400 sbc question about running hot? - Page 2 - Team Camaro Tech
Team Camaro Tech join team camaro
 
Camaro Parts at SS396.com     
GROUND UP & SS396.com         
Official Sponsor of Team Camaro
   

Auto Insurance



Registered users (free) do not see these large ads

Engine General Engine Discussion.

Reply
 
Thread Tools Display Modes
  #16  
Old Jul 14th, 10, 10:58 AM
Straight-line-69 Straight-line-69 is offline
Senior Tech

 
Join Date: Dec 2003
Location: Leander, TX
Posts: 2,719
Default Re: 400 sbc question about running hot?

Agree, do what you want to do.

As far as Dart blocks are concerned,..from here:

http://www.dartheads.com/products/en...ne-blocks.html

...is this:

"Scalloped outer water jacket walls improve coolant flow around the cylinder barrels to equalize temperatures."

Obviously Dart addressed the problem of hot spots (steam pockets).

And from World Products, here:

http://www.worldcastings.com/product...ron-block.html

...is this:

"The MOTOWN II boasts 152 fluid ounces of coolant per side and has demonstrated stability lauded by racers and professional engine builders alike."

...and this:

"Water Jackets: Expanded for better cooling"

Again, both Dart and World, addressed the problems of cooling problems and hot spots (steam pockets).
Reply With Quote
Sponsored Links
Advertisement
 
  #17  
Old Jul 14th, 10, 01:08 PM
SY1 SY1 is offline
Senior Tech

Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
Wink Re: 400 sbc question about running hot?

Cub not all 400 blocks are alike. Some have additional cooling holes in the decks and I'm NOT talking about the steam holes. Ligenfelter addresses this in his books and recommends adding the 7/16" cooling holes at the outer deck surfaces between and below the boresof the middle cylinders if yours doesn't already have them. This helps provide additional cooling to the siamesed exhaust ports of the cylinder heads, the hot spot. Also Ligenfelter, Yunick and others suggest tapping the large 3/4" coolant holes above the bores on you block deck surfaces with a NPT tap and installing Moroso deck plugs. While they arguably help strengthen the block deck surface they primarily restrict the volume of coolant that is allowed to move up into the heads at the intake side. This isn't where it's needed and also can prevent adequate coolant to the rear cylinders. The deck plugs reduce the hole from 3/4" to 3/16" and divert more coolant to the rear cylinder water jackets before it's allowed to move upward. If you do this mod, it's eary to do, go slow with the tap, keep testing the plug, you want the plug to tighten BEFORE all the plug is run down into the deck. Leave a slight amount above the deck and it'll be machined flush when the block is decked.

Another recommended action is to insert a brass plug into the bypass port on the passenger side leg of the water pump. Many aftermarket pumps come with this plug already installed.
__________________
"..............what, and get out of aviation??"
Reply With Quote
  #18  
Old Jul 15th, 10, 05:05 PM
cc82z-28 cc82z-28 is offline
Senior Tech

Chet
 
Join Date: Dec 2006
Location: Northern Ohio
Posts: 107
Default Re: 400 sbc question about running hot?

My 406 runs all day long with no issues, I do run a 2 row Griffin radiator, dual electric fans from a 4th gen z-28 or trans am, and yes I had the steam holes drilled into my Dart aluminum heads per their instructions. On the hot days such as today when the temps get into the 90's it will run at 190-195 sitting in traffic and start dropping as soon as I move. I run a high flow aluminum water pump with a 50/50 mixture of water and anti-freeze with some water wetter for good measure. You'll love the power and torque of a 406 without a doubt.
__________________
White and silver 82 Z-28 with a built 406 running a built 700R4 trans with 3000 stall convertor with 3.73 rear gears. Maroon interior with B+M mega shifter Autometer gauges. Custom 17" wheels and tires and C-5 Vette front brakes. Rear discs coming.
Reply With Quote
  #19  
Old Jul 15th, 10, 06:27 PM
Steptoe Steptoe is offline
Senior Tech

Steps
 
Join Date: Dec 2005
Location: New Zealand
Posts: 12,762
Default Re: 400 sbc question about running hot?

Quote:
On the hot days such as today when the temps get into the 90's it will run at 190-195 sitting in traffic and start dropping as soon as I move
A cooling system stock or whatever, ambiant temps make stuff all difference with engine cooling...expept if running in snow and a very low thermstat, runs colder.
And it good a few more guys are coming forward and basically saying so.
Ambiante temps mean squat..if the do effect, something is wrong.
Reply With Quote
  #20  
Old Jul 15th, 10, 08:01 PM
Steiner Steiner is offline
Senior Tech

Steiner
 
Join Date: Mar 2009
Location: Lyman, SC
Posts: 7,528
Default Re: 400 sbc question about running hot?

Alright alright alright. The 400 running hot thing more often then not came from running non-400 heads on a GM 400 block. GM put the steam holes in the block because the way it was cast it could have a pocket develop in certain spots and under certain conditions. 400 heads and gaskets have corresponding holes that let any steam that may form and get trapped at continuous low RPM operation (which Lingenfelter called under 3500RPM) up into the head so it can get swept away. High speed operation without steam holes in the heads can sweep the pockets away on its own. If you know that and you know how your engine is used, it's up to you whether or not to drill the holes in the heads.

Now, I think the confusion comes about because 400's don't necessarily "run hot" by the normal definition which is going by the coolant temperature. The pockets that can form cause a localized hot spot in a place on the block which is subject to high heat which is also a relatively thin spot. Over time this can lead to a crack forming and when it has happened I'll bet the majority of the time it has happened with non-400 heads without steam holes corresponding to the block holes. GM most likely did the steam hole thing not because it was the best option but because it was the cheapest and easiest.

My question is this: If every reputable head manufacturer on the planet says to drill the steam holes in the heads if they are being used on a GM 400 block, why would anyone not do it when using a GM 400 block regardless of what anyone else says? It certainly can't hurt, doesn't cost much, and takes no time. It's like saying that no one in your immediate circle of friends has ever lost an eye while using a grinder therefore safety glasses are never necessary.

The aftermarket blocks do not require it. Why? Because they do not have steam holes in the block. Why? Because the water jackets have been redesigned so that pockets do not form like in a GM block and the area is thicker.

Owner of a Dart SHP 400 block with AFR heads and NO steam holes.
__________________
'69 Camaro X11 Street Car
Dart 400 - AFR-195's - 224/224 HR - Powerjection III
TKO-600 - Moser 3.42 - Detroit Truetrac
538 lb-ft - 500 hp
www.cmengines.com
'69 Camaro X44 Beater - SFT 327 - M20 - Moser 4.10
'02 Z/28 vert - stock
Reply With Quote
  #21  
Old Jul 16th, 10, 07:13 PM
cc82z-28 cc82z-28 is offline
Senior Tech

Chet
 
Join Date: Dec 2006
Location: Northern Ohio
Posts: 107
Default Re: 400 sbc question about running hot?

Quote:
Originally Posted by Steiner View Post
Alright alright alright. The 400 running hot thing more often then not came from running non-400 heads on a GM 400 block. GM put the steam holes in the block because the way it was cast it could have a pocket develop in certain spots and under certain conditions. 400 heads and gaskets have corresponding holes that let any steam that may form and get trapped at continuous low RPM operation (which Lingenfelter called under 3500RPM) up into the head so it can get swept away. High speed operation without steam holes in the heads can sweep the pockets away on its own. If you know that and you know how your engine is used, it's up to you whether or not to drill the holes in the heads.

Now, I think the confusion comes about because 400's don't necessarily "run hot" by the normal definition which is going by the coolant temperature. The pockets that can form cause a localized hot spot in a place on the block which is subject to high heat which is also a relatively thin spot. Over time this can lead to a crack forming and when it has happened I'll bet the majority of the time it has happened with non-400 heads without steam holes corresponding to the block holes. GM most likely did the steam hole thing not because it was the best option but because it was the cheapest and easiest.

My question is this: If every reputable head manufacturer on the planet says to drill the steam holes in the heads if they are being used on a GM 400 block, why would anyone not do it when using a GM 400 block regardless of what anyone else says? It certainly can't hurt, doesn't cost much, and takes no time. It's like saying that no one in your immediate circle of friends has ever lost an eye while using a grinder therefore safety glasses are never necessary.

The aftermarket blocks do not require it. Why? Because they do not have steam holes in the block. Why? Because the water jackets have been redesigned so that pockets do not form like in a GM block and the area is thicker.

Owner of a Dart SHP 400 block with AFR heads and NO steam holes.
Very well put.
__________________
White and silver 82 Z-28 with a built 406 running a built 700R4 trans with 3000 stall convertor with 3.73 rear gears. Maroon interior with B+M mega shifter Autometer gauges. Custom 17" wheels and tires and C-5 Vette front brakes. Rear discs coming.
Reply With Quote
  #22  
Old Jul 16th, 10, 11:10 PM
68rs406 68rs406 is offline
Senior Tech

Sean
 
Join Date: Feb 2002
Location: N.W. Washington
Posts: 7,075
Default Re: 400 sbc question about running hot?

__________________
Sean

1968rs former 406 sbc, now a 354" SB2.2 pump gas motor

"I aint never seen talking win me nothin'" -Marshawn Lynch
Reply With Quote
  #23  
Old Jul 18th, 10, 08:59 AM
lt14spd lt14spd is offline
Gold Lifetime Member

 
Join Date: Jul 2010
Location: Norfolk, VA
Posts: 79
Default Re: 400 sbc question about running hot?

Not to highjack the thread, but where should the holes be drilled? How do you determine the exact location and size?
Thanks
Todd
Reply With Quote
Sponsored Links
Advertisement
 
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 06:42 PM.



Camaros.net - 2009 AutoForums.com