Technical Gasket Question from Downunder
Thread Starter
Heel & Toe
Joined: Feb 2005
Posts: 18
Likes: 0
From: Port Macquarie New South Wales
Technical Gasket Question from Downunder
I was about to fit new head gaskets when I noticed that the three large water holes in the heads & block are about 3/4" dia whereas the matching holes in the Victor Reinz gaskets are only 1/8 " dia. Can anyone give me a reason for this? Would it be wise to open up the gasket holes to the same size as on heads & block - coolant would flow faster through the heads hence lower engine temp.
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
No. It would be a huge mistake. The size of the holes in the gasket regulate the water flow paths. Some water will go from the cylinder jackets into the head. Most of the water will go from the pump, through the cylinder case to the rear of the block, up the large passage at the rear, into the rear of the head and pass through the head to the front where it will exit the head into the intake manifold.
This keeps the coolant temperature variations more or less even throughout the block and head. If you enlarged the holes, the front of the head would run much cooler than the rear since the water will take the path of least resistance.
This keeps the coolant temperature variations more or less even throughout the block and head. If you enlarged the holes, the front of the head would run much cooler than the rear since the water will take the path of least resistance.
Racer
Joined: Dec 2001
Posts: 328
Likes: 0
From: Dallas County Texas
I always wondered about doing that....
that seems a very good point. I came very close to doing that with some copper head gaskets when, I guess fortunately, the great gods of laziness intervened and prevented it.... 
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Gerry is correct. Water flow is regulated by the gasket. Enlarging the holes will mess up the flow rates front/rear and lead to problems. Everything I've read indicates the Chevy V8 cooling system is excellent and should be left as designed.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
The large holes are to get rid of the casting sands after the block is cast at the foundry. Most HP motor builders tap the deck and put a 3/4NPT plug into these holes, drill 1/4" holes into the pipe plug for water circulation. The pipe plug helps stabilize the top end of the motor at the m ost critical area around the top of the cylinder bores but, it must be done before final machine work is performed on the cylinder bores. I do this on any engine I anticipate making over 400HP with when I'm using a production type cylinder block.
Thread Starter
Heel & Toe
Joined: Feb 2005
Posts: 18
Likes: 0
From: Port Macquarie New South Wales
Thanks to all who replied & for all the good oil on the gaskets - I will leave the gasket coolant holes as is. What would we do without the excellent advice on this forum!!!!!!!!!
