Running hot issue, BBc

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Running hot issue, BBc

Post by 67 Nova »

I have a .030 427 shortblock with ported oval heads small solid flat tappet, strip dom intake, holley 830. Make 629Hp and 590Tq. On the dyno never noticed and heating issues. Put it in my car, 1967 Chevy II and it just wants to keep getting hot, like 215 and till climbing within say 2.5 miles. Car has aluminum 2 core rad and heater core is all connected and functioning too. Car was bought as a roller, BUT I got the waterpump and belt system with it. It was a 502.

So is the Gen V 502 waterpump the problem with the heating on a gen IV? I do have a waterpump I'm going to try. Just wondering if anyone knows before I pull the whole front off again.

Thanks, John
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Re: Running hot issue, BBc

Post by Newold1 »

The 502 water pumps are usually all reverse rotation. If you are using a standard rotation pulley and belt set up the water pump is not pumping water. Change the pump to a nice standard rotation water pump if that is the issue. You should also make sure you are using a 180 degree thermostat and don't run the engine without a thermostat.
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Re: Running hot issue, BBc

Post by makin chips »

Are you using a serpentine belt drive or v belts?
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Re: Running hot issue, BBc

Post by 67 Nova »

Serpentine belt. NO T-stat, just a restrictor.

I HAVE a nice Weiand pump, (both short and long) and 180 stat I'm going to try.

Serpentine belt only for crank pulley, waterpump and low mount alt. All March products that came with car.
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Re: Running hot issue, BBc

Post by Newold1 »

Even serpentine systems can be right hand standard rotation. If you have a 502 water pump and its rotating to the right it's spinning backwards!
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Re: Running hot issue, BBc

Post by 67 Nova »

Will double check? Looking at the motor (so drivers side is to the right), I think the pump is spinning CLOCKWISE? Will check when I get home tonight.

Tonight I'm going to pull it out and let it run/idle till it gets to 190/200. Time it. Then tomorrow will drain and switch waterpump and run till 190/200 again and see if it gets that hot, and if so, how long it takes.

THANK YOU for the inputs, John
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Re: Running hot issue, BBc

Post by MadBill »

FWIW, a centrifugal pump works in either rotation but usually the blades are curved to favor one or the other, so overheating as opposed to immediate boil-over is the usual result of spinning one backwards.
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Re: Running hot issue, BBc

Post by Circlotron »

Most (but not all) centrifugal pumps and fans I've seen have the blades angled away from the direction of rotation. As the water passes along the vanes toward the edge it is going in a spiral, and the back curved blades help to change the water exit path back to more or less radial, and in the process, convert some of the kinetic energy of the moving water back to static pressure. Somewhat similar in principle to zoomie headers facing rearwards and adding to forward thrust, rather than facing straight out sideways.

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Re: Running hot issue, BBc

Post by levisnteeshirt »

I would block the bypass at the front of the intake , I would route the heater core from the front of the intake on the top , at least use a restrictor if no thermostat , use a water neck with a 1/2 threaded hole and return the heater core to that , you need a pressure drop after the intake for this to work , so a restrictor at the intake is minimum
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Re: Running hot issue, BBc

Post by Newold1 »

Keep it Simple here guys!

If he is using a late model 502 water pump its a reverse rotation water pump. If it as configured now is rotating clockwise as viewed from the front of the engine it is rotating backwards and the engine will overheat under loads period! Put a standard rotation water pump on with a 160-180 degree thermostat with bypass on and the engine should not overheat all other systems working as they should. This ain't rocket science!
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Re: Running hot issue, BBc

Post by 67 Nova »

Ok so after looking into this some more, I think that a head gasket/deck surface is an issue. I had the rad cap off to check water movement. Well water get's pushed out of the rad and it's really foamy. It just straight water at this time. Going to double check head bolts and "possibly" try iron tight. But honestly I think that is the issue for starters. Going to change the water pump as well.

As I waited over night and removed the rad cap after running up to 180/190 in a couple mins. The rad after 12 hrs is pressurized and when the cars running #6 and #8 headers pipes are running alot hotter at about 265/280 and and the rest around 165.

So this is leading me to gaskets or head surfaces. Will double check the block as well. The the shop said it was done, but need to know for certain.
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Re: Running hot issue, BBc

Post by Newold1 »

Sounds like you might be going in to many directions here at once. If the radiator is holding pressure after 12 hours of sitting then a head gasket or head bolt issue does not seem to be the problem. If the water pump on the engine is really a reverse rotation 502 pump, running backwards in the pump vanes can probably whip the coolant up and it will pump some but at way less volume and pressure. You mention header temps? Those temps at between 195 -265 degrees I assume is in farenheit degrees and if that's the case the difference is notable but those temps would be way low for a header/port exit!

I think while you are at it you should pull the plugs and do a compression test to see if the cylinders are basically healthy. Look at the plugs carefully as they are a good telltale of other issues. Good Luck! :)
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Re: Running hot issue, BBc

Post by 67 Nova »

Thanks New,

Damn thing flooded 2 nights ago when I was in a rush. So changed plugs, and it fires and reset timing. It's a new car just going together and YES running into to many issues at once. Car is actually LEAVING tomorrow BACK to the trans guy. NEW T400 and GV OD just installed by him. Took the car out about 2/2.5 miles each way. motor was hot at 210/215 when I got back. Timing was up and engine running warm and NOT cooling when driving.

As stated, .030 over L88 12.5-1 comp shortblock. So was pinging with timing at 38. So retimed back to 32 and again while setting timing, temp just keeps climbing?? So went to put it back in garage, and not DRIVE/forward gear, just reverse? Trailer was broken into last year and comp tester was stolen. BUT yes thought of that too, and rechecking head bolts.

I was just figuring a leak/lean on/between #6 and #8 due to the much higher header temp (laser heat gun) and the foam in the water, along with pressure in system after 12 hrs. I didn't think that IF the pump runs backwards and foams up the water, that would create pressure in the system and keep it, but it is a close and pressurized deal???

I HOPE it's not head gaskets!!!!
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Re: Running hot issue, BBc

Post by rp930 »

It’s going to be head gaskets if you keep driving it while overheating. Why the reluctance to check the water pump?
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Re: Running hot issue, BBc

Post by 67 Nova »

NOT driving. Took out the new trans within the first couple miles. MAYBE 3/4 miles and no drive. Not reluctant, just checking all before it leave for trans shop at 9am tomorrow
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