Tubes in the block.

[Gnatsum]

Just wondering if anyone knows what these tubes are for. It’s a 351 Windsor block. The tubes are in the center of the block and each side has one.
14866

[mavrrrick]

Frost plug??... Meh, what do I know!!!


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[Ponyryd]

I think he’s asking about the thin tubes inside the frost plug holes, which I’m not really sure, but I wouldn’t worry about.

[ZR]

If I recall correctly (don't quote me on this one) something to do with the casting process.

[Gnatsum]

Yes talking about the small tubes in behind the frost plug. I have been blowing frost plugs out and can’t quit figure it out so I am resorting to tapping the holes for screw in plugs. The problem is these small tubes are in the way of driving a tap through. They look like they might break off if I try and bend them out of the way. I have never seen these in a sbf before. Any help appreciated.

[mavrrrick]

Ah... now I see them... looking at it on my phone and eyes are tired (old).


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[ZR]

Blowing frost plugs out?
Did it start immediately after a rebuild / new plugs installed?
Typically never happens if installed correctly.

[ZR]

Is that some kind of sealant on the edges?

[mavrrrick]

^^ looks like weather stripping glue?


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[Gnatsum]

Yes it’s a new build. The plugs were put in by the machine shop. It looks like they used a sealant of some sort, not sure what it is though. Some of the the checks I have done are verified head gasket are in right, replaced rad cap, installed new electric pump, both rad hoses and gutted the thermostat. Pressure check turned out ok and it flows water through the system with no restrictions. also pressurized all cylinders at 110 psi with no leaks at all. At a loss on this one other than plugs are put in wrong or someone cleaned the holes out a lil too much?

[ZR]

Odd part that struck me, how thick the sealant appears to be. Normally all but the smallest fraction of a layer is displaced knocking the plugs in. It would lead a person to believe the plugs all but fell in the holes. Being an old skool mechanic, back in the day we replaced rusted out plugs on a very regular basis. Never seen one come out of a spotlessly clean hole installed either dry or using gasket shellac. They didn't have some cheapie brass knock offs in there did they? Did you try knocking a steel plug in just to see how tight it fits? Normal would be a decent few cracks with a hammer to drive them home.

[Gnatsum]

I wouldn’t agree with you more ZR. I wish it didn’t take me 3 different times at the track to realize this but when I talked to the machine shop he assured me they where in right and that wasn’t my problem. I was lucky enough to put a pressure gauge inside the car last weekend so I could see if it spiked past 16lbs. During the 1/4 run it started at around 7psi and near the end it hit 15 than instantly zero. I knew another plug came out. Pretty bad when 15 psi blows out plugs. Here’s a pic of the hole it actually blew out of. I think only thing holding it in was the sealer they used.14869

[ZR]

Only reason to use some sort of glue is to fix a known problem, frost plugs don't just fall out. Sorry to hear it's been that kinda deal for you. Have you been using steel plugs?

[ZR]

You can see clear as day plug had no bite on the block what so ever, glue / goop holding it only.

[Ponyryd]

Could also use the “temporary” rubber plugs, I’ve used them before when access was tight, worked well but apparently aren’t permanent. Or for that matter, you could just use a block heater in each hole.
I agree completely that the plugs must be too small for the holes, way too much sealer there.

[ZR]

Temp plugs work well as a permanent solution but only if the inner lip is short enough (all around) which allows it to do a full overlap n keep it in place.

[Ponyryd]

Temp plugs work well as a permanent solution but only if the inner lip is short enough (all around) which allows it to do a full overlap n keep it in place.

I’ve found them leaking after a year or so, retightening seems to take care of it though, never seen one fail yet.

[ZR]

Back in the day, we had a few pop out without warning. Common denominator,holes that had an inner lip deeper than the depth of the plug itself (most common on Olds engines). On other applications, stood up fine but as you said, odd one would start to seep requiring just a hair of snug up then fine.

[Gnatsum]

Well I went against the grain when I replaced them. After measuring the steel over the brass I opted to go with brass. They measured almost 2thou bigger and my theory of thinking is that brass heats faster and would swell into hole tighter when hot. I also used red loctite on the two I replaced and they held. It took a big hammer to bang them out. Anyways so back to original question, does anyone know if these tubes are needed if I happen to break one off when I try and move it so I can run a tap into it. I thought about rubber but I already bought the screw in caps and tap for it. Going to tackle this Friday once I’m back in my shop. I just want to do it right because I’m getting tired of pulling motor out for this and not to mention the Wild ride it has sent me on about mid track.

[hammerhead]

I've heard of this from other people but don't know what the solution was or if they ever had one (solution) - your logic sounds good hope it works out for you - could have been a problem with block or poor quality replacement parts - the tubes I have no idea! Hope it all works out!

[Ponyryd]

I wouldn’t worry about the tubes, break em all off if you want, it won’t hurt anything.

[ZR]

Nice to meet you yesterday.

[Gnatsum]

Nice meeting you to Rick, great event with a bunch of awesome guys.
Just an update on the tubes in block, Apparently they are just thick wire that where left in there from the casting process and have no purpose what so ever. I just found it odd as I have never seen these before . I went to a different machine shop and showed him the plugs I had removed and showed him a few picks of the holes, needless to say he had a good laugh and said same as you guys is that only thing holding them in was the gasket material they applied. However on another note for any one thinking on "just tapping" the holes can forget about it. I bought the plugs and tap hoping to do just that. However the problem is the holes need to be reamed out considerably and the block should be bare to make it more manageable. Funny how ya can read on other forums of guys doing all 6 in like 20 minutes with motor still in car, ya right...…..
I wound up replacing all 6 with the deep plugs which drove in considerably hard and then on top of that I tack welded the lip in three spots just to calm my nerves. Had 5 solid runs on car yesterday so now just gotta get used to it again after being out of it for almost a year.
Thanks for all the help and info guys.

[ZR]

I've read similar blerbs from guys claiming taping the holes is a quickie slam dunk, not so much.
Upside, your back to enjoying your car, congrats.