Reverse Flow Cooling Questions

[toad490]

Hi, I bought a reverse flow plate from Indy, now I'm having second thoughts about it. Has anybody used this setup on the street how does it cool?

When I bought the plate I didn't realize it took a SBC electric water pump not a BB Mopar, so switching back isn't as simple as tossin the plate if it dosen't cool on the street. I've done a partial block fill, to the top of the frost plugs.

[sanborn]

Several years ago, "Reverse Flow" was the trick of the week. Everybody decided to "Monkey See--Monkey Do". And a lot of $$$ was spent on this. A lot of oval track racers found out that if coolant flow was not managed properly on a standard flow engine---that reverse flow didn't solve their problems. A lot of street rodders found the same thing.

Now, with all those negative comments said---"Reverse Flow" does work and does help to get the cooler coolant to where it needs to be---in the cylinder head first. But you still have the same problem of even distribution of cooler coolant in the cylinder head. You don't just dump it in the front of the head and expect it to be that much help. You need to plumb the coolant into the front and back of the head. And really, it needs to go into the center of the head also---since that is the hottest part of the head. The center of the head is really where the coolant should enter the head. But if you put the coolant into the center of the head, it should be extracted from the block at each end. If the coolant is inserted into the ends of the head, it should be extracted from the block in the center. And the head gasket needs to be for reverse flow as well---there is a difference.

I hope my explanation didn't go around in circles too much---but it really needs to be thought out properly.

[toad490]

Food for thought. The sbc pump is alot less than one for a 440. I don't have cooling a problem now but I'm putting in a 511" and I don't want any with it. Indy claims a 15 hp gain, it dosen't say if thats on top of any gains from the electric pump or not.

[DartGT66]

I thought about reverse cooling too, but decided not to. Just didn't want to be the one that does the trial & error thing. Have thought about pulling out or putting in water between the center exhaustports, but I think I have too much plumbing ahead for the new twin turbo even without that feature.

[HankL]

Interesting discussion.

Supposedly the Dodge smallblock for NASCAR had a lot of work done on the cooling system flow balance. Anyone have details?

I have been running the Evans NPG coolant on a 360 Magnum for nearly 100,000 miles now with 180, 195 and 205 thermostats. Very low corrosion, but no gains seen on reduced detonation.

[pishta]

There is a stout Ram SB Magnum stroker truck somewhere on this or other board that claims to run 11-12:1 compression on pump gas with reverse cooling and no ping. I would be on it if it cooled any better than standard cooling, but I would run a shogun remote pump with their manifold, very small system.

[sanborn]

I don't know about the CURRENT Mopar Nascar engine, we don't use the current engine. But, I can tell you about the prior Mopar Nascar engine---the "R" block, W8 headed engines.

They were standard flow coolant engines, with a small amount of coolant into the standard inlet---the bulk of the coolant fed a manifold down along the bottom of the block on each side. From the manifold the coolant entered the block at three locations along the bottom of the block(each 1/2"NPT), most flowed upward past the exhaust valves. A lesser amount flowed through the block and came up into the head along the top of the cylinder bores. The coolant exited through two outlets, one at the front, one at the back of each head. A few teams also brought coolant out of the head in the center---most didn't. Once out of the head, the coolant was collected into a manifold and went to the radiator for cooling.

[cageman]

I did almost the exact same thing on a 360 once, It didnt last 3 nights, and it always gave me iradict readings, I think I had too big of a manifold that came out of the head, I had four half inch lines into a 1 1/2 by 6 or 7 inch long manifold, I think I needed to restrict that manifold somehow with a venturi, as I dont think it kept any pressure in the block, kinda like running a garden hose in a hallway, you just cant get pressure like that
That poor motor went like a raped ape, but I ruined 5 pistons and melted the cylinder walls, or scored them I guess. I had to throw the block away, as it was 40 over(Rules). It was probably because the system wasnt under any pressure and when that happens, water boils at 212, probably less as it was tap water, so maybe around 200 in my case. when that happens, the exhaust gets so dang hot that the water just turns to steam, and steam displaces water at 7 times the area of water, so it pushes the water right out of the motor. If you have ever dipped red hot metal into a bucket of water, you can see that the water kind of dances on top of the metal and it never transfers any latent heat fom the metal, so the water in my system just flowed right over the metal and never displaced any heat at all, so that allowed the metal to get hotter with each igniton stroke. At low rpm it would spike the guage instantly, why, because the water slowed down and actually transfered the heat to the water from the heads, so it would read hot, I had the guage screwed in the manifold I made, and all of the engines water went thru it. I would rev on it a little and the temp would come down, as the fan was cooling the big ol dual pass alum rad I had. The race would start and I would go, the water showed cool, like 180, why, because the water just went right over the heads and into the rad as fast as it could and it wouldnt give an acuurate reading on the guage. A few laps of that and it completly melted my motor down.
I probably could have tried four 3/8 hoses from each head into the upper manifold and ran maybe a half inch hole venturi in the upper rad hose, to keep the block pressurized.
In all that, I learned that getting all the air out of a standard cooling sytem will by far be a superior setup, and it cost me a lot of money, trying to do something, Different.

[sanborn]

Cageman, you are correct about building pressure throughout the cooling system. You must build pressure in the engine in order to carry the heat away from the engine to the radiator where it can be cooled.

I do it by insuring the inlet(s) cross-sectional area going into the block is at least 25% larger than the outlets out of the head. If you do the reverse(outlets larger than the inlets), you drop pressure in the head/block and can lead to hot spots. And you just described the results.