so the next step in my v8 swap is bending up coolent lines for C4 im running a 302 with full length tubes so putting the lines along the side of the block like stock may not be the best because of the heat. i have a rad for an automatic car but ive also got an external cooler comming from mavdog71 (http://www.maverick.to/mmb/showthread.php?t=44696) i dont know if i should use the rad too or if that cooler will be fine on its own. i also have to mount it up some how if one of you guys could set me up with a shopping list, advice, and maybe some pics i'd really apperciate it. this will be my first time doing my own trans lines
I used 3/8" transmission cooler hose all the way from the trans to the external cooler. Some might say metal is better, and it does have its advantages in durability and probably a marginal amount of cooling help, but rubber has its advantages too, in that you can run them wherever you want and you don't have to worry about whether it's going to leak where you clamped in the hoses for your cooler. I bought brass fittings at Lowe's, and plugged them into the trans where the factory lines go. I got one piece threaded the same as the factory lines going into an elbow, and from there to a 3/8" barb fitting. I might have been able to just stick a barb fitting into the trans, but I felt like this would give me more clearance in the trans tunnel. Then I just ran my hoses straight up to the cooler in front of the radiator, making sure they were securely attached under the car and away from anything hot or mobile. I don't have a cooler in the radiator, however I do have a trans temp gauge, and with only a 15x7" cooler, (smaller overall than the one you're getting) I can say with total confidence that this is more than adequate for my application. (3.00 gears, 27" tire diameter, 2500 stall.) I romp on it pretty hard too. Granted I haven't been running this setup for long, but so far I'm very happy with it. I also haven't towed anything. Not that I plan to...
Since the ports in the C4 are under 1/4" lines larger than 5/16" are a real waste of time. Running metal lines is always best and if you have a radiator cooler then run the front line to the radiator cooler and the back line to the auxillary cooler. Then just connect the two coolers together. It is always best to run both coolers when you have them. If you want to run cooling lines along the fram then run rubber from the transmission to the fram and run metal lines from there on. The drawbacks to rubber are that they can get torn off easily, they hold the heat in, and they will need to be replaced periodically. Be sure to use hydraulic hose where ever you run rubber. You will need hose with a working pressure of 250 PSI and NEVER use fuel line - it will burst.
As always, I defer to the wisdom of PaulS. If I had a cooler in my radiator I would definitely do as he mentions and run it through the radiator before it hits the aux cooler. Also he's quite right about 3/8" hose being overkill, as the ports in the trans case are smaller by a wide margin. My only reason for using that size is simply to fit my cooler and keep the connection points to a minimum. (That's where the leaks always happen, for me anyway. Then again I'm special.) And as with all the rubber hoses in my car, they will certainly have to be replaced at some point.
Paul, curious as to why both coolers? It seems as if that would put your trans fluid through a hot radiator. I by-passed my radiator in lieu of a 15" x 7" and trans has not been over 170* since. (except in a prolonged stall) Not saying it is wrong, just curious... FYI: I ran my lines with braided, not cheap, but easy to route and safe.
after the fluid hits the stock cooler it will come out a little more cooled off before it hits the external cooler and on the way back to the trans it should be that much cooler then just using one or the other. the stock cooler is probably hotter then the aftermarket cooler so if the fluid went to your aux coller first and then into the rad it might gain some heat
My trans temp gauge is always cooler than my engine temp gauge, so I know the radiator is running hotter than my trans. The only benefit I can see in doing it Paul's way - and I DO believe this is a benefit - is to help get the trans up to its ideal operating temperature faster.
Getting the tranny hot (up to temp) is one benifit but when you are pulling a hill with a load your temp can shoot up fast. The oil to water heat exchange can protect the transmission by cooling it back down before it goes to the oil to air cooler which is not as efficient. If you are running a thermostat at over 180 degrees then cut it back down to 180. That way when the tranny temp peaks at 190 (destructive limit) the radiator is doing its job. It also helps vaporize water that may be in the transmission from condensation. Overall it is better for the tranny to use both.
Because in this thread you said it was too low of a temp. Your oil pressure is good - minimums are 5-10 psi for each 1000 RPM. Your tranny temps are definitely NOT normal! normal would be 250 - 350 and it would climb past 350 in a 10 second stall. Your cooler is working! Although the temp is lower than normal it will be fine! (better than good) At over 6000 RPM you could be experiencing valve float, coil saturation (lack of it) problems, induction between wires or poor conduction in the wires or preignition from hotspots in the combustion chamber. With Points it could be point bounce and electronic triggers it might be "rebound" (a pulse timing problem from the magnetic pick-up). An after market capacitive discharge ignition system with a companion distributor should eliminate ignition problems to 8-10,000 RPM. posted 9/9/05 Paul S
I don't remember what the conditions were on that thread - there is a lot of conflict between engine and transmission data in that post. I should let you know that I have just come off methodone after being on it for my back pain for just over three years - I could have said anything. The best temp - not normal but best temp for transmission life is 170 F. For every 20 degrees above that the transmission life is cut in half. The typical C4 runs temps as high as 280-300 F when under extreme load but on the average with normal operating loads it will rarely get above 200 F. Under stall conditions it is easy to get the transmission to the point of oil breakdown which is 350 - 375 F like stalling the converter in a power-brake situation. I do apologize if I misled anyone - it wasn't intentional.
No worries. I was just curious. I asked that question in 2005 with a new motor/tranny etc. My temps were and still are about 130-140* after an hour of driving. Your post stated that that was WAY below normal. I like to learn hence the quesitons. I hope the back feeld better soon! Stop lifting those C6's and it will help!!
c6s? NO WAY I am restricted to 10 pounds. I have a hoist that I use with my transmissions and I haven't touched a C6 in about 5 years (two years before the accident) 140 is a great temp as far as I am concerned - Are you having any condensation problems? I am doing OK with my back once I get out of bed and pace for a couple of hours. It is just real nice to be able to think clearly without having to work so hard at it. The normal level of pain is ok, I can deal with it without drugs. I find that I am smiling more! I will be ok and someday I will be able to lift a C4 again......probably not soon but someday.
