I’m building an engine and wanted to make sure the block was free of debris. I decided to remove the brass oil plugs (2) to assure the oil passages didn’t have any junk in them. I did not find a lot of info in my searches so I made this write up.

1. Buy a 1/4” fine thread tap and drill bit.
2. Buy a 1 1/4” fine thread 1/4” bolt.
3. Buy 3 fender washers (large OD)
4. Rent 5lb slide hammer and 3 jaw puller from auto store.
5. Drill and tap brass plug. It is about 1/2” thick and drills quickly. Nothing is behind it so it’s safe.
6. Install washers and bolt. Don’t bottom out bolt but make sure all it is threaded through the plug a bit.
7. Install 3 jaw to slide hammer and attach to washers. Pop plugs out.
8. Clean block and replace with new plugs Mazda part # 0221-10-327 Install plugs dry or with Indian head sealant.
9. Make some mint tea and a fresh grape mint hookah and relax while contemplating next project.

 

This is something that I'll always have done whenever building new blocks. My first built motor had a loose plug and it took forever to diagnose it to find out it was not the oil pump. Good info.

 

I did pretty close to the same thing using HF slide hammer. Surprised how much crap was in my oil galley behind the plugs. Here is my post from the HF win/fail thread.

Got my block back from the machine shop and just used this to pull my oil galley plugs and worked like a charm. Well worth $20 with the coupon. Drilled a hole and used a M8 x 1.5 tap and the shaft for the puller threaded right into the brass. That pile of crap isn't brass. I pulled all that out of the galley with that little extendable magnet in the picture. Come to think of it the tap and magnet probably came from HF too.

Win: Slide hammer and puller set 14 pc
https://www.harborfreight.com/slide-...-pc-62959.html

 

I never saw your post but nice work. That’s a lot of crap that came out. Hopefully this helps everyone in the future. It’s funny I talked to multiple machine shops and they weren’t sure if the plugs should be pulled or not. Most just said “ahh leave them alone it will be fine” probably out of laziness. It is the easiest drill/tap job I have ever done.

 

Thanks for posting this picture. I just got my block back from machine shop and will definitely pull those plugs to clean now that I see the crap behind yours.

 

Exactly what I did when I built my engine..

I bought a few brass brushes and long extensions that would fit my drill.
Then I went at it, made several passes, and chased it with compressed air and brake cleaner.
They were shiny when I was done.









Also, I tapped the plug bores and installed threaded plugs with liberal amounts of silicone, so I can remove them easily in the future if I need to.

 

Hope the thread bump is fine, but found a good alternate method.

Didn't have access to a slide hammer or gear pullers, so instead, I just drilled and tapped the plug, and placed an oversized deep socket over it. You can then adjust the depth using washers, but you'll pull the plug by threading a bolt into it through the socket and washers and torquing away.

​​​​​​Try to rock the plug loose as early as you can, however, so you have some purchase area to hold onto the plug to twist it off the bolt and get your socket free.

 

thats the way I do it, drawing with a thread being more gentle than the shock of a slide-hammer as brass has a granular structure & can fracture (was taught this as an apprentace)

Rich.

 

I realise this is an old thread, but do you (or anyone reading) know the plug size you used? I am hoping to just tap the hole without needing to drill it. I happen to have an m18 1.5 tap from plugging oil galleries in another (pushrod) engine I used to work on, but the drill size for that tap is 16.5mm, and I think the oil gallery is aleady 18mm at the ends.

I may have to go out to m20 (M20 x 2.5 drill size 17.5mm, M20 x 1.5 drill size 18.5mm)???

 

I just replaced the plugs with new brass units. I’m not sure if tapping is a good idea or possible. After pulling one plug the second can be pushed out with a metal rod. No need to drill and tap both. Do not use a wire brush, especially on a drill. It will lose bristles which can be hard to eliminate during cleaning and will do bad things to an engine. Use red loctite if brass plugs are used.