Hi all I am working on a 2.4l build right now.

I was using the summit compression calculator and am confused as to the results.

I am using wiseco K656m87 which are the e85 series for the 64 with 63 head and an advertised comp ratio of 10.5:1. I am running manley h beams with a 64 OEM crank.

Though for the head as of right now I am running the g4js Hyundai head which has a combustion chamber of 56cc.

Here are the factors I plugged into the calculator.

Bore 87mm

Stroke 100mm

Dome/Dish -4.5cc

Deck Clearance 0mm(what the wiseco spec sheet says)

Compressed head gasket thickness .030inch(oem spec)

The compression ratio came out to 11.62:1

With the evo head cc plugged in it came to 14.86:1

Where did I go wrong?

 

yeah the evo head is 43 cc. i have no idea man. your problem is you didn't post this on TGC

 

I got 10.79:1

http://www.csgnetwork.com/compcalc.html

 

Use the Eagle rod one, it seems to work more accurately. I think there is a good chance you have some numbers wrong. -4.5cc is for the 2.0L only (85mm) bore and 88m stroke. If you go to their catalog and look at the HD2 you will see the 10.5:1 87mm should actually be -12.5.

Your ordered a big bore 2.0L piston basically so it will end up too high. Order K669M87 instead and use a 0.040 gasket or use the Hyundai stuff with a .040 or larger (.030 is too close anyway) and I get 9.97:1 if the head volume is 56cc.

 

You ordered the wrong pistons. Check out the link in my how to post. There a spec sheet for ordering 4G64 pistons. You ordered the EVO 8 4G63 pistons for 10.5 to 1 and not the 4G64 high compression ones. You need the pistons with a -10cc or greater pistons.

https://www.speedproshop.com.au/inde...=51&Itemid=123

I also punched in all the numbers into this form. You are at 10.14:1

 

Here is the Evo head-



Here is the Hyundai-



I did them as long rod stuff but that doesnt affect compression whether you are doing a LR or STD rod.

 

He now shsssshhhh this is top secret stuff.

Well ****!!!!!

Here is the side of the box



So in order to have the 10.5: comp ratio I would need the 63 crank correct? Thus making it a 2.3l?

 

They'll still work. Like I said I wasnt sure where your math was all coming from but the second pic I posted shows a 10:1 motor with a 56cc head. Is the G4JS the same as the Sonata motor? I thought they were the same CC as an Evo.

 

I got the specs from wiseco and what I knew as far as stroke and bore. I used the summit calculator.

I am using standard rod.

Yes the g4js is the sonata motor. They have a bigger combustion chamber and flow more stock vs stock. From my research they have a 56cc. I can verify that later on at my machinists.

So these pistons will work? With as little dish as these have will I have issues with cams?

 

Well dish is less important than the valvepocket and then total distance to the valvepocket. Thats why I am recommending nothing closer than factory Evo (0.042) since thats what the pistons are designed around. Get an accurate CC of the head since my memory of the one we did is all I have to go by. It seemed it was closer to an Evo than that, 56cc is pretty large in comparison.

 

Well I will get back to you with that and update here.

Do you know what the thickness of the felpro permatorque MLS is? That is the gasket I was planning on running before. I may just end up getting the Cosworth if needed.

I am planning to run the s2 cams, maybe the r2 havent looked into those yet.

 

The only Felpro I know of that you would most likely use would be the 11531 which 0.055".