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pazzo_gem
tinkerer
Joined: 19 Jun 2003
Posts: 87
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 Posted: Sat Jul 26, 2003 4:45 am Post subject: valve clearence?? |
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| i have a g200 bottom end 40thou over with flat-tops and a 1600 head, both have been shaved. i want to put a monster cam in but dont know how much valve clearence i have. i want to go as big as i can with out fly cutting the pistons. how do find out what i need to know. |
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DrIFtA
tinkerer
Joined: 13 Mar 2003
Posts: 246
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| Posted: Sat Jul 26, 2003 4:08 pm Post subject: Re: valve clearence?? |
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| Assemble the engine with a dummy fitted head-gasket, but put a chunk of blue-tac on top of each piston crown. Turn the engine over by hand making sure that all four pots reach TDC. Pull the head off and use a set of vernier calipers to measure how much of the blu-tac hasn't been squished by the valves. Using that reading, you can determine how much lift you can use in a cam reasonably safely. |
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Ben Wight
backyard mechanic
Joined: 04 Oct 2001
Posts: 946
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| Posted: Mon Jul 28, 2003 7:36 pm Post subject: Re: valve clearence?? |
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That is the correct what to do it, but you also have to keep in mind that a bigger cam will open the valves sooner, and close them later, which means there is more chance of hitting.
The method above will tell you how much valve clearance you currently have, but the only way to tell with the cam you want to put in is to get the cam, and install it, then repeat the procedure. Worst case is you have to make valve reliefs. its not hard, can be done with pistons still in block.
Ben |
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