[mviker]

Originally Posted by tom s

FWIW,Fabcraft sold a alu 4 bolt water pump.Not sure if he still have them.I ran one for a long time.Have to see if I still have it.Tom

Tom,

I've seen the Fabcraft pumps on Ebay or heard about them on their site, but the cost is a bit much on those. Last I saw, they were $400 for one. I'd love to have one, but that's a lot of scratch. Maybe one of these days. On the positive side...Anything from Fabcraft is always a great part. I'm sure the water pumps are no different.

[mviker]

Ok, I decided to get rolling on the pump today and unfortunately, I have a v8 water pump. LOL... Knew that was a possibility, but was hoping the 4 cyl one was in there so I'd solve the overheating issue. On a side note, The water pump in the car is another variation I've yet to see. This impellor seems much beefier with machining that's not evident on typical impellors. It's also missing that one 'notched' bolt hole the others have. Seems like a decent part, so I wouldn't think it's contributing to the heating issues.

I'm still going to replace it though. Who knows...

Pics of the old water pump:

[mviker]

I just noticed another diference in my old pump compared to the others. The housing is beefier with the three supports instead of five like most. Someone mentioned it earlier. The old pump seems more heavy duty for sure.

Notice the height differences. The fan mount and impellors both seem to be in the right spacing on both even though they look off.

[Bill Hanlon]

Maybe it's just the camera angle, but A and B don't look like the same length to me.

[mechanickeith]

Dont know Bill,,,looks like one is closer to the camera also. That would throw off the dimentions in the pic.

The two main critical points to measure are depth of the impeller from the pump mount point on the timing housing & length between the same timing housing & where the pully/fan blade mounts.

[mviker]

There may be a bit of an angle in the pic, but the left pump is a bit shorter, however comparing them using the surface that bolts to the engine, they are very close. The distance from the impeller to the base is the same on bothe and the distance from the pully flange to the base is very close also. The shaft ilength is different in both though. I have the 'A' pump in the car now. Not done with the install yet, but maybe today or next couple days.

[Bill Hanlon]

The guys with the later than 63 water pumps go through all kinds of grief with improper impeller to divider plate clearance. See:
http://forums.maxperformanceinc.com/...d.php?t=411256
http://forums.maxperformanceinc.com/...d.php?t=659536

Even though our 4 bolt pumps do not use a divider plate, has anyone ever considered proper impeller distance from the opening in the timing cover's inlet port to the pump as being a potential cooling problem?

If the impeller is too "tall" on the shaft it will contact the timing cover. This would be pretty obvious (lots of noise). But if the impeller was installed too "short" on the shaft it could cause very inefficient pump action with subsequent overheating. The 8/11 bolt guys like about 0.10" clearance. Some rebuilt pumps were measured at 0.25".

One could do a test install of a pump (and gasket) with modelling clay on the impeller blades to see just how much clearance there is.

Or maybe this was already covered on the day I skipped class???

[Deadhead]

Originally Posted by Bill Hanlon

The guys with the later than 63 water pumps go through all kinds of grief with improper impeller to divider plate clearance. See:
http://forums.maxperformanceinc.com/...d.php?t=411256
http://forums.maxperformanceinc.com/...d.php?t=659536

Even though our 4 bolt pumps do not use a divider plate, has anyone ever considered proper impeller distance from the opening in the timing cover's inlet port to the pump as being a potential cooling problem?

If the impeller is too "tall" on the shaft it will contact the timing cover. This would be pretty obvious (lots of noise). But if the impeller was installed too "short" on the shaft it could cause very inefficient pump action with subsequent overheating. The 8/11 bolt guys like about 0.10" clearance. Some rebuilt pumps were measured at 0.25".

One could do a test install of a pump (and gasket) with modelling clay on the impeller blades to see just how much clearance there is.

Or maybe this was already covered on the day I skipped class???

This is what I was thinking too. With the plastic impeller above, you could set it so that it bottomed out and then sand off the corresponding amount of material to get the clearance you want.

[mechanickeith]

I have never checked the depth but have bolted a pump on with no gasket to see if it rubbed & it didnt.

[tom s]

I keep reading these over heating post and feel TOTALY left out!I have used 4 bolt,8 bolt and 11 bolts for 50 years and have NEVER even checked a pump!If the seal starts to leak I replace it.The only over heating I can rememeber was when I had a loose dist and it retarded itself and started running hot.Put it back where it belonged and temp went back down.Tom

[Bill Hanlon]

Must be clean living Tom.

My daily driver 57 GMC (with Pontiac 347" V8) has gone through a couple water pumps since I started driving it in 1990. I've changed them without being concerned. My truck has aftermarket A/C and except for the original radiator getting gunked up back in 1995 or so, I've never had an overheating problem.

Temp gauge started reading low last week. I run a 180 degree thermostat. Got out the IR thermometer and checked the intake manifold right next to the temp sendor. It was reading 185 degrees. Gauge said about 160. Putzed with the wiring under the dash with no luck. Touched the wire where it attaches to the sending unit and the gauge jumped up over 180. Gave that wire a little tug and it pulled out of the stake-on connector that attaches to the sender. Cut off 1/2" of wire to get new clean copper, put on a new connector and all is well.

[mviker]

Originally Posted by tom s

I keep reading these over heating post and feel TOTALY left out!I have used 4 bolt,8 bolt and 11 bolts for 50 years and have NEVER even checked a pump!If the seal starts to leak I replace it.The only over heating I can rememeber was when I had a loose dist and it retarded itself and started running hot.Put it back where it belonged and temp went back down.Tom

I don't know what to tell you Tom. Guess you're missing out on the overheating thing, huh. :P

I thought I had the problem licked, but I put on a new intake earlier this year and next thing I know, it was back. The car seems fine driving, but temps spike now when I roll up to stop lights or get caught in traffic.

I can say am fairly confident everything's been done that I know of to keep the car running cool.

1. Re-cored the radiator.
2. Put in a fan shroud and sealed all around it so air is only comng in through the radiator.
3 Water Wetter. ( Learned only recently that it's really only if you're running water. Doesn't work as well with antifreeze.)
4. Timing is set correctly.
5. 170 degree thermostat.
6. Replaced the water pump.

I can't think of much else that could be a problem. I was just recently talking to a guy with a 65 GTO that was saying it had to do with boring the motor 30 over. He was telling me anyone he knows that's had their blocks bored, has an overheating issue. I find that hard to believe though. There's lots of guys running rebuilt motors that aren't having problems. Another buddy of mine says it's just the hotter temps these days and that our old cars weren't made for them, but theb again, I'm sure it got hot in the 60's too. I can't imagine temps have changed THAT much since then.

Anyway...I got the new pump installed last night. Haven't gone for a spin yet, and probably won't know if anything's been fixed anyway since it seems to be cooling down around here. Will post the results after I get some miles on the car. Got a show I'm hitting on Sunday, so we'll see how it goes.

Kevin

[Deadhead]

I would guess that all the guys that have had their engines bored .30 that have this Prob have also lowered the Comp. ratios in their cars. I think when you do this/retard the timing is when the issues arise. That and the vac advance on the dist. out of whack.

This is partly speculation on my part, but I know that timing issues can cause this problem and be very hard to track down if you are not aware.

[mechanickeith]

Originally Posted by Deadhead

I would guess that all the guys that have had their engines bored .30 that have this Prob have also lowered the Comp. ratios in their cars. I think when you do this/retard the timing is when the issues arise. That and the vac advance on the dist. out of whack.

This is partly speculation on my part, but I know that timing issues can cause this problem and be very hard to track down if you are not aware.

Very true! If all the bugs are worked out on the cooling system, then other issues are causing it. Dont think its due to over size bore on the motor.

First,,cooling system,,,,Is the radiator clean? Has the block been flushed & cleaned out, to include both lower block drains? Does the thermostat open? Are you using the correct radiator cap? Is there coolant flow through the radiator when hot & T stat open? If you are running a fan clutch, does it cycle on & off when engine is up to temp?? Is the fan shroud correct for the motor & sealed correctly to the radiator? Is the fan set into the shroud to the correct depth? About 2/3-3/4 of the fan should be inside of the shroud opening. I usually set a car outside with the throttle at about 2500 rpm & let it sit & run up to temp. If the fan clutch is working correctly, you will hear it kick in & out. I like to use a lazer temp gun on the thermostat housing & also on the lower radiator hose to see how much of a drop in temp there is across the radiator. I have seen a temp drop across a radiator of over 100 degrees before.

If everything is ok with the cooling system, start checking the motor tune up. Are you using the correct octane rating fuel for your compression ratio? Is the distributor timimg correct, both initial & full advance. Are you using the correct heat range spark plugs? Are there any vacume leaks that will make the motor run lean? Is the carburetor size correct for the motot? Is the carb jets correct for that carb/motor. Take a pair of needle nose pliers & one at a time pinch off each vacume hose on the motor while it is running. Listen for a drop in engine rpm. If a drop, usually a vacume leak in that hose system. Had one motor that had a bad leak at the dist timing advance, motor was lean & didnt run right because of incorrect timing. Also ran hot because of it. Changing of the advance can fixed all issues.

[mviker]

Originally Posted by mechanickeith

Very true! If all the bugs are worked out on the cooling system, then other issues are causing it. Dont think its due to over size bore on the motor.

First,,cooling system,,,,Is the radiator clean? Has the block been flushed & cleaned out, to include both lower block drains? Does the thermostat open? Are you using the correct radiator cap? Is there coolant flow through the radiator when hot & T stat open? If you are running a fan clutch, does it cycle on & off when engine is up to temp?? Is the fan shroud correct for the motor & sealed correctly to the radiator? Is the fan set into the shroud to the correct depth? About 2/3-3/4 of the fan should be inside of the shroud opening. I usually set a car outside with the throttle at about 2500 rpm & let it sit & run up to temp. If the fan clutch is working correctly, you will hear it kick in & out. I like to use a lazer temp gun on the thermostat housing & also on the lower radiator hose to see how much of a drop in temp there is across the radiator. I have seen a temp drop across a radiator of over 100 degrees before.

If everything is ok with the cooling system, start checking the motor tune up. Are you using the correct octane rating fuel for your compression ratio? Is the distributor timimg correct, both initial & full advance. Are you using the correct heat range spark plugs? Are there any vacume leaks that will make the motor run lean? Is the carburetor size correct for the motot? Is the carb jets correct for that carb/motor. Take a pair of needle nose pliers & one at a time pinch off each vacume hose on the motor while it is running. Listen for a drop in engine rpm. If a drop, usually a vacume leak in that hose system. Had one motor that had a bad leak at the dist timing advance, motor was lean & didnt run right because of incorrect timing. Also ran hot because of it. Changing of the advance can fixed all issues.

Keith,

I'm pretty sure I've been through all that. One thing...No fan cluch, but I am running a 7 blade fan and it's sitting where it should be within the shroud.
My initial timing is good, but I do wonder about the advance. Wouldn't that be more of an issue running down the road than sitting? The advance kicks in at higher rpm and shouldn't be a factor idling at a light, right? No vacuum leaks that I am aware of, but will do a quick check on that to be sure. I was running an Offenhauser 2X4 intake that did have some leaks, but the leaks were solved when I upgraded to a factory 2X4 intake just this year. That's actually when I began having these overheating issues again. I had them solved on the old intake. I will be sure to look into that though.

Thanks for the tips.

Kevin

PS...Got the new water pump in and the car is back together. Will fire it up after work later this afternoon and go for a spin. I'll letcha know how it goes.

[mechanickeith]

Couple other things,,,You running ported vacume to the distributor or manifold vacume? Also if you can find a shop with a good gas analizer, get the exhaust sniffed at idle & at a steady 2500 rpm & see what the air/fuel mixture is. That will tell you if its running lean & causing the overheat.

[Engine-Ear]

Originally Posted by mviker

I was running an Offenhauser 2X4 intake that did have some leaks, but the leaks were solved when I upgraded to a factory 2X4 intake just this year. That's actually when I began having these overheating issues again. I had them solved on the old intake. I will be sure to look into that though.

What if your latest intake has a hidden (visually nonobvious) crack that is causing a vacuum leak? Or could it be warped causing a vac leak?

[mechanickeith]

Originally Posted by Engine-Ear

What if your latest intake has a hidden (visually nonobvious) crack that is causing a vacuum leak? Or could it be warped causing a vac leak?

Thats why I recommended getting the exhaust sniffed. I think its lean!

[mviker]

Matt,

I'm doubtful the intake is cracke or warped, but it may be possible I'm running lean. will need to look into that.

The intake and carbs were rebuilt by one of our members here and his work is top notch. I did inspect everything before assembly and found no visible issues I can say would be the culprit. I also followed spec when I installed it on the engine. I will say though, that I haven't done much with the carbs. They may need some further tuning.

I took the car out yesterday to a show and had zero issues, but of course, it was a cool 70-75 degree day here in Virginia. The car ran fine with no problems whatsoever. I'll get into the fuel mixture soon and make sure it's under control.

When I first installed this new intake, I noticed I had leaks with the old one. There was a significant boost in performance when the new intake went in as I made sure I wouldn't have the same issue as the old one. I guess the carbs and advance would be the next logical step.

Thanks for the advice. Not sure when I'll have a chance to dig into this, but will post what I find once i do.

Kevin

[ho421]

Originally Posted by BigAquaBonney

This is the seller from EBay:

http://www.ebay.com/itm/251069947599...84.m1423.l2649

My car isn't even back on the road and i'm dealing with this issue as well. i've attached a few pics of my existing and (ebay replacement) pump I picked up a couple years back. both have the same part number but (arrgg), the replacement pump appears to have the characteristics of a 4cyl with reversed veins. i had planned on putting the new pump on my 421 before painting the engine but am now considering putting the old pump back on. this pump hasn't been used since the mid-80s but was fine at the time. thoughts? noticed that the attached ebay seller says the rebuilt pump he is selling is for pontiac v8s but doesn't mention 421s. Would there have been any difference between the 389 and 421 for the 4-bolt pump?