dual valve springs
 

Considering replacing 1.677 manley triple springs to lighter 1.5 dual springs for my super stock 520 heads. Installed height is right at 2.050 and could get it to 2" if needed. Looking for recommendations regarding PAC's, Manley, comp or others. Understanding every application is different, how many runs can one expect from the dual springs and how are the springs holding up? Wanting if possible something that would last longer than 35-40 runs.

Ed

Re: dual valve springs
 

#1356 PACs, dual 1.5" diameter. Last all year on mine. Mine set up at 2.1", I have Victory retainers that are std, +.050" &. -.050" hight. I use .200" long valves, the -.050" retainers get away from rubbing my rockers.

Re: dual valve springs
 

thanks Ed. I was really leaning towards the PAC springs (1330 and 1356). I had thought more about the PAC 1330 spring as I don't have as much lift on my 283 (under .850). Still trying to keep coil bind close to .100. I can play with the keepers,/retainers and get installed ht close to 2.0 and end up with about 314 on seat. I too will have to deal with some .200 valves and rocker arm clearance.

Ed

Re: dual valve springs
 

Which Manley spring have you been using?

Re: dual valve springs
 

Jody, it's a set of heads I bought used prep by layer. The spring currently on heads are the manley nextek 221447 spring. spec (350# at 2.0 installed ht.)

Ed

Re: dual valve springs
 

Ed,

We have one engine with the PAC 1.5 springs. They have held up real good Lift is just over .800 at the valve. Installed at 2.100 we get about 350 on a new set. If your spring seats are cut for the triple springs you will need their spring positioners to keep the spring located properly to the guide. we had a learning curve on that.

Re: dual valve springs
 

Mike, thanks for the confirmation on locators. I suspected that would be the case.

Ed

Re: dual valve springs
 

And you're only getting 35-40 runs out of the Nexteks?

I was told by a reputable Class engine builder that some have had problems with the doubles.

Re: dual valve springs
 

No Jody, I have only heard good things from the nexteks in respect to durability. I'm in the middle of a re-build project and bought the used heads with springs already on them. I thought I would look at losing some weight on the valve side before final assembly. My comment regarding 35-40 runs was I did not want to install dual springs and have to have to replace after only 35-40 runs.

Ed

Re: dual valve springs
 

I don't see you having a problem with the PAC dual springs. I have four sets that have a full season on them that still check OK.

Re: dual valve springs
 

I had a set of those fail Manley NexTek springs pretty quickly. The engine had about 22 dyno pulls, and 25 passes on it. In fact, I'm not sure those springs were ever really controlling my valvetrain. The cam was not even close to radical. No expense was spared in building the lightest and best possible legal valvetrain, either. There was not a used piece in it, all the valvespring parts were new from Manley bought as a package at their suggestion. New Ferrea valves, new T&D rockers, and new Trend 7/16" x 0.165" wall pushrods, new Comp Endure-X lifters. The geometry was set up and verified by a Super Stock cylinder head specialist with 50 years experience. The failure ended the season, and did about $3K damage. I had run a set of Comp 26000 series springs the year before, for 50 passes or so, plus a dozen dyno pulls, and despite breaking a couple of inner springs, the rest of the valvetrain was fine.

Re: dual valve springs
 

Alan, were they set up per the "distance from coil bind" method?

Also were they losing pressure before they broke?

Thanks

Re: dual valve springs
 

I was told, by a gentleman from PAC to set mine up .050" from coil bind. They do live longer that tight. Makes for like 360/370 on the seat, like 1010/1015 open. The label on the end of the box shows set up at 2.1" but they live longer set up tighter. Maybe a harmonics deal? Don't know, but they last longer like that, so that's how I run them. Last set died by 64 passes, they were not set up that tight. This new set will be. Has been like that every time.

Re: dual valve springs
 

Back when I was running I had 947 Comp springs triples, they were set up tight 1.850 were 2.00 340 to 350 on seat. They would last two seasons or 200 runs without a problem with 9200 rpm shifts, pushrods are dual taper 7/16. It all depens on your camshaft and how everything is set up in your valvetrain. I was told a long time ago you can't put enough spring on your motor along as you good parts to go along with them. Tom

Re: dual valve springs
 

My pac #1356 are at 340 lbs.@2.075.Ten pull on dyno,30 pass. I don`t know if they drop again and again .Is there a safe limit ?

Re: dual valve springs
 

I have ran the Manley 1.5 and after a season they had only lost about 10 #

Re: dual valve springs
 

Was this a stocker or SS'er?

Re: dual valve springs
 

Sounds like a SS situation....