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-   -   Decked Zetec Head Question (http://www.focusfanatics.com/forum/showthread.php?t=302333)

79mgb 11-15-2012 08:56 AM

Decked Zetec Head Question
 
Hey guys. I'm trying to figure out what compression ratio a standard Zetec head decked to .050" would give me. I've tried searching around the forum but the CR's are all over the map.

I'm going to be using a stock block. I don't mind running on premium fuel, I just don't want to be running on racing fuel. [hihi]

I appreciate the help!

79mgb 11-15-2012 09:31 AM

After doing a little more research, it looks like 11.15:1. Does that seem right?

Magus2727 11-15-2012 05:44 PM

Not sure on that calculation. C-F-M has a calculator to use when you are looking at their Cometic's head gasket. not sure what all the numbers should be for a stock block and or head. Stock compression is 10.2:1. 0.50 is a large (think most are 20-30 thousandths) but not sure if you would get a full extra number on the left side.

I think at 0.050 you also are making the Zetec an interference type motor. I have asked before but dont recall ever getting an actual hard number of if you remove X material.

I think you will want a tune with that large of a change of compression also.

79mgb 11-15-2012 06:07 PM

I realized after I posted that I asked a question that was difficult to answer without knowing all the variables. Thanks for mentioning the calculator. That helped a good bit.

I think .050" will be a little too extreme anyways. Thanks for helping me out. I'm really liking this forum.

ah1f39 11-15-2012 06:14 PM

.040 was the number I was considering for the ported head.

79mgb 11-15-2012 06:24 PM

Quote:

Originally Posted by ah1f39 (Post 4457521)
.040 was the number I was considering for the ported head.

That seems to be the most reasonable amount for higher compression. I could avoid dealing with cam timing and tensioner issues.

ah1f39 11-15-2012 06:31 PM

Zetec cams are not indexed.

I've never understood how if the gears are tightened after the belt is set how there would be an issue.

The tensioner should be able to adjust for all but the most drastic milling.

79mgb 11-15-2012 06:55 PM

Blah. You're right. I'm having some massive brain farts today.

Also, I read about the tensioner on this old thread but it seems more like speculation than fact.
http://www.focusfanatics.com/forum/s...=265981&page=3

sleepyboy 11-15-2012 07:15 PM

Quote:

Originally Posted by Magus2727 (Post 4457472)
Not sure on that calculation. C-F-M has a calculator to use when you are looking at their Cometic's head gasket. not sure what all the numbers should be for a stock block and or head. Stock compression is 10.2:1. 0.50 is a large (think most are 20-30 thousandths) but not sure if you would get a full extra number on the left side.

I think at 0.050 you also are making the Zetec an interference type motor. I have asked before but dont recall ever getting an actual hard number of if you remove X material.

I think you will want a tune with that large of a change of compression also.



10.2:1 is the SVT's Compression ratio. The normal zetec's is 9.5:1 wish I could remember the how much to shave but I can't [V]

iminhell 11-15-2012 08:41 PM

http://www.focusfanatics.com/forum/showthread.php?t=199568

You're welcome.


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