69 L71 Valve Spring / Retainer Recommendation

**Joe L.** · October 11, 2016, 08:49 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Originally posted by Chris Hewitt (33863)

I'd like to change out the original springs. I understand that the Sealed Power VS 708 is identical to the GM service replacement spring, but the original retainer which is for a single spring design, wont work with the 708 as its a dual spring design.

I'm more than happy going with a single spring design if it means I can reuse the original retainers. Or go with the 708 if I can get a suitable retainer for the dual spring design.

Is there a 708 retainer out there? If not, what do folks recommend for a single spring replacement?

Thanks, Chris

Chris------

You've got a predicament here (as do others with 65-69 big blocks wanting to replace valve springs). Here's the deal:

First of all, if your engine still has its original valve springs, you're living a charmed life. The original springs, GM #3859911, were highly prone to breaking. I broke several myself "back in the day". I was lucky, though, as I never dropped a valve. Do that and a broken valve spring can get VERY expensive. So, you're wise to replace the valve springs now. If I bought a car with a big block originally and still using the 3859911 springs, the VERY first thing I'd do is change them. But changing them can be a problem. Here's why:

You have 3 options:

1) Use your existing retainers and find an aftermarket valve spring that matches the specs of the original 3859911. I don't know of any but there may be something out there. The Sealed Power VS-657 might come close (or, at least as close as you're going to get). Use these in conjunction with standard big block umbrella valve seals and your existing valve caps.

2) Use the Sealed Power VS-708 springs. These are IDENTICAL to the valve springs once included as part of the GM #3970627 spring kit. While I am one that generally believes that OEM parts are different than aftermarket, these springs are a rare exception. I have examined these CAREFULLY and I'm convinced they're the same and probably come from the same manufacturing source (which my guess is NOT Federal-Mogul). Here's the problem: The VS-708 valve springs must be used with the GM #3964264 valve cap (retainer). Federal-Mogul does not now nor ever has had available a replacement for this valve cap. In fact, they advise that the GM #3964264 valve cap must be used with these springs. The problem is that the 3964264 valve cap is GM-discontinued and hard to find. This valve cap contains an integral umbrella seal designed to fit within the inner spring AND the cap is designed so that it also centers the inner spring. The GM #3970627/VS-708 valve spring is the absolute best valve spring ever conceived for a street big block. Period.

3) You could probably use the VS-708 valve springs without the 3964264 valve cap IF you do the following:

a) find a valve cap configured to center the inner spring of the VS-708 and of the proper thickness and OD. I don't know of any but there may be something out there, and;

b) machine the valve guides for installation of an aftermarket positive type seal for which the OD will fit comfortably within the ID of the inner spring.

**Chris H.** · October 12, 2016, 04:30 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Thanks Joe. I'm leaning in the direction of the Crane Cam valve spring PN 99839-16 with matching retainer PN 99948-16. And I'd go with umbrella seal Fel Pro SS 71152. This way I know the spring is compatible with the retainer. Comments? Thanks, Chris

**Joe L.** · October 12, 2016, 07:56 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Originally posted by Chris Hewitt (33863)

Thanks Joe. I'm leaning in the direction of the Crane Cam valve spring PN 99839-16 with matching retainer PN 99948-16. And I'd go with umbrella seal Fel Pro SS 71152. This way I know the spring is compatible with the retainer. Comments? Thanks, Chris

Chris------

The Crane springs have somewhat greater valve closed pressure than the original springs. However, I think they'd be OK. It's better to use springs and retainers that you know are compatible than to "mix-and-match" indiscriminately.

**Patrick B.** · October 13, 2016, 07:26 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Chris -- I think there may be a good solution that will enable you to have a springs and caps essentially identical to the GM 3970627 springs package. My first photo is of the 627 springs. The thing to note is the step that the inner spring sits on in photo 2. The next picture are 4 types of valve spring caps in my collection. I think they are all GM caps. On the left is the 627 cap with the nylon umbrella seal, and on the right is the ZL-1/L-88 cap that has a smaller nylon piece pressed in. What is interesting is the other caps I have that came off ordinary Mark IV big blocks which I think had the bad single springs with damper. One is essentially identical to the cap with the 627 spring (but lacking the nylon umbrella), and the other is essentially identical to the ZL-1 spring cap without the nylon insert. The ZL-1 type cap is a little thinner and lighter than the 627 type cap. The next picture is the two regular caps with a nylon umbrella from a 627 cap. The interesting thing in the last picture is that the nylon umbrella would press into either on the regular caps making it the same as a 627 cap. The good news is that you can buy nylon umbrella seals that appear to be identical to those in the GM 627 caps under Fel-Pro part number SS72513.

I think the regular caps in my photos are from 68 and 69 engines. I threw away all the 65-66 caps and single springs I had because they are liable to break as Joe said. (I believe this is part of the reason so many real big block Corvettes are lacking their original blocks.) I don't know if the earlier caps can be converted, but I think Chris' 69 caps are probably like one of the styles in my photo and will accept the SS72513 nylon umbrellas and fit the VS 708 springs. Using these parts, I think big block owners can duplicate the extinct GM 3970627 springs and caps without resorting to heavier springs from cam companies and seals that may require machining the valve guides.

Attached Files

**Chris H.** · October 13, 2016, 08:04 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Thanks Patrick, very interesting. My original caps (retainers) have only a single step for a single, not double coil spring. The challenge with trying to use the VS708 dual-spring is finding a retainer for it. I believe all the dual-spring retainers in your photos are no longer available (Joe can confirm). Its the retainer challenge that is pushing me towards the Crane Cam single spring / matching retainer kit solution.

**Patrick B.** · October 13, 2016, 08:57 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Chris ---- Are you sure? Do you have any pictures of your caps? I think the stepped caps I have came off engines with single springs.

**Joe L.** · October 14, 2016, 11:52 AM

Re: 69 L71 Valve Spring / Retainer Recommendation

Originally posted by Patrick Boyd (9110)

Chris -- I think there may be a good solution that will enable you to have a springs and caps essentially identical to the GM 3970627 springs package. My first photo is of the 627 springs. The thing to note is the step that the inner spring sits on in photo 2. The next picture are 4 types of valve spring caps in my collection. I think they are all GM caps. On the left is the 627 cap with the nylon umbrella seal, and on the right is the ZL-1/L-88 cap that has a smaller nylon piece pressed in. What is interesting is the other caps I have that came off ordinary Mark IV big blocks which I think had the bad single springs with damper. One is essentially identical to the cap with the 627 spring (but lacking the nylon umbrella), and the other is essentially identical to the ZL-1 spring cap without the nylon insert. The ZL-1 type cap is a little thinner and lighter than the 627 type cap. The next picture is the two regular caps with a nylon umbrella from a 627 cap. The interesting thing in the last picture is that the nylon umbrella would press into either on the regular caps making it the same as a 627 cap. The good news is that you can buy nylon umbrella seals that appear to be identical to those in the GM 627 caps under Fel-Pro part number SS72513.

I think the regular caps in my photos are from 68 and 69 engines. I threw away all the 65-66 caps and single springs I had because they are liable to break as Joe said. (I believe this is part of the reason so many real big block Corvettes are lacking their original blocks.) I don't know if the earlier caps can be converted, but I think Chris' 69 caps are probably like one of the styles in my photo and will accept the SS72513 nylon umbrellas and fit the VS 708 springs. Using these parts, I think big block owners can duplicate the extinct GM 3970627 springs and caps without resorting to heavier springs from cam companies and seals that may require machining the valve guides.

Patrick------

I have many NOS examples of, with the exception of one (as of yet), every valve cap (retainer) used on every 1965-74 Corvette big block. I tried to install the Fel-Pro SS72513 umbrella shields on a couple of them and I could not get what was, in my opinion, a satisfactory installation. I'll try again after I get home from the trip I'm currently on.

**Joe L.** · October 14, 2016, 11:57 AM

Re: 69 L71 Valve Spring / Retainer Recommendation

Originally posted by Chris Hewitt (33863)

Thanks Patrick, very interesting. My original caps (retainers) have only a single step for a single, not double coil spring. The challenge with trying to use the VS708 dual-spring is finding a retainer for it. I believe all the dual-spring retainers in your photos are no longer available (Joe can confirm). Its the retainer challenge that is pushing me towards the Crane Cam single spring / matching retainer kit solution.

Chris------

The single step is how I recollect it, too. As I mentioned in a previous post, I'll check the many NOS valve caps I have when I get home in a week but, as I recall, none had the double step of the GM #3964264. One or more of them might still be available from GM, though. I'll have to check when I get home.

**Richard F.** · October 14, 2016, 11:57 AM

Re: 69 L71 Valve Spring / Retainer Recommendation

I monkeyed around a lot until I decided to bite the bullet and have the aluminum heads machined for PC seals. that was mid-80's. So far no drama.

**Joe L.** · October 14, 2016, 12:06 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Originally posted by Richard Flanagan (9850)

I monkeyed around a lot until I decided to bite the bullet and have the aluminum heads machined for PC seals. that was mid-80's. So far no drama.

Richard------

At that time you could have still gotten the GM #3970627 spring kits which included the spring and valve cap with seal. As I mentioned, I think this is the best set-up for a big block ever conceived. The PC seals will work fine, though. However, they can have the effect of rendering the valve stems too "oil-dry" for a street engine.

By the way, I've never liked the L-88/ZL-1 spring set-up (dual springs with damper). I do not consider the requisite valve cap with "mini-seal" to be effective enough for a street engine. Of course, the L-88 and ZL-1 were never intended to be street engines regardless of how some folks might have used them.

**Chris H.** · October 14, 2016, 03:39 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Patrick, yes unfortunately I'm sure the retainers have only 1 step. That's why I came onto the board to hopefully get some insight. I will post some pictures next week when I get into the job. Thanks.

**Richard F.** · October 14, 2016, 05:36 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Joe, I used the 627's. I had the retainers with the umbrellas. I just didn't like the concept of them. Don't remember if I used the retainers without the umbrellas, or some other type. In any case, 30 years later I am still happy.

**Patrick B.** · October 14, 2016, 06:11 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Chris-- I think the nylon umbrella seals will fit any cap with a 3/8" valve stem diameter and regular valve locks ( which I think are 7 degrees). The aftermarket caps for a double spring sold by Comp Cams and others look very much like the GM caps and are very cheap. I think they could be used with the Fel-Pro umbrellas and allow you to use the Sealed Power springs. I inserted a 1/4" drive socket into the umbrella and pressed it into the cap by hand.

I think it is very important to use the stock equivalent valve springs to break in stock type flat tappet cams.

**Mark E.** · October 14, 2016, 09:03 PM

Re: 69 L71 Valve Spring / Retainer Recommendation

Chris,

What's your motivation for replacing valve springs? Your signature says the '69 L71 has 14k miles, so the engine presumably has little wear.

Did something break? Or are you heeding Joe's warning the original springs are prone to breaking and dropping valves?

Is "do nothing" an option?