cylinder head valve springs preload
08-19-2017, 10:53 AM
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cylinder head valve springs preload
Re posted as no replies of Turbo forum. Need info urgently
Putting the head back together after cleaning and new stem seals
Little unclear what the length should be for the measurement between the spring cup in the head and the retainer. Should it be set to 41.0mm on both inlet and exhaust with the shims? This is a 87 turbo cylinder head, I cant access a turbo manual. Early NA heads have different lengths for exhaust and inlet. What does the Porsche manual mean 41+0.5? Is that between41.0 to 41.5mm but should not be less than 41.0
(An update on cleaning- Never found anything to clean off baked on carbon in exhaust ports. I had to carefully remove it by manually chipping it away carefully and then with rotary wheel brush.All ceramic on exhaust ports appears intact
Putting the head back together after cleaning and new stem seals
Little unclear what the length should be for the measurement between the spring cup in the head and the retainer. Should it be set to 41.0mm on both inlet and exhaust with the shims? This is a 87 turbo cylinder head, I cant access a turbo manual. Early NA heads have different lengths for exhaust and inlet. What does the Porsche manual mean 41+0.5? Is that between41.0 to 41.5mm but should not be less than 41.0
(An update on cleaning- Never found anything to clean off baked on carbon in exhaust ports. I had to carefully remove it by manually chipping it away carefully and then with rotary wheel brush.All ceramic on exhaust ports appears intact
08-20-2017, 11:46 PM
#2
Did you measure the spring rate for each spring? great to do this. Each spring is compressed 1.3 Billion times per 100,000 miles.
New springs on 944S were about 40 lbs. as measured by INDy Shop.
New springs on 944S were about 40 lbs. as measured by INDy Shop.