I'm freshening up the 392 Hemi for my hotrod and my head guy suggested that some people are having good experiences with conical valve springs. Not the same as beehive. But he does not have any first-hand experience with them yet. So I'm seeking feedback on them to help me decide whether I should make the switch. I don't like being a guinea pig, but if they are proven, and are right for my application, I would do it to get the benefits. This motor has a 700 lift roller cam and I was previously reving it to about 7200 RPM. I'd like to up the RPM a bit, trying for more horsepower. I'm considering a more aggressive cam lobe.
Currently it has titanium intake and stainless exhaust valves and steel retainers. I'm thinking of switching to titanium exhaust valves and titanium retainers and conical springs to try and get the RPM capability of the valve train up to at least eight thousand.

What advice do you guys have for me on this? Does anybody besides Comp cams make a conical spring? Thanks, Joel

No real world experience, but everything I have read there is really no downside, a few positives, and biggest hurdle is getting needed size/specs and price.

What are the spring pressures and what is the installed height? There are tons of people using Conical springs from Manley and PSI in road racing and other endurance applications *if* you can keep the spring pressure reasonable. There are conical springs that support in the neightborhood of 250/750psi at .800 lift but any more pressure or lift than that and yo are back to a conventional spring. I try to use dual springs (keeps the weight down) with no damper (eats the Ti retainer) if possible.

THe main problem I have had looking for conical valve spring for a big roller cam is installed height. It seems that the newer engines have tiny rocker boxes (aka LS platform) and the installed height is tiny (like 1.800). From my research most of the new style (conical, beehive, etc.) are geared towars newer engine platforms (G3 Hemi, LS, Coyote).

If you are looking for endurance springs the Isky Tool Room, Manley Nextek, and PSI RML series springs might have something for you.

It has been unanimous across all of the manufacturers I have spoken with that using the lightest valve, spring, retainer, lock and lash cap combo one could get away with *reliably* was preferred. That said they were all in to use a lighter spring until we started talking power adders and then they steered me right back to a 1.550ish OD spring again. In my case we are talking 2.050" installed height and 300/900psi with about .800/.787 net lift. I am going to use the PSI 1254RML dual spring in this case as it is the lightest valve spring I could find that supports the pressures my cam grinder spec'd.

I tested the dual conical springs from Comp. They worked fine in my application. Comp only lists one part number for the dual conicals but I'm sure other folks make them. Lots of people carry the single conical springs.

http://www.hotrod.com/articles/dyno-tested-dual-conical-valve-springs/

I think you may be good with conical springs. I've only been into a few of these old Hemis but if I remember correctly they have a fairly short valve and installed height is like 1.700
Gus

My heads are set up for PAC 1396 valve springs with 1.950 installed height. Here is PACs description:

Circle Track 1300 Series Valve Spring High Lift Roller Spring - damperless

Outside Diameter 1.574

Outer Spring ID 1.15

Inner Spring ID 0.826

Install Height 2

Load at Installed Height 260

Spring Open Height 1.2

Spring Open Load 690

Recommended Valve Lift 0.8

Spring Rate (lbs/in) 538

Coil Bind (max) 1.15

Joel what is the net valve lift on the intake and exhaust? That thing has a lot of seat pressure (like 305ish) and at .725 assumed gross lift you are at 673psi over the nose of the cam with about .080 to coil bind.

Out of curiosity what size are the valves? If your Ti intake valve is, for example 90g vs. 140g for SS valve how much can you take off of the spring rate...that is the question.

Food for thought...your current spring has a listed weight of 152g. Can you find a spring with comparable IH and spring rate that has less mass to control aka lighter? The accepted theory is lighter = more RPM so you would think moving in that direction will produce your intended results. Maybe we should be comparing the gross mass of the valve/retainer/spring/lash cap combo instead of just the spring vs. cam.

This is a very interesting topic to me as my new beater -1 combo is using 2.25 Ti intakes.

Sorry for geeking out on you lol

never mind

I was hoping you smart guys would "geek" this for me, because I don't know enough to do it myself.
THere is some nasty wear on the some of the valve tips. The one in the picture is by far the worst, some have the same pattern, but less deep, some are good. I don't see any evidence of the valve contacting anything. Also, I have only pulled the springs out of the #1 spot so far, but I found one of the steel locks on the ex side was split in half vertically. SO something bad is happening with the valvetrain.

Here is my stuff, and the cam card, and the weights:

2.205" TI intake valve with hard tips102g
1.800" SS exhaust valve 111g
steel locks 7 g
tool Steel retainer 22 g
exhaust pushrod 146g
intake pushrod 138 g
Isky bushed roller lifter pair with bar 294 g
PAC 1396 dual springs 150g
Missle aluminum rocker arms 1.5 ratio I&E
no lash caps


What do you think is going on?
THanks, Joel

Why doesnt the cam card have spring specs? How tight are the valve guides? If you split a lock what does the associated groove look like?

It looks like the tip is getting it's as$ kicked for a short duration of RPM. Have you ever found valve float RPM? Maybe if it isnt getting beat to death the guide is sticking keeping the valve from rotating causing the pattern? Is that roller on the rocker smooth in operation?

If that close up is a Ti intake it almost looks like the tip insert is coming out. Lack of lash could make things ugly too.

I'll get you some more info. I'm going to finish disassembling the heads, check all the valve spring pressures. The guides were not tight by any means, but I'll check the actual clearance. I don't know what the cam card doesn't have spring specs.

Boff, what's up with that, I thought you could help?

I would replace all the valves that had that ugly wear pattern on the tips now, not wait for them to fail on the road.
Something is really wrong somewhere Joel with the wear on the tips like that
Maybe a bad valve tip or something not correct to start with

My .02 is....... it looks like the tip isn’t hard enough...... and/or there’s not enough lube at the roller/tip.

I’d see about having the tip hardness tested on a couple of the ugly ones.

Do you have the springs set up so they are fairly close to coil bind?
You’re running .800 lift springs with what’s probably a net .700 lift cam.
There could be a spring surge condition going on if they’re installed too tall.

Is there any correlation between how bad they look vs being an intake or exhaust valve?

For the street duty portion of Drag Week....... the lash could really stand to be tightened up....... by quite a bit(vs what’s on the card).

Judging by my post above and the .700 net lift that makes .130 to coil bind. That is outside the spec.

Is this a custom cam?

Agree with this. What defines "hard tip" on a ti valve? Serious question, I do not know. Is it a hardened steel tip or hardening of the ti base metal?

Dealing mostly with LS engines over the years, the photos above look exactly like LS7's I've seen where previous shop/tech omitted lash caps on the ti intake valves or mistakenly put the caps on exhaust instead of intake.

How is the valve job? Are the Ti valves sticking coming off the seat. I have seen Ti valves with a valve job where when pushed to the outer edge of the valve, on a standard seat Iron/steel seat Begin to "stick /pop" when coming off the seat. What lash is there at operating temp. First reaction is lash is too loose. Second would be drag parts being used on the street. If they are hardened tip a magnet will stick to to the tip but not the stem. If you look close you should be able to see them fairly easily.

I’m not sure all the valve suppliers do it the same way, but custom Manley Ti valves can be ordered with or without hardened tips.
The hardened tip is easily seen if you’re looking for it(as well as being magnetic), and makes the tip length .049 longer.
Most Manley’s with hardened tips have a .290 tip length.
Ti valves w/o hardened tips require the use of lash caps.

The first pic is of a Del West Ti valve with a hardened tip.
If you look close you can see a slight different in color/texture at the top.
The tip length on that valve is about .310.

The second pic is what the top looks like after a few thousand miles of use in an 18* SBC that runs over 8000rpm lap after lap.