Broken Valve Spring- Suggestions?

Q

qwic87gn

Member

Joined

Jul 30, 2002

• Oct 21, 2016

• #1

Discovered that my dead cylinder was caused by a broken intake valve spring, so I'm turning to the experts for advice on a proper spring for my 218/212 cam. Cam card attached.
Heads are ported irons and Harland Sharp 1.65 rockers.

The whole build had around 4K miles on it when the K motion 750 spring let go. From what I've gathered searching the forum, this spring may not have been up to the task for this cam. Thoughts?

 

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T

TurboBuRick

Moderator

Staff member

Joined

Feb 18, 2006

• Oct 22, 2016

• #2

PAC 1201 or 1201x

 

Reggie West

Well-Known Member

TurboBuick.Com Supporter!

Joined

May 28, 2001

• Oct 22, 2016

• #3

Agreed. Im running that cam and springs. No problems with them.

You dont need a ton of seat pressure with that cam. 140 on the seat is fine.

 

Q

qwic87gn

Member

Joined

Jul 30, 2002

• Oct 22, 2016

• #4

The PAC 1201 seems to be very comparable to the k-motion springs that are on there now. Does it seem reasonable that the slightly higher seat pressure and coil bind would justify replacing all my springs with the PAC 1201?

I'm sorry for sounding ignorant on this subject. I appreciate the help on this guys!

 

T

turbofabricator

Well-Known Member

Joined

Mar 7, 2004

• Oct 22, 2016

• #5

I highly recommend replacing all the springs. Why did it fail? Bad heat treat? Defect in wire? Harmonics? Many different causes for a spring to fail. Not a lot of time or money to save your entire engine. If you were near me..........................., I would drink a Gatorade and watch you do it. LOL. (Turned 55 today. I'm tired of this stuff.)

 

Pronto

Believe nothing you hear and half of what you see.

Joined

Dec 9, 2002

• Oct 22, 2016

• #6

Happy birthday Ken!
Sage advice, replace them all...

 

1986 Buick GX1

GX1 #001 [The One and Only]

Joined

Apr 24, 2015

• Oct 22, 2016

• #7

Hardest part of changing valve springs is getting the valve covers off lol.
Just as well change them all with something else, not just putting another K-motion in there as you already DON'T trust them.

 

Q

qwic87gn

Member

Joined

Jul 30, 2002

• Oct 22, 2016

• #8

Thanks guys! One more question; can I just swap the PAC's in without new retainers and locks or do I need to replace them as well?

 

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TurboTdr3.8

Well-Known Member

Joined

Jan 15, 2013

• Oct 23, 2016

• #9

I use that same cam with pac 1201 but with 1.6 rockers on gn1 heads , I would make sure you have no spring bind on high lobe and 60 to 80 ths is what I would shoot for , I used the same retainers and locks that fit the K motion 750`s