Early 80's small block Water pump problem

azzkier · 06-09-2008, 12:49 PM

I have a early 80's small block 350 that keeps blowing water pump gaskets. If you're looking at the motor, it's the left side gasket , keeps leaking after about 1 hr of run time. I've tried all diffrent kinds of gaskets, water pumps. any ideas?

75K30 · 06-09-2008, 12:59 PM

Wlecome to the site;

How flat is the sealing surface on the block? Is there any gouges or problems with the matting surface?
What types of sealers are you using (if any) and are you using sealers correctly? Many times RTV type sealers will squeeze out if not allowed to set up properly before the fasteners are tightened down.

azzkier · 06-09-2008, 01:07 PM

Thanks,

Surface is perfect, i've tried sealers and gaskets. It's like there it too much pressure on it, just eats the gaskets away. I put a diffrent set of heads on it, ever since i did, it's done this.

Chevy_Finatic79 · 06-09-2008, 01:31 PM

what kind of heads did you install? did you put reverse water-flow heads on it? does the thermostat open

azzkier · 06-09-2008, 01:42 PM

Heads are just regular Gm iron heads, 202 valves. No stat, (guts been removed). Motor is in a mud truck, running 475-500hp on dyno. Im not up on all the older gm stuff, i only mess with the LS stuff. I didnt know if there was a cross over or something for the heads, steam building up, ect, ect.

75K30 · 06-09-2008, 02:19 PM

The heads should have little to do with the water pump itself. I do however have another theory though. Is it possible that one or more of the bolts is just barely too long, and the shoulder is bottoming out and not giving you proper torque?
Improper claming force could cause this issue.
with only 4 bolts holding the pump on, this should be a pretty easy fix. This one has me scratching my head a little.

azzkier · 06-09-2008, 02:29 PM

Very well could be that. I just assumed they were not blind holes though. I'll check it.

75K30 · 06-09-2008, 02:37 PM

Right on. I was just thinking that not all of the bolts are the same length, and if you have the long bolts in the wrong spot, it may bottom out on the shoulder, or maybe the bolt itself has a problem.
Good luck with that, sometimes those little things can drive you crazy.

azzkier · 06-09-2008, 02:47 PM

Ya...I was about the put the ls1 back in it! Hope that its just the bolt issue.

06-09-2008, 12:49 PM	#1
azzkier Junior Member Join Date: Jun 2008 Posts: 5	Early 80's small block Water pump problem I have a early 80's small block 350 that keeps blowing water pump gaskets. If you're looking at the motor, it's the left side gasket , keeps leaking after about 1 hr of run time. I've tried all diffrent kinds of gaskets, water pumps. any ideas?

06-09-2008, 01:31 PM	#4
Chevy_Finatic79 Senior Member Join Date: Mar 2008 Location: Lincoln NE Posts: 442	what kind of heads did you install? did you put reverse water-flow heads on it? does the thermostat open __________________ "She's gonna Freak when she see's my wheels" 85' Chevy C-10 Longbox (Rat) TBI 5.7 Liter/THM350 90' Chevy Suburban 4x4 TBI 350 Cu.In./700R4 http://www.truckforum.org/forums/truck-pictures-176.htm

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06-09-2008, 12:59 PM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 2,630	Wlecome to the site; How flat is the sealing surface on the block? Is there any gouges or problems with the matting surface? What types of sealers are you using (if any) and are you using sealers correctly? Many times RTV type sealers will squeeze out if not allowed to set up properly before the fasteners are tightened down.

06-09-2008, 01:07 PM	#3
azzkier Junior Member Join Date: Jun 2008 Posts: 5	Thanks, Surface is perfect, i've tried sealers and gaskets. It's like there it too much pressure on it, just eats the gaskets away. I put a diffrent set of heads on it, ever since i did, it's done this.

06-09-2008, 01:42 PM	#5
azzkier Junior Member Join Date: Jun 2008 Posts: 5	Heads are just regular Gm iron heads, 202 valves. No stat, (guts been removed). Motor is in a mud truck, running 475-500hp on dyno. Im not up on all the older gm stuff, i only mess with the LS stuff. I didnt know if there was a cross over or something for the heads, steam building up, ect, ect.

06-09-2008, 02:19 PM	#6
75K30 Senior Member Join Date: Jul 2006 Posts: 2,630	The heads should have little to do with the water pump itself. I do however have another theory though. Is it possible that one or more of the bolts is just barely too long, and the shoulder is bottoming out and not giving you proper torque? Improper claming force could cause this issue. with only 4 bolts holding the pump on, this should be a pretty easy fix. This one has me scratching my head a little.

06-09-2008, 02:29 PM	#7
azzkier Junior Member Join Date: Jun 2008 Posts: 5	Very well could be that. I just assumed they were not blind holes though. I'll check it.

06-09-2008, 02:37 PM	#8
75K30 Senior Member Join Date: Jul 2006 Posts: 2,630	Right on. I was just thinking that not all of the bolts are the same length, and if you have the long bolts in the wrong spot, it may bottom out on the shoulder, or maybe the bolt itself has a problem. Good luck with that, sometimes those little things can drive you crazy.

06-09-2008, 02:47 PM	#9
azzkier Junior Member Join Date: Jun 2008 Posts: 5	Ya...I was about the put the ls1 back in it! Hope that its just the bolt issue.