problem installing new valve springs!

-
dart360swinger

dart360swinger

Boosted
Joined
Dec 4, 2009
Messages
195
Reaction score
46
Location
Okinawa, Japan
I tried swapping out valve springs today in the dart. I'm going from a single valve spring setup to a twin valve spring set up. I'm also doing it while the heads are still on the motor. I'm using compressed air to hold the valves shut. My problem is the valve spring compressor I'm using. It compresses the single spring just fine, but when I put it on the new springs, it only compresses the "main" spring. The inside spring is still to stiff and hangs out the bottom, making it to difficult to get it down far enough to get the keepers on. What do I do? Do I need a different tool? I really don't want to take the heads off.


Thanks
Jake

DSCN0130.jpg
 
i use that same type comp. and when i install the new springs i would just turn it onthe spring and they would grap the springs.but you must keep your hand tight around the bottom while you turn the knob to lock down on the springs..if that makes since to you..

once you turn it on the spring take your other hand and put press. on both sides of the comp. at the bottom then turn the knob to get tight..okay i feel better now..hope this helps...also once you grab the spring you will have to push down just a tad on 1 side or the other to put the lock in then do the other the same way..:cheers:

oh yea the inside spring just set it the valve before you grab the other 2 you dont have to grab that 1...


thats right i forgot about the spring seat sorry...what he said on the next post....
 
Some heads will have to be clearanced for the inner spring and be refitted with different valve stem seals. Are the inner springs clearing everything and setting all the way down flat on the head?
 
Longgone said:
Some heads will have to be clearanced for the inner spring and be refitted with different valve stem seals. Are the inner springs clearing everything and setting all the way down flat on the head?
Click to expand...


Ya I'm regretfully leaning that way. I think that might be my problem. It's been so long since I built these heads I just forgot. I check it out in the morning. I might have to send the springs back and go with somethin different ](*,)
 
I have that same compressor and never could get it to work on dual springs. The jaws aren't long enough to grab the inner spring.
 
hi, have the heads been cut for dual springs? that includes, the raised inner seat and guide narrowed. how much pressure you looking for? a good, single spring will fit easier. If you insist on duals, get a spring tool that hooks under the shaft, then you can pull down on both springs. comp cams sells one. made for mopar shaft rocker. comp also has a 926 spring, it's a single, it has lots of pressure and will last.we run those on a stocker cam, usually replace them after 4 -5 seasons. our cams are very aggresive on lobe shape. just food for thought.
 
Here is the tool I made out of an old rocker arm and a 3/8 nut and bolt. All you need is a long 9/16 wrench then to use as a handle and is doesn't take up that much space in your tool box.

tool2.jpg


tool3.jpg
 
perfacar said:
hi, have the heads been cut for dual springs? that includes, the raised inner seat and guide narrowed. how much pressure you looking for? a good, single spring will fit easier. If you insist on duals, get a spring tool that hooks under the shaft, then you can pull down on both springs. comp cams sells one. made for mopar shaft rocker. comp also has a 926 spring, it's a single, it has lots of pressure and will last.we run those on a stocker cam, usually replace them after 4 -5 seasons. our cams are very aggresive on lobe shape. just food for thought.
Click to expand...


Ya I'll double check this morning but I dont think the heads are cut for duals :banghead: These springs are the ones lunati suggests for this cam, thats the only reason I went with them.

Any other suggestions on what springs to go with? Those 926 comp's seem like a little much for me. I dont really know what I'm talkin about when it comes to pick out spring though, and the car is turbocharged so there is a lot of extra pressor on the backside of the valve.
I might go over the .500 in lift someday but much over.
This is the cam I have:

bg_CamSpecCard.jpg
 
I bought a spring tool from Hughes. it works slicker than snot. it has a long handle for leverage. The best $65.00 i ever spent.
 
I got this tool from Mancini and like Mike it was money well spent. Of course that does you no good if your heads aren`t prepped for the springs. As someone mentioned earlier you mlght see what`s available in a single spring with a higher pressure. I`m sure there`s something out there you could use.

Recovered_JPEG Digital Camera_3511.jpg
 
hi, comp spring # 942 is very close to lunati specs, or the lunati 73084. the 73949 has a short installed height. just foodforthought.
 
Well the assumption was right, single's only....damnit! I'll send these back and go with somethin else. Anyone have any suggestions on a single spring. .474/.494 220/226 112lda 10#'s of boost or less.

Thanks
Jake
 
dart360swinger said:
I didn't mean any offense by it. I just wanted to hear other people weigh in on it. Thats all.

Thanks
Jake
Click to expand...

Understood. It's quite time consuming looking up valve springs so unless you know some right off hand.....well you get the drift. Your best bet is to go to Summit or Jegs website and do a search for springs that have the required pressure (or real close) and the correct installed height, which is about 1.65" and will accept the amount of lift your cam produces.
 
hi, the springs i stated, I looked them up in the catalog from comp and lunati.
summit and jegs don't list all the springs, just the fast movers!!! I build engines, i have to know what springs will work. the springs i looked up are for 1.65 to 1.70 heights. also, I race a 340 in stock eliminator, and springs are very important to us. height, rate, pressure all have to be considered. this wasn't just a fly by night about springs for you!! it is solid advice!!! next time, do your own foot work.
 
I was in the same position a few months back, I have a fix for one of your problems but I think you are going to have another problem on your hands. I am running a voodo cam as well and I have the next step up 494/510 lift. I had already bought a set of Eddy performer springs that matched the cam I had before so I looked up the specs and called Lunati and the tech person said they will work fine. because the seat pressure was around 120 and the opening rate was close to their springs he said he didn't see any problem. No I have not ran mine yet, but look at how many people are running eddy RPM heads and they come with single springs. The problem you might have is retainer to guide clearance I would just check that if I were you. I have a set of J heads and the max I had was 480 so I had to cut the guides down.
 
I have the very cam in this thread and have spent 2 weeks trying to figure out which valve springs. Thanks for the input. I am probably going to run with the 942s.


Dan...


perfacar said:
hi, the springs i stated, I looked them up in the catalog from comp and lunati.
summit and jegs don't list all the springs, just the fast movers!!! I build engines, i have to know what springs will work. the springs i looked up are for 1.65 to 1.70 heights. also, I race a 340 in stock eliminator, and springs are very important to us. height, rate, pressure all have to be considered. this wasn't just a fly by night about springs for you!! it is solid advice!!! next time, do your own foot work.
Click to expand...
 
If it was me, I'd be looking at the 942-16s if you had to stray from the recommended springs. Just be aware that the harder a spring works, the faster it gets used up. A single spring doing the work of a double will weaken faster. The dual has a stiffer spring rate than the single (363lbs/inch for the 73949s vs 339lbs/inch for the 942s) and because of Lunati's fast rate, they think that faster rate needs more spring. The spring requirements are one of the reasons I don't use a lot of Lunatis on small blocks.
 
I am jumping onto this bandwagon because I want to use a Lunati Voodo camshaft as well (60401 or 60402). The recommended Lunati 73949 springs are listed as 120lbs/265lbs for seated/open.

The Comp Cams 942s are listed as 115lbs/284lbs while the same manufacturer's 972s are listed as 124lbs/293lbs. The 942s are $16/set cheaper.

Based upon their use (318, cruiser car), which would be the better set for use with 340 heads on this block and compression of 9.2:1 or a bit higher?
 
Claudius, Look at more than the pressures... The installed heights and spring rates and especially the coil bind figure are what you need to compare apples to apples and these vary from part number to part number and manufacturer to manufacturer. It's easier for me to just use what the cam guy wants... and in some cases, a spring may look like it will work but due to something else (like safe harmonic range, rocker ratio or overall valvetrain weight, too large a diameter of wire in s single spring, etc) the other spring may not work as well, over the full rpm range, or for as long. So the right (or usable) spring has nothing to do with compression, type of head, or block. So for the two cams listed I'd go something like Comp 901-16 would work for the Lunati 401 , but the 402 IMO needs more and that one the 942-16s. Unless your goign to buy new retainers to raise the installed height I dont think the 972s are the best way to go. They have a coil bind height of 1.195. If they are isntalled at the std 1.650 height with a std retainer, the spring will bind at .455 at the valve.
 
I am in the same boat. I have the a Lunati 60402 cam and need springs. From my math the 942s will coil bind. From all my research I think I am stuck with the 73949 Lunati springs.

Everything I have found that is close has coil bind issues. 901s are too soft, 942 has coil bind problems.

So the Lunati springs have 120 @ 1.650 installed height with 265 or 275 at open.

I called Comp Cams help line and the tech said that the only ones he liked to match that are bee hive springs.

So I am about to order the Lunati springs tonight.

To the experts out there. How much give do you have on springs. would 110 @ 1.65 work how about 130 @ 1.65. What are the rules for valve springs?

Dan...
 
What rockers are you going with? I don't think you'll have coil bind w/the 942s if you stay with 1.5s and use +.050 retainers. That leaves your clearance at .101" at max lift assuming the std loss of .020 due to the pushrod angles.
 
You must log in or register to reply here.
-

Back
Top