[grandville455]

Yea thats screwed up I did the same thing as you bought what i thought was a cast opened it up was a stamped you just dont know unless you actually look in the box before you buy one!
Minority=Grandvilles running 13's

[BOB VIDAN]

This is a very interesting thread. All I can say is I have had maybe 20 or so good running 64-7 mostly GTO's over the years and have never had a problem with running hot and I can't believe it's all luck. I have made sure that all the cars had not only cast impellers but the right one to the car. I have never measured any clearance cause I didn't have to.

[WallyB]

I'm glad I read these posts as I had cooling problems when I first got my 69 Firebird 350 about 5 years ago. It was abused - after a new stock type rad (old one came apart because rubber isolation nuts were not used), 4 blade stock fan was replaced with a 5 blade clutch fan (just to be safe) and a OEM shroud was put in (as it was missing). It always runs 160-180 now with a 180 stat, as I think I still have cast impeller style water pump. I was looking to get a spare water pump, just to be on the safe side. Now I know a cast one will be a safer bet when I go shopping & will watch for that gap when it needs to go in! Thanks guys.

[aerosmyth]

Cooling Forum Folks, re '66 WS389 Tripower
overheating.

Just a quick update: #70 jets now in center
carb, recurved distributor (heavier OEM weights
and lighter springs, 34deg mech in by ~2600)
refueled with BP-Amoco 93. Results: a 45mph cruz into town (82 deg ambient) brought temp
up to a hi-temp indication per last hot runs
(looks to be ~230 on Rally Gauge. Doesnt
seem any cooler...yet. Need the T/C test to calibrate, though open hood radiation feels like
a bed of coals. Plugs now back to tan.

I didnt get thermocouple set-up done so will
try this week. Napas rebuilt pump 58-299 I
found (5 of 5 were cast impellor) has a 6
vane, .610 depth of vane, 4.640 diameter,
.450 impeller projection above gasket surface.
Impeller has minimum .260 clearance to divider plates on a spare set in a -3130 timing housing.
SO that seems excessive too.

Tomorrow; thermostat out with stove boil check,
radiator flow test at a claimed guru here, then
if required rod out this 4 core Harrison (again)
and maybe a baffle scheme. Retry with T/Cs
before pump teardown. Going to be a busy week.
keeping a log/journal on this project....

aerosmyth

[grandville455]

Yeah thats too hot Brad...Do you need any help this week?

[GR8ONE68]

George,

Go back to page 16 of this novel. The pictures are of a rebuilt (factory piece) pump from NAPA. The vanes are not tapered on that one and it has the Pontiac part numbers cast into the W/P housing and the impeller.

Kevin

[leecorrell]

Back on page 18 of this book, I posted where I had been unable to find a cast impeler pump. I tried the plate clearance mod with my stamped impeler pump and it did not help. I've had everyone I know hunting a cast pump since and I finaly got my hands on on this weekend. I'm running the '67 style timing cover with the 8-bolt pump and two plate setup. The '67 cast impeler has "flat" vanes instead of the tapered ones like the later style pumps. My 8-bolt stamped impeler was also tapered like the later style pumps. I had to do major rework on my plates to get minimal clearance to the "flat" vane style cast impeler pump. It was only in the low 70's here Saturday after I got the pump installed and the temps seamed to be lower after the swap to the cast impeler pump. Sunday the temps were back into the mid 80's and my temps were also back up. So, it wasn't the silver bullet, but it may have helped some.

[mc67gtoconv]

Well here in northern IL it has been in the 80's this past weekend and my 67 GTO has been running anywhere from 205-220.
I replaced the PCV valve grommet yesterday,the old one was cracked and swollen. I also reset the timing to about 9-10 degrees BTDC,readjusted the idle speed and will be checking the mixture with a vacuum gauge soon but the old plugs I just replaced looked good (tanish white).
Also I bought an advance style timing light so when I get a chance I will be checking total timing and how much advance I am running,I believe I have 24 degrees mechanical.
Still waiting on my Rodney because I am convinced my car needs the extra cooling capacity in addition to the impellor mod I have done.
I am determined to solve this problem.
When I had the initial timing set to 10-12 degrees I was experiencing some ping on acceleration but as far as temps go I see no difference,but the pinging is gone.
I figure anything I can do to get my temps down is a good thing.
And I switched to manifold vacuum advance and I do believe she is running a bit cooler at idle.
With so many variables it is hard to tell unless only one is changed at a time.

[aerosmyth]

Adding a chapter to this cooling thread.

For some good additional reading about thermal management see the
following from a 'nukleer' engineer.

http://yarchive.net/car/radiator_diagnosis.html

Here's my thermocouple test report (brief summary);

Cond 1: 55 mph(2500RPM), 68deg ambient, 160 T/S, #70 jets, 34deg adv by ~2600RPM
Rad inlet temp 195, outlet 187, Rally Gauge indicated ~212 (mark between 180 and 245)
Remark: R-gauge indicates false reading of ~20 degrees too hot, time to recal.

Cond 2: Idling hot for 5 min, 66deg ambient
Rad inlet 175, outlet 166, RG dropped to mid point 180/212 markings

Also had T/Cs on the rear of left head (in rear frost plug used for heater nipple
on right head) and on the temp sender boss. These locations were within 2-3
degrees of the rad inlet temps during testing Cond 1 and 2.

DECISION: Removed radiator for the removal of tanks and rodding out. The radiator
guy said it looked perfectly clean by looking in the inlets, but would take it apart
and clean. He promoted a three pass baffle system which would be accomplished by two
blocking baffles; top tank 1/3 over and bottom tank 2/3 over. He said my thin dusting
coat of laquer paint could also be the culprit so that'll be stripped off also.

We'll see tomorrow how it works. Will dilute 50/50 coolant to 30/70H2O after radiator
test for another data point if required. After that off with the pump.

aero

[Malky]

Great info, aerosmyth. The bit that got me thinking is the nukleer engineer's post where he says that a pure water flow problem (ie no other problems with the cooling system but a bad pump or t/s not opening enough) will show up as a large temperature drop across the rad, since the residence time of the water in the rad is high. This may be a major clue to look for with people whose problem is caused by simply an ineffective pump. He says if you see the outlet tank at ambient you have a flow problem, but I don't think it would have to be this cold. Any temperature drop greater than,say 50 deg, may be a clue.

[aerosmyth]

Malky & CO., that part of the cooling link also confirmed my visualization of my hi-flow coolant in the top tank and delta-T during testing being only 7 to 9 degrees. Corallary:if coolant flow rate is infinite, then delta-T is very small, if coolant flow is nearly stagnant, then delta-T is Inlet minus ambient (or maximum). Basically what you said.

It's all BTUs generated in the engine that needs to be rejected by a sufficiently sized and efficient heat exchanger.....below thermostat
opening rating.

Not sure now if I stated that the 160 deg T/C
began opening ~165-170, was full open at ~190,
closed back tight at ~160. Diameter through aperture is 1.070 (.90 sq-in). Fully opened gap in boiling water is ~.25 gap (1/4" bit=GO, an 'F' drill(.257)=NoGo. Thus, cylinder area of opening (Pi*D*.25) is .84 sq-in (93% of max area). Is this adequate? Would seem so by the flow volume
assessment.

Radiator was checked by rodding out all 180 core
tubes: very little scale or blockage (7 had bits
of gasket silicone stuck in them). Basically it
didnt need to be taken apart. Installed 2 baffles
for three pass scheme (4X15 tubes each pass). Preliminary operational test shows uncertain
benefits (same Rally Gage readings 180 sneaking
up to 212 indication). Which, per my -20 degree error correction factor; 160-192....BUT the night
was a cool 65 degrees. Will do the T/C test this
weekend.

All for now....trying to get KOOL

aerosmyth

[A1Judge]

I just went to three parts stores and looked at three different late model pumps thay had on hand, AutoZone, Advance and a local parts house.

All the pumps had stamped impellers. Bummer.

Since my motor is apart I really want to put it back together with a good pump. I'll try NAPA tomorrow and a few other local places.

Great information from everyone!

Don

[pops66gto]

Hey guys,
Just wanted to put a thread in this book. I have not read all of it but have read about 7-8 pages of it. I built a 66 GTO for my father that I put a stock 455 out of a 70 bonneville in it with a 400 tranny. The motor has stock pistons with new rings, bearings, valve job on stock 15 cast heads. Small Summit cam with Edelborck performer intake with a 600 holley. It has a points ignition and factory cast iron manifolds with dual 2 1/4" exhaust with turbos mufflers. It had 3:55 gears with 275/60/15R tires on it.
The cooling problems started from day one and I have been chasing this problem for 3 years now. I am using a set of Auto Gauge gauges that I used to have in my hot rod so I know that they are accurate. I've got a griffin 26x19" 2 row radiator with a single electric fan/shroud combo from a 1985 Escort. I have a Mildon water pump and a 160 T/S. This thing is one hotblooded beast. I have tried everything to get this thing to stay under 200 but to no avail!!!!!!!!!!!!!!!!!!!!!!! I have tried timing changes, carb jets (plugs look great by the way), all kinds of water and AntiFr additives, a 160, 180, 195 T/S and they all do the same thing. This thing will idle OK and stay at a certain temp but as soon as you drive around at a speed higher than 45 or 50 then the temp just climbs up to 210-225 all the time. I did the impellar trick today and yes the milidon pump has a cast impellar. We put a 160 back in and it sat in the garage and idled for 20 minutes at 170!!! Then we took it out on the interstate (about 65F outside) and it just slowly crept up to 210 after about 10-15 minutes at 70 mph and 3400 RPM. When we got back home it sat in the driveway and idled at 200 for 5-10 minutes and never went up anymore. The only thing I can think of is a dual fan setup or maybe the fan now is blocking the air daown the highway. I don't have a stock shroud for it so I don't know if that would help either. The impellar trick was my last hope and it has raised my blood pressure about 20 points!!!! If this was a dog I would shoot it!!!!!! Thanks in advance for nay suggestion you might have.
-frustrated karl

PS (when I rebuilt the block I did not have it bored out so I don't know if the block has ever been boiled out or not.)

[pops66gto]

that should read: It HAS 3:55 gears and 275/60/15r tires on it. Sorry!!

[Blue '66]

So the electric fan is on the grill side of rad?That would be the first thing to try,change the electric fan to the engine side of the rad and see if the fan is blocking the rad.The next choice would be a bigger aluminum rad.I think the radiator you have is just too small with a 455.
Another theory that is is comming out recently is that on a rebuild one should "zero deck the pistons."That is deck the block so that the pistons are even with the block and not down the hole.Original pontiac pistons are about.020
down the hole and aftermarket pistons are worse.
The theory is you are heating the top of the clyinder walls and less efficent with a piston
down the hole than at zero deck.Cliff Ruggles is
one of the guys that zero decks all engines he does and he says that with that it is possible to use pump gas (92-93 octane)even with a little higher compression ratio.
Of course I find out this and lots of other good engine rebuilding tips AFTER I rebuilt my 389 in my '66 GTO.

[pops66gto]

The rad is on the engine side. I was thinking about the rad also. Maybe try to fit a wider one in there. Thanks for the suggestion.
-karl

[aerosmyth]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blue '66:
one should "zero deck the pistons........
Of course I find out this and lots of other good engine rebuilding tips AFTER I rebuilt my 389 in my '66 GTO. <HR></BLOCKQUOTE>

Blue 66, I 'zero-decked' my WS 389 with my dished Ross pistons. Have 11.7cc dish, 72cc 093 heads, .035 thick Fitgerald head gaskets for a estimated 9.7:1 compression ratio. It still gets hot like the same story POPs GTO reads. It hits a temperature, then begins to creep up untill it gets so hot and boils over.....see all my other posts if interested.

Good luck to us all. Are we chasing the correct parameters? I think I know what hot is, but now Im beginning to wonder what criteria we are using to gage all this excess heat. A friend told me he drove his 400 Safari wagon for about
60 miles with a blown upper hose, the manifolds were cherry red, the engine 'tinked and crackled' on cool down, then when he put on a hose the thing ran fine for years...whatsup?

aerosmyth

[A1Judge]

Woke up this morning and remembered I had saved the pump that was on the Judge when I bought it. Dug it out and this is what I have:


The date code on it is Sept 29, 1968. The vanes are 1.5 inches and the impeller height is 3/8 inches above deck.

I pulled apart my current pump and discovered I had the stamped impeller. Vanes did not come to the edge of the inner circle opening of the divider plate, and had a .25 inch gap. Based on what I have been reading, it is junk!

The divider plate fits the old pump impeller much closer, although the gap is still pretty large. Correctable...

Do you think the old pump is still good? Turns freely. Any way to check it before I put it on a fresh motor. I would hate to have overheating issues during break in.

[grandville455]

Now isnt that weird the original pump and the vanes dont go to the end.man this gets even more intense,lol.......whoever figures this out will be king of the ponchos

[android 211]

To Pops GTO with the overheating 455 in the '66 GTO I want to say get rid of the electric fan setup and go stock! Get a stock fan shroud, a good fan clutch and a seven blade fan. Pontiac put 421s in some GTOs when they ran short of 389s and those cars never overheated. A mild 455 shouldn't be running at 225. The Escort fan set up moves enough air to cool a 4 cylinder of 2.2 liters - you have 7.4. Keep the aluminum radiator; its probably better than a standard brass unit. Properly seal it around the perimeter of the radiator like the factory did. I'm keeping a 500 Cadillac under 220 in the cramped confines of an '87 Cutlass; you shouldn't be having these problems in a roomy GTO engine compartment. Keep us posted.