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Old 03-15-2010, 07:37 PM
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Overheating BBC Gen 5

OK...so I've put together a 92' BBC Gen 5 4 bolt mains 454, with Pro Top line's 320 aluminum cylinder heads. I'm running a 6-71 blower w/twin 850 demons. Timing set at 14*base/34 total. High cap. wieand water pump, aluminum radiator. Twin fans w/shrouds.
It overheats....like runs upwards of 215-230! I've heard that I may have the wrong head gaskets on it?, and that I should have plugged the forward water passages,( that would force the water through the engine up through the rear of the cylinder heads, then forward & out the top front). This block was designed to have the water pump run in reverse rotation, but I now have it running in the early version standard rotation clockwise.
Has anyone heard of this...or fixed this problem?
Thank you.

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Old 03-15-2010, 07:56 PM
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I have limited expierence with blowers, however I am a journeyman for a monster truck team. We run a 15-1 comp BBC alky with a intercooler.

I have a few questions for you. Is this a new build? How much compression do you have and how much boost are you running?

When you say that it was designed for reverse flow, what did you do to make it a standard flow?

Boost proportional timing retard?

If you can answer these questions it may help in tracking down your heat problem.

Small blowers and big engines don't like to spin very fast. The faster the blower spinsthe more heat it generates. It will heat up the intake charge, in turn heat the whole engine.

I am not saying that your blower is too small, just has to spin faster than a 8-71 to make the same boost.
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Old 03-15-2010, 08:35 PM
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Quote:
Originally Posted by 68prostreet
This block was designed to have the water pump run in reverse rotation, but I now have it running in the early version standard rotation clockwise.
Are you saying that you're running a serpentine-style water pump that was intended to turn counter-clockwise, but you are driving it clockwise. If that's the case, then remove the serpentine-style pump and bolt up a vee-belt pump that is meant to turn clockwise.
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Old 03-15-2010, 08:45 PM
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Quote:
Originally Posted by techinspector1
Are you saying that you're running a serpentine-style water pump that was intended to turn counter-clockwise, but you are driving it clockwise. If that's the case, then remove the serpentine-style pump and bolt up a vee-belt pump that is meant to turn clockwise.
That's what I was thinking in my post.
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Old 03-15-2010, 10:02 PM
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answers

The Gen 5 BBC was designed to run a serpentine belt water pump that ran counter-clockwise. I'm running a standard 68 short BBC water pump that runs clockwise on a v-belt. From what I've learned, the coolant holes in the deck are different than the Mark IV & earlier blocks. Even when the blower is running 9% under driven, with a max of 3psi of boost, it still runs warm. Obviously, not as warm as when it's running 12psi of boost, 9% over driven.
Built the engine 4 years ago and have been trying new items since then to bring down the temp. It has 8.5 - 1 compression, runs on pump gas but "Loves" race fuel. Runs warm then too. And yes...the MSD 6BTM is a boost reference retart system that is controllable from the driver's seat.
I guess I'm looking for someone who has experience with the Gen 5 block, that has tried this combo.
When I'm running down the highway, even on a hot summer day I can just keep it at the operating temp., otherwise if it's stopped for more than say 5-10 minutes....it overheats.
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Old 06-28-2010, 11:50 PM
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Problem repaired!

So here's the fix....Victor makes headgaskets that are specific L/H & R/H. They block off the water ports on the front of the engine, and open up the rear ports. They also have more material along the lifter valley. This is for when you use the early cylinderheads on the Gen 5 block, (91-95 454).
I put them in & have no overheating problem's...none...nada!
Time to go cruizn'!
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