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GTOken · 08-27-2002, 10:41 PM

Ok, my turn for an overheating story.

New 462 and 200-4r with 3.73 rear gear.

Engine Specs (click here)

» FlowKooker waterpump.
» Good divider plate and new seals.
» Original 4-row radiator relatively clean.
» Upper and lower baffle/air stops.
» Lower hose has spring.
» 75/25 water/antifreeze.
» New HD fan clutch.
» Shroud.
» Initial timing at 12°
» Total advance 32° @ 3000rpm
» Robershaw hi-flow 160 T-stat (also tried 180)

At first the temps would go to 220° and pretty much stay there. I tried running a Griffin radiator and it did absolutely nothing. So I yanked it out and put the stock radiator back in. Today I changed from ported vacuum advance to manifold vacuum and it seems to help a little. But outside temps tonight were about 20° cooler than when I was driving it previously. I think it actually runs cooler when just putt-ing around. Tonight it got up to 205° on the hiway and came back down to around 195° in town.

The jetting is slightly on the rich side so Im not running lean. Unless maybe somehow its running lean at cruising speeds. With the Overdrive tranny hiway rpm is around 2000rpm. But it even gets hotter if I cruise in 3rd gear (1:1). I can only think I need to do something with the advance curve or run a helper electic pusher fan all the time.

I may try a different brand of aluminum radiator. Possiblly C&R, they make most of the radiators for the Winston Cup cars.

What else should I try?

GTOken · 08-27-2002, 10:41 PM

Ok, my turn for an overheating story.

New 462 and 200-4r with 3.73 rear gear.

Engine Specs (click here)

» FlowKooker waterpump.
» Good divider plate and new seals.
» Original 4-row radiator relatively clean.
» Upper and lower baffle/air stops.
» Lower hose has spring.
» 75/25 water/antifreeze.
» New HD fan clutch.
» Shroud.
» Initial timing at 12°
» Total advance 32° @ 3000rpm
» Robershaw hi-flow 160 T-stat (also tried 180)

At first the temps would go to 220° and pretty much stay there. I tried running a Griffin radiator and it did absolutely nothing. So I yanked it out and put the stock radiator back in. Today I changed from ported vacuum advance to manifold vacuum and it seems to help a little. But outside temps tonight were about 20° cooler than when I was driving it previously. I think it actually runs cooler when just putt-ing around. Tonight it got up to 205° on the hiway and came back down to around 195° in town.

The jetting is slightly on the rich side so Im not running lean. Unless maybe somehow its running lean at cruising speeds. With the Overdrive tranny hiway rpm is around 2000rpm. But it even gets hotter if I cruise in 3rd gear (1:1). I can only think I need to do something with the advance curve or run a helper electic pusher fan all the time.

I may try a different brand of aluminum radiator. Possiblly C&R, they make most of the radiators for the Winston Cup cars.

What else should I try?

Lemans1 · 08-28-2002, 12:57 AM

Wow, the aluminum radiator did nothing?? My best suggestion is to replace your lower radiator hose and be sure it the type with the spring inside. Could be that your hose is collapsing at higher rpms. On a side note, if you are going to sell your griffin and try a different type of radiator, shoot me an email, I would be interested. my email is gto65convt@comcast.net

Rick Lightfoot · 08-28-2002, 11:33 AM

Howdy Ken! I'd say, the Flowkooler is giving you some problems. A friend used one on his car, and it flowed the coolant too quickly to adequately cool the car. What did the car run with a stock cast impeller pump? BTW Lemans1, Ken already has the lower hose with a spring.

Lemans1 · 08-28-2002, 12:15 PM

Ahhhh....need to read a little more closely! [img]redface.gif[/img]

David Holmberg · 08-28-2002, 05:49 PM

Ken, Overheating on the Hwy is a capacity/flow problem. Knowing that radiator is new, you are probably pushing the water too fast to cool properly.

Try replacing the thermostat with a washer, the Stat may have too large of an opening.

The ignition advance can and will have have an impact on cooling as well.

David Holmberg · 08-28-2002, 06:03 PM

On a side note...

My 77 TA with an almost exact motor combo did the same thing while driving on the hwy(220). It would be fine with in town (180) driving.

I changed the Q-jet to a 750 DP holley and it never got hot again...

Do you have a chassis dyno locally? They can check your exhaust temps.

GTOken · 08-28-2002, 07:41 PM

The Griffin has already been sent off to a new owner with a 69 Firebird. Here are some pics of my installation though, Aluminum Radiator Installation .

I also installed an external trans cooler at the same time, Trans Cooler Installation .

Waterpumps arent that expensive, I could try a replacement cast impeller pump to see what happens. And at the same time check the tubes, seals, and plate while its off.

Im sure Ive got a good Holley somewhere I could swap to see if that makes any difference. As for the water flowing too fast, Ive read on too many companies websites that deal with cooling products that its a myth. I do agree that some restriction needs to be there to cause proper water flow through the block and heads. But water that is staying in the radiator longer just means there is water staying in the engine longer getting hotter.

Im leaning towards an airflow, advance curve, or lean condition. I wish there were a dyno somewhere close, when I get this ironed out Id like to see what its pumping out.

Thanks.

A455GTO · 08-28-2002, 08:06 PM

Quote:

Originally posted by GTOken:
» FlowKooker waterpump.

<font size="2" face="Verdana, Helvetica, sans-serif">That's your problem, you were supposed to get a Flowkooler waterpump!!

Just kidding, hope you figure it out.

Maybe you can find a chassis dyno nearby here: http://www.smokemup.com/utils/dynosearch.php

71 T/A · 08-30-2002, 06:57 AM

Where do you buy a cast impeller water pump? All the parts seem to sell is the stamped style.

'ol Pinion head · 08-30-2002, 10:12 AM

Quote:

71T/A sayzzzz:
Where do you buy a cast impeller water pump? All the parts seem to sell is the stamped style.

<font size="2" face="Verdana, Helvetica, sans-serif">Just have to ck around, if auto parts stores you frequent do not have have GM casting with cast impeller, one can have an original rebuilt. Over the last 12 years have had 6 or 7 dozen rebuilt, mainly for high point #'s match resto's but also for normal drivers. Not that expensive. At one time I was having these rebuilt for $21 a piece.

In ck'ing waterepump cores, just have to be careful about which cast impeller one is using. Original pumps used on 265's & 301's had shorter cast impeller blade at slightly different angle (less drag). The cast impeller in 350-455 pumps was slightly longer & moved a little more water.

[ August 30, 2002, 10:13 AM: Message edited by: ol' Pinion head ]

GTOken · 09-14-2002, 04:13 PM

Ok heres the latest run. Today its 85° outside and 55% humidity, about 15° cooler than my previous outings. I switched the FlowKooler to a standard cast impeller pump. Since that is the only non-standard part of my cooling system other than I joined the rear head outlets together. It got up to 195~200° on the hiway. Back down to 180~185° going slow or idling.

Ive got it nailed where the problem is, just not sure yet what causing it. It gets hot when the rpm is over 2000. Doesnt matter how fast your moving. So its not an airflow problem. It will cool back when going slow or idling. So I figure its got to be running lean or the advance curve is goofed up.

BTW, the replacement pump looked to be a new pump, cast housing with cast impeller. Got it from Auto Zone for $17. It weighs 10lbs. The aluminum housing FlowKooler weighs 2lbs. Im still looking for a replacement aluminum housing, cast impeller pump. Im not impressed with the FlowKooler gimick at all. Anybody have any proof that it does any better than a standard pump?

gtoguy1967 · 09-14-2002, 08:57 PM

ken, i notice that you still have your condensor for the air conditioning in. im sure you would get more air to the radiator if you took it out as it looks like the rest of it is long gone.
also it looked like your fan is too small as in not enough coverage. is it pushing the air or pulling the air? hope you get it fixed i know what is like too be in your shoes.i bought a pump with a cast imperler from performance years but have not put it on yet.
Don

GTOken · 09-14-2002, 09:16 PM

The aluminum radiator and fan are gone. I put the stock 4-row radiator back in it. It has the original fan which is an 18" I think with shroud covering the entire face of the radiator. Also has a new HD GM clutch. I probably didnt make that too clear previously. The Griffin made NO difference so I didnt feel like that was a good place to spend $300.

Also, while I was puttng the old radiator back in, I took the AC condensor coil out. It really didnt make much difference either. Thats another thing that tells me its not an air flow problem. Maybe tomorrow I will play around with the distributor.

Here is the FlowKooler and the AutoZone pump,
link: Waterpumps

Rick Lightfoot · 09-14-2002, 10:30 PM

I had a Flowkooler in my recently purchased Can Am, and it was a total POS. The car ran much hotter with it, and it eventually literally fell apart. I only recommend the stock cast iron cast impeller pumps.

WDCreech · 09-15-2002, 12:40 AM

Ken, If you're using "D" port heads, you might want to advance the timing to about 36 to 38 degrees total. That should cool it down. If you're running round ports, I don't know what to tell you.

Dave A · 09-16-2002, 07:59 AM

Double check the guage that's giving you the high reading, too. Where in the system are you measuring temps?

Is the airflow path to the radiator (in the car) clear and unobstructed (no 2000 year old crusty old A/C condensor in the way, nothing impeding airflow through the grill into the radiator, radiator fins free of debris)? You mentioned clean, does this refer to inside and out?

Agreed...flowing water too fast through radiator is a myth. Having the wrong balance between flow through the radiator and flow through the block and heads is real, though, but you are running a t-stat and have the spring in the lower rad hose....seems OK in this area.

Is the clearance between the water pump impeller and backing plate OK? I've heard of this being a problem before (another gentleman posted awhile ago about this making a big difference in his setup).

Half-Inch Stud · 09-16-2002, 09:00 AM

Are you using a Q-Jet???

Get the Q-Jet on and Richen up the idle mixture screws (like run with at least 3-turns out for each screw). See how much cooler it runs.

H.I. Stud

mike nixon · 09-19-2002, 09:54 PM

check your mechanical advance system and be sure it's not sticking at the problem rpm.

is the exhaust free from restrictions?

if the above checks out i'd richen the high speed jetting a couple of sizes and see what happens.

GTOken · 09-21-2002, 01:07 PM

I made some progress today. But I dont know if its from what I did or the fact that its only 82° outside. I took out the clutch fan and installed an 18" flex fan. Went out on my normal test loop and the engine never got over 180°. Of course it got hottest out on the hiway which is what still baffles me. Back in town it cooled down to almost 160° which is what tstat I have in it now.

'68 GTO, '68 Firebird, '77 CanAm

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