Valve springs

[5.7 hemi]

Here's my cam...
Comp XE285HL

These are the springs 924-16.

Now to my question. Since these are double springs, I would like NOT to run them as changing them in my Dart is a pain. So what single spring can I use with the Stealth heads?

 

[5.7 hemi]

Bueller, Bueller?

 

[funknut]

I'm also interested in some guidance here as I have the same cam and heads. I found a couple threads from comp that recommend the 911-16 for up to .600" lift but I know lift isn't the only consideration. Spring rate looks to be higher in the 911 (373 lb/in) vs the 924 (347 lb/in).

Here's one of the threads I found:

http://www.cpgnation.com/forum/threads/valve-spring-recommendation-mopar-440.25553/

 

[lewtot184]

the 924 isn't a strong double spring but will allow some extra lift. the 911 is an aggressive single spring but according to comp is lift limited. probably due to only 4 coils and the angle of the wire. i'd look at a set of edelbrocks. they seem to be somewhere in the middle.

 

[5.7 hemi]

Doesn't the eddy's go to 600 lift on their heads? If so, that would do it.

 

[lewtot184]

Doesn't the eddy's go to 600 lift on their heads? If so, that would do it.

that's what edelbrock rates them at. the fly in the ointment would be a rocker ratio higher than 1.5.

 

[5.7 hemi]

True, that's why I'm staying at 1.5.

 

[lewtot184]

True, that's why I'm staying at 1.5.

aftermarket adjustable rockers are usually higher ratio than their rating.

 

[5.7 hemi]

I've got done Erson adjustable rockers coming and the have new ARP adjusting screws with nuts. They are 1.5, so I'm good there.

 

[lewtot184]

I've got done Erson adjustable rockers coming and the have new ARP adjusting screws with nuts. They are 1.5, so I'm good there.

they're probably between 1.55 and 1.6. they're crane clones. tested many of those rockers.

 

[Bighead440]

A 3605D Isky single spring should do the trick, but I like a double spring like a Comp 925 or and Isky 8005A with fast-rate-of-lift hydraulics and solid flat tappets.

 

[moper]

The XE series likes a lot of spring pressure. If you look around there will be single spring options with similar pressure/inch. That is what you use to figure if a spring is right. Not max lift. The other thing is, a single spring working harder to keep those pressures will fatigue faster. So if this is a long life deal you might want to just go through the misery of the inner spring installation in-chassis, or have the cam/engine broken in on a stand or dyno before you put it in the car so the springs can be added easilly.

 

[5.7 hemi]

That makes sense.

So if I use double springs, can I break in the cam with both installed?

 

[HEMI-ITIS]

I just bought a set of Manleys from Marsh performance.Todd was very helpfull going back & fourth with measurements and spring rates.So new springs,titanium retainers and .060 cups.

 

[5.7 hemi]

Friggin' beautiful!!!

 

[Bighead440]

That makes sense.

So if I use double springs, can I break in the cam with both installed?

Yes you can, as long as the seat pressure is less than 130# and the open pressure is around 300#. I have even broken in with more seat/open pressure, carefully, and always use a ZINC-rich additive..

 

[HEMI-ITIS]

One of the big advantages to a roller lifter,,,,,,NO break in

 

[moper]

I never do, but I know others that have. Given the cam choice and the spring needs - I would not break them in with both. Ask yourself what your risk is if you spend a few hours of swearing vs the time and expense pulling the engine to clean out all the crap from a cam lobe going bad, and then having to either pay to have it broken in or dyno'd, or spending those few hours the second time. Things used to be different. Cam profiles were very different, springs were weaker, oils were better... but nowadays there are 16 reasons why every cam manufacturer says if you don't leave the inners out the warranty is void.

 

[lewtot184]

seat pressure at 1.90" is 112lbs with the 924's; so says comp cams. over the nose would be about 300.

 

[Bighead440]

seat pressure at 1.90" is 112lbs with the 924's; so says comp cams. over the nose would be about 300.

RUN 'EM both. I used #925s on a custom Comp hydraulic flat tappet with .545" lift (think XE285HL) and Crane 1.5 ductile iron rockers with zero problems, has run for 10 years+!!!