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-   -   Are Rotary Engines that hot? (https://www.rx7club.com/1st-generation-specific-1979-1985-18/rotary-engines-hot-431776/)

Manntis 06-08-05 03:13 PM


Originally Posted by ray green
When you turn off the car, it's not making heat anymore, so just forget about it, it will cool down in an hour or two

It may not be 'making' heat anymore, but it's also not circulating coolant to take the heat away. Engine surfaces tend to warm even more after shutdown, as the still-hot internals radiate the heat to the outside. It peaks about 20 minutes after the fact, then cools from there.

Bass 06-08-05 03:27 PM

You should definately get a shroud around your e-fan. Looking at the gap between your fan and the rad, there's going to be a lot of air being pulled from the sides rather than through the rad itself. I'm in the middle of this mod myself. What I'm doing is modifying the stock shroud so that the fan bolts to the shroud and it's a perfect fit to the rad. It lays nice and flat as I have cut away all the extra material that used to cover the clutch fan.

Eriks85Rx7 06-08-05 03:30 PM

I still have the old shroud i will try modifying it to fit around this. We would have use the plastic clips to make the fan hang on the radiator but after time these tend to sag and ruin the radiator. So we got some aluminum pieces and made a frame to bolt it on to.

bliffle 06-08-05 05:05 PM


Originally Posted by Manntis
It may not be 'making' heat anymore, but it's also not circulating coolant to take the heat away. Engine surfaces tend to warm even more after shutdown, as the still-hot internals radiate the heat to the outside. It peaks about 20 minutes after the fact, then cools from there.

Good point. It would help if an electric fan was coordinated with an electric water pump to circulate hot water from the engine to the radiator after the engine is shut down, but I've never heard of such a thing.

A rotary mechanic once told me that there is danger of the engine overheating at a place near the bottom of the engine after it is shutoff because the water is trapped and can go over the superheat temp of the pressurized system because it can't circulate.

F

PaulFitzwarryne 06-08-05 05:35 PM


Originally Posted by Manntis
It may not be 'making' heat anymore, but it's also not circulating coolant to take the heat away. Engine surfaces tend to warm even more after shutdown, as the still-hot internals radiate the heat to the outside. It peaks about 20 minutes after the fact, then cools from there.

In theory yes, but if you measure the surface temperatureoutside of the housing the actual variation is minor mainly caused by lack of air flow. The total heat of the engine will not increase. Thus, I cannot see how any damage will be caused to the engine. As I said earlier, the only possible exception would be the turbo with its high rpm needing lubrication on the spool down. This is the benefit of a turbo timer which keeps the engine running for a short period.

As for rotary temperatures, I suggest headers reach around 1500 degrees, mufflers around 600-700 degrees with the engine housings 180-200 degrees.

A rotary and modern high performance oils should easily handle normal temperatures. Loose the water pump and watch the engine destroy itself!

ray green 06-08-05 09:06 PM

"It may not be 'making' heat anymore, but it's also not circulating coolant to take the heat away. Engine surfaces tend to warm even more after shutdown, as the still-hot internals radiate the heat to the outside. It peaks about 20 minutes after the fact, then cools from there."

Youch, teenagers beware! Don't move too fast!

Ray

smnc 10-11-05 12:22 PM

Reviving a dead thread...!


Originally Posted by bliffle
Good point. It would help if an electric fan was coordinated with an electric water pump to circulate hot water from the engine to the radiator after the engine is shut down, but I've never heard of such a thing.

Interesting idea... There are a couple electric waterpumps available...

Combined with a temp sensor... Plus a timer or low voltage sensor to make sure the battey doesn't drain...

Hmmm...

skrewloose78 10-11-05 06:26 PM

there was a controller available at one time that when the car was shut down it would toggle between the water pump and fan(run fan for set amount of time then run water pump). i looked but i wasnt able to find it now.
you could however run an electric water pump (or a universal remote mounted one) with an electric fan off of a thermostat(1 for both or 1 on each) hooked directly to the battery. this would allow the pump and the fan to run as long as the temp was above the set limit . to keep it from running the battery down you can run a battery buddy(device that disconnects the battery if voltage gets too low so you can still crank it) although i never had a problem with the fan killing the battery on my -se

rootbeerdragon 10-11-05 07:41 PM


Originally Posted by ray green
Maybe you shouldn't be sticking your fingers on a hot engine? I'll bet you are a teenager. Teenagers think everything should have happened like yesterday. When you turn off the car, it's not making heat anymore, so just forget about it, it will cool down in an hour or two (also, you might want to check the thermostat on that electric fan install, or go back to the stock fan, the way it's supposed to be). If the engine temp goes up while your driving around, give us another call.

Respectfully yours
Ray


Im 16, i dont go and sticking my fingers on hot housings, but they sure fit well in your womens pussy

Respectfully Pimpin' your wife
Bitch

smnc 10-11-05 09:56 PM


Originally Posted by skrewloose78
you could however run an electric water pump (or a universal remote mounted one) with an electric fan off of a thermostat(1 for both or 1 on each) hooked directly to the battery. this would allow the pump and the fan to run as long as the temp was above the set limit . to keep it from running the battery down you can run a battery buddy(device that disconnects the battery if voltage gets too low so you can still crank it) although i never had a problem with the fan killing the battery on my -se

That's pretty much what I was thinking...

Just a nice low setting, say half speed for both the fan and pump...

jays83gsl 10-11-05 10:19 PM

Hmm, mine only takes about an hour to cool down. . . . maybe stock exhaust vs manifold, for some strange reason that defies logic, has something to do with this?


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