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rusty70f100

Building an E85 optimized motor

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I look forward to that video.

 

I am debating Clevite or ACL for bearings......

My buddy at the speed shop sells lots of Clevite bearings, but lately he's been trying King bearings with great sucess.  They Plastigage out much more accurately than even the expensive Clevite "H" series bearings, at a fraction of the cost.  They're made in Israel, and are a simple babbitt bearing, not a tri-metal like Clevite are. 

Honestly, I've never liked Clevite bearings.  They're too soft, unless you get their heat-treated "H" series, which aren't available in all applications.  For normal use, I like Sealed Power (the old TRW) bearings.  They're similar to King bearings, but seem to have a much better coverage for the oddball stuff I like to work on.

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Oh **** I never did get that video!  I'll get it one of these days.

 

I *thought* I had the water leakage stopped.  Turns out, I only had it slowed down a whole lot.  So I stopped driving it a couple weeks ago.  I had the intake milled .020" on the bottom to make up for the block and head milling, and I'll put it on as soon as I get time.  Then I'll get that video going.  Promise.

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Back at it...

 

During the time I was driving it (with 11:1 compression), the mileage was very close to what it got on gasoline.

 

Problem was, the heads were cracked.  >:(  Talked to they guy at the machine shop, and apparently you need to pressure test them at 150 degrees F before the leak shows up.  So now they're badly cracked, and need to be replaced.

 

So I got some aftermarket non-Ford '95 and later heads with the smaller combustion chambers.  He's checking them, so I'll let everyone know what the combustion chamber volume is after that's done.  It should raise compression at least 1.5 points above the 11:1 that it's already at, as well as fix any water leakage.

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Alright, got the new heads CC'd.  Came out to 44cc.

 

Lets see, everyone make sure I got my math right:

 

Bore = 3.983"

Stroke = 3.32"

Pistons = true flat top, with no dish, dome valve reliefs, etc.

Heads = 44cc

Head gasket = 4" bore, .040" thickness (maybe a bit more on the thickness)

 

Compression ratio = 14.1:1

 

Might that be a bit much?  Or just right?  Opinions?

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I have seen references mentioning 14:1 as the upper limit for common engines although the high efficiency engine DOE developed was 19:1 as I recall but it was a direct injection designe if I remember correctly.

 

You don't mention your deck height on the pistons, do they come up to zero deck height at TDC?

Was the head CC'd with the spark plug you intend to use installed? At higher compression ratios things like different spark plugs can change the CC volume by a CC or so.

 

The other question is if your cam will have much over lap, your running compression ratio might be lower if cam timing allows much overlap.

 

Larry

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Lets see:

 

1. Yes, I forgot the deck clearance.  The pistons are out of the hole .002".

 

2. Close to the same spark plug.  I actually don't have my new plugs yet, but I'm going one heat range colder than stock.  Stock is an NGK number TR55; I'm going with a TR6.

 

3. Cam is a Comp 49-422-8, with the following specs:

 

IVO: 27

IVC: 63

EVO: 78

EVC: 26

Intake duration: 270

Exhaust duration: 284

LCA: 112

Lift: .5"

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I punched those numbers in here:

 

http://www.kb-silvolite.com/calc.php?action=comp

 

Shows ~14.1 CR with the piston .002 out of the hole.  So looks like your math is right on.

 

Guessing that thing has a rod length of about 5.750, with your IVC of 63 gives a dynamic compression of 11.3:1.  Maybe you know the actual rod length and can refine that further.  Also double check that your IVC is the number at .050" lift - that may tweak it a bit, too.

 

Definitely be interested to hear how this runs and see how the mpg compares to the gas engine!

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