Blue RTV cure time, 300 Six water pump.

[Ray Cecil]

So, ive usually always used blue rtv in the correct manner. On water pump and t-stat housings. Ive always followed the cure time. Let sit for 1 hour before torquing to spec.

I followed this procedure on the water pump on the 300 in Little blue. No leaks. Then, I was pulling out of a tight spot and got the revs up a little. I drove 1/2 mile and got out. I was dripping coolant suddenly.

I drove home with it leaking, only about 2 miles. It wasnt fully warmed up when I got into the gas, so the t-stat probably wasnt opened. Without an anti-collapse spring in the lower hose, I wonder if the impeller sucked it closed and created a vacuum between the hose and the pump sucking part of the seal enough to cause it to leak.

I just got around to fixing it. I never figured out where it was leaking from. Went ahead and got a new pump. Blue RTV, dab of rtv on bolts, etc.

The only other thing I could think of was the old pump shaft seal was leaking out the weep hole. I inspected the 4 pump bolts as I pulled them out, they looked dry.

I know I waited 24 hours before adding coolant last time. Is it necessary to wait that long? Can I get away with maybe 8 hours? I need to wrap this job up.

If anyone else has had issue with sealing the 300 six water pump up, and figured out what they did wrong, please chime in. Hopefully this time it wont leak. Thanks.

 

[ArdWrknTrk]

I'm not sure which 'blue' you're using.

I always use "Right Stuff" or Ultra gray.

There are three types of cure I know: oxime, acetoxy, and peroxide cure.

The vinegar smelling stuff uses humidity to catalyze the cure, so water surely won't hurt it.

Sometimes contaminated surfaces can retard or entirely stop the cure. (silicone oil, sulfur compounds)

But I usually go with 6 hours cure before pressurizing.

I don't have a 300, but I doubt you could suck the lower hose closed with the thermostat not fully open, and/or any pressure in the system.

That usually affects noob drag racers who have no thermostat, start cold, and hammer the throttle past red line from idle.

 

[Ray Cecil]

I'm not sure which 'blue' you're using.

I always use "Right Stuff" or Ultra gray.

There are three types of cure I know: oxime, acetoxy, and peroxide cure.

The vinegar smelling stuff uses humidity to catalyze the cure, so water surely won't hurt it.

Sometimes contaminated surfaces can retard or entirely stop the cure. (silicone oil, sulfur compounds)

But I usually go with 6 hours cure before pressurizing.

I don't have a 300, but I doubt you could suck the lower hose closed with the thermostat not fully open, and/or any pressure in the system.

That usually affects noob drag racers who have no thermostat, start cold, and hammer the throttle past red line from idle.

Permatex Blue RTV. Its specifically for use on t-stat and water pumps or anything else in cantact with coolant.

 

[ArdWrknTrk]

Permatex Blue RTV. Its specifically for use on t-stat and water pumps or anything else in cantact with coolant.

So it's not 'sensor safe'?

Does it smell like salad dressing? (Acetic acid)

ETA :

You're not using it in thick sections -like front & rear intake manifold seals-

Should be fine in just a few hours.

 

[Ray Cecil]

So it's not 'sensor safe'?Does it smell like salad dressing? (Acetic acid)ETA :You're not using it in thick sections -like front & rear intake manifold seals-Should be fine in just a few hours.

Salad dressing? What flavor? Its regular old blue rtv. So, it smells like rtv. I dont know how to discribe it. 

 

I have no sensors to worry about, so I dont.

 

 

Its been a few hours. I just filled it up. I wont start it or pressurize it yet.

 

 

 

 

 

 

On Sun, Jun 30, 2019, 1:49 PM ArdWrknTrk [via Bullnose Enthusiasts] <redacted_email_address> wrote:

 

 

 

[ArdWrknTrk]

Sensor safe polysiloxane formulas use different curing catalyst chemistries.

They don't smell like acetic acid because that byproduct would contaminate something like an O2 sensor.

As long as all the glycol was cleaned from the mating surfaces your RTV should get a good bond and not leak.

I usually use one of those (isopropyl) alcohol swabs.

[Ray Cecil]

Sensor safe polysiloxane formulas use different curing catalyst chemistries.

They don't smell like acetic acid because that byproduct would contaminate something like an O2 sensor.

As long as all the glycol was cleaned from the mating surfaces your RTV should get a good bond and not leak.

I usually use one of those (isopropyl) alcohol swabs.

I always use a knife stone and wd40 on any mating surfaces to clean all oil and old gasket off. If you havent tried this trick, you are missing out. Not only does it remove old gasket material, it takes out any burs, rough edges, and cleans the surface. Wipe down with a clean rag, then a little alcohol or acetone. If the mating surface isnt flat, you will see shiny high spots, and dirty low spots. It gives you a nice visual and acts like a flatness checking procedure. If the whole surface is clean and shiny, its flat.

[ArdWrknTrk]

I always use a knife stone and wd40 on any mating surfaces to clean all oil and old gasket off. If you havent tried this trick, you are missing out. Not only does it remove old gasket material, it takes out any burs, rough edges, and cleans the surface. Wipe down with a clean rag, then a little alcohol or acetone. If the mating surface isnt flat, you will see shiny high spots, and dirty low spots. It gives you a nice visual and acts like a flatness checking procedure. If the whole surface is clean and shiny, its flat.

Good advice!

I try not to pry on -or chisel at- the gasket surfaces.

Sometimes corrosion sets in, like my aluminum timing case.

Then I fill with JB Weld and file flat before using that file wrapped in crocus cloth to finish off.

A little tooth never hurts, especially when using sealant on a gasket.

Too smooth can be trouble.

My knife stones are dished from years of use and my shop stones are going nowhere near engine repair!

But whatever works.

It's always good to hear how other people do things.

[Ray Cecil]

Good advice!

I try not to pry on -or chisel at- the gasket surfaces.

Sometimes corrosion sets in, like my aluminum timing case.

Then I fill with JB Weld and file flat before using that file wrapped in crocus cloth to finish off.

A little tooth never hurts, especially when using sealant on a gasket.

Too smooth can be trouble.

My knife stones are dished from years of use and my shop stones are going nowhere near engine repair!

But whatever works.

It's always good to hear how other people do things.

A drag racer and veteran power plant mechanic taught me that one.

[ArdWrknTrk]

A drag racer and veteran power plant mechanic taught me that one.

Precision ground flat stones seem to be a huge thing on YouTube machining channels lately.

Not that I think we need Robin Renzetti's level of aerospace precision, but it's nice to know how universal the idea of lapping a flat surface is.