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Old 03-02-2011, 09:18 PM
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Flug540 Flug540 is offline
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Location: Hayward, CA
Join Date: Nov 2009
Posts: 606
Mein Auto: 1998 BMW 540i 6-spd
Originally Posted by franka View Post
In the April issue of Popular Hot Rodding (PHR) they have an article called 'Power Tricks for any Engine'...
Wow! Thanks guys, I'll look into it. I wonder if it will affect long term reliability.

Originally Posted by franka View Post
An engine with enough miles to have low compression could also have less than specified closed and/or open spring loads on one or more valve springs. Please don't misread this. I'm not saying weak springs are the case of your low compression. I am saying that the miles that would cause your worn seats would probably cause some springs to be below spec loads. With your meticulous cleaning it would be a shame to reinstall even one weak spring.
That makes sense, how does one go about checking the springs? My plan is to redo leak down test once I get the heads back on. That would be one indication; is there anything else I can check?

I'm also concerned with head sealing of coolant passages. When the heads are back on, I plan to do coolant system pressure test, that should show if there is a bad seal anywhere, right? Also, I think I could put a pressure gauge on the coolant system and then pressurize cylinders one by one and see if the coolant system pressure changes. Don't want to find coolant leaking into the combustion chambers when everything is back together.
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