[69RA3]

Re Grandville455 Q's: Shroud = Yes, nicely shrouded. Using a 6-blade 18" fan, and I read that I should have 7-blade 18.5" fan in there. Blah. I checked for any "open holes" around shroud, none. Fan is sitting 1/3 out of shroud, as seen on another post.

Re George's Q's: Yes it heat soaks big time. Car is off. I can now idle and sit a medium rpms and no voerheating, sweet. But turn it off and up up & away!

Temp used to go up when exit a highway to city driving, but it stopped when I removed the Tstat. It was my third tsat in last 6 months. U never know if those dang things are working or not.

When just driving around (slower and faster speeds) the temp used to cycle up&down when driving slower & faster, but when I hit a region around 220deg, it was a runaway and creeped up to 250 in 10 minutes. Not any more, with tstat out (and your pump spacer mod) is equalizes nicely when driving..yeah!

Temp goes up now only when I turn off the engine and sit there with ignition on and just watch the temp guage. Car is off. It rises from like 190-200 up ,and pegs to over 250deg, in a few minutes. A Turkey thermometer placed in what I think is hottest spot (around the choke coil) went up to 270-280+! Whew!

Re mixture, I was told to turn the two carb mixture screws in "until it almost stalls" and then "turn out 3 & 1/2 turns". But once, when I really accelerated the car, it bogged big time, bog glug choke death. The guy behind me said he smelled fuel on that run. So I went home and I turned the 2 screws in one whole turn and maybe I am too lean now.

I have the heavy duty Hayden clutch (big one) on the fan now.

My green book says R/A timing is not like the 9degC BTDC of normal '60 400ci, but needs to be set at 15degC on 700rpm idle.

I can tell vacuum advance is working when I watch with timing light, rev up the rpms, and see the indicator jump out to like 30degrees, right? Then it is working? That is what I see.

I will trun in the 2 mixture screws, one turn, and check it out. If no joy, then I will advance timing to 15deg and see what happens. If still nothing, then i will go get a new pump and a high flow 160degC STANT and see what happens. If nothing, then I will pull the dang thing apart and start over.

[69RA3]

Stupid me. I turned the two mixture screws in "all the way" and it didnt flinch in rpm at all.

Also, disconnected distributor vacuum advance line at the carb. Whistled nicely, confirming vacuum, but timing rested aroun d6degBTDC, which seems too retarted.

How the heck do I know how to adjust mixture..is it those 2 screws. Screw all the way in and then open 3 1/2 turns? Or do I turn them out until it begins to sound flooded, drops rpms, and turn in 1/2 turn to set? IDLE SPEED IS FINE AS IS.

[george kujanski]

Ok, hang on. The max temp during heat soak indicates to me that the engine is possibly hotter than it could be when running. Obviously, you would want to keep the temp during heat soak as low as you can, but I haven't got any data as to what is "normal".

Perhaps others can provide some insight.

On the ignition advance issue, the timing increase when you rev it up is the MECHANICAL advance, that's good. However, your vacuum advance should be working also. While idling, pull off the hose going to the vacuum advance can on the side of the distributor. The timing should drop if, indeed, it is working. Also, set your idle timing with the vac advance DISCONNECTED. Once adjusted, reconnect the vac advance. Vacuum advance working properly is important at part throttle conditions (cruise), will give you better economy and lower temps.

For carb adjust, start with the engine off, lightly bottom both screws & then back them out to say, 3 turns, evenly.

Restart and turn both screws in about a quarter turn at a time until the engine begins to run unevenly. (if already rough, back out to 4 or 5 turns then slowly lean it out). Then back out about a quarter turn on both & that should be pretty good; slightly lean but not to the point where it idles roughly.

If you have a vacuum gauge, turn the screws in (leaner) or out (richer) whichever gives you the highest vacuum reading, object being to set on peak vac reading.

Check the above B4 you start spending money.

George

Just read your most recent post. With the screws turned all the way in, your engine should die. Is that a Qjet, or a Holley with the backwards idle mix screws?

If it doesn't die, you are getting fuel into the engine somehow & not calibrated well by definition. Perhaps your cam is causing nozzle drip from the main circuit. If that's the case, post your issue on the Street performance forum & ask for help from Cliff Ruggles or Carbking. Those guys WILL fix you up.

BTW, welcome to the boards!

[69RA3]

George, thanks for repost. Yes, the hot soak is so hot it had deformed the gasked of one of my oild filters before. That must be >350deg at worst case! That was back in texas when I drove once when 102deg outside (average Texas summer day, heh).

Guess what, it doesn't die when I turn in the mixture screws all the way in. Even when I turn out as far as 5 turns, there seems to be no difference in idle smoothness. This is very wierd. I think I turned those 2 screws out so far they were going to fall off the carb! Turning them in all they way nada. It used to not be like that. I think we havbe found a culprit here! So we have two choices, a bunch of chemtool fixes anything, or slap in that new refursbished identical carb I have sitting here.

BTW - It is stock Roch 4MV, orig R/A carb. I'm going to go try that again to be sure I am not dreaming. Very Twilight Zone.

The vacvcuum advance disconnect does not seem to change the timing advance. It stays in same place with or without that distibutor vacuum connected. Vaccuum is definitely there, I'll try a hose change and then move on from there. Again, I have the pertronix igniter II in there, but I think that doesnt change anything rte vaccuum advance?


Thanks for all your help man!

[69RA3]

Ok,
Opened up screws, richened mixture.
Advanced timing to 15deg.
Rund smooth at low speed cruise, acceleration and high speed,,,no misses.
Thing romps over & over and stays nice and cool at 175-185.
When turn off, no deisling occured. Heat soak jumped to 350deg fast!!. I turn on elec-fan and circulate cool radiator fluid, then drops to 220deg ... and stays there. So this really helped a lot! Going to drop in new carb and head over the Street Performance forum. Thanks again George!! Im getting there.

[Malky]

69,
You said you heard a whistle when you disconnected the vacuum line to the vacuum can, so you must be connected to full manifold vacuum. If you were connected to one of the "ported" vacuum ports on the carb you wouldn't feel any vacuum. So you should get a big change in timing when you disconnect the line. Since you don't, I think your vacuum advance can is shot. The diaphragms fail quite often. That causes gas mileage to drop and some overheating, although not a lot on my experience.
Could be another part of the puzzle.

[69RA3]

I just had to say...know I got off the water pump subject here, but the gapping of the divider plate to impeller to 0.045 helps flow a lot. I can see the water thrusting at a good flow now.

BTW - The vacuum that I pulled off was a carburetor outlet (front side) connected to the distributor. When I remove it at the carb, there is serious vaccuum, it even whistles loudly.

I will:
(1) Disconnect at the distributor to be sure
(2) Check the whole vaccuum connections per specs

Also, if there is vacuum from the carb, this might explain why the idle scews don't change anything...as George stated, could be pulling gas off a mains, anyways regardless of the screw settings. Thanks all! This is a great forum.

[grandville455]

HEARS THOSE PICS GUYS

[grandville455]

one more

[george kujanski]

So you found a good one; that's one out of how many that you bought Gville?

George

[grandville455]

i have three sitting here BUT they will be going back after i put in the one I need ,cause right now car does not run no where near hot..So it will be interesting to see what comes off there

[428GTO70]

Cool you got one, hey one more post and you are an ultimate Warrior!

[slowbird]

So, after I reading this whole thing, I have learned alot and got confused alot. It seems that we need a cast impeller and set the clearances to about .060-.080. But the confusing part is where to get the right pump and what is the right pump. Is there really a difference in the long vanes vs the shorter ones? It would be great if someone would run all the pumps that are out there and document the results from it. Are the aftermarket ones any better than the stock replacement ones, like the Milodon one that says its high volume? What we really need is for some Pontiac supplier to make the effort to either make the right pumps with the right impeller or for them to only sale the right ones so we know where to go and that we are sure that we get what we want.

[george kujanski]

Slowbird, that about sums it up!

George

[grandville455]

Yeah like george said earlier its a crap shoot!I mean to have to buy three pumps to get the right one thats rediculous and whats worse 2 pumps remaned by the same company and different impellers!Wouldnt it be something if when i take this pump off next week its stamped or the short vaned one then what? But I will measure the clearance cause this car doesnt overheat or run hot at all!

[PMDRACER]

69RA3 -
If you can turn in both mixture screws all the way to the stops and the motor runs, you have a vacuum leak.

Brake booster
Intake gaskets
Carb gaskets
Vacuum A/C or heater valves
Throttle plate on the carb
PCV hose cracked, loose.

Do this. Run the motor and with a rag, cover the carb. Should die almost immediately. If not, you have a leak. Get some ether and (carefully!) start spraying it where you might have a leak. If the idle changes, you found it. Plug the line going to the booster to see if you get a change. It is possible to have a leaking booster and the power assist still works BTW. Saying you need to pull out the mix screws 3 and 5 turns to get it to idle right tells me you have other problems.

Geez. A simple post about water pump has come to this?????

[george kujanski]

It's our 15 pages of fame.

George

[Trevor99TA]

OK, how about this? After all this talk or reading I get the itch to take mine off and just see (hell i've got the pass head off anyway, see street forum) I've got the Flow Kooler with cast iron blades. (smaller design though) It has a plate brazed onto the fins and the gap between the plates is 1/4". Do I want to hammer my divider plate down closer to the water pumps plate? Has anyone tried this yet with the Flow Kooler?

[slowbird]

Who makes the Flow Kooler?

[Malky]

Trevor,
If I understand you correctly, you have the normal integral cast back-plate on the impeller and also a brazed-on front plate, so you can only see the impeller vane inlet and outlet ends.

On an industrial pump, this design of impeller normally has a close fitting (~0.020") running clearance down at the suction eye to stop the high pressure water discharging from the impeller outer diameter from just flowing down the outside of the impeller back to the low pressure suction eye.

Since Pontiac water pumps don't have that, you need to run a tight clearance between the brazed-on plate and the divider plate to minimize this bypassing. With 1/4" gap, you must have a lot of recirculation, may be as much as 50% of the pump flow since the impeller blades are only 1/2" high, although that is just a guess.

I would suggest a 0.060" gap like mentioned by other posters, although industrial pumps normally run much tighter than that.
Malcolm