head volume

Alex170984
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head volume

Postby Alex170984 » Sun Oct 09, 2016 5:54 am

I have discovered that my smallport cylinder head is 115.95mm

I have seen somewhere that standard is 116mm

As I do not have any valve springs installed, measuring with liquid is not possible. I will be purchasing these soon, but is there any blurb that can determine the volume of my head based on the depth measured?

cheers

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oldeskewltoy
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Re: head volume

Postby oldeskewltoy » Sun Oct 09, 2016 9:35 am

Alex170984 wrote:I have discovered that my smallport cylinder head is 115.95mm

I have seen somewhere that standard is 116mm

As I do not have any valve springs installed, measuring with liquid is not possible. I will be purchasing these soon, but is there any blurb that can determine the volume of my head based on the depth measured?

cheers


chamber volume on an uncut head typically measures to 36cc. In MY experience... an uncut head is 116mm. I've never seen a head measure more than 116mm, I have seen some uncut heads between 116, and 115.95.

It is possible to measure chamber volumes without springs - use a small amount of grease, or even Vaseline all around the valve seat, then re-seat the valve. Unless the seats are really terrible, this method typically works. Only use enough grease as a seal, and any that squeezes out, wipe away.

What chamber volume are you looking to have after the head is machined??
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

Alex170984
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Posts: 339
Joined: Thu Jun 20, 2013 4:08 am

Re: head volume

Postby Alex170984 » Mon Oct 10, 2016 12:33 pm

Well I'd like to keep it close to stock, but maybe 35.5

Out in the numbers in the comp ratio calculator and I get 11.2 with no major mods. Looking for 11.2-11.5

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oldeskewltoy
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Re: head volume

Postby oldeskewltoy » Tue Oct 11, 2016 7:46 am

Alex170984 wrote:Well I'd like to keep it close to stock, but maybe 35.5


since your desire is between 35.5 and 36, I'd cut it .003". That should get you a nice surface and yet not remove too much material. Volume change for a .003" cut is likely to be less then 1/2cc
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

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Alex170984
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Posts: 339
Joined: Thu Jun 20, 2013 4:08 am

Re: head volume

Postby Alex170984 » Tue Oct 11, 2016 8:52 am

My mate has brought me over from the States the 10.3 smallport pistons.

The comp height is less than standard, but this doesn't appear to be a problem. However I do not know if the distance above the deck of the piston is going to be a problem if i shave the head 0.003" and put on a 1.01mm head gasket.

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oldeskewltoy
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Re: head volume

Postby oldeskewltoy » Tue Oct 11, 2016 3:31 pm

Alex170984 wrote:My mate has brought me over from the States the 10.3 smallport pistons.

The comp height is less than standard, but this doesn't appear to be a problem. However I do not know if the distance above the deck of the piston is going to be a problem if i shave the head 0.003" and put on a 1.01mm head gasket.


shave the head all you want it never gets closer to the piston then the height of the gasket and the pistons deck measurement. All that happens when you cut the head is you lose chamber volume... but squish remains the same.

What is your deck measurement? Piston above, or below the edge of the block?
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

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