locator. I don't see why you can't grind the top collar down, it's not a crucial tolerance.
Your spring measurement is similar to what I found on my 1.25" springs. They are typically good to .600" before coil bind. If you shim them up high enough, you can use that. However if you cam is .520" lift, i'd shim it so you can get to .550" or so. That gives you a margin of safety, but you get max seat spring force.

 

You provided him a lot of great information earlier, but I think you just misunderstood his later posting.

I think he's saying that the bind height for those springs is a bit less than 1.04 so he has room to spare. I also think he was talking about just grinding the steel spring seats, or cups and not the aluminum of the spring pad.
There really isn't any problem with these methods.
______________________

In fact you could cut off the bottoms of those umbrella seals if you didn't want to run different seals. They should only take up about 0.120" of your clearance at that point.

Your guides look to be trimmed to a 0.500" diameter, so if you order positive seals they would need to be about 0.470" inner-diameter or less, and your stem diamter is 11/32". Positive seals take up about 0.150" of your clearance.

If your installed height from shim to retainer is in fact 1.7" then you have no problem with the springs as long as they have enough pressure. You might want to take what you've got to a shop and have them double check your installed height and test one of your springs for pressure at installed height and installed height minus the maximum valve lift you're planning to use.

If the shop has a hole-mic you could have them check your valve-to-guide clearance too.
It usually doesn't cost a lot to freshen up the guides with bronze inserts.

 

ory for the misunderstanding, I did not mean cutting into the head itself. I have a buddy with a magnetic base dial guage he used for finding TDC and cam lift, I could use it to find out how much play is in the valve guide with the valve open @.5" and if its to much or real close Ill pay to have bronze inserts put in. I checked the dia of the guides and they seem to be stock at .56". Also the vice I used was small but to get the spring close to bind height was tuff, I had to put a spark plug socket on the handle just to turn the vice, I also put in a vortec stock spring(100k) and a new spring (0miles) from a set of 601s I have and those two were like butter to compress next to this one( especially the worn out vortec) .