People running 918's w just over .600
10-20-2006, 10:39 AM
#1
People running 918's w just over .600 How many people are using 918's with cams over 600 lift.
I have a 233/239 595 603 and have been inconclusive on using it because I wonder if the springs will hold it at upper rpms. being as its only .003 over 600 and the exhaust valve is smaller and weighs less than the Intake. I think it will be alright I plan on advancing it 4 degrees advanced and keeping the rpms below 6300-6500 if that.
My engine is a 6.0 LQ4 ,243 heads, LS6 intake, 1 3/4 long tubes, A4 2800 convertor 3:73's and the vehicle is 3100 lbs w/ driver. It will be used 10k miles a year.
these are also the blue stripe 918's they are
130 lbs at the seat 1.800
318 lbs at 1.200
1.14 coil bind.
Any comments or thoughts on this subject would be apreciated.
BTW I have searched and came across a LOT of really old post with the older defective 918's and actually was more confused.
I have a 233/239 595 603 and have been inconclusive on using it because I wonder if the springs will hold it at upper rpms. being as its only .003 over 600 and the exhaust valve is smaller and weighs less than the Intake. I think it will be alright I plan on advancing it 4 degrees advanced and keeping the rpms below 6300-6500 if that.
My engine is a 6.0 LQ4 ,243 heads, LS6 intake, 1 3/4 long tubes, A4 2800 convertor 3:73's and the vehicle is 3100 lbs w/ driver. It will be used 10k miles a year.
these are also the blue stripe 918's they are
130 lbs at the seat 1.800
318 lbs at 1.200
1.14 coil bind.
Any comments or thoughts on this subject would be apreciated.
BTW I have searched and came across a LOT of really old post with the older defective 918's and actually was more confused.
10-20-2006, 10:49 AM
#2
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You'll be just fine. I was told that even though they're rated to .600 lift that they handle more than that, and as close as you are, I wouldn't even be concerned about it.
Do you have the springs already, or are you trying to decide which ones to get?
Do you have the springs already, or are you trying to decide which ones to get?
10-20-2006, 12:07 PM
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Originally Posted by dnm12
i will have to throw a shout out to PRC dual springs, which have seen 7000 grand during tuning with no problems
10-20-2006, 03:36 PM
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just a related question (I think) 
now I`m planning to go the same way Beehive comp 918 (using stock retainers and lucks means saving money right?) my reasons are and I need correction as this is the idea that I have from reading and not sure:
1-they are more durable than double springs (more springs life milage with the same cam) <===a cam with 580-600 lift with the double springs being rated to 650 lift
2-they will make a little more power from the reduced valvetrain weight)
3-power band should be the same since the steel retainers beehive are almost the same weight of the titanium retainers on the double springs. (this might be only true to bbc changed over to beehive)
now I`m planning to go the same way Beehive comp 918 (using stock retainers and lucks means saving money right?) my reasons are and I need correction as this is the idea that I have from reading and not sure:
1-they are more durable than double springs (more springs life milage with the same cam) <===a cam with 580-600 lift with the double springs being rated to 650 lift
2-they will make a little more power from the reduced valvetrain weight)
3-power band should be the same since the steel retainers beehive are almost the same weight of the titanium retainers on the double springs. (this might be only true to bbc changed over to beehive)
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10-20-2006, 06:32 PM
#8
Originally Posted by monicaz28
You'll be just fine. I was told that even though they're rated to .600 lift that they handle more than that, and as close as you are, I wouldn't even be concerned about it.
Do you have the springs already, or are you trying to decide which ones to get?
Do you have the springs already, or are you trying to decide which ones to get?
I wonder if the most Possible failure with 918's and this type cam are valve float or spring breakage.
If valve float was the problem, I would figure the PSV clearances more closely and keep the rpm's reasonable (the plan). If breakage was the prob I'd just get a smaller cam.
10-20-2006, 08:03 PM
#11
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918's here on the MS3 cam (603/609) mine revs to 7K shifts at 6800 but I havae hit the rev limiter a handful of times when the car spun to hard but yeah about 10K miles on them so far and no problems at all. (Stock retainers too) As long as you let the spring heat up all the way before exposing it to abuse you shouldnt ever have nay problems. A lot of people dont understand springs like that are more brittle before there as hot as they are when the engine has reached full operating temp. This info has been verified by Comp Cams to.