SB Chevy valve springs in Type 1 head?

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nbuscemi
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SB Chevy valve springs in Type 1 head?

Post by nbuscemi » Mon Apr 24, 2017 9:43 am

I know I can get High-Rev valve springs for a VW pretty cheap, but I have access to SB Chevy valve springs and was wondering if anyone has installed them on a VW Type 1 head. I tried searching for spring dimensions for either spring without any luck.

-Nick-

nbuscemi
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Re: SB Chevy valve springs in Type 1 head?

Post by nbuscemi » Sat Apr 29, 2017 9:48 pm

For what it's worth:

This afternoon I removed one of the valve springs off my 1600cc, measured and compared it to both a Small Block Chevy valve spring and one from a 5.7L LS1. To my surprise, both the SBC and LS1 springs fit the VW type 1 head. The GM springs will need to be used with their perspective retainer (SBC coils are a hair thicker than VWs and the LS1 springs are of a "bee hive" design). I plan to take all three springs (VW, SBC, and LS1) to work with me on Monday and measure the spring rates at an installed height of 1.50".

For future reference here are the dimensions for the stock VW Type 1 valve springs from a 043 Mexican head.
Uninstalled height: 2.08"
OD: 1.232"
ID: .931"
Coil thickness: .153"

Here are the dimensions for the SBC valve springs with the inner (flat) spring removed
Uninstalled height: 1.98"
OD: 1.235"
ID: .880"
Coil thickness: .175"

I'll measure the LS1 spring tomorrow and post it.

-Nick-

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Piledriver
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Re: SB Chevy valve springs in Type 1 head?

Post by Piledriver » Sat Apr 29, 2017 10:29 pm

AFAIK the typical aftermarket "vw" springs were originally for SBC.
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nbuscemi
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Re: SB Chevy valve springs in Type 1 head?

Post by nbuscemi » Wed May 03, 2017 11:53 am

So I took both a stock VW valve spring and a stock SB Chevy valve spring and measured the tension using a spring press. After seeing the results I'm not surprised why my 1600cc was falling on its face at 4K rpm and 3psi of boost. Here are the results:

Stock VW:
1.5" installed height = 70psi
1.2" at .300" valve lift = 115psi

Stock SB Chevy w/o inner dampener spring
1.5" installed height = 145psi
1.2" at .300 valve lift = 220psi
Coil bind at 1.125" compressed height.

Im going to try using the Chevy retainers using the VW valve keepers. This will increase the installed height by .100" or so giving me a slightly lower seat pressure but still much more than the stock spring. I'll post results after I do the swap.

-Nick-

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Piledriver
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Re: SB Chevy valve springs in Type 1 head?

Post by Piledriver » Wed May 03, 2017 12:57 pm

The factory keepers should be replaced with crmo.

Also, they typically need some grinding so they clamp properly.
(can only touch on one side)
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nbuscemi
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Re: SB Chevy valve springs in Type 1 head?

Post by nbuscemi » Sun May 07, 2017 6:12 pm

After a few VERY long hours in the garage I had my Chevy springs installed in my 1600cc. This biggest pain in the butt was getting the lash caps off of the valve stems without jacking anything up. I didn't like the way the Chevy retainers fit so I ended up reusing the VW retainers and keepers. I also reused the VW aluminum pushrods.

I took the car for a drive (along with my new AEM wideband AFR gauge) and did a few pulls and some tuning.
No more valve float. The valves need to be readjusted as I'm sure the lash caps are now fully seated.

So, for future reference... stock Chevy small block valves springs seem (for now) to work very well in a stock VW Type 1 head.

-Nick-

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Lo Cash John
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Re: SB Chevy valve springs in Type 1 head?

Post by Lo Cash John » Fri Jun 02, 2017 11:31 am

I don't think the stock VW aluminum pushrods are going to last long. You'll probably find them starting to bend or the steel tips will start driving themselves deeper into the ends of the aluminum tubing the pushrods are made from, thus shortening the rods.

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