4.3LX 88 drain plugs

[JoshNZ]

What thread are the drain plugs in each side of crank case and bottom of exhaust manifolds? A boat I'm using has a bunch of mongrel plugs that don't look like originals but do look like the correct thread according to part no.16951A1. I read somewhere they're just 1/4" NPT.

What do yours feel like when you insert them? I can get 1-2 turns before it really has that cross-threading feel... And they drip without teflon tape.

 

[kevinj]

I don't recall the thread diameter and pitch. I broke a couple winterizing 2 years ago. I went online and bought replacements pretty cheap.

http://www.marineengine.com/newparts/part_details.php?pnum=SIE18-4226

 

[JoshNZ]

I don't recall the thread diameter and pitch. I broke a couple winterizing 2 years ago. I went online and bought replacements pretty cheap.

http://www.marineengine.com/newparts/part_details.php?pnum=SIE18-4226

The ones I have here are brass, are these an aftermarket substitute? http://www.go2marine.com/product/158177F/pipe-plug.html are the correct part for this engine and are what I've got but, they sure don't feel like the right plugs.

 

[sandkicker]

Threads need cleaned out before putting plugs back in, especially in a raw water engine. Bad cases may need "chasing" with a tap.

 

[bondo]

Ayuh,.... The block drains are 1/4" pipe,....

The manifolds could be 1/8" pipe, or 1/4" pipe,....

 

[JoshNZ]

I did write a reply here a couple days ago looks like it got caught in the mods net.

The plugs I have are brass not plastic, are the plastic ones aftermarket? I bet they would do a better job than brass.

If any are 1/4" pipe they're all 1/4" pipe I bet, all 6 look like identical threads. Will see if I can clean it with a tap thanks for the help guys.

 

[kghost]

If your motor is a 1988 then the drain locations had a two piece fitting.
A brass piece that threaded into the block this had a internal threaded portion with a taper at the inside end and a second piece with a wing nut type end and the end of it was tapered to seal to the first piece when tightened.

Here is a picture of that set up.

 

[JoshNZ]

If your motor is a 1988 then the drain locations had a two piece fitting.
A brass piece that threaded into the block this had a internal threaded portion with a taper at the inside end and a second piece with a wing nut type end and the end of it was tapered to seal to the first piece when tightened.

Here is a picture of that set up.

Yep you are right, the sides of the block and bottom holes of the manifold are that cock-type plug but the sides of the manifold are plain plugs. I think they are all the same thread anyway they all seem to be mix and matchable. And none of them fit right. The best plug in the best condition hole still strips a bit of brass off the plug when forced in...