I've used the conical duals on a solid roller Drag Week application as well as their single conical on a hydraulic roller, drag race only deal and so far, all is good.

The weight saving is worth it.

 

Anybody here have one break? I like and get the idea behind the conical spring just there is no safety net if one breaks. A big block chevy is not known for its light valve train so I could see some value here running these springs.

 

Running dual conicals here too. .730 lift HR

 

I have used the 953 on many hydraulic roller street/strip engines. Its a great spring for that use.
I wouldnt consider it a solid roller cam spring for any serious performance use.

 

A few words spring out of your post...
"Cast Core Solid Roller". I was under the assumption that all solid rollers were forged/billet steel. Is that why they are recommending such a weak spring for a solid?

The 473 lb/in spring rate on the recommended spring seems on the low side for that heavy of a valve in a BBC wanting to spin 7k rpm.

I don't have a definitive answer for you, but if I were building the engine, those two points would be worth a little more research.

 

The conicals have excellent valve train control. However, it does come at a cost. They are extremly high stressed and I would not recomend them in a application that will see a lot of street driving.

 

I agree as we have had incredible results with them but they seem to time out sooner than you might want and have had several break. With a more aggressive replacement schedule they are very good though.

 

Thanks for the insight all.
I've been looking at this for a couple of weeks now. Research , I thought was done. Posted in the hope someone had done something similar and could confirm, or suggest another direction i could look in.
The not alot of street time for the conicals does stand out. On paper they look like the solution. Don't want to find out the opposite the hard way. And comments on line to the effect of 500lb on the nose of this cam won't be good. Why would comp sell these as warm solid roller options and recommend such a soft spring. I've emailed them twice to get to the bottom but no reply. Hard work.

 

Conical/beehive springs can run with lower tension because the valve train sees less weight, plus they are less prone to the surge that parallel springs get. Very good info on this in D.Vizard's books.
I have used BH springs for 20 yrs. I doubt that these springs would be used in production engines that rev to 6000+ .....where the car maker has to to provide a long warranty period.

 

Yeah, Vizards book is what got me looking. Have you done any BBC heads with intake valves around the 132g mark? The conical springs look like the solution to the heavy valve problem but in a 90% street car, l need to know it's going to stay together for a reasonable amount of time. 1220x beehives @ around 500lb open and 933-16s at around 460lb is what I'm up to at the moment. Comp reckons 500lb is too much because their cam is made from some sort of Korean cheese...so still digging. My machinist is ordering a cutter I want to try so thats a couple of weeks out so still have some time to investigate.

 

BBC 2.250"-2.300" stainless valves weigh more like 145 grams with 11/32" stems and +.250" length. What valves are you using?

 

Manley racemaster going off their listed weights in their catalogue. Their +.250 was 137 I think.

 

The Manley valves I use on Dart Pro 1 heads are Severe Duty 11854 and 11843. 2.300" x 11/32" x +.250", Listed in Manley catalog @ 148 grams and 1.880" x 11/32" x std length. 122 grams. The common PAC 1224 spring AFR and others sell in the complete heads is marginal in my opinion @ 250-275 # @ 2.000" for a 145 gram valve. The PSI R425RML is more seat pressure at 300# + @ 2.030"

 

There are conical springs, and even double conical springs that will take an amazing amount of lift and RPM. Yes, those are highly stressed, but you can't throw all non-cylindrilical springs in the same pot. Springs like the Comp 26918 is a beehive spring that can withstand long use. I used these in an 0.600" lift SFT in an FE ford that turns around 6k rpm, and they've been flawless. Built the engine 20 years ago. Car just got sold this summer, and still going strong. I believe there are similar springs used in the LS engine as well.

 

You dont need nearly the outright spring pressure with the conical springs, but the rate it way up there. We have a set of in a low lash solid that has seen 400 passes (maybe hundred or two when it was still a hyd) Also had one car break a spring in a pretty typical hyd cam. i tend to think that was a customer beating on a cold engine type thing - as the car picked up much valvetrain control and power up top from the original spring that was on it and seemed VERY happy. But magically broke a spring in his hands.

Anyone else broke a conical and if so use case scenario and which spring?

 

You dont need nearly the outright spring pressure with the conical springs, but the rate it way up there. We have a set of in a low lash solid that has seen 400 passes (maybe hundred or two when it was still a hyd) Also had one car break a spring in a pretty typical hyd cam. i tend to think that was a customer beating on a cold engine type thing - as the car picked up much valvetrain control and power up top from the original spring that was on it and seemed VERY happy. But magically broke a spring in his hands.

Anyone else broke a conical and if so use case scenario and which spring?

Thanks for posting, always nice to see you on here👍. I'm running a more endurance application, since I run a ton of street miles and beat it to death. The more research I do, the more it's leading me to just running duals. I still like the idea of less spring mass/more control, but if I can't squeeze out 30-40k between swaps, it's a negative.

 

Reach out to Eric Roycroft. He built my 450" ls with HR and dual conicals.
@E.R. Racing

 

Whats it make whats it run?




DualQuad - I prob agree with you here just because there isnt a ton of longevity data with these highly stressed conicals. Yes we have them in a car thats made 400 passes at 1500-2000hp... but it doesnt see the amount of cycles that 40k miles does either