Now HERE"S an interesting Valvespring Question...

[steddy]

Has anyone here had to increase the ID of an LS6 valvespring to fit a 3.8L head (don't know if this is relavent, but '96 3.8L)? I've got two sets of springs, both beehive style (the LS6 are stock [yellow]), measured at 95# seat pressure @1.800 height. The other has 120# seat pressure measured @ 1.800 seat height (my guess they are the 130# beehives from Comp because they do have the light blue stripe on them). For the life of me, though, I do have to say...I'm stumped that they both have smaller IDs than the stock springs that I'm replacing. Has anyone heard of this?.

[ssms5411]

Re: Now HERE"S an interesting Valvespring Question...

It is in the stickey for heads and cam:


http://www.zzperformance.com/grand_p...les1.php?id=53

[steddy]

Re: Now HERE"S an interesting Valvespring Question...

Maybe I'm not seeing something, but, I read the ZZP write up and it doesn't mention the differences between the thickness of the valve guide at the seat in relation to the inside diameter of the seat end of the valvespring. Which is where my question lies. The LS6 spring's inner diameter is .040" smaller than the outside diameter of the valve guides at the seat. This is where I get puzzled about the statement on their page that ZZP uses LS1 springs on their heads but they don't mention requiring machining:

"Safely increasing cam lift or maximum engine RPM can require new valve springs. On the 3800 we use LS1 valve springs which means that when running new springs you will also need LS1 retainers."

So, I have both LS1 and LS6 springs and they are both sitting at .040" narrower than the valve guides on the heads at the seats.

[flamingchicken]

Re: Now HERE"S an interesting Valvespring Question...

I put LS6 springs in my 00 bird on stock heads, and they went on fine...i used my stock retainers too, you are talking about putting the springs on stock heads right?

[ssms5411]

Re: Now HERE"S an interesting Valvespring Question...

ZZP uses either COMP 105's or the 130lb springs on their heads, they recommend the 105lb springs due to their seat pressure being lower and not putting more stress on the timing chain. I use the Comp 105's with the modded steel retainers , I like the retainers just for the peice of mind I have extra .050 clearance with the Viton guides.

[bigbrian442]

Re: Now HERE"S an interesting Valvespring Question...

Maybe I'm not seeing something, but, I read the ZZP write up and it doesn't mention the differences between the thickness of the valve guide at the seat in relation to the inside diameter of the seat end of the valvespring. Which is where my question lies. The LS6 spring's inner diameter is .040" smaller than the outside diameter of the valve guides at the seat. This is where I get puzzled about the statement on their page that ZZP uses LS1 springs on their heads but they don't mention requiring machining:

"Safely increasing cam lift or maximum engine RPM can require new valve springs. On the 3800 we use LS1 valve springs which means that when running new springs you will also need LS1 retainers."

So, I have both LS1 and LS6 springs and they are both sitting at .040" narrower than the valve guides on the heads at the seats.

What your saying here is the LS6 valve spring will not go on over the stock 3800 valve guide because the inside diameter of the LS6 spring is too small??

[steddy]

Re: Now HERE"S an interesting Valvespring Question...

What your saying here is the LS6 valve spring will not go on over the stock 3800 valve guide because the inside diameter of the LS6 spring is too small??

Flamingchicken and bigbrian, you're both correct. Neither spring is going into the seat because of the valve guide outer diameter. Never experienced this with the V8s. I'm not sure if my guides are beefed up (for whatever reason) or the heads are just not compatible for anything other than stock, but there's quite a difference between the OD of the guide vs. the ID of the spring.

[bigbrian442]

Re: Now HERE"S an interesting Valvespring Question...

Have you removed the valve seal. The stock valve seals on some of the newer heads have a seat that the valve spring sits on. Not sure if your heads have these but if they do you might need to use LS seals. I think they are both 8mm valve stems. A good picture would help a lot.

[ssms5411]

Re: Now HERE"S an interesting Valvespring Question...

On my 96' there are no seats, just metal, (stock valves, Viton guides, ZZP modded retainers, stock locks and 105lb springs) , and on the 99+ heads(my spares with SI stock valves, 105lb springs, ZZP modded retainers , Viton guides and Comp locks) they are also metal at the bottom. Their is a difference in stock guides and the Viton guides, Viton guides are in 1 peice and the stock ones I beleive have a seal that is at the top held on by a retainer. Both stock and SI valves I had no problem with the Viton guides fitting. I don't know if this is what your talking about , but I thought I would post.

[bigbrian442]

Re: Now HERE"S an interesting Valvespring Question...

Have you removed the valve seal. The stock valve seals on some of the newer heads have a seat that the valve spring sits on. Not sure if your heads have these but if they do you might need to use LS seals. I think they are both 8mm valve stems. A good picture would help a lot.

Do they look like this?


http://www.partsamerica.com/ProductD...Number=SS72851

[steddy]

Re: Now HERE"S an interesting Valvespring Question...

Do they look like this?


http://www.partsamerica.com/ProductD...Number=SS72851

At the seats, it looks as if there is a provision for that type of seal. The machine shop ordered a cutter to grind the "shelf" down to accomodate the LS6 springs though. They don't have one that is skinny enough to turn on the heads. The shelf, as I am putting it is about 1-2mm high, is cast into the head and looks as if it accomodated the bottoms of the old seals. This was the part causing the springs to wobble a little. The shop had an extra spring lying around and grounded the inside out a little (maybe .040"). After that, the spring sat solid. I'm also running the Vitons with 1.800 modded retainers.

I would suspect that after they take a little material out, the springs will sit well and the troubles should be over. Next, on to the block and fitting a double roller chain. I wish I would've taken a pic, time just didn't provide.