midyearvette

did he say it is leaking again or just the gasket is deformed? i think it is over tightened?.......wtf?......btw the by pass issue is a great opinion...

Mikey65

I have no problem giving the bypass solution a try... I assume everyone needs a bypass though? Otherwise there is still something wrong and something is overpressurizing for some reason. And if it was, isn't the the job of the coolant cap to release pressure at 13#? Cap is new. Someone mentioned drilling bypass holes in the thermostat? Is there one made that already has this feature??

I will recheck the bolt length. I am already using lock washers. I will remove the washers and see if the bolts go in all the way without them.

The fan clutch is now centered perfectly.

I have been using the blue FELPRO gaskets. Is there something better?

I will try another sealant, but have honestly already tried 3 types.

I will also recheck the surface to make sure it's square.

Other than that, all I can do is try it again, run tests, and if it doesn't work take it to the builder and just have them fix it.

magicv8

Put the bolts you are using into the block holes with the pump off and
make sure that they will easily (no wrench if possible) seat in the block
deep enough to hold the pump without the gasket.

IMO if they don't, they are too long, or your threaded holes are not clean.

Mossy66

A water pump pumps water with the use of an impeller, which is not like a piston or screw type pump. (positive displacement?) Would it not act like a fan with the damper closed and not really develop any pressure if there is no open bypass?

I know that when I worked at a city water pumping station, they would start the pumps against a closed damper and let the motors get up to speed before opening the dampers. This was done to keep the motor start up amperage low, (these motors were in the 750-1000 HP range)and the motors were running with almost no load (therefore no pressure) until the dampers were opened.

Am I missing something?

65 vette dude

I may be wrong, but I don't think not having a bypass is your problem. Most SB,low hp,C2's came with a 608 pump,which did not have a bypass. The high HP SB came with the 326 and 609 pump,which did have the bypass. I thought the reason for the bypass was a way to provide coolant to the engine at very high engine RPM's,due to water pump impeller cavitation on high hp engines. Did cast iron intakes have a threaded hole for the bypass? Do you have a aftermarket intake ,and does it even have a hole for the bypass? I think NEVERL8's suggestion of a vibration problem has a lot of merit,and deserves investigating.

Coves4me

OK, here's my $0.02 worth....based on your photos, I'm guessing that you aren't getting your bolts fully tightened against the water pump. You've got some threads internally that are corroded, or worse, a partial bolt in one of the threaded bolt holes. I'm guessing the former. I doubt that you are building up that much pressure to cause a good gasket to be forced out of the joint if the water pump was truly tightened down with 30# of torque. You would blow coolant out of your overflow, crack a soldered radiator joint or blow a hose first before that thin compressed gasket with sealant would let go. When you have your water pump off, check for the flatness of the pump sealing surfaces and also the block. I'm guessing you have something wrong with one of your threaded holes that is keeping the water pump from mating squarely with the block. Good luck.

vetrod62

A water bypass is not in the t-stat. It can be anything that relieves pressure when the T-stat is closed. In some sbc blocks it is drilled into the block ( by the factory ) where that extra hole in the water pump gasket that goes on the right side of the water pump. In the picture below the hole is not drilled. Some cars use the heater as the bypass so there is a constant place for the water to go. This is not a good way to go. I have seen heater cores burst this way. On my own car I blew out the new 90* rubber couple on the heater by running thru the gears at 7000+. The best one I saw was at hot rod party. My friend wanted to put on a show and pulled a 7000 rpm 1st and 2nd with an engine not warmed up. He blew the water pump gaskets out both sides on the pump. I know that my crowd drives their cars a little harder than most, and most will not have these problems.

If the T-stat is closed, the lower hose is in suction and the same with the upper hose to some extent. The water pump pressure has no where to go other than the heater. In C1s the heater is controlled by closing a valve in the heater. This creates another pressure sitituation. On both my cars I have valves to shut off the heater and a bypass installed to return water back to the engine for when I race. Those Edelbrock pumps will pump more water than the stock ones.

DansYellow66

A possibly imbalance in the fan or fan clutch sounds like a good item to check. I can imagine an out-of-balance situation working bolts loose, especially at high RPM. As fast as he is going through gaskets I don't think it has time to wear out the pump bearing.

obx2323

Run the bolts in WITHOUT the water pump on, ck clearance and are you still using the aluminum water pump?? or did you switched back to cast iron? I know aluminum is great but....you've exhausted almost everything else.

I feel for you pal

Dennis Beck

Mikey65

Ok... removed the washers, and reinstalled the bolts... they bolt up fine and run all the way down. No gaps. But here is a question... I removed the water pump and checked out the gasket. Someone tell me what you make of these pics.. does it look like the gasket is pushing out or what? Why is it appearing to curl over the pump? If you look, the gasket around the upper bolt hole it still intact around the bolt hole. What's the deal with this?



















And the passenger side now... which looks fine for the most part....

KC John

Those gaskets look fine to me. All you are seeing is the part of the gasket that hasn't been squashed.

If you don't want to see that, just bolt it all up again and trim the gasket that sticks out with a razor knife.

toddalin

That is the part that hangs over the machined faces and when you torque it down you are just cutting that area off. If it were pushing out from excess water pressure, you would see it pushing away from the water passages BIG TIME to be pushing out that far.

The gasket looks to be fine. If you are still leaking, then a surface is not flush and the water is seaping over the face of the gasket.

Alternatively, from the prior pics, it doesn't look like the faces are coming together evenly, but that could be illusion...

But, is it possible that the back of the water pump is hitting on a timing cover bolt so that you can torque the water pump without it really sealing it down all the way? If you have the pump off, is there any evidence that this could happen (e.g., dimple, nick in paint)?

DansYellow66

I would find a higher class gasket to use and be very careful to make sure the fan and fan clutch are properly mounted and centered and see if it doesn't hold together after that.

By now you can probably rival a NASCAR pit crew in pulling a water pump.

midyearvette

the sealing surfaces look fine to me...possibly the casting on the pump is not quite as large as the stock unit?....obviously the pump and bolts are tight enough and since there is an over lap at the gasket surface, the pump is digging the gasket and over some time and heat cycles this is happening....you could actually under trim the gaskets and be fine, or run a new set again and when this happens, try to trim them......they are not leaking....

jim lockwood

Other than some (well deserved) paranoia, I don't think you've got a problem here.

I just re-read your initial post and there is no mention of leaking. Now that you've posted some in-focus pictures, it seems that what concerns you is the shred of gasket hanging off in space.

No big deal.

Clean the pump and the gasket, reseal, reassemble, and just drive it.

I think you are done.

Jim

Averyd1

The reason you are tearing up water pump gaskets is the design of the water pump to block. I have had this problem over the years with my 62 vette. The twisting (rocking motion) of the engine will cause the front motor mount to move slightly with frame movement. and the motor mount being between the block and water pump will actually cause the gasket to deteriorate prematurely over a short period of time.unlke a conventional small block chevy with side motor mounts.where the water pump is directly mounted to the block and can move with the engine.. The more HP the more the frame will rock and twist. Use heavier gaskets and tighten the bolts every 500 to 1000 miles because they will also loosen but not always.

Don Avery
802-484-5936

65GGvert

I'm betting that since it's been 8 and 1/2 years he probably resolved it one way or the other.

65hihp

How do people find these ancient threads? It's fun to see the screen names of people we used to banter with but have long forgotten since they fell out of the hobby. Mikey65 hasn't been on the scene since 2012. I sure hope he fixed that leak.

Easy Rhino

Or quit driving it.

One of these days, somebody will find Jimmy Hoffa's body.