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Discussion Starter #1
I have a 67 with a 351w out of a 74 Galaxie. I have the standard 67 A/C sb Radiator (for 90 deg water pump) and a V belt system. I keep blowing out the Water Pump Gasket on the bottom of the water pump by the crank. It is the inside gasket between the backing blate and the actual water pump. I have replaced the gasket about 4 times and it keeps happening. I have replaced my thermostat twice as well. I have a non collapsible lower rad hose. I have a 13lb cap and Im pretty sure I have a correct flow direction pump. It appears that I have been creating too much pressure in the water pump housing. I dont understand what it is doing. I warm up the car before I drive too. I even took it to the strip and had no problems doing a dozen passes at 6k RPM but a day later I blew the water pump gasket out when I took it to 4k RPM. I am lost. Thanks in Advance.
 

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Assuming there isn't a problem with the mating surface on the engine itself,I would check to make sure the water pump is perfectly flat.We used to do this by placing the pump on a piece of glass,then check all around the perimeter of the pump body mating surface with a feeler gauge.If the pump isn't flat in the area where you are having the problem, the pressurized coolant can escape,taking the gasket with it.
 

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both the water pump
and the engine surfaces
would need to be checked
for adequate flatness
iowa
 

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Discussion Starter #4
Ill check the current pump I have now but when I said I kept replacing the water pump gasket I would just take the pump back to kragen and said it was broken and they would give me a new pump so this is the 4th pump this has happened to me
 

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what gaskets are you using if they are the cheap printer paper style that came with the water pump that might be your problem try some better ones like felpro and check the mating surfaces before you install it. i noticed when i installed a new water pump the gasket that came with it did not even line up with the holes so when you pushed the bolts through it broke the gasket
 

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Ill check the current pump I have now but when I said I kept replacing the water pump gasket I would just take the pump back to kragen and said it was broken and they would give me a new pump so this is the 4th pump this has happened to me
Just a shot in the dark here but, I would look at the head gaskets.
The coolant is not passing thru the block properly and the pump is fighting it with the weakest spot being the plate gasket giving out under pressure.
 

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When you say that your gasket blows out, does it just start leaking, or does the gasket actually have a spot where it is torn and blown out? Also, are you having any problems with overheating or is your temperature normal?
 

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Discussion Starter #8
The gasket blows out, if you drive it for more than a few hundred yards you run out of water. It is instantaneous
 

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I think what he is asking is does it physically push gasket out from where is should be or seem to be leaking between gasket and housing or pump.

Is it always from same spot?

Geez, by now I'd have replace timing cover as well just out of frustration, or pushed it off a cliff!
 

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Also, did this just start happening out of blue, or after putting on new pump or is it a newly installed engine.

i.e. Was it ever working correctly?
 

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Are you putting Permatex Ultra Blue on both sides of the gasket before you install it? If you are putting on the gasket dry without adequate sealer, Then that IS your problem.

Tony K.
 

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Discussion Starter #12
It started happening after I changed the water pump (bearing started to go). I have changed the water pump multiple times since it started happening thinking it could possibly be a faulty pump.

It always happens right where there is that little slit in the timing cover but it blows between the backing plate and pump (between the two flat bolts) not between the backing plate and the timing cover.

It also actually pushes the gasket out, you can see the little bit of gasket hanging out afterwards. I have always used some gasket sealant between the backing plate and timing cover. I however have never used it on the pump/backing plate before because they come pre-assembled.

Today I went ahead and got new gaskets (both sides of the backing plate), cleaned up all the surfaces really well, and used gasket sealant both sides of both gaskets. I also checked the flow through both sides of the block with a hose and through the radiator. Couldnt find any problems there. I also got a new radiator cap just to be safe.

I am going to do a compression check tomorrow to make sure I dont have a faulty head gasket. If this doesnt show anything then I will just cross my fingers and hope it doesnt happen again. It never happens immediately so I may not know for a while.

Thanks everyone for all the help, I really appreciate it.
 

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Here's what I saw on mine that COULD HAVE caused this, but I prevented it.
It may not apply to you but hopefully it helps.

My timing cover is aluminum. My water pump is cast iron and has a sheet metal back plate. It uses 2 gaskets.

The timing cover has a notch at the bottom where the water pump mounts so the first thing I said when I saw that notch was "Why do I need 2 gaskets, since that space has a drain notch and no water ever gets back there?"

Well, after looking closer, I realized that at the openings in the block, where water enters and exits, the water passes through the timing cover.

Forty years of erosion eats at the front cover on this area and leaves very little surface area for the rear gasket to seat against.

I had a coworker weld in some aluminum replacing the erosion. Then I milled the gasket mounting surface flat.

Moral-- BOTH GASKETS ARE IMPORTANT IN THE BLOCK INLET/OUTLET AREAS. GASKETS NEED AT LEAST 1/8" OF "FACE" TO BE COMPRESSED AGAINST. PERMATEX OR SIMILAR ATTACHES THE GASKET TO THE SEALING SURFACES SO IT DOESN'T MOVE.
 

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Discussion Starter #14
After not blowing for 11 months now my water pump gasket blew it again (after my dad was hot rodding it, parents so irresponsible these days). Anyways is blew out the gasket from the pump to backing plate again after sealing it with 3m Weatherstripping and Gasket adhesive. I took a further look and came up with an idea with my dad. Could it possibly be the ratio between my water pump pulley and my crankshaft pulley that is giving me over pressure? The Water pump pulley diameter is approx 5 1/4" and the crank pulley is approx 7 3/4". What is the standard ratio between water pump and crank pulleys? I have the 67 289 Pump (exits to the passenger side) on a 74 351W block if that makes any difference. Thanks.
 

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Usually the water pump pulley is about the same size as the crank pulley. I'm surprised the pulleys aren't hitting each other.

March sells a 5.5" crank pulley and a 6" wp pulley and a 5" underdrive wp pulley. That 7 3/4" crank pulley might just be your problem.
 

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Discussion Starter #16
Thanks Dan,
Yeah there is maybe 1/4"-1/2" in between the WP and Crank Pulleys. The stuff from March seems kinda expensive, is there a good source for cheaper stuff like just a standard steel crank pulley of the correct size?
 
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