Head Bolts won't line up

Jim Brierley said:
If it's a Denver Miller, I would suspect the head is off a little. I once had a new one and the push-rod holes were not drilled all the way through.
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Jim, do you mean a Miller head produced in Denver? Are all Miller heads slanted on the left side? I believe mine is a Cragar since it is square all around. Of course, mine now has a Brierley cam.
 

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George Miller said:
All engine blocks that I worked on are coarse thread. You would never use a fine thread for cast block.

I would get a .015 over size drill bit, and drill out the holes that are off. Or use a 15/32 on the hole that does not line up.
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George, you need to invest in a Dodge Brothers. Their head studs are fine thread in the block, 7/16 X 20 if I remember right. It goes against everything I know as a lifelong machinist. Rogeroadster, I'm glad you figured it out, sounds like an easy fix.
 
Tod said:
I don't know how thick the material is on the head you are talking about but Snyder told me they had occasional problems with bolt holes from the shop that machined the 5.5:1 heads before I took them over. They were not peck drilling them and so there was wandering of the drill. This may have happened with this head you have. It would most likely present itself towards the end of the drill's life. I use only carbide tipped drills and flood them with coolant and peck the drill at .150 per peck. I have had to start programs over after drilling is finished and when the drilling portion runs again there is no sound coming from the drill re-drilling the drilled holes. That's when you know you have things in order.

Tod
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Not to hijack my own thread but what are the advantages of peck drilling? Do you have a program that does this or must you manually feed .150 each time? The head is 4" thick.
 
rogeroadster said:
Jim, do you mean a Miller head produced in Denver? Are all Miller heads slanted on the left side? I believe mine is a Cragar since it is square all around. Of course, mine now has a Brierley cam.
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From the picture that you show, that is a 'cragar' rocker box cover, produced in LA.
Since there were a number of different rocker boxes made, and they all fit other such heads, by itself, that does not prove anything about who made this head.
Is there a large 'A' in the corner, top of head...outside the rocker box ?

BTW..what LENGTH of bolts are you using/going to use ? Got to be careful there also.
 
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rogeroadster said:
Not to hijack my own thread but what are the advantages of peck drilling? Do you have a program that does this or must you manually feed .150 each time? The head is 4" thick.
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If you force a drill bit through solid material it will most likely lead off to one side. The hole will not be straight. By pecking the drill has time to correct itself on it's travel through the darkness. It can be done by hand or CNC program.
 
noboD said:
If you force a drill bit through solid material it will most likely lead off to one side. The hole will not be straight. By pecking the drill has time to correct itself on it's travel through the darkness. It can be done by hand or CNC program.
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This pretty much sums it up. Plus, pecking allows coolant to access the inside bottom of the hole and the whole length of the drill to keep things from overheating and to keep the drill lubricated, as well as removing unwanted chips. Small increments are not bad when a CNC machine is doing it because they rapid travel in and out of the hole so quickly.

Tod
 
Tod said:
This pretty much sums it up. Plus, pecking allows coolant to access the inside bottom of the hole and the whole length of the drill to keep things from overheating and to keep the drill lubricated, as well as removing unwanted chips. Small increments are not bad when a CNC machine is doing it because they rapid travel in and out of the hole so quickly.

Tod
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Thanks, that's a new term for me...just when you think you've heard it all.
 
Roger, I have Chevy main bolts on my B and have used them on many B's. I like the look and no seaping of water.
 
Further inspection reveals...Looks like someone has modified this head (shouldn't be surprised, these things have had long and colorful lives). Looks like the original hole size is 15/32, the left front hole has been counter bored to 1/2" all but about the last 1/2"of the depth of the hole then it remains 15/32". The left rear hole has been drilled out to 5/8" and then sleeved with a copper tube and reamed to 31/64". I'm thinking about reaming the left front hole the rest of the way to a size of 31/64". Does this sound dangerous?
 

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some one may have tried to repair cracks by installing sleeves in bolt holes. I had a damaged miller head that was repaired that way. be sure to pressure test it. Also check your pushrod side clearance particularly if you are plugging the stock valve seats in the block with aluminum inserts. I found the rocker tips and tappets did not align causing the pushrods to rub on the insert.
 
jetmek said:
some one may have tried to repair cracks by installing sleeves in bolt holes. I had a damaged miller head that was repaired that way. be sure to pressure test it. Also check your pushrod side clearance particularly if you are plugging the stock valve seats in the block with aluminum inserts. I found the rocker tips and tappets did not align causing the pushrods to rub on the insert.
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This head was pressure tested by the seller but speaking of cracks, here's what I discovered today. The brass is a past repair and it looks like it won't be long before this reaches into the #2 combustion chamber. I guess I'll make a trip to the machine shop on Monday. Hope they can stitch it.
 

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hardtimes said:
From the picture that you show, that is a 'cragar' rocker box cover, produced in LA.
Since there were a number of different rocker boxes made, and they all fit other such heads, by itself, that does not prove anything about who made this head.
Is there a large 'A' in the corner, top of head...outside the rocker box ?

BTW..what LENGTH of bolts are you using/going to use ? Got to be careful there also.
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No A cast into the head but there is the numbers 5007 and NI-CH. Bolts are 7/16 by 5 1/2 grade 8. That's what came with the head.
 
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