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MadMarv

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Discussion starter · #1 ·
I am sort of worried that my engine builder went too light on the springs. Can anyone tell me what they think? (or rather will they....)

Comp CR lift rule lobes 287/291 256/260 .643 112 LS 104.75ICL (this may sound dumb, but does ICL change the performance of the cam at all..? I never could quite grasp the concept of ICL).
here are the springs.. comp 933.. I think he said at 1.950 installed they are 175 seat 475 open .650 max lift.
Do you think I need more spring here? the valves start to turn a tiny bit in the retainer at 6300. I hit 6500 by mistake today when I floored it and the tires went up in smoke so fast it hit 6500 before I even knew it (rev limiter).

matt
 
#2 ·
Originally posted by MadMarv:
I am sort of worried that my engine builder went too light on the springs. Can anyone tell me what they think? (or rather will they....)

Comp CR lift rule lobes 287/291 256/260 .643 112 LS 104.75ICL (this may sound dumb, but does ICL change the performance of the cam at all..? I never could quite grasp the concept of ICL).
here are the springs.. comp 933.. I think he said at 1.950 installed they are 175 seat 475 open .650 max lift.
Do you think I need more spring here? the valves start to turn a tiny bit in the retainer at 6300. I hit 6500 by mistake today when I floored it and the tires went up in smoke so fast it hit 6500 before I even knew it (rev limiter).

matt
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Matt,

My feeling is they are too light.
I would prefer 225-250 on the seat & about 550 open minimum.

In my opinion one of the worst thing you can do to a billet roller is not run enough spring. It beats the crap out of the lifters if they don't follow the cam.
Another is idling a lot
 
Discussion starter · #3 ·
Wolfpace, do you think it would be out of the question for me to call him and express my concern? he said he wanted to go as light as possible because its a 3k miles a year street car with 4-8 trips to the track and 3-4 runs a trip.
Would you consider if reasonable if I paid for new springs and asked he install them for free? (I don't have the tools?)
AFAIK this was not an off the shelf roller and I don't want to to croak early. I think something like 220 on the steat and 525 sounds good to me, but I don't know. These numbers just seem really light. My hd. roller #'s werre not all that much different..

matt
 
#4 ·
Matt,

That is a very similar spring to what I use and I don't have any trouble.

I have been running an Isky mechanical street roller (248 @ .050, .602" lift) and the spring that Isky recommended was 185lbs.(@ 1.875") and 465lbs. open good to .650 net lift (PN# 9005). I have been running these springs for the last 3 years with no problem.

I recently had my cam reground (248/252 @ .050 / .602"/.646"), installed a set of Red Zone lifters and a fresh set of springs (same 9005 springs). I double checked with two people at Isky ( one was Ron Iskendarian) and they both told me the springs I have will work fine.

If you are running a true "street roller" IMO, I don't think you need quite as much spring pressure because the lobes are a little more gentle.
 
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#5 ·
Matt & Darren,

The CR lobes are not street lobes.
Most "street" profiles are gentler but I still prefer more spring.
I talk with Ron two or three times a week & have discussed this with him also.
The feeling is even though you tell people not to sit & idle with aggressive lobes most don't listen & then blame the cam or lifters when something fails.
Even with "street profiles I don't like to go below 180 / 500 lbs. on a billet.
about the lightest spring I would recommend is the 9265 for a street profile which is about 180 on the seat & 500 open
The only exception to all this would be a combination that the manufacturer has run on a spintron & has shown to be stable with less pressure.
This includes valves, retainers, rockers & pushrods etc. equivalent to your weights.
Then if the cam designer says to run less I would have no problem with it.
I almost always go with what they tell me,,, it's what they do ;)

Also, the only roller lifter I use is the Isky Red Zone, excellent choice
Image


Which we have pretty good pricing on BTW.

Just some of my thoughts on roller spring pressures.

Matt,
On your original post,,,
Yes, ICL will change how the cam responds.
In theory advancing it (smaller number) favors lower RPM & retarding it (larger number) favors higher RPM both at the expense of the other.
In practice I have found that most cams like 4-6 degrees advance for best power.
Before someone gets their shorts in a knot :D
I said "most cases"
 
#6 ·
Mike,

I was originally going to go with the 9265 spring but Ron told me that between the rpm's I am shifting at and the lobe profile of my cam (very gentle ramps for a roller)that the 9005 spring would work ok.

Maybe I should have gone with a little more spring, but after 3+ years it worked with no problems.
 
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#7 ·
Mike, would it be benificial (if spring pressure is a little on the lite side) with a roller to run a Rev-kit? What kind of spring pressure are rev-kits? Are they difficult to install?
 
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#8 ·
Originally posted by 71454Chevelle:
Mike, would it be benificial (if spring pressure is a little on the lite side) with a roller to run a Rev-kit? What kind of spring pressure are rev-kits? Are they difficult to install?
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It would help a little but the rev kit is more to keep the roller in contact with the cam so it doesn't skip or slide as bad as without it.
The only thing they put pressure on is the lifter.
The weight of parts on the cam side of the valve train are not really all that important compared to the valve side.
As a side not you never want to sacrifice weight for rigidity,, never!!

As an example, I just ordered a set of pushrods for an 18 deg 311" small block that are
.125 wall 7/16" double tapered :eek:

The springs vary & are about 30 lbs or so.
Much easier to put in when you install your heads but are no big deal afterwards.
You obviously need to remove your pushrods.
BTW, Isky does not make a rev kit for the rat but recommends the crane one & if you talk to Ron he will probably tell you that he recommends one.
Tell him I said Hi when you speak to him ;)
 
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Wolfplace
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