My head is about to explode
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I can see how it can be missed at installation.
Looks like there just wasn't enough meat cast into the manifold and it sticks out past the wall of the block. Got a pic of the underside of the manifold?
Seems like the proper way to repair is to build it up on the bottom side with alum tig and refinish the surface.
BTW, the new Permatex stuff mentioned before is some amazing stuff, not RTV, but a new compound. Probably would work, but the cure time might be too fast for a manifold install.
Looks like there just wasn't enough meat cast into the manifold and it sticks out past the wall of the block. Got a pic of the underside of the manifold?
Seems like the proper way to repair is to build it up on the bottom side with alum tig and refinish the surface.
BTW, the new Permatex stuff mentioned before is some amazing stuff, not RTV, but a new compound. Probably would work, but the cure time might be too fast for a manifold install.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
I used Ultra Blue on a similar situation with success. I applied it from the backside and through the dist hole and let it set for 24 hours. Getting it clean is tough with the manifold in place.
Thread Starter
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
The manifold actually lines up, there just seem to be a spot on the manifold mating surface that makes the gap. Why the RTV doesn't fill that in in the first place I don't know.
There is more to this than meets the eye, speaking of which there is no way you can see it, I even scraped the old RTV off with a razor blade so there is some thing weird going on and I will get to the bottom of it sooner or later.
Maybe someone putting together a motor now with a new Vic Jr can take a close look at it for us
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
On the one I did I had bulk on the back side and bulk on the inside so even with pos or neg crankcase pressure it couldn't come out. ( I do think I had a wider opening though)
To clean I used a thin rag that I fed through the crack soaked in brake clean,actually I used many rags. I cleaned the @#$% out of it.
I squeezed the Ultra through from the backside and contoured it through the dist hole with my finger.
To clean I used a thin rag that I fed through the crack soaked in brake clean,actually I used many rags. I cleaned the @#$% out of it.
I squeezed the Ultra through from the backside and contoured it through the dist hole with my finger.
Thread Starter
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
It was compressed all the way across, I've taken off a few hundred intakes and since it was leaking I am going to be scrutinizing the bead across the back even closer so I am expecting to see something that tells me why it's leaking but I don't, sorry not taking the blame for this one. If you had any idea how **** I am when it comes to building motors...well I guess I don't really have to say anymore other than the fact is the truth about this will come out sooner or later.
Melting Slicks
Joined: Feb 2003
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Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
I think the pic is deceiving , he already said it does line up. I was thinking at first the manifold and the china wall didnt meet in the lit area , but I dont think thats the case.
If there has been RTV in between the 2 surfaces , the surfaces were clean,and the RTV cured completely (which I'm sure they were ) , then IMO I would be looking for Pos or Neg crankcase pressures. Lets face it he did not build this motor to idle back and forth to the grocery store.
Motorhead , was the dislodged RTV outside or inside of the china wall ?
If there is no pressure problems I can think of several ways to secure the RTV depending on how wide the gap is.
If there has been RTV in between the 2 surfaces , the surfaces were clean,and the RTV cured completely (which I'm sure they were ) , then IMO I would be looking for Pos or Neg crankcase pressures. Lets face it he did not build this motor to idle back and forth to the grocery store.
Motorhead , was the dislodged RTV outside or inside of the china wall ?
If there is no pressure problems I can think of several ways to secure the RTV depending on how wide the gap is.
with Roger :
Race Director
Joined: May 2003
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From: California
moterhead..... just read your thread, looks as if you got it down, but I feel for you, that is a bunch of 
about that manifold. I very much would like to hear Vic's reply to your email. i am sure after 20 years they must have heard about this somewhere along the line.... just wondering what type of line they are going to try and feed you?
good luck my friend, plz keep us posted... p
about that manifold. I very much would like to hear Vic's reply to your email. i am sure after 20 years they must have heard about this somewhere along the line.... just wondering what type of line they are going to try and feed you?good luck my friend, plz keep us posted... p
Melting Slicks
Joined: Jun 2002
Posts: 2,844
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From: Orrtanna Pa.
This is starting to make sense now. In the past I never had leaks like this either. But I also never had a 7000 rpm beast. Even this same 406 in earlier trim did not leak. Once I did the solid cam and started turning up the rpms,.....the leaks began. I just figured it was because I changed intakes with the engine in the car, and I didn't get a good seal on the rear of the intake because I couldn't see it.
If pressure is the issue,....what's the work around.
If pressure is the issue,....what's the work around.
Pro
Joined: Jun 2005
Posts: 725
Likes: 1
From: FL.
After a fairly meticulous intake bolt up, I still had a leak, The Black RTV fixed it. Next time, Im going to make guide studs for the four corners and hopefully drop the manifold on without it moving and smearing the bead.
PS..Be sure you unplug all Orifices before Sploding, should minimize the splatter area, dont know by how much though?
PS..Be sure you unplug all Orifices before Sploding, should minimize the splatter area, dont know by how much though?
Last edited by 69vettester; Jul 29, 2010 at 04:50 PM.
Thread Starter
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Well that small annoying leak is now gone, took it out for a spin and looked under the car a few minutes later and it is now a small pond, had to shoo the ducks away so I could get a closer look at it.
Whatever I did last night made the leak twice as bad or more. There was one small pond of oil and above that there was another one but this one was water / coolant I think. It was further back than the bottom of the rad so this is just getting better and better as time goes on. The good news is I should have all the required skills to land a job at BP.
First I'm going to pull the distributor and see if that hole came back but I don't want to speculate right now but the fact I haven't had a 600HP small block that has been revved to 7500RPM's is starting to make me think who the heil knows what's going on at that RPM ?
Whatever I did last night made the leak twice as bad or more. There was one small pond of oil and above that there was another one but this one was water / coolant I think. It was further back than the bottom of the rad so this is just getting better and better as time goes on. The good news is I should have all the required skills to land a job at BP.
First I'm going to pull the distributor and see if that hole came back but I don't want to speculate right now but the fact I haven't had a 600HP small block that has been revved to 7500RPM's is starting to make me think who the heil knows what's going on at that RPM ?
Thread Starter
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
Wayne,
Are you running two valve cover breathers or just one? I still run just one, and had a thought that maybe two would help this. I may try it myself at some point. Right now I just don't have the time to tinker.
Are you running two valve cover breathers or just one? I still run just one, and had a thought that maybe two would help this. I may try it myself at some point. Right now I just don't have the time to tinker.
Burning Brakes
Joined: Dec 2008
Posts: 971
Likes: 45
From: Middlesex NJ
Missed it by that much......Thats terrible.
Makes me wonder how everything else matches up like your distributor shaft etc.
Makes me wonder how everything else matches up like your distributor shaft etc.
Can you get me one of those hats so I can put it under his leaky parts, don't really care if it's signed or not probably wouldn't even do a good job at catching oil.
Here's the pic, I put a flashlight at the back a directed the light at the hole. You can see the gap about an inch long and 1/16 to 1/8 inch high. And please I really don't need anyone telling me that RTV should have filled that gap as others have had the same problem and the china wall on my Motown block is actually about twice as wide as a normal OEM block and you still get this F ing gap.
I can see why it hasn't been fixed in the 20 some odd years they have been selling them, looks like a pretty tricky milling job and a first year apprentice might need about 5 minutes to fix it
PS I never use RTV around the distributor gasket just so sick and tired of this leak I put it everywhere there was a remote possibilty of a leak
Here's the pic, I put a flashlight at the back a directed the light at the hole. You can see the gap about an inch long and 1/16 to 1/8 inch high. And please I really don't need anyone telling me that RTV should have filled that gap as others have had the same problem and the china wall on my Motown block is actually about twice as wide as a normal OEM block and you still get this F ing gap.
I can see why it hasn't been fixed in the 20 some odd years they have been selling them, looks like a pretty tricky milling job and a first year apprentice might need about 5 minutes to fix it
PS I never use RTV around the distributor gasket just so sick and tired of this leak I put it everywhere there was a remote possibilty of a leak
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I hated to see old Pontiac engine go by the wayside, so much better a design concept than the SBC it's not funny.....never an issue with them...
and yet with this vette engine '89 roller 355 engine, I have had some issues, with stockish intakes to boot...an Edel base for a large mouth TPI being the worst...never noticed that gap though....but I found a cure....
idled the engine and sprayed carb cleaner down the back side enough to find the leak, then put a second PCV valve to mani vac in place of the valve cover vent to the induction/air cleaner....
now engine ran at a crank case vacuum.....so to spray some carb cleaner into that spot it was leaking, hear/feel the suction as it was sucked in and cleaning the passages.....not a TON of it, not trying to thin the oil, just clean the leak passage.....
let it dry, then take some RTV on a finger and let it get sucked/flowed into the leak spot....pull the dizzy B+ wire off VERY quickly before all the RTV gets sucked into the engine where it don't belong....
smooth over the outside.....
done deal, no more leaks.....worked for ME....obviously to let cure overnight, and put the normal PCV setup back in position....
and yet with this vette engine '89 roller 355 engine, I have had some issues, with stockish intakes to boot...an Edel base for a large mouth TPI being the worst...never noticed that gap though....but I found a cure....
idled the engine and sprayed carb cleaner down the back side enough to find the leak, then put a second PCV valve to mani vac in place of the valve cover vent to the induction/air cleaner....
now engine ran at a crank case vacuum.....so to spray some carb cleaner into that spot it was leaking, hear/feel the suction as it was sucked in and cleaning the passages.....not a TON of it, not trying to thin the oil, just clean the leak passage.....
let it dry, then take some RTV on a finger and let it get sucked/flowed into the leak spot....pull the dizzy B+ wire off VERY quickly before all the RTV gets sucked into the engine where it don't belong....
smooth over the outside.....
done deal, no more leaks.....worked for ME....obviously to let cure overnight, and put the normal PCV setup back in position....
Pro
Joined: Jun 2005
Posts: 725
Likes: 1
From: FL.
yes, First I got a good idea where the seep was, then I cleaned up 6-8 inches span along the gap, Then with a putty knife , packed the Black RTV along the 8 inch gap as tight as I could. If I remember right it slowed the seep and then it stopped completely. I thought I would end up pulling and resealing the intake but I lucked out....