Removing Bypass Fitting
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
Removing Bypass Fitting
I getting ready to begin the build phase of my 427 tear-down. It will be coming back as a 496 and I want to eliminate the thermostat bypass to increase flow to the radiator (I will put 3 -1/8" holes in thermostat to compensate).
I notice many folks put an NPT plug in the top of the water pump. However, mine fitting looks to be pressed in to the pump, with no way to remove it. There is no visible evidence of threads. The pump is an original GM and I assume it is from '69 with the rest of the engine. Did some of these units have pressed in fittings?
Thanks.
I notice many folks put an NPT plug in the top of the water pump. However, mine fitting looks to be pressed in to the pump, with no way to remove it. There is no visible evidence of threads. The pump is an original GM and I assume it is from '69 with the rest of the engine. Did some of these units have pressed in fittings?
Thanks.
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
No. The 5/8" hose end fitting is comletely smooth with no visible means for turning or rotating it. Further, I can see no threads on the fitting or the pump where the fitting enters the pump. It LOOKS like a press fitting, but cannot be sure.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
It's entirely possible, and I just have not seen one. Limited experience with big block water pumps.
I suppose if you really wanted to plug it and keep the stock pump, you could cut the nipple off, drill and tap for a fitting, and seal it that way.
Personally though, I would just save that pump, and buy a new pump that has a threaded port for a plug.
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
A couple of possibilities for installing and removing:
- Are there 2 notches at the top of the fitting across from each other? I remember some with these notches and you unscrew by outting a flat in them and turning.
- Is there a square or hex INSIDE the fitting? If so, you can insert a matching tool to unscrew.
Bottom line is that it is most likely screwed in and if neither of the above are available, you should be able to grip it with a pipe wrench and back it out.
- Are there 2 notches at the top of the fitting across from each other? I remember some with these notches and you unscrew by outting a flat in them and turning.
- Is there a square or hex INSIDE the fitting? If so, you can insert a matching tool to unscrew.
Bottom line is that it is most likely screwed in and if neither of the above are available, you should be able to grip it with a pipe wrench and back it out.
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
thanks for the suggestions. I looked a bit closer inside. The fitting is definately not thick enough to have threads, so it must be pressed in. I can actually see the collar the represents the stop for fitting.
I wonder if I can get a small rubber cap to replace the hose. Has anyone ever seem something like that?
I wonder if I can get a small rubber cap to replace the hose. Has anyone ever seem something like that?
Melting Slicks
Joined: Mar 2004
Posts: 3,472
Likes: 18
From: Lake Ozark, MO
I seen them capped. Uses a spring clamp to hold the rubber cap on. Check marine catalogs.
http://www.parts123.com/parts123/yb....~P2.59~~~~~~~F
http://www.parts123.com/parts123/yb....~P2.59~~~~~~~F
Last edited by Hvymtlc5; Apr 8, 2008 at 01:01 PM.
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
I tired to run without the bypass hose, the temp fluctuated so much I reinstalled the hose. I am runing a strwert stage III pump with there T-stat and they suggested to remove the bypass hose, some people have luck with removeing the hose and some don't. The pump that came with the Zoops serp drive had a smoth hose fitting in the top of the pump for the bypass hose, no way to fit a wrench to it, had to use a set of channel locks, I could see the threads at the base of the fitting. Sounds like yours is pressed in. I would try to run the bypass hose if possible. I also tried the rubber caps to cap off a intake heater fitting, the cap blew off and caused a real mess just after I polished the serp drive. It was a little old so I can't blame the misshap all on the rubber cap and I'm sure the stewert pump had some to do with it to. The cap split open right at the clamp.
Neal
Neal
Last edited by chevymans 77; Apr 8, 2008 at 02:59 PM.
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