rear radiator sbc 383 on race fuel temps?

skipnrocks · Sep 9, 2015

I just started driving my buggy a little. Cooling system seems to flow good. T-stat opens about 200 on my dash guage and runs about 220. I haven't wheeled it or rodded it yet so the temp has me worried a little. I don't think there is air but Not sure how to tell. I ran coolant to the rear in the 1.75 in upper rails, and hold about 8 gallons. I filled the system with the spill free funnel everyone recommended. What should I look for?

CHASMAN9 · Sep 9, 2015

SBJeepn said:
I just started driving my buggy a little. Cooling system seems to flow good. T-stat opens about 200 on my dash guage and runs about 220. I haven't wheeled it or rodded it yet so the temp has me worried a little. I don't think there is air but Not sure how to tell. I ran coolant to the rear in the 1.75 in upper rails, and hold about 8 gallons. I filled the system with the spill free funnel everyone recommended. What should I look for?

One thing I did to make sure I didn't have an air pocket was to put a Schrader valve on the intake manifold to bleed off an trapped air. Also, do you have an overflow container? :dunno:

skipnrocks · Sep 9, 2015

CHASMAN9 said:
One thing I did to make sure I didn't have an air pocket was to put a Schrader valve on the intake manifold to bleed off an trapped air. Also, do you have an overflow container?

I thought about doing that too. I have a Schrader on the water pump but not the intake. Did you get air out of your intake bleeder? I do have a coolant overflow reservoir. I read up on thermostats and how they start to open at a set temperature but a 195 may not open till it 212. So I thought maybe I should also get a lower temp thermostat. Something that will be fully open at 195 ish. I don't mind adding a Schrader on the intake also. I have a tuned port manifold with multiple accessory ports on the front of the intake. But if I crack the system open again I want to do all the suggestions. I don't want to keep bleeding and switching things etc. I did talk to the company that sells the manifold he said he had not heard of any issues with air on these ones.

al1tonyota · Sep 9, 2015

My experience is don't run a thermostat but a restrictor plate instead just make it out of a thin flat plate and make a few of them with different size holes from 7/16-3/4 and see which works best for your setup. The longer the water stays in the radiator the cooler it'll get on the other hand same effect in the engine longer it stays the hotter it gets. Also agree with a petcock or schrader valve on the tstat housing.

CHASMAN9 · Sep 9, 2015

SBJeepn said:
I thought about doing that too. I have a Schrader on the water pump but not the intake. Did you get air out of your intake bleeder? I do have a coolant overflow reservoir. I read up on thermostats and how they start to open at a set temperature but a 195 may not open till it 212. So I thought maybe I should also get a lower temp thermostat. Something that will be fully open at 195 ish. I don't mind adding a Schrader on the intake also. I have a tuned port manifold with multiple accessory ports on the front of the intake. But if I crack the system open again I want to do all the suggestions. I don't want to keep bleeding and switching things etc. I did talk to the company that sells the manifold he said he had not heard of any issues with air on these ones.

The intake is usually the highest water flow point on the engine and is way above the water pump, so you definitely can have an air pocket there. I am also running a small block stroked with a rear radiator and from experience, definitely run one as well as what al1tonyota said to do with the restrictor plates instead of a thermostat. It is because of the distance the water has to travel to get to the radiator, you want consistent flow through it.

skipnrocks · Sep 9, 2015

So the restrictor plate just has a single hole up to 3/4 inch in it? Would it be wise to just gut the thermostat to limit flow but have always open?

skipnrocks · Sep 9, 2015

also when letting air out the Schrader on the intake do you do it right at start up before coolant begins to warm?

skipnrocks · Sep 9, 2015

Not sure this would work but I don't know if you could run a line from the intake to the water pump to constantly release steam like 6.0

FlatlandFSJ · Sep 9, 2015

here is a link to the plates if you don't want to make them.

http://www.summitracing.com/parts/mor-63440?seid=srese1&gclid=Cj0KEQjwsb-vBRCLj7TvqpGx_MoBEiQALgFGnqBMXk38XNTnu9canBdSIr8WSL3ZOr70jVQholzZWmUaAhJ48P8HAQ

al1tonyota · Sep 9, 2015

SBJeepn said:
Not sure this would work but I don't know if you could run a line from the intake to the water pump to constantly release steam like 6.0

It would need to run to the top of the radiator or close to it to work but yes if you run a hose from the highest point wether it be tstat housing or intake crossover to the top of the radiator it would most certainly keep airpockets out!

Nuts · Sep 9, 2015

Where are you guys mounting the overflow tank with a rear radiator? I'm fighting this same issue right now.

CHASMAN9 · Sep 9, 2015

SBJeepn said:
So the restrictor plate just has a single hole up to 3/4 inch in it? Would it be wise to just gut the thermostat to limit flow but have always open?

I would just eliminate the thermostat all together and try plates with different size holes to adjust the flow.

also when letting air out the Schrader on the intake do you do it right at start up before coolant begins to warm?
If you use a restrictor plate, it won't matter hot or cold. Just as long as you have flow through the intake, it will release.

Where are you guys mounting the overflow tank with a rear radiator? I'm fighting this same issue right now.
I have my overflow back by the radiator and sits a little higher than the cap.

skipnrocks · Sep 9, 2015

I mounted my overflow to the radiator. I used an aluminum tank and had it welded it onto one side

skipnrocks · Sep 10, 2015

I moved my Schrader to the top of the intake. It puts my highest point on the motor coolant system the Schrader. In its position its probably an inch and a half above the thermostat.

It was cool because even with the engine off and my spill free funnel on the radiator it had enough pressure that when I pushed it even with the motor off air hissed out for a few second then fluid came in. Hopefully that takes care of that. I also added some of the royal purple additive to see if it could help also.

If I still have an issue this afternoon when I take it for a drive I will be pulling the thermostat in favor of a restrictor plate.

CHASMAN9 · Sep 10, 2015

SBJeepn said:
I moved my Schrader to the top of the intake. It puts my highest point on the motor coolant system the Schrader. In its position its probably an inch and a half above the thermostat.

It was cool because even with the engine off and my spill free funnel on the radiator it had enough pressure that when I pushed it even with the motor off air hissed out for a few second then fluid came in. Hopefully that takes care of that. I also added some of the royal purple additive to see if it could help also.

If I still have an issue this afternoon when I take it for a drive I will be pulling the thermostat in favor of a restrictor plate.

Good start... Hope it cures your issue.

skipnrocks · Sep 10, 2015

Me too. I hope to drive the buggy to work this afternoon and will let you know if it works out.

skipnrocks · Sep 10, 2015

Well I think I got it licked. I went home installed the spill proof funnel and started it up. It took about 10 minutes for the thermostat to open and never got so hot I couldn't touch the coolant line. The temp gauge got up to 220. I went to the little bleeder on the manifold and sure enough some air came out and the temp dropped to 210 and stayed. There even during my test drive which was brief. I am getting an 02 circuit check engine code I need to figure out. So hopefully it will continue to read 210 all the time.

The guy at tech support said that tuned ports are more accurately measured at the manifold and I should run my sensor there for a more accurate reading. Since it came down to 210 in a hurry I wont worry about it since the check engine light will come on if it gets too hot by the system standard.