The Money Pit

Got a leak that's been driving me nuts on a new water pump.

The short story is that I blew up the engine last summer, and when I reassembled, I decided to put on one of those nice billet timing covers. Had clearance issues with the cover and the new "short water pump", and did what I needed to do for clearance. The leak is from the lower passenger side water pump bolt that goes into the block.

I tried teflon tape, teflon thread sealer, Permetex for water pumps, a new .100 thick gasket, new ARP waterpump bolts, and it still leaks. The leak is not a drip,....it's more like a steady trickle.

When I assembled it last I Permetexed the gasket to the pump (one side), and let it dry over night on the kitchen counter. Then I assembled to the block, which was clean, with Permitex on the other side of the gasket. The gasket does not look to be leaking,...just the bolt!

My next idea is to try another water pump. So I will ask you guys what pump you think will work to clear the billet cover, look decent,...and hopefully not leak.

I've built over a dozen smallblocks in my life, and this is the first one I ever had that leaked...........

cv67

Hard to say
I also used one of those billet covers and had to do some grinding on both the back of the impeller cover and the timing cover, too. If I remmeber right the pump hits the edge of the cover as it curves aroudn it think I had to do some grinding there also to get it not to leak.

Check it carefully. Pain, huh?

Sure its not the water pump bypass hole seeping out through the bolt due to not seating right?

The Money Pit

I did some hand filing on the cover to clear the pump arms. I used button head screws on the rear pump cover, and have .070 clearance between the cover and the billet timing cover. I can see light everywhere between the pump arms and cover. Nothing is hitting.

I was thinking about that bypass hole myself, but it leaked exactly the same way when I first installed it with standard gaskets. I got .100 thick gaskets from Summit, and reinstalled but still have the same leak. Hard to believe two gaskets leak exactly the same place.

I had the same brand pump on the engine prior to my "blow up", and had no problems with that one until the balancer let go and destroyed it.

birdsmith

Could be related to some distortion in those thick gaskets. Have you thought about possibly fabricating a couple , say, .080" thick aluminum spacers that you could install on either side of the pump with a thin gasket on either side? Also, what kind of RTV are you using? I've had the best luck with permatex Hi-Temp Grey. It just flat works twice as good as any other silicone/RTV product I've ever used, and I have tried them all over the years. It's all I use anymore. I would think that any teflon product would not be the best thing for thread sealing...

7T1vette

Polished billet and chrome covers have gasket sealing surfaces that are TOO SMOOTH for the gasket to get a good 'bite' into the surface. It would be best to scuff up that surface with some 150 grit paper first.

Also, use Permatex #2 gasket sealer or black RTV sealer. Do not use the 'run of the mill' silicone sealant on gaskets trying to seal petroleum substances. And, if you use any sealant on the gasket, put a light wipe on both sides, install the parts with bolts finger-tight, torque to about 25 in-lbs (2 ft-lbs) and let the sealant set up for a few hours before torquing the bolts down to proper torque. With a smooth/slippery gasket surface, gooey sealant will just allow the gasket to slide around when bolts are torqued down, if not allowed to cure first.

And, as mentioned above, any interference between parts that could cause the gasket/part surface not to be in good contact with each other should be resolved before installing the gasket.

birdsmith

It's not the cover that's leaking...it's the lower RH bolt that attaches the pump to the block.

C3Paul

Perhaps you could substitute the bolt with a stud and use some ARP Teflon thread sealer on the thread?

fugawi

use rtv on the bolt. i do on my water pump bolts. no leaks.

7T1vette

Measure the depth of the bolt hole in the block. Then compare to the length of threads on the bolt. Your bolt might be too long...because the hole is too shallow.

'75

You might try a copper washer on the bolt.

moosie982

Seems very logical !
Peace,,, moosie