Quick question regarding the rear of the block

[Laddy]

Hello, I am rebuilding my spare 302 that I have in my garage, and I'm trying to strip the block as much as I can for the machine shop.

I'm at the point where I'm cleaning up the back side of the block and I'm wondering what those square plugs(?) are for, and whether or not I need to take them out and replace them. You can see them circled in my picture.

Lastly, the middle cover there, is it an expansion plug that I can just take out like the rest of them?

Apologies for the noob questions, but I'm learning as I go.

Thanks

 

[Mustang5L5]

You can leave them as is. They were part of the original machining of the block. You’ll notice they match up with the holes on the front around the cam retainer plate.

Those are generally left alone. The plugs on the front are freeze plugs and folks sometimes will remove those and drill and tap for plugs. One gets a small hole drilled into it for oiling of the cam gear.

 

[limp]

One gets a small hole drilled into it for oiling of the cam gear.

How was the cam gear lubed when stock?

 

[AeroCoupe]

Those are the lifter oil galleys. A good machine shop will remove them when they vat the block including removal of any of the freeze plugs. Typically they replace the square head plugs with a hex countersunk plug. IMO the three plugs on the front of the block should all be tapped and plugged with the same plugs. Couple of videos by Woody (builds alot of SBF motors) showing the front plugs:


View: https://www.youtube.com/watch?v=FnB-3TVgqRc



View: https://www.youtube.com/watch?v=Rb5mms_Bs6A


I asked a friend that machines and builds lots of motors (Ford, Chevy, Mopar) how the cam gear gets oiled on a SBF. The cam timing chain gear is via oil splash (galley plug can be drilled as well) and the gear on the cam that turns the distributor gear is also via splash.

 

[limp]

So I assume drilling the galley plug gives a pressurized stream of oil directly on the gear??

 

[AeroCoupe]

That is correct. You have to take into account it will drop the oil pressure and whoever does it need to know where to place it or the stream will miss. I think this is done in really high rpm motors. I turn my 331 about 7,600 and it’s not done on it.

 

[Mustang5L5]

I didn't do it to my engine when I had it apart. Wish I had

 

[AeroCoupe]

It's one of the cheapest things you can do to the block that ensures they will not push out and drop the oil pressure. For me a ten cent freeze plug vs. $40 for a tapped hole with a pipe plug is not worth having to go back through the motor. This is something anyone can do at the house and yes the driver side one goes into the first lifter hole but all you need is a break cylinder hone and WD40 and follow that with some 1000 grit to quickly clean that bore up or have your machinist do it. Tap is an 1/4"-18 national tapered pipe tap SHORT and typically runs about $15. Plugs are standard 1/4"-18 countersunk hex plug and use blue loctite. Make any of them that are close to the cam thrust plate are counter sunk so that they do not interfere with it seating correctly.

Up to you guys but it's cheap insurance. My luck that damn freeze plug would pop out and somehow get in-between the crank or cam timing gear and the chain and all hell would break loose.

 

[KZGUNS]

My Boss block came with a threaded plug already drilled. Its a tiny hole smaller than a paperclip

 

[limp]

I had my machinist tap and plug mine while it was getting machine work... $15... But I do not believe he drilled a hole in it.....

 

[Mustang5L5]

You can actually buy the plugs that already have the hole pre-drilled.

Pioneer PP-454-25

Problem is that they are usually bulk only

Pioneer 1/4-NPT Pipe Plugs 25pk w/Oil Relief Hole https://a.co/d/1EHEddn


Group buy?