They are approximately 2.16" high, and 1.24" outer diameter. They look pretty stock to me. The only reason i am wondering is I bought these heads with some machine work done to them already, and stock springs really don't make much sense one heads with bigger valves, screw in studs, and guide plates. That said, the guy who sold them may have just put them on to sell the heads as "complete". Is there anyway to tell for sure what these are? I am pretty sure they are GM, but GM makes a lot of different springs. All opinions are welcom. If I cant figure out exactly what they are, I will probably just buy a new Summit spring and retainer kit and be done with it.

 

Okay, I got a caliper and the exact dimensions are:

uncompressed Height = 2.150"

Width (Outer Diameter) = 1.264"

Width (Inner Diameter) = 0.886"

The Installed height (at the top of the exhaust retainer) = 1.885"

Any Ideas as to what is going on here? The factory installed height is ~ 1.7xx" correct?

Any way to get an idea on seat pressure?

There was definitely some machine work done, so factory springs would be surprising, unless they were just slapped on so the heads could be called "assembled".

 

They look stock or stock replacement.
The best way to find out is to throw one of them on a spring pressure tester. You'll have your answer for sure then.

You might want to check the guides for slop while you're at it. It doesn't take long and you'll know where you stand as far as the head reconditioning goes.

 

I am pretty sure that they are stock. I know this is not a very acurate test, but when I lean on them I can compress them. In a bathroom scale if I do this they will compress to installed height with ~ 80 lbs. I may as well toss these things.

On a brighter note, I only paid like 150 for these things and everything else seems kosher. There are new intake and exhaust valves, (w/ intakes machined for 1.94") they were also machined for guide plates, and screw-in studs. He claimed they had a valve job, and the guides look they were machined for clearance. I don't think these were run (that's what the seller said, and there is no carbon on anything. I checked for slop, and it is essentially nonexistent.

I guess I just need to find a set of appropriate springs and retainers. I would really like to run an XFI cam from comp, but it recommends beehive springs, and those suckers are expensive. Any reason I couldn't just use these? http://www.summitracing.com/parts/SU...0/?image=large or will the oober fast ramp rates of the xfi kill them?

The valves look new. What does +15 mean? I assume it means they have a longer stem?


I am still learning this stuff so please excuse my ignorance.

 

Many replacement valves are longer by 0.100" or 0.150".
Very few replacements have thicker diameter stems.

With thicker stems you can get away with just reaming worn guides instead of installing new ones or liners. It's usually not the best way to go. Bronze liners are preferred.

Longer stems increase the spring install height without machining down the spring pads. It's not a bad way to go, but you generally need more spring to make them work right.

You say you're going with an aggressive camshaft. I seriously suggest not skimping on the springs. Use the springs that are recommended for your camshaft and make sure the installed height and clearances are correct.

edit: Those valves are in serious need of backcuts to radius the backs of the valve heads.

 

What exactly are you referring to? The surface where the valve meets the head in the combustion chamber?

Here is what they looked like installed before I took it apart.


Here is what the seats look like with out the valves

 

Backcutting gets rid of the sharp ridge on the back-side of the valve head, and gives a smooth radius between the 45* cut on the valve and the stem area.

Here's a picture to roughly show the difference.
http://www.thedodgegarage.com/turbo/turbo_backcut.jpg

Your exhaust valves have a very large ridge, though backcutting is more effective on the intake side. You can backcut and/or radius both intake and exhaust if you want. It adds a significant amount of flow, especially at lower lifts.
Your valve-seats in the head look pretty good.

 

Okay, I see what you are saying. However I am trying to keep costs down, and machine shops = $$$ But perhaps I am wrong in this case? I can imagine it possibly being cheaper just to get valves that are already back cut.

You are in IL, what do they charge around here to machine valves like this?

 

hey smurf how goes it?
what kind of cam are you going to run?
if you run a zz4 cam with the standard .474 intake and .510 exhaust you can get away using springs that work up to .520 and not worry about having to pin your studs or drill them out and and put in screw in ones.
my friend atilla the fun gave me some good working info and if you see him on the board he will be happy to give it to you or i can.
i am running the 081 heads with tpi - or at least i will when i get them put together.

tony

 

Well, the cam I am leaning toward once these heads are ready (That could be a while since I want to port them, and I am no hurry since I have working stock heads on the car right now) is the Comp XFI260 216/223 , 0.499"/0.493" with 1.6 rockers. Comp recomends beehive springs, and that is sort of a turn off due to the price. This cam looks great since it offers only slightly more duration that I am currently running, and boatload more lift (Current stock '85 cam w/ 1.6 rockers = 215/220 .433"/443")

Pinning, and/or drilling are not an issue since they were drilled and tapped for studs before I bought them. I know I do not need to run guide plates, but it was already machined for them too, and I would like to run the 1.6 comp magnum rockers I already have running on my '416s (which are not self aligning).