I've been running a TR224 with 918 springs for about 2 1/2 years (16-20K miles) without issue. I was swapping cam/springs a couple of days ago and when I removed one of the springs, it came apart in my hand. Lucky me!

The spring fractured in the first coil from the retainer just past the flat part of the upper coil. The crack started on the top of the wire where it had been rubbing the top coil. Based on the surface appearance, it appears this spring was shot peened. Where the coils rubbed it had worn through the peened layer. That reduced the fatigue life of this spring.

TR recommended checking the springs at 20K miles at the time I bought them--so they were pretty close. This one had at most that many miles on it and probably a few thousand less. Something to consider when it comes time to check the springs. Another thought, I'm not sure I would have caught this if I hadn't actually removed the spring. A quick visual inspection indicated all was well. I would have had to actually spot the crack in the wire.

FYI - These were purchased after the problem period with the 918s.

 

same thing happend to me when i was swapping heads.. noticed i had a weird tick when i was driving around like 2500-3000 rpms with like 80% throttle.. took the heads off and noticed one of the retainers looked like it was slipping off the top of the spring.. it was definitly broken, and i was definitly lucky i didnt drive that car longer or else i could have been in some trouble. from now on ill spend the extra cash and get duals.. i highly recommend you doing that.. BTW i only had my springs for like 9k

 

I saw that 9K figure in your other post. That's worse than mine. Glad you caught it in time.

I put Patriot Golds in with the new cam. I'll be checking them every year from now on though.

 

same thing happend to me with the 918s. Half of mine broke at the retainers. We thought that maybe the retainers were too tight where they fit down in the spring. After that I used the stock retainers. Even then I didn't feel safe so now I have the Patriot Golds duals

 

man patriot golds look so nice.. i didnt even wana put on my heads

 

Sure do, They still look nice after 1500 miles. None broken unlike the the 918s.

 

The 918's are the best spring on the market for any cam in the .600 lifts.
There is nothing wrong with them quality wise.

Breakage is usualy related to the way they are installed, or driven.
ALL aftermarket springs need to reach warm temps before being driven.
Starting those in sub freezing weather and reving repeatedely,is not too good either.

Guys, these are racing springs and are brittle so they have to be treated right. I've run 918's in 4 different motors, 1 with .612 lifts and none ever broke.

Also, like oil changes, springs should be taken off the car once a year and tested/inspected. Otherwise you are being a "Lazy Modder"

 

I agree but there must of been something not right with mine. I let mine warm up fully before I go anyhwere and when my springs broke i haven't even hit 4krpms yet. They all installed at 1.800 so I don't know what the deal is. Dam,n, isn't 612 kinda risky with the 918? I like my duals because this way if one would break I still have another spring to hold the valve from saying hi to the piston.

 

your making me worried, lol.

I have a .598 lift cam(Its hyd. rolling so some lift will be "sucked")

 

They are good to .620 unshimmed and more if shimmed (which reduces life though).
It also depends on seat pressure cam requirements. Also the weight of the valve plays a role, but in general these are run on stock valves.

Also, there is the issue of proper valvetrain geometry and preload.
Or if you get valve float, your harmonics go out of whack, and that can kill those springs.

OOC, what retainers did you use originaly?

 

I hear you and yes was maybe lazy. But with the .563 lift, low miles and only driving this car on the street, I wasn't overly concerned (thought I had a much larger safety margin). I am aware of everything you mentioned above. This car isn't abused, hasn't even been raced and spends its life in a mild Seattle climate. It doesn't get much easier.

The problem I saw was the contact wear between coils where the crack initiated. I initially suspected that maybe I scratched or nicked the spring with a tool or something (I'm a metallurgist). Nope--right on top of the wire between the coils. Once it wears through the shot peened layer, fatigue life drops substantially. There's no getting around that. Based on what the others have said about the crack location, they likely experienced the same thing.

BTW, I was running the stock retainers whereas others mentioned Ti aftermarket retainers.

 

I ran 918's on my stock heads back in 02 when I put the TR224 in. Set them up at the correct installed height etc. They were not driven overly hard and always saw 165+ oil temps before WOT runs. I popped a few off at 4-5K miles and they had lost considerable spring pressure compared to new. I replaced them a month later when I got my heads with new Patriot Duals. My Gold's now have close to 15K on them and the most recent pressure test showed they had only lost a little pressure over new.

Search for my post as it shows alot of info I have forgotten about.

 

Plenty of blokes over here are using the Comp 918s on anything up to .600" - even in stock cammed cars.

I agree that they are a GOOD spring (even though I have them on a smallish cam (222/224@112 .566/.568) - as compared to the specs some of you people run).

Also, it is very important - Comp even tells you this - that you MUST have the car warm before you give it a big crack, or the valve springs are liable to breakage.

Cheers,

Macca

 

Agreed. Welcome to the board. We hear a lot about things going on down under but don't see too many on the board.

 

Think of it this way, just because you put a chicken into a 350* oven, in 5 minutes that doesn't mean the chicken is 350* inside of it.
Allowing initial warm up and as soon as seing 160* oil and hammering it doesn't mean the springs themselves have reached that temp.
So the morale is start car, let warm up a little then drive normally for a few minutes before you hammer.

 

CW00BlackTA, cheers mate and thanks. If you have the time check-out our LS1 and Holden forum.

www.ls1.com.au

There is PLENTY going on here in Oz - cams/strokers/turbo/twin turbo/superchargers and plenty more.

Macca

 

yep, I'm a member

 

I most certainly agree. I ran 918's in a LT1 car with a cam going over .605" int/exh, on a 224/224 degree cam, 110 LSA, pretty aggressive ramp. It worked fine. You just needed to let it warm up. I'd put them in my LS1 car, I dont expect lift to be above .580"

 

I understand what you mean but I and no one ever could figure why the springs had lost the pressure after only 5K miles. They were not abused in the least. Motor had ran 10 mins at minimum before WOT. It's not a situation of pulling out of the driveway and WOT to the next stop sign. I have an oil temp gauge to monitor. The only time WOT before 165* temps was after long waits in the staging lanes. All I can add is that my Duals under the same conditions have not lost much pressure over 15K interval.

 

FWIW putting 921's in w/ my G5-X2 cam. I recently popped out my '01 Z06 springs w/ 64k on them for a fresh set of '04 yellows.

My rule always was no WOT and nothing over 3000 rpms until the oil temp hits 150 on my DIC. Works for me.

BTW I run 3-5 HPDEs a year w/ this car and the stock springs did great... now w/ the 921's they'll probably be annual maintenance.