Intake won't bolt up after milling heads.. [Archive] - Chevelle Tech

: Intake won't bolt up after milling heads..


Importtech
Feb 18th, 06, 6:24 PM
I'm in the process of assembling my circle track engine. I had the heads flat milled .035 and the block decked to 9.010. Additionally I am using a .015 gasket trying to get my compression as close to 10.0 as I can.
I was about to bolt on the intake (cast iron qjet) and the bolt holes will not line up. I'm assuming was brought about due to the machine work. They are tight to the inside of the holes. I'm using the standard blue felpro intake gaskets. What are my options. Can I slot the holes? Thanks for any help as this is alittle out of my experience range. Please help as I'm now at a standstill.

DOUG G
Feb 18th, 06, 6:42 PM
Slotting the holes may be a quickie fix but I would have the machinist mill the intake to fit. Sounds like too much was taken off or measurments stacked up.

driver
Feb 18th, 06, 6:52 PM
Went thru that last year on my 502 and had to take a dremel (if I spelled it correct) and make the bolt holes larger.I had to do a little at a time and then recheck it.If it's anything like mine was you'll notice it will need more on the bottom side of the holes.It takes a little time and work.I did mine on a angle taking more off the bottom side.

10secBu
Feb 18th, 06, 7:02 PM
If it's a single plane intake, look down through the plenum to the ports where the head mates. You'll likely see the intake sitting way too high and need to mill the sides to get the ports in alignment.

Importtech
Feb 18th, 06, 7:26 PM
Driver
yup it's the bottom of the holes to the inside..

10secbu
Its a gm dual plane so I can't see the ports but I suspect your right about the alignment


I guess I'll call the machinst and see what he thinks..Don't know why he didn't
say anything about it while I had the intake at the shop for cleaning. :(

Thanks guys...

driver
Feb 18th, 06, 8:50 PM
Almost forgot,I also had trouble getting it to seal.Had it off and on three times before I got it to seal.

nitrofox
Feb 18th, 06, 9:01 PM
Do your track rules specify a stock intake [unmilled] ? I've seen one track use a stock manifold to see if the bolt holes line up.

Jeff

pdq67
Feb 18th, 06, 10:01 PM
I guess I don't understand this at all b/c a flat-top pistoned old L-48 motor , (295 and 300hp), will be 10 to 1 with stock double-hump heads so why did you go through all this??

pdq67..

Importtech
Feb 18th, 06, 11:05 PM
I guess I don't understand this at all b/c a flat-top pistoned old L-48 motor , (295 and 300hp), will be 10 to 1 with stock double-hump heads so why did you go through all this??

pdq67..


Gotta run 76CC head castings!

Wolfplace
Feb 18th, 06, 11:27 PM
Gotta run 76CC head castings!

I'm in the process of assembling my circle track engine. I had the heads flat milled .035 and the block decked to 9.010. Additionally I am using a .015 gasket trying to get my compression as close to 10.0 as I can.
I was about to bolt on the intake (cast iron qjet) and the bolt holes will not line up. I'm assuming was brought about due to the machine work. They are tight to the inside of the holes. I'm using the standard blue felpro intake gaskets. What are my options. Can I slot the holes? Thanks for any help as this is alittle out of my experience range. Please help as I'm now at a standstill.
=
Best scenario is to take .050 off the intake side of the heads.
This is the amount you removed from both pieces
This should put you back to "normal"
Any time you have the heads milled this much you should also have the intake side cut by 1.2 & the bottom of the intake or the top of the block by 1.7 according to theory on a small block.
I have used 1 to 1 for years with no issue.
The next best is to cut the intake but I don't like to do this as you are now married to this intake/head combo but if the heads are on then,,,,

Importtech
Feb 18th, 06, 11:43 PM
Thanks for the input Mike. Yes the heads are on and valves are set. I'm not worried about cutting the intake as I can't see ever using it for any other purpose. I didn't really think about all the consequences of cutting the heads and block like changing pushrod lenght,intake fit etc or I might just changed the pistons and been done with it. Just trying to get an edge :)

Mike
Feb 19th, 06, 11:09 AM
http://home.isoa.net/~mharrisj/mill.html

JimM
Feb 19th, 06, 9:42 PM
Last year I milled my dart heads .040, plus used a 1094 shim gasket. I had to hog out the manifold bolt holes to get it together. It sealed just fine. It's apart again, making it a 383 this year. The gaskets look great, it was sealing, and any mismatch does not seem to be enough to be a problem.

Wolfplace
Feb 19th, 06, 10:29 PM
Last year I milled my dart heads .040, plus used a 1094 shim gasket. I had to hog out the manifold bolt holes to get it together. It sealed just fine. It's apart again, making it a 383 this year. The gaskets look great, it was sealing, and any mismatch does not seem to be enough to be a problem.
=
Hi Jim, :waving:

What the hell kind of machine shops are you guys using that don't know how to correct the intake face of a set of heads?? :D

If the bolt holes don't line up neither do the ports.
If the ports don't line up you are probably leaving power on the table,

You go out, spend the money for decent heads & then kill part of the flow by half as$ing the intake installation ???

Why not have your heads corrected while they are off?

540Hotrod
Feb 19th, 06, 10:59 PM
NO heads should be milled without also milling the intake face to correct the angles. I've yet to figure out the logic of milling intakes. There's nothing wrong with intake..it's the heads that are out of whack.

There are "machinists" and then there are "hackers" and "whitlers"!!

JIM

driver
Feb 19th, 06, 11:33 PM
I knew something was slowing my 502 down!!

Importtech
Feb 20th, 06, 7:20 AM
=

What the hell kind of machine shops are you guys using that don't know how to correct the intake face of a set of heads?? :D

If the bolt holes don't line up neither do the ports.
If the ports don't line up you are probably leaving power on the table,

You go out, spend the money for decent heads & then kill part of the flow by half as$ing the intake installation ???

Why not have your heads corrected while they are off?


I'm kinda wondering this myself....the machine shop I've always used has been in business for at least 20 years. I know for a fact the owner built/runs a blown altered that ran 177mph in the 1/8th mile. It's called outlaw racing so you'd think he should know. I didn't specifically asked to have it done but then should I have had to? I would have preferred to have the intake side of the heads cut if thats the way to do it however since they are on I guess I'll opt for cutting the intake. Fortunately I'd consider this intake a sacrificial piece. This brings me to another thought..What happens if you cut say the .050 I've lost (.035 heads, .015 block) on the intake side of the heads then later you want to used these heads on another engine which hasn't been decked don't you run again into a similar issue? What about changing head gasket thickness?

GOSFAST
Feb 20th, 06, 7:42 AM
While you're getting all the milling done, make them take .100" off the block on the end rails. For the most part we don't stop to "measure" this area (only) anymore and automatically "chop" that right off the ends. Haven't had any problems up to this point. We use only "The Right Stuff" on these rails. front and rear, in all our units except the "resto's". Thanks, Gary in N.Y.

540Hotrod
Feb 20th, 06, 9:16 AM
You want to get the heads as close as you can to being right all by themselves. When you do, a few .000's either way won't kill you as you juggle head gaskets and decks. At this point there isn't an intake made that will work with those heads. You will be forever milling intakes no matter what you put them on. If done right you can swap intakes all day long and know they will bolt up.

Pull the heads back off and go have the faces cut. It's only bolts and they turn both ways. the head gaskets aren't ruined yet...just reuse them.

You'll be much better off in the long run.

JIM

71454Chevelle
Feb 20th, 06, 11:18 AM
I had my 049 oval ports flat milled by 0.040".

If I remember correctly, they took 0.020" off the intake side of the head.

No problems with alignment. Went together with zero problems. :thumbsup:

CharlieCobra
Feb 20th, 06, 11:27 AM
No doubt.

Wolfplace
Feb 20th, 06, 2:33 PM
I'm kinda wondering this myself....the machine shop I've always used has been in business for at least 20 years. I know for a fact the owner built/runs a blown altered that ran 177mph in the 1/8th mile. It's called outlaw racing so you'd think he should know. I didn't specifically asked to have it done but then should I have had to? I would have preferred to have the intake side of the heads cut if thats the way to do it however since they are on I guess I'll opt for cutting the intake. Fortunately I'd consider this intake a sacrificial piece. This brings me to another thought..What happens if you cut say the .050 I've lost (.035 heads, .015 block) on the intake side of the heads then later you want to used these heads on another engine which hasn't been decked don't you run again into a similar issue? What about changing head gasket thickness?
=
It is not free to cut so it should have been your decision but I think they should have asked if you wanted it done & at the least explained what you could run into not doing it.
Me,,, if you bring the head in & want more than .010 or .012" you are gonna get it done & get charged for it or you can take the heads elsewhere,,,
I don't want to hear how stuff didn't fit after you leave because I didn't do it right. :D

Just have the heads cut the next time you have them off. :thumbsup:

If they had cut .035-.040 off the intake side of your heads chances are we would not be discussing this,,,

Also, as was mentioned if the top of your block wasn't cut you may need to whack some off the bottom of the intake in your case but this is doubtful.
There is normally enough gap here that it's not an issue but it can bite you.
I don't recommend .100 off but I do normally take off 1.5 times what I cut off the block.
It depends on the measurement from the crank centerline as a lot of blocks are short from the factory print here & end up not needing anything but a clean-up cut,,
Just did a 350, cut the deck to 8.977 which is .048" from nominal & the top of the block (china wall) only needed about .015 to put it .070 below spec & I don't think it had ever been cut??
Never assume :sad:

Importtech
Feb 20th, 06, 8:07 PM
Well took my intake to the shop today...Apparently they use an "eyeball method" to decide how much to cut an intake when they build one which would be pretty difficult since the shortblock is at my house. He didn't seem to think it would take much however we "agreed" to take .040 off. We'll see how it goes. I may have to rethink where I go next time... Not pulling the heads off and wasting 2 special order steel gaskets and unwilling to risk reusing them. I don't mind paying for the work but allitle perturbed about having go back. I'll fix the heads next time they are off. Appreciate the advice...good learning experience for me :)

Importtech
Feb 21st, 06, 8:36 PM
Got the intake back today....The .040 cut seems to have done the trick as the intake bolts up now. I did a dry mockup (with intake gaskets in place) and I only have .030-.035 clearance on the end rails between the block and intake(they didn't cut ends on intake dont ask me why). Will this be sufficient and seal okay with silicone.

GOSFAST
Feb 21st, 06, 9:35 PM
Got the intake back today....The .040 cut seems to have done the trick as the intake bolts up now. I did a dry mockup (with intake gaskets in place) and I only have .030-.035 clearance on the end rails between the block and intake(they didn't cut ends on intake dont ask me why). Will this be sufficient and seal okay with silicone.

Get a hold of "The Right Stuff" by Permatex if you can locate it where you live. It's not cheap, but it's about the best silicone/adhesive sealer on the planet. The clearance you have now is fine, but you see why I stated above to take .100" off the ends of the block. If the shop had done it in the beginning you would have about 1/8" between the block and intake. But you're good to go anyway! Thanks, Gary in N.Y.

Importtech
Feb 21st, 06, 9:44 PM
Thanks Gary!!