milling intake manifolds

[69427]

Bump for some information help please.

I have a MarkIV BBC that has had some extensive head work done. The heads have been flat milled .050 this time around to keep compression up to 13.5.

The heads are torqued down to the block. With a .060 intake gasket on each side the intake is mismatched with the heads.

What I want to know is there a way to measure the amount of material that needs to be milled off the intake??????

So if the intake is sitting on the China wall, with no gaskets, and I slide the intake over against one head, can the measurement between the opposite head and intake be used to determine the amount to be milled????????? If this was a stock deck and head surface would that gap be .120 doing this?

Thanks for any input.
Tom

[groberts101]

http://www.wallaceracing.com/calc-intake-mill.php

[Dave Koehler]

You will be better served to mill the manifold side of the heads despite the hassle.
Otherwise you wind up with a manifold useless for anything else.

[69427]

Thank you for the Wallace calculator. I don't see big block, but it should be the same as SBC. I will run some numbers through it.

Problem is, these heads have been cut before lightly, but I don't know what the total amount adds up to.

[groberts101]

Thank you for the Wallace calculator. I don't see big block, but it should be the same as SBC. I will run some numbers through it.

Problem is, these heads have been cut before lightly, but I don't know what the total amount adds up to.

oops.. sorry for the quick fly by.. didn;t even notice that. lol

Then you'd need to trig it out or use a protractor. Would still need to know the amount milled but maybe this would help as well?

http://www.crankshaftcoalition.com/wiki ... nder_heads

[69427]

You will be better served to mill the manifold side of the heads despite the hassle.
Otherwise you wind up with a manifold useless for anything else.

The heads where milled but not enough. I suspect the manifold China wall will need to be done any how.

[Wolfplace]

Thank you for the Wallace calculator. I don't see big block, but it should be the same as SBC. I will run some numbers through it.

Problem is, these heads have been cut before lightly, but I don't know what the total amount adds up to.

Try these
https://www.hastingsmfg.com/ServiceTips ... _heads.htm

http://www.goodson.com/blog/2012/01/13/ ... e-milling/

From Jeffery Diamond's site Victorylibrary.com.
http://victorylibrary.com/mopar/intake-mill-c.htm

BB is 1 to 1 for the intake face, China wall would be the same as any 90° head. ford, Pontiac etc. or 1.4

To answer your question, yes if you pull the intake against one head the distance on the other side will be the amount needed to correct minus the two gaskets of course but you need to have the intake at the correct height first or the numbers will be incorrect because as the intake lowers the gap decreases so,,,
If it is sitting on the china wall before the ports/ bolt holes align you need to remove some off the bottom before you will know what if any to take off the faces
If at or below the ports you are good, measure & cut so the gaskets fit then get enough room at the ends for some sealant
Don't forget to leave enough for when the gaskets compress you obviously don't want the intake sitting on the block,,,,

[69427]

Thank you for the Wallace calculator. I don't see big block, but it should be the same as SBC. I will run some numbers through it.

Problem is, these heads have been cut before lightly, but I don't know what the total amount adds up to.

Try these
https://www.hastingsmfg.com/ServiceTips ... _heads.htm

http://www.goodson.com/blog/2012/01/13/ ... e-milling/

From Jeffery Diamond's site Victorylibrary.com.
http://victorylibrary.com/mopar/intake-mill-c.htm

BB is 1 to 1 for the intake face, China wall would be the same as any 90° head. ford, Pontiac etc. or 1.4

To answer your question, yes if you pull the intake against one head the distance on the other side will be the amount needed to correct minus the two gaskets of course but you need to have the intake at the correct height first or the numbers will be incorrect because as the intake lowers the gap decreases so,,,
If it is sitting on the china wall before the ports/ bolt holes align you need to remove some off the bottom before you will know what if any to take off the faces
If at or below the ports you are good, measure & cut so the gaskets fit then get enough room at the ends for some sealant
Don't forget to leave enough for when the gaskets compress you obviously don't want the intake sitting on the block,,,,

Mike
Thank you for taking the time to post that. I have some figuring to do.

And your signature fits this problem:

"Life is tough. Life is even tougher if you're stupid"
John Wayne

[cgarb]

Whats wrong with using offset dowels to move the manifold face of the head away from the intake...same as milling it correct?

[69427]

Whats wrong with using offset dowels to move the manifold face of the head away from the intake...same as milling it correct?

In my case it would throw the chamber out of whack with the bore.

[Adger Smith]

Off set dowels creates a completely different "Bag of Worms"
I have used the same method/numbers Mike Lewis has posted.
The old VN charts and info will not get you in trouble.
I had a chart that came with my first 85B. It finally turned to dust, but
it used the same calculation method that Van Norman used.
On heads that I've done a sever angle mill on I always do the heads, not the intake.
I have not figured out a real easy way to do them accurately, but cut and try.
If I'm doing BB I usually do a 1-1 as a starting place. On a 10 deg SBC I use a 1.2 factor.
I never try to do the cut in one step. I cut at least 2 times to make the "Fit"
That is just one of the reasons I've always worked slow.

[69427]

Off set dowels creates a completely different "Bag of Worms"
I have used the same method/numbers Mike Lewis has posted.
The old VN charts and info will not get you in trouble.
I had a chart that came with my first 85B. It finally turned to dust, but
it used the same calculation method that Van Norman used.
On heads that I've done a sever angle mill on I always do the heads, not the intake.
I have not figured out a real easy way to do them accurately, but cut and try.
If I'm doing BB I usually do a 1-1 as a starting place. On a 10 deg SBC I use a 1.2 factor.
I never try to do the cut in one step. I cut at least 2 times to make the "Fit"
That is just one of the reasons I've always worked slow.

Thank You for the reply Adger

[69427]

Well it looks like a .090 mismatch after some creative measuring.

Thanks

[MadBill]

A 'no math' approach is to use shims/feeler gauges at each corner to space the manifold to achive alignment, then machine the head faces accordingly. e.g: perfect alignment occurs with 0.020" shims and the gaskets are 0.060" compressed, so mill 0.040" from each. (Of course this only works if the manifold aligns with more than zero shim thickness...)

[69427]

A 'no math' approach is to use shims/feeler gauges at each corner to space the manifold to achive alignment, then machine the head faces accordingly. e.g: perfect alignment occurs with 0.020" shims and the gaskets are 0.060" compressed, so mill 0.040" from each.

Thank You MadBill

I will use that to triple check what I have found before I commit.

Tom