5.7 Mercruiser Block Drains

[Johnson110]

I removed the bushing which are brass from the block, it seems that the treads in the block are bad, I have 1/4 national-standard pipe tap to use, the engine is a raw water cooled 5.7 mercruiser year in 1995, I just want get the brass plugs back in, can a heli coil be used if these treads are too far gone?

 

[Scott Danforth]

if your tap has a point on it, grind the point off (so it doesnt hit the cylinder liner), chase the threads. As I indicated, should only take 1/4-1/2 turn normally once the tap is started since the threads are tapered. you may need to first clean out the rust on the hole with a small rat tail file, or run the correct pilot drill for the 1/4" tap (7/16") and clean the hole first.

Helicoils leak normally, I dont think you could get one to seal on a pipe thread. Then again, with enough sealant anything is posible.

 

[Bondo]

I removed the bushing which are brass from the block, it seems that the treads in the block are bad, I have 1/4 national-standard pipe tap to use, the engine is a raw water cooled 5.7 mercruiser year in 1995, I just want get the brass plugs back in, can a heli coil be used if these treads are too far gone?

Ayuh,.... If it's that bad, I doubt a heli-coil will work either,... Not enough meat,.... 'n the back-wall is too close,...

Ya might be able to cast new threads with a metal blended epoxy,.....

You'll have to clean, 'n scrape the hole for the epoxy to bond too, 'n use a release agent on the plug, so it'll unscrew after the epoxy sets up,.....

The trick will be gettin' enough epoxy to cast a new hole, without blockin' the hole from drainin' in the fall,......

 

[Johnson110]

I took fuel line hose and pushed it into the block with a plug on te end of it started her it runs very good! the hose is not leaking on either side so I am thinking there not a lot of pressure in the block, I read Bondo's suggestion what I wanteed to try is to just put some jb weild on the plugs and try to screw it back in, this is the bushing that goes into block or maybe a radiator drain plug epoxy into block? I really pisses me off as the engine runs very good!

 

[Bondo]

so I am thinking there not a lot of pressure in the block,

Ayuh,.... I believe it runs 'bout 15 psi or so on average,....

 

[Johnson110]

Ok, What I would like to know can I keep a piece of rubber fuel line in the block drains and run the engine this way, I have a brass plug at the end of the hose to drain the block, Is it safe to run it this way there are no leaks.

 

[Fun Times]

Ayuh,.... I believe it runs 'bout 15 psi or so on average,....

Ok, What I would like to know can I keep a piece of rubber fuel line in the block drains and run the engine this way, I have a brass plug at the end of the hose to drain the block, Is it safe to run it this way there are no leaks.

As in shove in a piece of rubber hose and run it?

With around 15 PSI water pressure, Sorry but I don't believe anyone here on iboats is going to recommend doing that just for the safety/liability factor involved to both you and others with or around you.

 

[Johnson110]

Ok Thanks It was a dumb thought, hard to get to the holes in the block!

 

[Johnson110]

Update, I purchased new mercruiser brass drain plugs, I was able to get enough tread on he block and get them in, Thanks for all the help and suggestions from everyone this site is great!