400 stamped 77c21P:

Okay,got my new steel core plugs to replace the rough and, apparently previously leaking, plugs (they had sealant around them).

First, I couldn't get out the allen screws to drain the block. I have socket type allen set but it wouldn't budge though I torqued it short of rounding them out. Should I soak in solvent, drill them out, or leave well enough alone? My core plug kit has replacements for them I was wanting to use.

Second question, after carefully punching in the plugs and removing them with channel-locks, a worrisome oozy, dense yellow silt similar to plumbers pipe joint compound came out of the block with some coolant. I scooped out the real thick stuff and broke up what I could of the harder deposits with my fingers. Is this normal for an engine this age? I'm constantly on the look out for signs of bad with this motor.

I sanded the core openings with 500 grit wet/dry sandpaper. Some of the openings had uniform nicely machined surfaces that cleaned up well but others appear potentially problematic, being pitted or thin. Thus the Third Question: Do I use sealant as insurance of a good seal like someone else had done, alternatively go after what was described to me as a universal type plug of rubber with metal backing, or just put the steel ones in?

The parts guy says the rubber ones expand by torquing on a nut but he suggested the steel ones. Though I haven't seen the rubber type, the way it was described seems similar to the plug in a boats transom.

Thanks for advice, I like doing things the best way possible but am obviously not long on experience.

 

Okay, first don't sweat the pipe plugs for the cooling system, you're coolant will drain out perfectly fine when you remove the freeze plugs.


Second, Skip the sealant. If you can manage to sink these plugs flush as far as the rim of plug to orafice ridge aspect is concerned you should be fine. If they leak after a couple of heat cycles then take them out and redo them with water pump and thermostat gasket sealant.

Third, rubber freeze plugs are junk! Brass and only brass! The size for our beloved blocks is 1"1/2. I am a professional parts guy for a major auto parts retailer whose name I am not allowed to mention. I make the assertation that rubber freeze plugs are junk based on what I have seen others who are less fortunate go through.

Hope this sheds some light on you're dilemma.

 

I once had a 78 F-150 (400 CID) that developed a pin hole leak right in the middle of a freeze plug. It was in a location where I could get the old one out but could not drive a new one in. I used one of the rubber ones and it lasted at least 10 years and wansn't leaking when I sold the truck.

 

I'm up early was glad to see your replys. That's 1 for, and 1 against ...and I believe both .

I already have a steel plug kit at someone else's recommendation who preferred them over brass and rubber, and since I can't return them on Sat. I guess I'll use them in the better ports.

The gouged/scored ports... that's different. I thought about liquid steel or some sand-able material and use it to build the surface then smooth it over. Another thought was to use teflon tape around the perimeter of the plug, etc. The previously used adhesive was a yellow-like and hardened, and had begun separating from the plug area, though I don't know if it was leaking again or not.

Whether it's an adhesive (for water pumps) or rubber plugs I'd rather a reliable fix then chancing it through a few heat cycles. I do not want to pull the engine for want of a core plug.

thanks!

 

P.S. My post shows 7:45 and my house and 'puters clocks are 40 min earlier... I was wondering why I'd been getting to work early everyday... I've been logging in every morning lately and using FTE's clock! Maybe I can make a case to my managment to pay my subscription!

 

First I'd recommend brass over steel for 1 simple reason: brass doesn't rust, steel does. If you take care of your cooling system, i.e. keep a good anti-freeze/water ratio then you may never have a problem. IMO the rubber expandable plugs are short term stop gaps and have no place in an engine that's already out of the truck and torn down.

Second, use sealant! Your local parts store will have a tube of the stuff and it's just cheap insurance. It also makes installing the core plugs easier since it basically acts a lubricant before it sets up. Make sure you use a large diameter punch or a socket that fits the ID of the plug closely.

Finally remember that these aren't really "freeze plugs". I guarantee if you let an engine full of water freeze that the block will crack regardless of what material the plugs are made of. The plugs are installed in holes which are necessary for the casting process so the sand can be emptied out of the piece after it's been cast.

 

Thanks for everyone's help.

In future I'll use brass, but since I already have the steel I'll go with them. I'll use the sealant; it'd make me happier since the holes aren't pristine (gouge in one of the ports). What type? Is there one for this purpose alone or is it something I might have like RTV, gasket maker, anti-seize, etc.?

Also, I think it'd be good to flush the block at this time while I'm at it. Thought I'd run a pressure nozzle in. Any suggestions on doing this?

 

LocTite makes a sealant specifically for this application. I'm sure you can find it or a suitable substitute at your local parts store.

 

thanks bill, going to the parts house tomorrow.