Replace Valve Springs?
Thread Starter
Racer
Joined: Aug 2006
Posts: 330
Likes: 3
From: Wellington, New Zealand
Replace Valve Springs?
While replacing my valve stem seals a month ago I found that one of the damper springs was broken. This is a stock L48 with 115,000 miles on it, runs perfectly.
Should I replace all the valve springs and dampers with a stock rated set?
What are the stock pressures, seated and opening?
Would replacing the springs cause any added wear to the cam and lifters?
I was intending to do this with the heads in place.
Should I replace all the valve springs and dampers with a stock rated set?
What are the stock pressures, seated and opening?
Would replacing the springs cause any added wear to the cam and lifters?
I was intending to do this with the heads in place.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,172
From: Hermosa
I guess if it were mine I would probably just replace what is broken. That being said I would also take one more step and take a few springs off and get them tested to see if they still met the open and closed specs for the engine and to check the condition of some of the other dampners.
According to my manual for the 77 L-48 the spring pressure is;
75-84 lbs @ 1.70" intake and 1.61" exhaust.
194-206 lbs open which is @ 1.25" intake and 1.16" exhaust.
Hard part is taking the springs off. I can say using this style valve spring compressor is a real hassle, but I see you've already done this if you just replaced the valve sem seals;
http://www.summitracing.com/parts/otc-4573/overview/
After my last valve spring job I got this style instead and it is much better.
http://www.summitracing.com/parts/mor-62371/overview/
Although that price is a bit much. Shop around and you can do better.
According to my manual for the 77 L-48 the spring pressure is;
75-84 lbs @ 1.70" intake and 1.61" exhaust.
194-206 lbs open which is @ 1.25" intake and 1.16" exhaust.
Hard part is taking the springs off. I can say using this style valve spring compressor is a real hassle, but I see you've already done this if you just replaced the valve sem seals;
http://www.summitracing.com/parts/otc-4573/overview/
After my last valve spring job I got this style instead and it is much better.
http://www.summitracing.com/parts/mor-62371/overview/
Although that price is a bit much. Shop around and you can do better.
Thread Starter
Racer
Joined: Aug 2006
Posts: 330
Likes: 3
From: Wellington, New Zealand
Thanks for the replies, I think the original springs will be pretty tired, my thoughts were that while replacing the broken damper I might just as well replace all the springs and dampers. I have been looking at the Edelbrock 5802 springs, 80lbs seated 200lbs open.
My main concern was placing a bit more pressure on the cam and lifters might create problems.
My main concern was placing a bit more pressure on the cam and lifters might create problems.
Le Mans Master
Joined: Oct 2007
Posts: 7,474
Likes: 993
From: RI, Now Franklin/Nashville TN
I had a OEM valve spring break in the 80's on my L-82…Replaced that one spring and drove that valve train until Spring 2014 when I completely rebuild the motor with roller cam and AFR heads…FWIW
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
I have this tester:
http://www.cylinderheadsupply.com/kl1469.html
I used this calibration spring to calibrate the tester:
http://www.compperformancegroupstore...Category_Code=
I purchased these:
http://www.compperformancegroupstore...Category_Code=
They were off more than the allowable variance.
I called them up, had them grab a set off the shelf, had them measure them and those were also out of spec.
Other brands & manufacturers had the same issue.
No quality control anymore.
http://www.cylinderheadsupply.com/kl1469.html
I used this calibration spring to calibrate the tester:
http://www.compperformancegroupstore...Category_Code=
I purchased these:
http://www.compperformancegroupstore...Category_Code=
They were off more than the allowable variance.
I called them up, had them grab a set off the shelf, had them measure them and those were also out of spec.
Other brands & manufacturers had the same issue.
No quality control anymore.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,172
From: Hermosa
I found that you can get your springs tested at some machine shops and most engine shops.
The springs you are looking at sound good if those specs are accurate. For $30 I guess I'd replace them all too.
You can get a couple checked to see if they meet the advertised spec. I don't think 10lbs one way or the other is going to matter much on a stock L-48.
Too little pressure valve control could become an issue.
The springs you are looking at sound good if those specs are accurate. For $30 I guess I'd replace them all too.
You can get a couple checked to see if they meet the advertised spec. I don't think 10lbs one way or the other is going to matter much on a stock L-48.
Too little pressure valve control could become an issue.
Last edited by REELAV8R; Apr 3, 2015 at 11:28 AM.
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From: Millington Illinois
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Thanks for the replies, I think the original springs will be pretty tired, my thoughts were that while replacing the broken damper I might just as well replace all the springs and dampers. I have been looking at the Edelbrock 5802 springs, 80lbs seated 200lbs open.
My main concern was placing a bit more pressure on the cam and lifters might create problems.
My main concern was placing a bit more pressure on the cam and lifters might create problems.
Always replace all the springs. The stockers are 40 years old. have 115,000 miles on them and fatigued if one broke.
Thread Starter
Racer
Joined: Aug 2006
Posts: 330
Likes: 3
From: Wellington, New Zealand
Once again thanks for all the advice, it seems that replacing them all is the best thing to do.
I have been using a pretty cheap little compressor to do the stem seals but will upgrade this to one of the tools suggested and make my life a little easier.
I have been using a pretty cheap little compressor to do the stem seals but will upgrade this to one of the tools suggested and make my life a little easier.