Shim ? For Setting Valve Spring Height
10-01-2016, 02:05 PM
#16
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The spring base or seat is hardened steel. The adjusting shims are made of mild/rolled steel, not hardened. The shims are placed between the spring base and the cylinder head (bottom of lifter bore).
Chris, you do not need to use the factory shims. I have plenty of shims in many different sizes to be used when installing valve springs in many different types of cylinder heads when performing a porting job. I also make my own shims when anything else do not fit.
For the 928 32v I had a look at the Goodson shims and I find the 107 shims to be a perfect fit. They come in 1.5mm, 0.75mm and 0.4mm thickness.
Åke
Chris, you do not need to use the factory shims. I have plenty of shims in many different sizes to be used when installing valve springs in many different types of cylinder heads when performing a porting job. I also make my own shims when anything else do not fit.
For the 928 32v I had a look at the Goodson shims and I find the 107 shims to be a perfect fit. They come in 1.5mm, 0.75mm and 0.4mm thickness.
Åke
Last edited by Strosek Ultra; 10-03-2016 at 12:20 PM.
10-03-2016, 10:08 AM
#18
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Thread Starter
The spring base or seat is hardened steel. The adjusting shims is made of mild/rolled steel, not hardened. The shims are placed between the spring base and the cylinder head (bottom of lifter bore).
Chris, you do not need to use the factory shims. I have plenty of shims in many different sizes to be used when installing valve springs in many different types of cylinder heads when performing a porting job. I also make my own shims when anything else do not fit.
For the 928 32v I had a look at the Goodson shims and I find the 107 shims to be a perfect fit. They come in 1.5mm, 0.75mm and 0.4mm thickness.
Åke
Chris, you do not need to use the factory shims. I have plenty of shims in many different sizes to be used when installing valve springs in many different types of cylinder heads when performing a porting job. I also make my own shims when anything else do not fit.
For the 928 32v I had a look at the Goodson shims and I find the 107 shims to be a perfect fit. They come in 1.5mm, 0.75mm and 0.4mm thickness.
Åke
Somewhat on topic, I find it strange that there isn't crap for info on cylinder heads, installing/shimming valves and springs, etc... on the 928 board. All the searches I have done come back with mostly 944 stuff, not 928 (yeah I know it's mostly the same, but still....) I guess everyone just sends them to Greg and forgets about them. LOL.
Last edited by Chris Lockhart; 10-03-2016 at 10:14 AM. Reason: Add info.
10-05-2016, 02:37 PM
#21
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I thought it was 50 shims as well, but it turned out to be 100 for $20.00. I was very pleased. Plus the fit was great, and it's going to give me lots more flexibility on setting the spring heights closer to the same rather than one at the low end and another at the high end, etc.... Thanks for your help and guidance Ake. 
10-06-2016, 04:54 AM
#22
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Chris, I am sure you are aware of that valve springs set to the correct height in one engine do not show the same pressure. There are always some tolerances. Racers do not set the spring pressure by installed height, they check each individual valve spring using a spring pressure tester. For the 928 32v engine, if you add or remove a 0.5mm shim, the spring pressure will change by appr. 2.4kp or 5.3lbs which probably is less than the difference between the softest and hardest spring in one engine. According to my measurement the 928 32v stock valve spring pressure is seated 35kp (77lbs) and open 78kp (172lbs).
http://www.kenlowe.com.au/How_to_Val..._Procedure.htm
Åke
http://www.kenlowe.com.au/How_to_Val..._Procedure.htm
Åke
10-06-2016, 08:24 AM
#23
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Thread Starter
Chris, I am sure you are aware of that valve springs set to the correct height in one engine do not show the same pressure. There are always some tolerances. Racers do not set the spring pressure by installed height, they check each individual valve spring using a spring pressure tester. For the 928 32v engine, if you add or remove a 0.5mm shim, the spring pressure will change by appr. 2.4kp or 5.3lbs which probably is less than the difference between the softest and hardest spring in one engine. According to my measurement the 928 32v stock valve spring pressure is seated 35kp (77lbs) and open 78kp (172lbs).
http://www.kenlowe.com.au/How_to_Val..._Procedure.htm
Åke
http://www.kenlowe.com.au/How_to_Val..._Procedure.htm
Åke
10-06-2016, 01:00 PM
#24
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Yeah, and I would've love to use the actual spring pressure method, but being limited on dedicated engine building equipment, I am working within my means. I have to say though, that it's been an enjoyable learning experience, and it feels good knowing that I've done almost everything myself. Thanks again for your help and advice. It is much appreciated my friend.
Åke