Hydraulic roller cam spring pressure?

J

jamesmac

Member
Joined
Nov 12, 2001
I have purchased a roller cam kit from a T.R. owner in my area & on installation, my machinist informed me that @ the proper installed valve spring height, the springs are @ 100# seated pressure. As far as I know hyd. rollers should be @ 140.
To shim these to the proper pressure I will be into coil bind.

Is anybody else here using such a low spring pressure on a turbo motor.
It is a crane cam & calls for 99838 springs. Cam is PN-81hr00003

I think that these springs were ordered wrong, & are for a non turbo motor.

I am not new to turbo buick motors, just looking for some other feedback to offer to the seller.

Thanks, James
 
Hey James , Crane cam card says #99838-12 are the right springs for that cam (#81HR00003) . I also have the "original invoice" from "Northern Auto Parts" for the springs . check out www.cranecams.com/springs/dual.htm for the specs as follows . I guess Crane must know the type of spring required for their cams .



Seat Pressure - 112 lbs @ 1.650

Open Pressure - 336 @ 1.100

Coil Bind - .950

Max Net Lift - .690

Rate (lbs./ins) - 438 lbs/in

Maybe you need a new machinist or unless you know something Crane doesn't ! lol :D

Give me a fax number and I'll fax the invoice to you .
 
My roller cam is an old Ruggles 206/206 and the cam card says:

110 lbs. seat @ 1.750"
315 lbs. open @1.020"

Lift is .532" with 1.6 ratio


FWIW all the springs were dead on as stated at 110 lbs. I tend to go with the MFG because they usually know their stuff.


:)
 
Intercooler , thanks for the info. I'm wondering if you run into valve float @ high boost due to what I had concidered low spring pressure with a roller cam. I just did not know if crane had taken into account they were selling these springs for a boosted motor.

Hey Tim, I already know your answer.
 
Not here.....it just rocks:D


FWIW you may want to step it up a little and I wouldn't think it would hurt anything. I would change them every year though.
 
Originally posted by jamesmac
Intercooler , thanks for the info. I'm wondering if you run into valve float @ high boost due to what I had concidered low spring pressure with a roller cam. I just did not know if crane had taken into account they were selling these springs for a boosted motor.

Hey Tim, I already know your answer.
Click to expand...

-----------------------------------------------------------------------------------

my answer is. those are the springs Crane Cams recommends , those are the springs I got . no feed back needed :)
 
BTW.... I think you are focusing on the seat pressure and not open. Open pressure is the important one and it is much higher than a flat tappet. Some people problems with certain lifters RPM-ing over 6k. I can't even tell you what lifters I have other than Speed-Pro but they seem to be working great!
 
Those crane springs caused light popping after 6 months above 5000 rpm's. I switched over to K-Motion 750 springs (130lb seat pressure) As per some research done by Lonnie Diers . Do a search on this subject here and the GN/t-type archives and you will find alot on this. I use a crane billet roller. 214/210
 
I use the Comp 941 "Hi Tech" series with my 210/210 billet roller. 135lbs @ 1.750 installed with a 447lbs spring rate. Like the KMotions suggested, these should last a while.
 
My buddy went racing last night and switch from the soft PTE valve springs supplied with the original PTE Econo roller to K-Motion 750's. He has the Crane cam that you have because he was pissed off at PTE and didn't want to send them any more money for the replacment billet cam. I'm sure many of us remember that fiasco. He reused the parts from the econo kit including the valve springs. Now with just a valve spring change, he picked up mph. The shop he uses tested both springs an they said the original soft springs were LT1 springs.
 
Hey James , Crane cam card says #99838-12 are the right springs for that cam (#81HR00003) . I also have the "original invoice" from "Northern Auto Parts" for the springs . check out www.cranecams.com/springs/dual.htm for the specs as follows . I guess Crane must know the type of spring required for their cams .



Seat Pressure - 112 lbs @ 1.650

Open Pressure - 336 @ 1.100

Coil Bind - .950

Max Net Lift - .690

Rate (lbs./ins) - 438 lbs/in
Click to expand...

The cam card says 112 lbs at 1.650 but stock valve spring height is 1.700 and some builders set them up at 1.750. At 438 lbs/in, 0.050" is 21 lbs which would lower the seat pressure from 112 lbs to 91 lbs. Your machinist measured 100 lbs so most likely he has them set at 1.700" or maybe a tad less with some shims. You didn't give the valve lift but I'm sure it's under 0.550, and 1.650-0.550=1.100", still 0.150" away from binding which is a plenty safe margin. So why can't he just shim them up to 112 lbs without binding?
 
I'm running Comp #941's on my Comp billet 215°/210° roller. Pressure is 123# at my installed height of 1.775". So, at 0.517" lift, the open pressure calc's to be 362#. I think if I was to do it over, I'd have gone with the K-Motion springs, just on their reputation.
 
There is no point in calling the Comp tech line!!!:mad:

1: They don't know crap about our cars.

2: They don't know what springs to use with there own cams.

3: 90% of the time they give you wrong info just so they can get back to SB Chevy calls.

4: this all = bad cams for us, springs that float and last a year or so, or broken parts and more crap to deal with.

If you need good springs call Isky,Crane or Crower and tell them what you have.

OK I feel better now.:D
 
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