How often should you change comp 918 valve springs
09-25-2010, 09:24 AM
#21
Thanks for all the replies guys! In my situation though I just picked up the car according to the previous owner the build has about 10k miles on it. Im sure I will have to change them at some point i was aiming for when the car hit 100k which means 31k on the springs it has. When I do end up doing it what would you suggest for a daily driver that seldom will see heavy rpm, only when a mustang has a death wish here and there, no drag strip no 5000 rpm between shifts just the occasional romp to prove its an LS1.
Thanks again
Thanks again
I ALWAYS recommend doing these things when buying a previous owned cammed or heads/cam car:
-Change the valve springs
-Change the oil
-In that order
Good luck.
09-25-2010, 11:00 AM
#22
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ok I will do that ASAP sadly part of the deal on getting the car was I am not allowed to mod it. Which I understand, I have another thirdgen racecar thats going to be the play toy. I just have to play the politics game with the person I got the loan to get the car with from. But trust me the oil will be changed the day I get it home and the springs asap. Ive done it on an LS1 before. It sucks, but can be done. Thanks Again to everyone
09-25-2010, 12:11 PM
#23
yup bought it last july with 11k mi for 12,500.
The "blue stripe" 918's were prone to breakage, but it was seldom. For peace of mind I'd switch over to the 1218 PAC's, or new revised Comp 918's rated to .625 lift.
The 918's from 02 were known to break. Maybe not on a stock cam profile, but they were known to break with aftermarket camshafts. I'd change them if it were me. The PAC's are cheap. They're $130 from Texas Speed So are you saying to change them if I ever go with a cam? Or change them even running the stock cam profile? Thanks!
*Op, sorry not trying to hijack your thread!
The "blue stripe" 918's were prone to breakage, but it was seldom. For peace of mind I'd switch over to the 1218 PAC's, or new revised Comp 918's rated to .625 lift.
The 918's from 02 were known to break. Maybe not on a stock cam profile, but they were known to break with aftermarket camshafts. I'd change them if it were me. The PAC's are cheap. They're $130 from Texas Speed
*Op, sorry not trying to hijack your thread!
09-25-2010, 12:49 PM
#24
When i had my car tuned, i didnt have any signs of float, but no more than a month and a couple hundred miles later, i lost a spring and measured the pressures (in my previous post) so you wont necasarily see it.
+100
Ive had all sorts of issues with my current car due to the previous owner.
IMHO, its not that you HAVE to replace them every 20k, but ATLEAST pull a few springs, and have them checked for pressure. If they deviate noticably from advertised pressures, replace them. 150-500 for springs (depending on what you buy) is a whole lot cheaper than the 4k im droppin on a motor now.
First thing you do when you buy an already internally modded car.......Assume the previous isn't telling the truth about anything. Cause unfortunately, most of the time they're not telling you a 100% accurate truth. People will bullshit their way into selling a car they don't want anymore, even if it means shaving off a few thousand miles on the internal parts.
I ALWAYS recommend doing these things when buying a previous owned cammed or heads/cam car:
-Change the valve springs
-Change the oil
-In that order
Good luck.
I ALWAYS recommend doing these things when buying a previous owned cammed or heads/cam car:
-Change the valve springs
-Change the oil
-In that order
Good luck.
Ive had all sorts of issues with my current car due to the previous owner.
IMHO, its not that you HAVE to replace them every 20k, but ATLEAST pull a few springs, and have them checked for pressure. If they deviate noticably from advertised pressures, replace them. 150-500 for springs (depending on what you buy) is a whole lot cheaper than the 4k im droppin on a motor now.
09-25-2010, 01:38 PM
#25
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yeah I agree with you its a whole lot cheaper, at this point I just have to figure out how to explain that to a person that has never had a performance vehicle ever and expects to hop into a car and it run to 500k miles with nothing but oil changes. but Ill figure it out. I may have to run what I have for a little while but its definitely something I'm planning on regularly checking and changing. What is the method by the way to checking springs? to I need to take them to my local machine shop or is there a simpler method? thanks guys, btw hijack all you want its still information beneficial to me
09-25-2010, 07:37 PM
#28
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just bought my second set of pac 1518's today...around 200 bucks shipped from scoggins dickey...
i am seeing a marked decrease in mph at the track lately and the current set of pac's have near 30,000 miles on them...
as much as i dislike those comp 918 springs i did get near 22,000 miles out of them before 4 of them on the intake side failed...
maybe the N2O was freeze drying them out some along with 7000 rpm's...lol...
i am seeing a marked decrease in mph at the track lately and the current set of pac's have near 30,000 miles on them...
as much as i dislike those comp 918 springs i did get near 22,000 miles out of them before 4 of them on the intake side failed...
maybe the N2O was freeze drying them out some along with 7000 rpm's...lol...
09-25-2010, 10:51 PM
#29
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Ive been looking at the double springs from prc off of texas speed for 379$ anyone else have a better idea for me? You guys seem to be sold on double springs and that would give me a little extra breathing room on the lift numbers. Its a little higher than I really want to pay since its the daily driver that im not supposed to be putting money in but that seems to be the best bang for the buck, not to mention ive installed those on my buddies 233/239 cammed WS6.
Thanks
Thanks
09-25-2010, 11:05 PM
#31
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Oh trust me I know that, I promise I do. Its just convincing the family members that don't understand that I'm not upgrading just maintaining. I love working on cars and I'm sure Ill love this one I just have to walk the tightrope with my grandfather. He thinks everything should run forever with zero maintainence.
09-25-2010, 11:14 PM
#34
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well....i know that...i guess i just don't want to let him down. He wants the thing to be bullet proof, and it is. Ill probably just pick up the springs and just do it at my buddies shop and he doesn't have to know. Im sure its nowhere near as big of a deal as Im making it but like I said I just dont want to let him down
Thanks again
Thanks again
09-26-2010, 07:15 AM
#35
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http://sdparts.com/details/pac-1518
09-26-2010, 07:29 AM
#36
Double springs are overkill with that cam. Grab a set of Pac 1518s.
http://sdparts.com/details/pac-1518
http://sdparts.com/details/pac-1518
double springs are never overkill....drop a valve once and you wont think double springs are overkill
and double vs single has nothing to do with what cam you are using...
double springs control the valve better than a single, which means you can rev higher without valve float. granted if your mods don't support spinning up past 6k, then there's no point to spinning to 7500...but that doesn't mean you don't need double springs.
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09-26-2010, 08:09 AM
#37
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double springs are never overkill....drop a valve once and you wont think double springs are overkill
and double vs single has nothing to do with what cam you are using...
double springs control the valve better than a single, which means you can rev higher without valve float. granted if your mods don't support spinning up past 6k, then there's no point to spinning to 7500...but that doesn't mean you don't need double springs.
and double vs single has nothing to do with what cam you are using...
double springs control the valve better than a single, which means you can rev higher without valve float. granted if your mods don't support spinning up past 6k, then there's no point to spinning to 7500...but that doesn't mean you don't need double springs.
09-26-2010, 11:04 AM
#38
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I really have no intention to get past six grand. I know doubles are better than singles. thats just given, two vs. one. But I am curious if I need them or not. Im going to look into these pac springs and compare them. Thanks for the opinions
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09-26-2010, 11:08 AM
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can i reuse the pushrods if I use pac 1518's($249.99). Im not sure yet if he put hardened pushrods in it. I would assume so, but if he didnt can i use the stockers on pac's or should I just get the TSP PRC .650 lift double kit with springs seats retainers seals and hardened pushrods(379.99)?