Meen95z

iTrader: (26)

Im going solid roller and have some Manley Nextek 1.580 springs and didnt even think about until now how the center head bolt is gonna work? I mean guys running these, can you get the 12 point nut off (with studs) with a spring this big? Or bolts? Just curious if I have to take the 2 center springs off to torque the head or not.

Ed Wright

iTrader: (1)

I answered this one, right? You could use an Allen bolt in the center position with those big-assed springs. A 12 point is too big to install or remove with a 12 point bolt, without removing the center springs. The pn 1350, 1.5" dia PAC springs I told you about are 350 on the seat, well over 900 lbs open. They last just as long as those Manleys, and you won't have to pull the center springs to get the heads on & off. Normal SBC heads don't have this issue due to the different valve centerlnes.

joelster

I had to try a few different sockets, but finally found one thin enough to fit between the springs. Make sure the washer under the nut doesn't interfere with the springs too. I had to trim the washer a bit with a grinder on each side.

Puck

iTrader: (17)

With 1.55" valvesprings I used ARP head studs with the smaller 12pt head, then ground the walls down on a socket to fit between them. Also had to trim the sides of the middle washers as well.

Tight fit.

Meen95z

iTrader: (26)

With the cam im running I was told I need around 250 seat and 630 open. Those ones you have alittle much psi.

SS RRR

iTrader: (2)

Just like dufus here all you really need to do is grind down the washers. I had a socket that fit fine on my six-point ARP headbolts. Excellent choice on the springs.

Ed Wright

iTrader: (1)

1.580" and 1.550" are two different deals. 1.550" clears easier. PAC makes several springs that size. This last set if heads I have, I spot faced the center bolt hole so the washer slides in under the Manley valve spring seats.

quik95lt1

iTrader: (7)

that is a monster spring, why so big??

Ed Wright

iTrader: (1)

Somebody just bought some wrong parts. That's how you learn.

Did I mention he could use an Allen bolt in the center? Plenty of clearance.

SS RRR

iTrader: (2)

Dunno why an allen bolt is necessary? I had little difficulty removing/retorquing. As far as it being too big? I was told by a machine shop and a friend of mine who ran the same cam I am, which is considered a small SR by today's standards, that it required approx 250 on the seat and 500 on the nose. Right now mine is set up with 240 on the seat. Within about 5 to 7K miles worth of driving the springs have consistently lost about 5lbs.

Ed Wright

iTrader: (1)

If somebody has big enough springs they can't get a socket in there without pulling the center springs they can use an Allen bolt if you can get a socket in there you don't need to worry about it. Very simple.

SS RRR

iTrader: (2)

I understand that part, Ed. I did not have that problem on my heads. Why are you so quick to judge that this individual bought the wrong springs when you don't know the cam profile?

Puck

iTrader: (17)

I don't see a reason to run a 1.58 spring when you can get 1.55 springs that have more then enough pressure for 99% of us and are much easier to install. That .03 doesn't sound like much but it's the difference between having to grind a ton of a washer and bolt head down or just being able to trim a bit off each side.

My 1.55 PAC springs are 260 closed 740 open, and I have some of comps most aggressive non-drag SR lobes. Don't see too many LT1s running pure drag lobes that need a triple spring with 900+#s open, so I think a better spring choice could have been made then 1.58" Nextek's.

Manley makes a great spring, I just don't think it is probably needed in this case - but the OP never told us specifics so who knows, maybe it is a nasty 270+ duration .800" solid roller that needs a giant BBC spring.

96capricemgr

iTrader: (1)

These days solid roller spring pressures are dropping, even 250 is high on the seat.

Ed Wright

iTrader: (1)

If an 8500 + RPM, .850" lift 290@ .050" cam doesn't need big diameter springs, why would any of you? Mine uses 350/360 lbs on the seat, 1015 open. I ran 1.625" Manley springs, I get just as many runs out of these 1.5" PAC springs with plenty of room on the 12 point center head bolts. They also make milder springs that size.

SS RRR

iTrader: (2)

Meh, whatever. Perhaps the builder chose this spring for longevity sake since it sees more street duty than anything else? I don't know. These decisions were made back in 2005 or '06 IIRC so not sure if that may have been before the "breakthroughs" of lighter duty springs for aggressive lobes...

Ed Wright

iTrader: (1)

I don't know about lighter duty. LOL
As I said, these smaller diameter springs last as long as the bigger ones. No rocker arm clearance problems either. None of the race engine builders I deal with have found a down side.

SS RRR

iTrader: (2)

What I mean by "lighter duty" is all the chatter that has been going on the last few years using significantly smaller springs for cams that normally use a heavier spring. Regardless, I'll take what you said into consideration if/when I need a new set of springs.

Ed Wright

iTrader: (1)

Who is doing that? Nobody I know. Mild street cars maybe, I would never go lighter than that. I've had too many failures over the years from low spring pressure. None from plenty.

quik95lt1

iTrader: (7)

im running mine fairly low, 225lbs on the seat 650 open, it remains stable well over 8krpm, if you run lightweight stuff you don't need a million lbs of pressure