reverse flow cooling a BBC?
Thread Starter
Heel & Toe
Joined: Apr 2002
Posts: 22
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From: boise id
reverse flow cooling a BBC?
Any engine experts here ever try to modify a big block chevy to flow coolant to the heads first? Its hard to ignore the perfomance advantages while running low octane fuel. If so how was it done? Did it work? What compression was tested etc? Thanks!
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: reverse flow cooling a BBC? (neckcrank)
I have never done it to a big block but I have done it to a few small blocks. To just reverse cool it was only slightly benificial. To supply coolant to the front of the head and exit it from the front of the block still left a lot of temerture variation throughout the motor.
To reverse cool and balance cool was very benificial. But to do that I had to supply coolant at three spots on top of the each head (front, center and rear) and exit coolant at three spots on each side of the bottom of the block (front, center, and rear). By doing that it was not allowing heat from each cylinder to heat the water as it traveled from the front to the rear of the head. You also have to study the coolant flow very closly and adjust the size of the passages on the heads/head gasket/block to eliminate any hot spots. This whole process requires a lot of external plumbing to accomplish.
The end result was I was able to raise the compression ratio a full point and show no negative signs of detenation.
The motors I did this on were a 420 CI with -12 Brodix heads at 14.8-1 compression and a 434 CI with Brodix 18 degree heads at 15.6-1 compression.
To reverse cool and balance cool was very benificial. But to do that I had to supply coolant at three spots on top of the each head (front, center and rear) and exit coolant at three spots on each side of the bottom of the block (front, center, and rear). By doing that it was not allowing heat from each cylinder to heat the water as it traveled from the front to the rear of the head. You also have to study the coolant flow very closly and adjust the size of the passages on the heads/head gasket/block to eliminate any hot spots. This whole process requires a lot of external plumbing to accomplish.
The end result was I was able to raise the compression ratio a full point and show no negative signs of detenation.
The motors I did this on were a 420 CI with -12 Brodix heads at 14.8-1 compression and a 434 CI with Brodix 18 degree heads at 15.6-1 compression.
Thread Starter
Heel & Toe
Joined: Apr 2002
Posts: 22
Likes: 0
From: boise id
Re: reverse flow cooling a BBC? (Pete79L82)
WOW! What if you also ceramic coated the combustion chambers, valve faces, exhaust ports and while you're at it the exposed area of the exhaust valve stem? I did all this and it never gets over 190* water temp. but its low compression for a tow vehicle So if both were done...I wonder :crazy:
Burning Brakes
Joined: Nov 2001
Posts: 787
Likes: 1
From: Toronto Ontario
Re: reverse flow cooling a BBC? (neckcrank)
Why do it. I run my 70-454 BB with the stock 4-core Rad and a 180 Stat it runs at 180F to 190F with the air on. Dont waste your time and money on crazy crap. Fix what you have as so it performs like new. Dont try to outsmart the engineers.
