M20 45mm welch aka core plugs (DO NOT USE FEBI)

[zaq123]

Just a word of caution, do not use febi Welch plugs when rebuilding your engine. I built this stroker a while ago and used Febi plugs ($1 vs $10/each for OEM). One started to drip so I pulled it out, found why it was leaking (defect in the plug edge that no loctite 540 could seal) and ordered a set of six new plugs. Well looks like all 6 are of a terrible quality. Like all are messed up like the one I pulled but worse, Febi is probably having China make these anymore.
Replacing core plugs while the engine is installed and everything bolted isn't fun job.
So it looks like only two choices are left for these M20s, OEM steel for $10/ea or quality aftermarket bronze for $5.50.
A damn core plug... how can one mess up its production? Stay away from FEBI core plugs.

[digger]

This was the case 20years ago as well

[zaq123]

This was the case 20years ago as well

unfortunately I didn't see it. Now paying for it. Decided to pull all 11 Febi plugs out because I don't want to do it again ever again. Major pain to do with the engine in the engine bay. Especially that one behind the starter as the brake booster and the starter has to come out to install it properly.

[McGyver]

Is there a reason to replace original plugs during a rebuild if they aren't currently leaking?

[zaq123]

Is there a reason to replace original plugs during a rebuild if they aren't currently leaking?

plugs rust on the inside so it hard to tell their condition. Additionally, once you bore/deck the block. all that crap is gonna sit everywhere and it's easier to clean the block with plugs out.

[e30austin]

good to know. i installed a set in an M10 earlier this summer with good results, but seem to recall them fitting much tighter than i preferred.

[reelizmpro]

I'd like to think any machine shop worth their salt will change the freeze/core plugs when tanking the block. One of the originals on my M3 developed a pin hole leak at 190k that was hard to trace so I decided to change them all. The leaky plug was leaking through the plug itself at the corner due to corrosion. I managed to change the ones on the intake side but the exhaust side is much harder due to the angle of the engine and lack of space. The trick is putting them in the freezer so they will be easier to install.

[zaq123]

I'd like to think any machine shop worth their salt will change the freeze/core plugs when tanking the block. One of the originals on my M3 developed a pin hole leak at 190k that was hard to trace so I decided to change them all. The leaky plug was leaking through the plug itself at the corner due to corrosion. I managed to change the ones on the intake side but the exhaust side is much harder due to the angle of the engine and lack of space. The trick is putting them in the freezer so they will be easier to install.

Tanking M20 block is no go unless one has a plan to replace the intermidiate shaft bearing which is a pain and I wouldn't do unless the bearing is shot. But I'd replace them plugs for sure. Wish I'd inspected those febi plugs a little closer initially. Also Freezer wouldn't do much help. I did considered dunking them into the liquid nitrogen but wasn't sure how Loctite 540 would react with the cold ass metal.
I was able to drive them out/in with the short piston air hummer, the air hammer socket adapter and large socket that fits snug inside the plug. Def no room in there to swing the regular hammer.

[McGyver]

Interesting. I've heard it's best to leave the plugs alone unless you've got a problem. I had the shop leave them in when they did my bottom end, so fingers crossed that they're all good!

[reelizmpro]

Interesting. I've heard it's best to leave the plugs alone unless you've got a problem. I had the shop leave them in when they did my bottom end, so fingers crossed that they're all good!

Same here, I never knew them to be problematic but when they leak it becomes a problem because that leak is often small, only under pressure and will likely evaporate before you notice it. My car was running hot for years. I changed radiators, radiator caps, thermostats, puller fans, etc nothing helped. Pressure checked the system to find a very small drop. One day I let the car idle in the driveway a while and I saw a tiny puddle. I popped the hood and saw remnants of coolant spray on the drivers side so I dug deeper and found the leaky core plug. The PO must not have been changing the coolant like he should have but 35 years isn't a bad run for original core plugs.

[zaq123]

It's a gamble. New plugs can leak too as you can see. Looks like I got a few bad brand new ones when I did my block. Now it looks like there are no longer good ones from Febi at all. I actually ended up replacing all of them again with bronze because OEM steel is 2x as much (I know right). I really should have inspected every damn plug but I didn't so I didn't know which one was good with one was a ticking time bomb . So all are replaced with a quality plugs which were inspected. It's a silly 30 min job with the engine out so if one is rebuilding, I would definitely replace them. Why not, you are right there. It's like saying why change main seals if you are rebuilding the engine unless there is a problem? Because crap is old maybe and I got the engine on the stand in front of me :)

[McGyver]

Well shit. I guess I'm adding some freeze plugs to my next parts order. I'd rather install them and fix any issues while the engine is on the stand.

[zaq123]

Well shit. I guess I'm adding some freeze plugs to my next parts order. I'd rather install them and fix any issues while the engine is on the stand.

45mm brass from them is almost 1/2 the price of OEM steel. Loctite 540 is crazy expensive too so if you need just for one block, I'd consider Vibra-TITE 550

https://goodson.com/products/freeze-plug-brass-metric-cup

[McGyver]

Well, double shit. I didn't realize I'd need a retaining compound too.

Vibra-tite is waaaaay less expensive, do you have any long term experience with it? Realistically, this engine should have a relatively short life since it's the weekend/around town car and will end up making some power with a turbo. I can't imagine trying to get more than 50k miles out of it over the next 10 years, so I don't think I need the best of the best.

[zaq123]

Well, double shit. I didn't realize I'd need a retaining compound too.

Vibra-tite is waaaaay less expensive, do you have any long term experience with it? Realistically, this engine should have a relatively short life since it's the weekend/around town car and will end up making some power with a turbo. I can't imagine trying to get more than 50k miles out of it over the next 10 years, so I don't think I need the best of the best.

yes its good stuff. Its actually the same price per ml as Loctite but you won't find lactite in small quantity, the smallest is 250ml