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Oil Gallery Plugs what size Tap?
- Thread starter 68Sprite
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Dug
Jedi Trainee
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I've used 1/4" NPT. The hole is right at 1/2" diameter at the end and steps down approx 3/8"
-7/16" back in the block. Tap drill size for a 1/4" pipe tap is 7/16", however given that you will want the plug to sit flush or a slight bit below the surface the sealing part of the threads will be in a spot that is correct. The large diameter of a 1/4" pipe plug (hex end) is bigger than 1/2" so there are no issues. I have had no problems doing this on blocks for a lot of years. A little bit of Teflon tape and never worry.
Doug W.
-7/16" back in the block. Tap drill size for a 1/4" pipe tap is 7/16", however given that you will want the plug to sit flush or a slight bit below the surface the sealing part of the threads will be in a spot that is correct. The large diameter of a 1/4" pipe plug (hex end) is bigger than 1/2" so there are no issues. I have had no problems doing this on blocks for a lot of years. A little bit of Teflon tape and never worry.
Doug W.
Hap Waldrop
Yoda
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The only tip I would give you on this, is sneak up on your tapping with the NPT 1/4 tap, you want the plug flush, not sticking out, or countersunk in. tap alittle bit and check, then a lttle more, to get it exactly where you want it. Oh and get steel plugs and avoid the brass one, they tend to strip out the allen head when you want to remove them in the future.
Dug
Jedi Trainee
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Good tip on the tap, Hap.
Cris, kind of a standard is to leave 5-7 threads of the taps top threads showing at the top edge of the hole. This will leave the plug "about" 2-1/2 turns from being flush with the block ("approx" 1/8") so go from there.
Plugs can be had at most good hardware stores. Fastenal, McMaster Carr and the like. Look in the yellow pages under fasteners is the best.
Do stay away from the brass ones and settle in on a steel or stainless steel hex head (meaning an allen wrench will be needed). Purchase the plug first and then tap to fit.
Easy-peasy
Doug W.
Cris, kind of a standard is to leave 5-7 threads of the taps top threads showing at the top edge of the hole. This will leave the plug "about" 2-1/2 turns from being flush with the block ("approx" 1/8") so go from there.
Plugs can be had at most good hardware stores. Fastenal, McMaster Carr and the like. Look in the yellow pages under fasteners is the best.
Do stay away from the brass ones and settle in on a steel or stainless steel hex head (meaning an allen wrench will be needed). Purchase the plug first and then tap to fit.
Easy-peasy
Doug W.
Hap Waldrop
Yoda
Offline
Mcmaster Carr has a outlet in Georgia, I order from them all the time, they are super quick on their shipping, in Dallas, Ga. you get next day for the cost of ground shipping for where you located.
tony barnhill
Great Pumpkin - R.I.P
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Talked with my machine shop today...he removed my plugs & is threading them for pipe fittings like Hap said up above.
Follow what Hap said above and I'll add a bit..............
the front galley plug had a spun plug as well as in the rear of the galley. I assume you are doing both.
The front has an intersecting galley about 5/8" from the front face if the case . You do NOT want to run the plug too low so as to block part of that intersecting galley. Internal hex wrenching steel 1/4" pipe plugs come in two heights. Any engine shop (larger ) will have both. the first 3/8 " or so of the front hole is a bit big to accomodate threads well....and you only have a very few threads in the stepped hole to grab onto and not get the plug too far down the hole. go slow with the tap as you want the low part of the tap just registering at the end of the threads. Seal -Tite or other valve seat sealer is what to use. Epoxy also does well. But clean all oil off the threads and plug with a primer. After your done, take the front motor plate and radius the area around the plug so you can remove if needed (leaker) with the motor in the car.
The rear plug is not as complicated as there is no intersecting galley. Still tho use Seal -Tite of epoxy on it tho as it is a stepped hole like the front. Just using teflon tape just wont cut it. Even the Loctite Hi-temp pipe thread sealer is not enough.
You should do the other spun plugs also....there is one on the oil pan gasket face in the rear. 1/8" npt there.
the front galley plug had a spun plug as well as in the rear of the galley. I assume you are doing both.
The front has an intersecting galley about 5/8" from the front face if the case . You do NOT want to run the plug too low so as to block part of that intersecting galley. Internal hex wrenching steel 1/4" pipe plugs come in two heights. Any engine shop (larger ) will have both. the first 3/8 " or so of the front hole is a bit big to accomodate threads well....and you only have a very few threads in the stepped hole to grab onto and not get the plug too far down the hole. go slow with the tap as you want the low part of the tap just registering at the end of the threads. Seal -Tite or other valve seat sealer is what to use. Epoxy also does well. But clean all oil off the threads and plug with a primer. After your done, take the front motor plate and radius the area around the plug so you can remove if needed (leaker) with the motor in the car.
The rear plug is not as complicated as there is no intersecting galley. Still tho use Seal -Tite of epoxy on it tho as it is a stepped hole like the front. Just using teflon tape just wont cut it. Even the Loctite Hi-temp pipe thread sealer is not enough.
You should do the other spun plugs also....there is one on the oil pan gasket face in the rear. 1/8" npt there.
tony barnhill
Great Pumpkin - R.I.P
Offline
Yep, doing both...good points..I'll tell machine shop.