M20/ M42 radiator adaptability.

[FunfGan]

I'm currently doing a Ford 302 swap into my car, and had a question about radiators. Now, I have a few m20 and m42 radiators lying around, but they all have 3 inputs/ outputs for coolant, as apposed to the 302 engine which has only a cold side and a hot side outlet/ inlet. Is there a way to convert either of those radiators to simple have a hot side and cold side?

[FunfGan]

anybody?

[JGood]

I'd be hesitant to run a radiator that small for a 302, especially when you need to modify it to make it fit in the first place. I think I remember reading somewhere that a foxbody 5.0 radiator fits within the e30 frame rails... and it would have the correct hose outlet locations for your application as well. Maybe check the dimensions?

[nando]

I'm currently doing a Ford 302 swap into my car, and had a question about radiators. Now, I have a few m20 and m42 radiators lying around, but they all have 3 inputs/ outputs for coolant, as apposed to the 302 engine which has only a cold side and a hot side outlet/ inlet. Is there a way to convert either of those radiators to simple have a hot side and cold side?

3? huh? my E30 radiators have 2. the "third" is for the expansion/overflow tank and that won't matter what motor you have (and all radiators have them).

[FunfGan]

I'd be hesitant to run a radiator that small for a 302, especially when you need to modify it to make it fit in the first place. I think I remember reading somewhere that a foxbody 5.0 radiator fits within the e30 frame rails... and it would have the correct hose outlet locations for your application as well. Maybe check the dimensions?

I actually bought one, and it didn't fit haha. Should have checked first. But thanks!

3? huh? my E30 radiators have 2. the "third" is for the expansion/overflow tank and that won't matter what motor you have (and all radiators have them).

Thats what I was wondering actually. So the one thats the top left(sitting in the car) of an m42 rad is essentially just overflow for the expansion tank? That actually works wonderfully, thanks! I should have asked that originally.

[FunfGan]

Anybody? Trying to figure out which to block off.

[JGood]

Thats what I was wondering actually. So the one thats the top left(sitting in the car) of an m42 rad is essentially just overflow for the expansion tank? That actually works wonderfully, thanks! I should have asked that originally.

Are you sure you're looking at an m42 radiator? It should look like this:





You can see the main rad hose inlet/outlet (upper left, lower right), and the spider hose outlet (lower left). Obviously the upper left inlet isn't overflow, and you can't block it off...

I'd be very hesitant to use a radiator with that core size for a 302. I can almost guarantee it will not be big enough. Not to mention, m42 radiators are leak-prone.

[FunfGan]

I meant the bottom left, sorry about that. So the spider hose can be blocked off? I'm only going to be using this to start up/ test drive the car until I find an m20 radiator. I don't think it would be big enough either...

[Jonsku]

www.bmwfans.info will give you diagrams where all the hoses are going ;)

[FunfGan]

Thank you!

[eurotrash]

Ok so going thru this already ill try to help best i can. If your running a stock expasion e30 tank like me u need 2 "feeds" tied into the expansion inlet. 1 has to run from the heater return on the waterpump and the other can run from either a port on the intake or i ran a t off my hot hose after the t stat as it was less plumbing for me and i didnt need the constant hot water for the heater. For u i would run the hot line from the back intake port to keep things reasonably clean to the heater inlet. Then run the outlet to the wp with a t going to the expansion.

If your running a "normal" radiator setup then ull have a fill on the rad and u can just run your hose from the tstat housing to the top inlet and one from the lower outlet to the waterpump and use your little nipple for an overflow. Heater hoses will run like it does stock for a 302.

Im curently using a 5serries rad because my wp inlet is on the pass side unlike the later 5.0s but its the same rad just dif inlet/out sides. It seems to stay reasonably cool. Normal street driving i never see over 195 freeway stays under 180 and hammering on it stays around 205. This is with the stock ac pusher. I havent had it to a drift event yet though so we'll have to see how it stands up to a real flogging.

Ive seen a couple buddys sbc's get up to like 265 after a run group so i wont be surprised if ive got to upgrade the rad and fan

[FunfGan]

Awesome, thanks man! Need to remember to go to you first with questions.

[eurotrash]

Glad i can help. I spent alot of hours researching the same thing so i understand the headache it can cause. Are u running the stock expansion setup?

[FunfGan]

Figuring that out. I was planning on running the m42 rad(built in expansion tank) for the time being, then an m20 which has the external expansion tank. I think I'm going to run the m42 rad for now with the big fan I have, and just block the extra outlet off.

Unfortunately, the deadline I've set for myself requires a 2 1/2 hour drive, then a full day of hpde, and drifting. So if I made a bad cooling decision, its going to bite me in the ass hahah.

[eurotrash]

Pretty much any event is going to require an overflow. Even if its got the built in tank (just looks like part of the rad to the tech guy) so i'd use it and stick a little overflow on there too. There cheap and u wont be running around frantic looking for one the day of cause u cant pass tech