Fresh Rebuilt 12a Running Hot!
Fabricator
Joined: Jan 2004
Posts: 1,322
From: Central Ohio (Hebron) Zephyrhills Fla.
[quote name='baja bug 12a' date='Jul 25 2005, 05:19 PM']I have a 12a in my baja bug, and can't seem to keep it cool when im out running it hard. I have a big radiator with dual fans, So i was thinking about putting a oil cooler with a fan on it. Any thoughts.
[/quote]
The engine expells about one third of its total heat load through the oil.
A Very large oil cooler is a must.
Lynn E. Hanover
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The engine expells about one third of its total heat load through the oil.
A Very large oil cooler is a must.
Lynn E. Hanover
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Member
Joined: Dec 2004
Posts: 40
[quote name='Lynn E. Hanover' date='Jul 26 2005, 03:57 AM']The engine expells about one third of its total heat load through the oil.
A Very large oil cooler is a must.
Lynn E. Hanover
[/quote]
So you think i should get a larger oil cooler? Any brands you can think of??
A Very large oil cooler is a must.
Lynn E. Hanover
[snapback]742647[/snapback]
[/quote]
So you think i should get a larger oil cooler? Any brands you can think of??
Fabricator
Joined: Jan 2004
Posts: 1,322
From: Central Ohio (Hebron) Zephyrhills Fla.
[quote name='baja bug 12a' date='Jul 26 2005, 03:36 AM']So you think i should get a larger oil cooler? Any brands you can think of??
[/quote]
I have three thirteen row Setrabs on the race car. Very pricy though. In older days when money was tight, we used GM evap cors from full size cars.
Wrap them in wet towels and TIG on some dash 12 AN fittings. They are about 4" thick and 13" by 13". One fan on each and you are there.
The late style Chrysler Mini vans have very nice evaps also.
Two stock RX-7 coolers in paralell would work well. Get them cleaned but don't paint them.
Lynn E. Hanover
[snapback]742650[/snapback]
[/quote]
I have three thirteen row Setrabs on the race car. Very pricy though. In older days when money was tight, we used GM evap cors from full size cars.
Wrap them in wet towels and TIG on some dash 12 AN fittings. They are about 4" thick and 13" by 13". One fan on each and you are there.
The late style Chrysler Mini vans have very nice evaps also.
Two stock RX-7 coolers in paralell would work well. Get them cleaned but don't paint them.
Lynn E. Hanover
Senior Member
Joined: Jun 2004
Posts: 524
Originally Posted by Lynn E. Hanover' date='Jul 26 2005, 04:44 PM
I have three thirteen row Setrabs on the race car. Very pricy though. In older days when money was tight, we used GM evap cors from full size cars.
Wrap them in wet towels and TIG on some dash 12 AN fittings. They are about 4" thick and 13" by 13". One fan on each and you are there.
The late style Chrysler Mini vans have very nice evaps also.
Wrap them in wet towels and TIG on some dash 12 AN fittings. They are about 4" thick and 13" by 13". One fan on each and you are there.
The late style Chrysler Mini vans have very nice evaps also.
Very interesting! I never thought of evaporator cores in that way. But when you think about it, they are built to handle high pressure, and transfer heat efficiently.
I have an evaporator from a Ford Windstar in my project bin. I was contemplating making a water-air intercooler out of it. It's about the same area and thickness as a stock '79-82 RX-7 oil cooler.
So you plumb your oil coolers in series, or in parallel? If you do it in series, do you try to bias airflow to any given cooler?
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Joined: Jul 2001
Posts: 17,839
From: NJ
[quote name='aspirated' date='Sep 8 2005, 09:38 AM']my opinion is that you should have gotten the water jackets modified
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it would probably still over heat even if they were modified
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it would probably still over heat even if they were modified
Super Moderator
Joined: Jul 2001
Posts: 17,839
From: NJ
[quote name='re10' date='Sep 10 2005, 05:11 PM']You can't beat factory Mazda oil coolers... and you should not run a rotor without one!
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he has one on there now already. time for a second one or to go way bigger
[snapback]757177[/snapback]
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he has one on there now already. time for a second one or to go way bigger
Fabricator
Joined: Jan 2004
Posts: 1,322
From: Central Ohio (Hebron) Zephyrhills Fla.
[quote name='heretic' date='Aug 19 2005, 04:33 PM']Very interesting! I never thought of evaporator cores in that way. But when you think about it, they are built to handle high pressure, and transfer heat efficiently.
I have an evaporator from a Ford Windstar in my project bin. I was contemplating making a water-air intercooler out of it. It's about the same area and thickness as a stock '79-82 RX-7 oil cooler.
So you plumb your oil coolers in series, or in parallel? If you do it in series, do you try to bias airflow to any given cooler?
[/quote]
One Setrab is in the pressure loop after the filters (two K&N 8001s).
Two Setrabs in series after the scavenge section of the pump, then two Peterson in line 70 micron filters in paralell.
In theory, the first cooler in the series arangement will require less airflow to be as effiecient as the second because of a higher delta T. In other words, the higher the difference between the oil cooler temp and the air temp the better.
The downside that engineers overlook is that lower lower flow rate of a paralell system lowers the turbulant scrub effect, where the cooled oil tends to stick to the inside of the tubes and insulate them from the hotter oil. Higher velocity means more scrub and better cooling. A big deal in aircraft, where cooler sizes tend to be too small to start with because of weight.
If you can get the wide open throttle oil temps under 180 degrees, your water temps will come down to normal.
Lynn E. Hanover
I have an evaporator from a Ford Windstar in my project bin. I was contemplating making a water-air intercooler out of it. It's about the same area and thickness as a stock '79-82 RX-7 oil cooler.
So you plumb your oil coolers in series, or in parallel? If you do it in series, do you try to bias airflow to any given cooler?
[snapback]750328[/snapback]
[/quote]
One Setrab is in the pressure loop after the filters (two K&N 8001s).
Two Setrabs in series after the scavenge section of the pump, then two Peterson in line 70 micron filters in paralell.
In theory, the first cooler in the series arangement will require less airflow to be as effiecient as the second because of a higher delta T. In other words, the higher the difference between the oil cooler temp and the air temp the better.
The downside that engineers overlook is that lower lower flow rate of a paralell system lowers the turbulant scrub effect, where the cooled oil tends to stick to the inside of the tubes and insulate them from the hotter oil. Higher velocity means more scrub and better cooling. A big deal in aircraft, where cooler sizes tend to be too small to start with because of weight.
If you can get the wide open throttle oil temps under 180 degrees, your water temps will come down to normal.
Lynn E. Hanover
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