Part III

I put back in the 180 Thermostat drilled a hole to let air out.

The engine got hot again around 210-220. Shut off got a little pre-ignition. SO the gauge can't be to far off.

The engine held around 170-175 without the thermostat the other day, this is when I thought I cleared an air-pocket.

DO I need a heavy duty waterpump or something? I'm baffled.

It's a 383
471hp
New dewitt Alum rad, 3-core
dual fans...(working high speed)

I'm stuck.

Chris

 

A high flow water pump and themostat wouoldn't hurt, but aren't required.

When you fill your cooling system, do you leave the radiator cap off, run the engine, and watch for flow through the radiator, adding water till it likes to run all over the floor, put the cap on then add to the reservoir to the correct level.

Man...you should be out driving that thing.

 

For the record, we don't make a "3 core". It's actually ROWS that we are all talking about or the number of TUBES that the core has. If we had a 3 core, then you would have three radiators. Anyway...

Last thread you said you were going to refill with antifreeze because the test you did was straight water. Water cools a lot better than antifreeze. You didn't go straight coolant I hope?

I think your solution could be a higher flow water pump but before I just throw out some wild comment, like many do, here is the reason.

All radiators have an optimum cool point vs flow rate. On a graph it looks like a hump. Too slow (low flow) and you're in front of the peak, too fast and you're behind the peak. The key is to match the radiator with a flow. That's what GM did and sometimes when people add high flow water pumps it actually makes it worse.

Now you upgraded to a "two row" aluminum radiator with 1" tubes. The flow path in these two rows much bigger than the four row copper unit because the copper unit uses small tubes. So for you to get to the top of the hump with the aluminum radiator you might need more flow. When you removed the stat you probably eliminated any back pressure it created and the existing pump put out more, and it worked better. You could either go with a bigger pump for try one of the aftermarket high flow stats. I understand the Robert Shaw unit is normally open instead of closed and that might help reduce the back pressure and maintain control over low end when it gets colder out.

 

Are you using the stock guage to tell temps?what happens when you run without thermostat.leave it out if it runs cool,put it back in the winter or run a 165 therm.

 

Ok Tom I was with you until you got to the open Robert Shaw-I heard someone else talk of these-how does this work-how does it force the engine to heat up-when does it close or does it-is it simply a restrictor?So many questions-sorry

 

Hello Again,

Thanks for all the thoughts and suggestions.

I did not go all coolant. I only added a little bit actually. Emptied the radiator down a bit and added coolant.

Now for the flow and pump. What I am hearing is I might need a pump with more flow ability for this radiator. The flow is very definitely not happening with the stat in. I saw good flow with the stat out.

I do understand eliminating the back pressure made the flow increase. So the question becomes what kind of water pump and how much flow will be right for this radiator and block.

I will also look into the Robert Shaw stat as well.

 

Vermel....FWIW I'm running a ZZ430, DeWitt aluminum direct fit w/ dual spals, Edelbrock aluminum water pump and MrGasket 180 thermostat (I think it's the same as the Robert Shaw). One fan is controlled by a sensor located in the passenger head, the other fan is controlled by another sensor located in the intake. As of yet the head controlled fan is the only one that has come on. It's been able to stablize the coolant temp at 195 and below by itself. The other fan may never come on.....unless the head controlled fan self destructs for some reason. Hope this helps and good luck

 

You shouldn't NEED to, but it sounds like for you it might help. I guess it's also possible that stat isn't openning up all the way. Stat's are cheap, try another one

 

Lastest attempt met with some success.

I took a 160 thermostat, drilled 7 3/16" holes in it, and put it in.

Car held at idle for a good 20+ mins around 165-170.

Both fans on high speed. (there still set to low) I just wanted to see a nice constant temp.

Check this out, put on the air-filter and closed the hood. temp creeped up to around 180.. nothing unusual.

Took her for a spin on the highway and temp got to around 190-195... I got on it a bit too. Stopped at a friends house and let it sit at idle... the car held steady in the 195 ballpark, both fans on high speed. Shut it off to check for any pre-ignition...there was none.

However it seems, sense my fans are set to low (which I will correct), when I restared the car the fans didn't come back on?? temp around 200.. So I guess the spal has a certain band or range it looks for if it's not within in it they don't start. So I let it cool to within 150 and the fans kicked back on again, car warmed right up to 190 and held..

I saw cooler temps with the thermostat out so I'm taking it back out, I simply think I'm getting better flow for this radiator while it's out.

I might just need a beefer pump.

Thanks Mr. Dewitt I appreciate you chiming in and providing help.

I'm going to cool down in my pool right now.

 

Did you say before the fans were on at 170 and then they were not at 200 ?Sounds like that controller might be acting up.I read an awful lot of posts that said they had to send them back.Maybe you should ask Tom how to check it properly.I havent followed your posts completly so fogive me if I'm not up to speed.Sounds like your right on the edge of not having enough flow and when you remove thermostat that seems to improve.I'm "NOT" in favor of running without a thermostat but is one way of increasing flow.Most of these guys say that it will make one run hot-but I have taken normal running cars and removed the thermostat and I have never had one run hotter-Never.I have tried my best to prove that theory.I can see if you have one of Toms radiators and a super pump this could happen.The cars I tried had stock pumps and high flow style pumps-nothing of racing quality and stock radiators.Did you set your timing correctly? I always fill the cooling system after having it open through the plug in the top of the water pump except for early cars with no plug and then through heater inlet hose.That way your sure pump is full of only fluid.Good Luck

 

That's correct, I have to reset them.

My low setting is around 130 and high is at 150, they'll stay on up to 200, but shut the car off and restart they don't come back on until it cools down. So what I'm thinking is the digital logic in the SPAL unit has a certain activation range around your settings if your out of that range and even hot like for me around 200 they won't kick on. I believe by setting my fans for higher temps I'll solve this issue no problem.

 

Hey Tony, yeah I run it tell it's overflowing, I don't get a bunch spilling out it holds steady and dribbles out if I give it a little gas you see the level drop then come back up, then I'll add a little more.

 

Another idea....??

With the cap off and the radiator filled to the top if I give it a little throttle the level drops in the radiator then comes back up to full.

I just realized that while driving I'm seeing RPMS around 2500-2800 cruising so the level must drop off again inside the radiator. So I need to fill up the overfill can to the hot level ,so the engine can draw in that extra coolant. Never really needed it with the old motor.

Just something I overlooked..

 

Sounds like this high tech unit could cost a guy an engine !

 

Did you read my post on filling pump?

 

I never thought of opening up the plug on the waterpump.. Your referring to the one at 12 O'clock on the pump? I'm inclined to agree that thermostat out, is looking like the way to go. What do you think about my post regarding the overflow.

 

Something easy thing to check is to make sure that you have a wire reinforcement in the lower radiator hose. Your symptons sound like the lower radiator hose is collapsing.

Just my .02

Jay

 

I have a sense something is hooked up backwards, altho I know nothing about SPAL's...if it was my car, I'd want that fan to be on anywhere over 190, and off about 180...regardless if it's been restarted or not....not coming on when it hits 150...seems backweirds...am I missing something here????

 

On your overflow-naturally you want the system full but if the differance you were talking about was only say 1/2 gallon then I dont think thats your problem.I have to ask a few questions to maybe generate some new thoughts-sounds like your old pump was shot-the new pump comes with a 3/8 diameter dowel plug-you didnt install this did you?To be honest I'm not familiar with this SPAL switch and where its temp sensor is located but direction of air flow is important-are your fans moving air the right direction-towards engine and possible over or past a temp sensor.You mentioned direction that Sixfooter brought up -I'm pretty sure he meant to be aware of by "mistake" a pump could have an impeller installed that is for the opposite direction of drive-if this is done then it would be very poor flow-remove back plate on pump and check-I always remove this plate on a new pump and check the impeller and silicone gasket suface-only takes a min. and removes any doubts.I've seen bent impellers and missing blades-if the impeller is too far away from back plate the flow will be diminished.You can rivet a thin plate to the impeller and make a high volume out of pump(not recommended just buy one)When building your engine did anyone stuff a rag somewhere to temporarily block off or to paint areas.You said earlier you had a new pump-did you install it? 2 bad pumps in a row(not likely)?maybe you havnt installed it yet.OK I'll shut up now and wait for you to post more input.

 

I meant to say -yes kb2 there is a little gremlin here.