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Author
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Topic: how much can you mill off sbf heads....
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-10-2003 12:32 AM
   
before you would need to mill the intake to match??I have a haynes manual that says .020" is the max, but was looking to push that to get some extra compression. Don't really want to mill my nice new intake since these heads won't be on the engine forever
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Fastymz
Moderator Posts: 13090
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-10-2003 01:23 AM
Dubz I'm not sure the cost of milling the heads,are worth the gain. Seems like to much work to pick a half point or so. I'd think some better gears would be money better spent. I know all about being low budget and wanting more POWER.  I think it's cool that you ask all kinds of questions, and your always looking to sneak alittle more out of your motor. But these guys have told me for years. You have to save up and build a better motor. I'm lucky enough to have do that. I tuned the heck out of the motor I have now. I really feel I've got all it has to give. To me thats a great feeling. So then I started on the drive train and suspension. Both helped out some too. But the C-4 and gears made the biggest difference so far. ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-10-2003 02:19 AM
Yah, i got a set of 3.56 for my car, havn't set them up yet though. Which should be a night to day difference over the 2.75's that came stock. Also looking at getting wide ratio trans gears with needle bearings for extra low end and less internal friction (but that's a big $$ upgrade)And when you have 8:1 compression like i do, going to 8.4-8.5 i think would help alot. Especailly if i am going to follow in your footsteps with a summit cam or something similar but as cost effective. Plus i was going to take the heads off to check them over, clean up the ports a bit, and put new gaskets on anyway, so i figured while i had them off it wouldn't hurt. I've watched your setup carefully since the guys are helping you build your 351 i figured the same stuff would help me the same. (other than the compression) ------------------
1974 Gran Torino
351W with rpm air gap intake, Holley 670 carb, 1" 4 hole spacer
Planned : Summit cam, cheap headers, milling cylinder heads, and alot of non engine stuff
My Page
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indyphil
Gearhead Posts: 1163
From: Lafayette, IN, USA
Registered: Jul 2002
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posted 12-10-2003 08:31 AM
My local "expert" said 0.030 before milling the intake. If i remember right Thats still only going to take about 2to3 CC off a 60CC chamber? ------------------
'68 coupe 289 C code
66 heads, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
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V8 Thumper
Gearhead Posts: 3817
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 12-10-2003 08:42 AM
Depending on the chamber volume to begin with, it could shave as much as 5cc. Still not a whole helluva lot... doing the math, if you started at 8:1, you'd wind up at 8.37:1 with a reduction of 5cc's of combustion chamber volume, if all other variables remained the same. If you were to use steel shim head gaskets (.025~ish compressed) along with milling the heads, it could bump you up to as much as 8.8:1. Still alot of work/expense for not even a full point  If it were me, I'd keep stashing the dollars away when you can, save up for a shortblock and really do it up right   ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html [This message has been edited by V8 Thumper (edited 12-10-2003).]
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Buster
Gearhead Posts: 1020
From: Orlando
Registered: May 2002
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posted 12-10-2003 09:58 AM
Why is it not recommended to use Steal Shim Head gaskets on Aluminum heads?
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V8 Thumper
Gearhead Posts: 3817
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 12-10-2003 10:32 AM
Aluminum expands and contracts at a far greater rate than the shim can keep up with. Iron heads don't 'move' nearly as much as alloy heads do, so a shim can maintain seal between two static surfaces; it cannot seal between one stationary surface and one active one, at least not to any serious cylinder pressure or rpm ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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69maverick
Gearhead Posts: 933
From: Thomaston,CT.
Registered: Jan 2001
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posted 12-10-2003 11:06 AM
My 63cc heads where angle milled down to 50cc all I did was not use the intake gaskets. I used a high temp sealer and I have no problems.
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-10-2003 12:50 PM
Thanks for the input guys, i figure any increase in compression is worth the money. Thinking it would cost about $70 to mill the heads, where as a proper rebuild, in the thousands, so waiting for another $70 later won't be a problem.Where could i get a set of steel shim gaskets that don't cost an arm and a leg In the 1hp per cid writeup Alex wrote he said they cost about $40
but when i asked Alex which to use he said use cometic which sells for about $200
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Rustang
Gearhead Posts: 548
From: Clarion PA
Registered: Nov 2000
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posted 12-10-2003 12:50 PM
My C9 windsor heads were decked .050" Don't know what the CC was, though.------------------
'68 mustang 351 clevor- 10.92@124
'67 Stang, 351W -11.18@118
'69 351C Torino-14.90@100
'78 Pickup 351W-15.56@88
'79 Pickup 460 ET=??
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N266fords
Gearhead Posts: 906
From: Spokane ,WA USA
Registered: Apr 2003
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posted 12-10-2003 02:01 PM
that low of compression sounds like a 100 hp shot of nitrous is just what the doc ordered. Bruce
P.S. going from 2.75 to 3.55 is a kick in the pants. You will not regret it. I took it one step further and mini spooled it. I drive on the street and have no problems, just use common sense do not open it up while turning or going around a corner because it will bring you around quick. (dont ask my wife why she wont drive the beast). but hey her mustang is better looking than mine.
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Fastymz
Moderator Posts: 13090
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-10-2003 02:23 PM
Dubz I do know where your coming from on this. I think it's great your looking at all over to pick up some power. Yea if I had that compression I'd be looking for more too. How does the motor run now ? does it leak oil, burn oil, have you done a compression check on it yet. If it's a good tight motor I would touch the heads. I put a cam in it and maybe some better rockers. The stock ones are never 1.6 like they say they are.
If you can wait until I pull my motor. You can have my summit cam it only has about 2000 miles on it. I'll lable all the lifters and you pay the shipping. Your right these guys have helped me a lot over the past few years. I'd like to pass alittle of on to you. I even talked to the guy that doing my motor. He said he'd do the gears,and cam and go have fun with it. Until you can rebuild it and replace the heads. Just his and my .02 Ron
Email me about the cam, but it'll until Feb, at least before I get to it. ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Fastymz
Moderator Posts: 13090
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-10-2003 02:27 PM
From what I know which is not a lot.
All 351w heads until 1976 had 60cc. The other the engine told me is that if you mill a lot off, you might need to change your push rods too. So add up for the work,plus gaskets,plus push rods ect. For about a .5-.8 gain not sure it's worth it ?------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-10-2003 03:32 PM
The motor runs wonderful, ran a compression check and they were all within 10psi so everything seems to be in order there. Doesn't seem to use oil at all, has some leaks at the oil pan but probably becaue the gaskets are 30 years old.As with the thinner gaskets if you get a shim kit for the adjusting nuts you don't need to get different pushrods(as far as i know, and comp cams sells a kit for about $30) And pretty much everyone said that to run a cam of any size 8.0 was way too low, where as 8.4 was bearable. And thanks a bunch with the cam offer, might just have to take you up on that
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Fastymz
Moderator Posts: 13090
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-10-2003 03:38 PM
quote:
Originally posted by Dubz:
And thanks a bunch with the cam offer, might just have to take you up on that
If you can wait please do.
------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-10-2003 04:20 PM
bargan hunters are allways willing to wait for a deal
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steve'66
Gearhead Posts: 6852
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 12-10-2003 10:08 PM
Dubz,I flat milled .040" off the heads on the old 289 w/o touching the intake. You just have to throw away the cork intake gaskets and use silicone on the front and rear of the block-intake surfaces. It's a cheap mod and should raise you c/r almost 1/2 point. SteveW
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-11-2003 01:50 AM
Well if i could get away with 0.040" that would be great.Quick question when milling the heads, can you mill the manifold mating surface instead of milling the intake?
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Ryan Wilke
Gearhead Posts: 1613
From: Stanton, Michigan 49707
Registered: Oct 2000
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posted 12-11-2003 08:15 AM
quote:
Originally posted by Dubz:
Quick question when milling the heads, can you mill the manifold mating surface instead of milling the intake?
If I understand your question correctly, you're suggesting milling the head at the head-to-intake surface instead of the milling the intake.....problem there would be that you would need to stretch your intake from side to side (head to head) because you removed material from each mating side surface. The mating problem isn't at those side surfaces - the problem is when you mill your heads at the head-to-block surface it results in dropping the intake surface closer to the block surface. So if you cut your heads excessively or you use OE gaskets, when you set your intake manifold on, it will bottom out or touch at both ends (front & back) on the block and leave a gap at the manifold-to-head surfaces. So, when you mill your heads MORE THAN .030" to .040", AND you use OE gaskets without milling the bottom of the manifold, the manifold will be laying on the block & leave your intake 'high & dry' at the head to intake surfaces. That's why SteveW suggested tossing the OE end gaskets and just using a thin bead of silicone at both ends...by doing this trick, it would allow you to 'sink' your intake a little lower toward the block without milling the ends of your intake. Clear as mud???
Ryan
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Fastymz
Moderator Posts: 13090
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-11-2003 01:08 PM
quote:
Originally posted by steve'66:
Dubz,I flat milled .040" off the heads on the old 289 w/o touching the intake. You just have to throw away the cork intake gaskets and use silicone on the front and rear of the block-intake surfaces. It's a cheap mod and should raise you c/r almost 1/2 point. SteveW
Steve on his motor whats a half a point going to net him, in HP or TRQ ??
Is it money well spent ? I guess thats my main question. ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-11-2003 01:43 PM
I wasn't thinking that that is where the problem was....and i thought everyone didn't use the end gaskets, just used silicone instead (what i did when i put my intake on)And according to phm going from 8:1 to 9:1
will be at least a 3.5% increase in power, which isn't alot for a 300ft-lb motor (about 10ft-lbs)...and i won't be getting a full point either. With my desktop dyno going from 8.0 to 8.5 gives 11hp and 11ft-lbs with avg increases over 2000 to 5500 of 6hp and 9ft-lbs [This message has been edited by Dubz (edited 12-11-2003).]
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indyphil
Gearhead Posts: 1163
From: Lafayette, IN, USA
Registered: Jul 2002
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posted 12-11-2003 02:40 PM
Im thinking geometrically that the cork end gaskets are not affected by milling the heads. Sheesh I need a white boardhttp://geocities.com/ottouk_77/images/nomill.jpg compare with: http://geocities.com/ottouk_77/images/milled.jpg I see the heads just come in, but the intake stays put, this mis-alignes the intake bolt holes into the heads but doesnt change the height of the intake. Im just doodling, I may be wrong. anyone got better diagrams?! ------------------
'68 coupe 289 C code
66 heads, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
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Fastymz
Moderator Posts: 13090
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-11-2003 03:03 PM
We really need a white board for Phil. Dubz I'm not trying to shot down your idea, just want to see you get what you want for your money. ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-11-2003 03:22 PM
I know you're trying to help me weigh the benifits against cost. And i was kind of wondering that myself.And your diagrams make sence to me Phil I was thinking of pulling off the heads anyway to do clean up the ports some, so i'd need to get a new head gasket anyway. I'll need to take off the intake manifold to install the cam, so i'll need that gasket as well. So really the only cost difference will be the cost of getting them milled. $60-100 for 11hp and 11 ft-lbs seems good to me. [This message has been edited by Dubz (edited 12-11-2003).]
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indyphil
Gearhead Posts: 1163
From: Lafayette, IN, USA
Registered: Jul 2002
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posted 12-11-2003 04:01 PM
A goog home porting job is often worth more than 11hp anyway. It seems people get mixed results but a gasket match and clean up job should net you more power. also milling the heads give you a nice clean flat sealing surface which should keep things running smooth for longer. Its not going to hurt but im not sure its the best bang for the buck. ------------------
'68 coupe 289 C code
66 heads, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-11-2003 08:00 PM
How thick would the stock head gasket be? 0.045 or so? The only steel shim head gaskets around are 0.030" so not worth .3 more compression [This message has been edited by Dubz (edited 12-11-2003).]
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Ryan Wilke
Gearhead Posts: 1613
From: Stanton, Michigan 49707
Registered: Oct 2000
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posted 12-12-2003 09:37 AM
quote:
Originally posted by indyphil:
Im thinking geometrically that the cork end gaskets are not affected by milling the heads. Sheesh I need a white boardhttp://geocities.com/ottouk_77/images/nomill.jpg compare with: http://geocities.com/ottouk_77/images/milled.jpg I see the heads just come in, but the intake stays put, this mis-alignes the intake bolt holes into the heads but doesnt change the height of the intake. Im just doodling, I may be wrong. anyone got better diagrams?!
OK - from what I see, your (helpful) diagrams do make sense.... so it seems that as you mill off of the block surface of the heads, the intake ends DON'T become closer. However, not only do the attaching bolt holes become mis-aligned (as you mentioned above), but so does the alignment of the head-to-intake ports - since the intake will sit on a 'higher than OE' location of the head surface. So why do folks need to mill their intakes at all? So is the bolt hole and port mis-alignment the limiting factor in milling heads?????? I understand the loss of valve-to-piston clearance and the need for shorter pushrods as you mill off the block-to-head surface..... Ryan
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indyphil
Gearhead Posts: 1163
From: Lafayette, IN, USA
Registered: Jul 2002
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posted 12-12-2003 09:46 AM
If you do mill your intake (according to my diagram which is not the gospel)
your intake will drop down a little and you can keep your bolt hole alignment. But it would seem that for small head milling (like 0.030 or 0.040) that it wouldnt matter.Some people ANGLE mill the the heads and its a whole new ball game. By ANGLE milling you can take more material off the side that has the most combustion chamber volume. But now the angle that the head sits at is new so you are supposed to mill the intake. Please beware - I know not what I talk about. Im talking about my diagram which does make some sense but may not be accurate. Dont let the "gearhead status" fool you into thinking I know what Im doing. I have only torn into 3 engines my whole life. ------------------
'68 coupe 289 C code
66 heads, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
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Dubz
Gearhead Posts: 823
From: Manitoba Canada
Registered: Oct 2002
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posted 12-12-2003 02:10 PM
bolt hole allignment will never be right no matter how much you mill the intake. Think about it for a second, you move the heads inwards and down, and if you mill the intake it just goes straight down. The holes in the intake don't move. I think the main thing would be the port matching, which since my intake has bigger ports than the head it doesn't make a big difference (i think)
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indyphil
Gearhead Posts: 1163
From: Lafayette, IN, USA
Registered: Jul 2002
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posted 12-12-2003 02:37 PM
Youre right. I didnt give that enough thought. So maybe intake milling is really for the ANGLE milling folks. Perhaps You cant take too much off the bottom of the head before you need to angle mill for other reasons, like taking the combustion chamber down too much on one side or maybe valve clearance or something.------------------
'68 coupe 289 C code
66 heads, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
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