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S4 Head Question

 
Old 12-31-2018, 08:58 AM
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DeWolf
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Seasons Greetings and a Happy New Year to all the members.

What blocks will S4 heads screw too? Can you put them on a 4.5 for example?

Cheers
Scott
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Old 12-31-2018, 01:39 PM
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davek9
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I don't recall anyone going that way, some do the 16v heads on the 5.0 block, so with some mods it should go the other way too, right.?
Remember Piston and or valve work will also be required, lots of work to use a 4.5lt engine, what are you looking to gain by doing this?
You will also need to change the cam drive gears to the Round tooth.

Dave K
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Old 01-01-2019, 06:03 PM
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The Forgotten On
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The bore the heads are cut out to is 100mm, the 4.5 is 95mm and it wont seal well.

You can stick S4 heads on a S3 block and get 12:1 compression though.

The S3 heads bolt onto the 4.5 though without issue IIRC.
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Old 01-01-2019, 06:57 PM
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the S3/S4 combustion chamber is right about 100mm across, so you'd have overhang on top of the cylinder barrels...like a mushroom
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Old 01-10-2019, 08:07 AM
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DeWolf
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Can the 4.5 be bored to accept 100mm S4 pistons?
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Old 01-12-2019, 03:54 AM
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Originally Posted by DeWolf View Post
Can the 4.5 be bored to accept 100mm S4 pistons?
No, there isn't enough cylinder wall for it.

I think you can do it in a 4.7, those are already 97mm.

I would just buy a S4 bottom end instead, the pistons need to be precisely matched to the bore after machining based on the tolerance group they fall into.

It's why you should never hone a 928 engine unless you are boring it out or else you will have bad piston fitment issues.
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