Dodge Challenger Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
1,026 Posts
Discussion Starter #1 (Edited)
Lesson Learned: If you have 15,000 or so hard miles on your 6.1, you might have sacked out valve springs.

The Liability: A sacked spring can break under high revs; the more likely scenario is that the valves will float. Pretty easy to have a valve float in the open position. If the valve contacts a piston, you'll be getting a new motor under warranty or building that stroker you always wanted.

The Fix: Upgraded valve springs. Upgraded springs are about $200, and you'll spend another $300 or so for install or an afternoon doing it yourself if you're pretty handy at these things, and have the shop and tools for it.

My Story: Have about 16,000 hard miles on my SRT8. I redline the car probably 2 to 5 times every time I get into it, and have done so since I broke it in two years ago. Have run a few road track sessions on it as well.

I'm having an SRTMax cam installed in my 6.1 as I write this. The baseline dyno was surprisingly weak, and the engine has felt less than sharp on the top end for some months now.

When the hotter cam was installed, you can see valve float from the mid range through the top end of the revs on the dyno chart. The dyno graph looks choppy in these scenarios. New valve springs installed (you don't have to pull the heads but it's still a fair amount of work at a specialty shop), and voila, better breathing, smoother dyno graph lines, more mid range and max power on the same tune.

Bottom Line: Consider upgrading your valve springs if you have 10K or more miles on your 6.1- if you run your car hard. It may not be an issue if you don't hammer the car every time you get into it.

I don't wish to start a flaming thread on warranty work, or "a car this expensive shouldn't do that". My view is this car was meant to be run hard. That's an expensive hobby and besides- $500 isn't an costly mod on this car, IMO. Your engine will breathe better- and more importantly- you're less likely to punch a valve through a piston.

Hope this helpful!
 

·
Administrator
Joined
·
17,155 Posts
Along with the upgraded springs, I would recommend titanium retainers.
 

·
Registered
Joined
·
448 Posts
What valve springs did you put in? This is one of my future mods (having already had a valve spring break, I don't want to hear about it later).
 

·
Registered
Joined
·
1,026 Posts
Discussion Starter #5
My original post isn't about broken springs; it's about valve float.

A floating valve can sure as heck bust a piston, regardless of the retainer, or whether the spring breaks or not.

The point of my thread is that if you run your 6.1 hard for 10K or so miles, you might have sacked (less resilience and shorter) springs.

It's cost effective to take a look at them after some miles. We've definitely had some folks on this forum who've broken springs, rocker arms, and pistons.
 

·
Registered
Joined
·
126 Posts
I totally agree with this post. Definitely a good idea. Cheap mod for good ease of mind.( First hand experience )
 

·
Registered
Joined
·
1,026 Posts
Discussion Starter #8
Thanks Sam.

Right on Clinton- where in Canada are you from? While I live in Texas, I was born in Calgary.
 

·
Super Moderator
09 RT Challenger auto
Joined
·
3,467 Posts
Internetguy, I think you spot on. Myself also EVERY time I get into the car I put a few hard pull on it.
On you dyno chart, can you post it ? I got to see how yours is/was choppy as you say. My dyno pull was choppy on the chart after I put the SC on, made 491whp, before I had a tune. Have not been back to the drums for another pull since.
Id like to compare the chop.
FT

PS. Seems my challenger clocks more miles than I realize. Odometer rolls faster than any other car Iv owned, Go figure.
 

·
Premium Member
Joined
·
5,634 Posts
Internet Guy good info. I am kinda surprised a stock set of springs would be so poor after 15K miles with a stock camshaft?
 

·
Registered
Joined
·
1,026 Posts
Discussion Starter #12
Flat top- we didn't print the dyno sheet where we saw the saw toothing on the graph. Begins mid range and gets worse with rpm. In retrospect I should have kept the graph to show you guys, but it was undeniable on the graph.

After the springs- voila, nice smooth curves like you normally see. Noticeable increase in mid range and top end power. Same tune.

Buckwheat- agreed with you my friend. I was as surprised as anyone, hence the post. I've run it pretty hard, but would have guessed easily twice this longevity from the valve springs. Interesting that the sawtoothing didn't show up on the baseline pull (stock cam and the usual other mods). It was unmistakable with the SRTMax cam though which isn't that wild of a cam; 218/222, 114LSA. I believe the lift is pretty close to .050. You can use stock springs with it.

I'm considering it a bit of luck and gave thanks to the great techs at SNL performance in Ft. Worth (Haslet) who noticed it. Would have been a bummer to grenade the engine because weak valve springs.

Live and learn!
 

·
Registered
Joined
·
448 Posts
Thanks Internetguy! I was born 3 hours north of you lol The Canadian invasion is a great thing!

Thanks for the link on the springs, I've been debating between a set of arrington ported heads, or just building up the stock heads. This might be the right answer.
 

·
Registered
Joined
·
180 Posts
Last month my local Performance shop told me If I was going to pull the heads off for any work, I should consider replacing the springs, for the same reasons. They also told me I was better off having a shop do the work because the spring tool required is worth more than the parts. Other than the springs, he said the rest of the motor was strong and could stand up to a lot of mods, and hard driving.
 

·
Registered
Joined
·
533 Posts
Last month my local Performance shop told me If I was going to pull the heads off for any work, I should consider replacing the springs, for the same reasons. They also told me I was better off having a shop do the work because the spring tool required is worth more than the parts. Other than the springs, he said the rest of the motor was strong and could stand up to a lot of mods, and hard driving.
Well, if they're doing other work, have them do the springs. Otherwise, Sears sells a simple spring compressor for around $15. Two claws with a turn handles at the top. It works on most single spring setups, and sometimes double springs. It's a time consuming job, maybe 1.5-2 hours to do all 16 springs, but not too bad. Easiest time to do it is when the heads are off, so you'll same money doing it yourself.

If you're inventive, you can make your own spring compressor, like I did. On my DragCad race car, I have double springs so a lever-style compressor works best. So I made one out of steel stock, a bolt the same threads as the
rocker mount bolts, and well placed drilled holes. Make a hole at the very end of the steel bar and use the bolt though it in the rocker mount holes to create your fulcrum, then make another hole in the bar where your valve and keepers can fit through, then use the bar to compress the spring around the valve. Simple and effective. Plus you can make it any length you need for various engines. No one makes a specific one for Cadillacs. ;)
 

·
Registered
Joined
·
533 Posts
Harpslinger- sorry I didn't respond sooner- we installed Ferrea aftermarket valve springs.

Good overview here: Ferrea Beehive Valve Springs Chrysler Hemi 5.7L 6.1L - eBay (item 170603973177 end time Mar-17-11 12:14:03 PDT)
Thanks for posting this link. The ad says no retainers included, however. I don't imagine the stock retainers will work with beehive style springs, will they? What retainers would you recommend? Does Ferrea offer matching retainers? Thanks again.
 

·
Super Moderator
09 RT Challenger auto
Joined
·
3,467 Posts
I know that choppy look, up the curve. The dyno operator said somthings not right and mentioned it. I figured it was in the tune. And I wouldnt let him touch my tune. Just watched a GTO get 610rwhp and go boom !
So at this point my assumption may be right. I will hit the drums wed. Since tuning has been done on mine, this will tell me alot if its still choppy.
I was just getting ready to change my springs anyway. I cant even count how many passes my car has put down. Yesterday alone at track was 7 runs. And 5 runs before I trailored it to go. Gotta be hard on the springs. Back door got me 116.9mph all day long. ET cant say yet. Its down there. I will stay in the low 12s position. For Now !
FlatTop
 

·
Registered
Joined
·
3,532 Posts
Anyone who races or runs their car hard should know about valve float and how it can kill valve springs. It's common knowledge. Stock motors don't use race valve springs to keep the pressures down and hp up. If you're going to hit redline alot, u should upgrade stuff like that.
 

·
Registered
Joined
·
1,207 Posts
How difficult is an in-frame spring swap?

I wonder if the old "cotton rope pushed through the spark plug hole trick" would work.

I'm at ~27,000 miles and the motor sees a lot above 5 grand.
 
1 - 20 of 27 Posts
Top