Steam Holes
Thread Starter
Racer
Joined: Jan 2004
Posts: 398
Likes: 0
From: Eastern Shore Maryland
Steam Holes
I have a set of RHS 220 Iron heads, are the steam holes needed in the heads? The deck thickness of the heads seem to be way thicker than GM heads and I'm not real comfortable drilling that deep if not really needed.
400 519 block .030 10.4:1 Thanks
400 519 block .030 10.4:1 Thanks
Last edited by qwik-tripp; Oct 1, 2008 at 07:03 PM. Reason: spelling
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Yes, you will need the steam holes.
I would not recommend doing them free hand with a power drill. If you don't have the ability to jig the head into a drill press or mill and do it right then I would suggest dropping the heads off at a machine shop and have them drill the holes.
Here locally it's only $40 - $50 to have the steam holes drilled.
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
Yes, you will need the steam holes.
I would not recommend doing them free hand with a power drill. If you don't have the ability to jig the head into a drill press or mill and do it right then I would suggest dropping the heads off at a machine shop and have them drill the holes.
Here locally it's only $40 - $50 to have the steam holes drilled.
I would not recommend doing them free hand with a power drill. If you don't have the ability to jig the head into a drill press or mill and do it right then I would suggest dropping the heads off at a machine shop and have them drill the holes.
Here locally it's only $40 - $50 to have the steam holes drilled.
steam holes are a must on sbc400
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Several aftermarket iron sbc blocks available ... and those with siamezed cylinders (like OE 400) do not have steam holes in block ... I see this in both 4.000 & 4.125 aftermarket iron sbc blocks.
Seems like maybe member "Motorhead" may've recently completed a siamezed aftermarket sbc about 427"??? wonder if he had steam holes in block/heads?
Wondering why? ... if OE must have them ... why not aftermarket also?
Seems like maybe member "Motorhead" may've recently completed a siamezed aftermarket sbc about 427"??? wonder if he had steam holes in block/heads?
Wondering why? ... if OE must have them ... why not aftermarket also?
Last edited by jackson; Oct 2, 2008 at 01:32 AM.
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Most aftermarkets are considered race blocks and they also have bigger bore walls, which would interfere with the steamholes. It was said that the steamholes were only necessary below 3000 rpm.
Race Director
Joined: Jul 2004
Posts: 12,684
Likes: 329
From: Scottsdale Arizona
BUT, I would just go ahead and do them. I've read lots of debate about the need or lack of it for the steam holes, but didn't ever see anything conclusive or side by side.The bottom line is that they are easy to do if you have a drillpress. If not, is it worth saving $50 and then wondering if this is the reason that you're having overheating problems?
Race Director
Joined: Apr 2000
Posts: 17,672
Likes: 199
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I would drill them if the heads are going on a block that has them
The Motown block I have doesn't have steam holes, it has enlarged areas around the cylinders for extra cooling, kinda hard to see but you can see the bulges at each cylinder in the second pic
The Motown block I have doesn't have steam holes, it has enlarged areas around the cylinders for extra cooling, kinda hard to see but you can see the bulges at each cylinder in the second pic
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Dart's take on (block) steam holes
Interesting response from Dart when asked about steam holes in block.
jackson's Q:
I see new 4.125" bore SHP block looks nice. Seems 4.125" bore block does not have steam holes. Is that so? If so, why does 4.125" SHP not need steam holes.
Dart's A:
None of our 4.125 bore blocks have steam holes, they are the same blocks as the 4.000 bore blocks as well. The reason the factory blocks have them is more of a design flaw than a need. They factory blocks have a pocket where the air could not escape and would cause a steam pocket, therefore the engines would run hot, the idea of the steam holes would be to allow that steam (air pocket) to release and fill with water. They only get used once, from there the air pocket is filled and never again will they make steam inside a sealed water jacket that is full. Our blocks are designed internally in a way to increase coolant capacity, and without any voids, or pockets that water can not get to during that initial fill.
Thanks
John Keyes
Dart Machinery, Ltd.
Phone: (248) 362-1188 ext. 105
Fax: (248) 362-2027
jkeyes@dartheads.com
jackson's Q:
I see new 4.125" bore SHP block looks nice. Seems 4.125" bore block does not have steam holes. Is that so? If so, why does 4.125" SHP not need steam holes.
Dart's A:
None of our 4.125 bore blocks have steam holes, they are the same blocks as the 4.000 bore blocks as well. The reason the factory blocks have them is more of a design flaw than a need. They factory blocks have a pocket where the air could not escape and would cause a steam pocket, therefore the engines would run hot, the idea of the steam holes would be to allow that steam (air pocket) to release and fill with water. They only get used once, from there the air pocket is filled and never again will they make steam inside a sealed water jacket that is full. Our blocks are designed internally in a way to increase coolant capacity, and without any voids, or pockets that water can not get to during that initial fill.
Thanks
John Keyes
Dart Machinery, Ltd.
Phone: (248) 362-1188 ext. 105
Fax: (248) 362-2027
jkeyes@dartheads.com
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Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Interesting response from Dart when asked about steam holes in block.
jackson's Q:
I see new 4.125" bore SHP block looks nice. Seems 4.125" bore block does not have steam holes. Is that so? If so, why does 4.125" SHP not need steam holes.
Dart's A:
None of our 4.125 bore blocks have steam holes, they are the same blocks as the 4.000 bore blocks as well. The reason the factory blocks have them is more of a design flaw than a need. They factory blocks have a pocket where the air could not escape and would cause a steam pocket, therefore the engines would run hot, the idea of the steam holes would be to allow that steam (air pocket) to release and fill with water. They only get used once, from there the air pocket is filled and never again will they make steam inside a sealed water jacket that is full. Our blocks are designed internally in a way to increase coolant capacity, and without any voids, or pockets that water can not get to during that initial fill.
Thanks
John Keyes
Dart Machinery, Ltd.
Phone: (248) 362-1188 ext. 105
Fax: (248) 362-2027
jkeyes@dartheads.com
jackson's Q:
I see new 4.125" bore SHP block looks nice. Seems 4.125" bore block does not have steam holes. Is that so? If so, why does 4.125" SHP not need steam holes.
Dart's A:
None of our 4.125 bore blocks have steam holes, they are the same blocks as the 4.000 bore blocks as well. The reason the factory blocks have them is more of a design flaw than a need. They factory blocks have a pocket where the air could not escape and would cause a steam pocket, therefore the engines would run hot, the idea of the steam holes would be to allow that steam (air pocket) to release and fill with water. They only get used once, from there the air pocket is filled and never again will they make steam inside a sealed water jacket that is full. Our blocks are designed internally in a way to increase coolant capacity, and without any voids, or pockets that water can not get to during that initial fill.
Thanks
John Keyes
Dart Machinery, Ltd.
Phone: (248) 362-1188 ext. 105
Fax: (248) 362-2027
jkeyes@dartheads.com
