Head Milling

[oldbones]

Is there anyone in here that has mill their head much?

What issues did you have?

-I just sent my Cyl. heads to the porter and I'm contemplating how much to have them mill the cylinder heads.

-It looks like there is going to be an issue with the VCT solenoid alignment and some with the intake manifold, but not much. As milling only moves the ports closer to the vertical center line of the engine.

-I wish I still had a mill because the VCT timing cover would be short work, but as it stands I will have to pay someone to modify the timing cover.

 

[5lho]

the begging question is why? The engine's already got 11:1 compression and is pushing it for pump gas. There isn't going to be much power from milling the thing .030, which is probably about as much as you can go and still fit the manifold. It may cause issues with the cam chains too, as the tensioner is picking up a little more slack. Someone school me if I'm off my nut but, I don't think it's worth the hassle it'll cause.

 

[oldbones]

I see your point and that's why I'm seeing if anyone has done it this way. I never run pump gas, so that's a mute issue for me. The car is on E85 or on the trailer.

I had not planned on this being a issue, but I did not know that Mahle calculated there pistons compression at a zero deck height. They actually sit down the hole .009, so with the factory gaskets it's less then 11:1 compression, which for a NA motor like this is no bueno. If I use a .027 head gasket it'll put it at 11.4:1 compression. With about .024 of head milling it would be at 11.99:1.

Here is probably, what is going to happen. I'll have them do a clean up pass on the deck which will be around .006 and I'll use the .027 head gasket and it'll sit around 11.60:1.

Here is my question, the head it still moved down .019 inches and has anyone had an issue moving the head .019 inches?

 

[BPatterson]

Where were you able to find that info about the depth of the piston in the hole? I'm currently building an na motor using the Mahle 12.5:1 piston, and have quite a bit of headwork done, to include chamber work. My heads were decked, but just for cleanup, so they only removed .002. I'm using a stock head gasket. I'm trying to figure out what my compression will be considering these newfound facts.

 

[Paul.]

There's lots of calculators online. You'd have to measure a bunch of things including chamber size, piston down-in-bore, piston dome, etc. to figure it out precisely.

 

[BPatterson]

That's just it, I have all the info except for how far the 12.5:1 piston will be down in the bore. I already have my chamber size, dome volume, gasket thickness, etc

 

[oldbones]

Where were you able to find that info about the depth of the piston in the hole? I'm currently building an na motor using the Mahle 12.5:1 piston, and have quite a bit of headwork done, to include chamber work. My heads were decked, but just for cleanup, so they only removed .002. I'm using a stock head gasket. I'm trying to figure out what my compression will be considering these newfound facts.

I measured it on my motor from the top of the deck, and it checks out with my math.

I can calculate block deck surface to top piston if you give me the compression height of your pistons. I'll need to know if you have had the surface of your block decked and if you're running a standard crank and rods.

Since you have had your chambers worked you'll need the CC's of your cylinder heads to be able to accurately calculate compression. The Ford factory chamber vary from 54.5 CC to 57.5 CC, but since yours are worked it'll be different.

 

[oldbones]

That's just it, I have all the info except for how far the 12.5:1 piston will be down in the bore. I already have my chamber size, dome volume, gasket thickness, etc

Send me your info and I'll plug it in my homemade calculator or I can email you my calulator.

 

[BPatterson]

Compression height is 1.167. Using a Boss crank and Molnar rods. Block has been decked. Not sure of the CC's of the chambers yet. Will find out next week.

 

[oldbones]

Compression height is 1.167. Using a Boss crank and Molnar rods. Block has been decked. Not sure of the CC's of the chambers yet. Will find out next week.

How much did the machinist remove from the deck of the block?

 

[oldbones]

Here is the sheet I use.