Freeze plug?

[racerman16]

I have the merc 3.7 v6 (85) and I need a freeze plug. Does anyone if any other years or engine size fits this block? It's hard to get to it and measure it.

 

[Don S]

Re: Freeze plug?

I have the merc 3.7 v6 (85) and I need a freeze plug. Does anyone if any other years or engine size fits this block? It's hard to get to it and measure it.

I assume you mean a 3.8 229 cu in V6 and not the 4 cyl 3.7. If so, the core plug is a 1 5/8" brass.
The 3.8 was only used by Merc in 83 and 84.

 

[racerman16]

Re: Freeze plug?

Ok. So here's my story sorta long, sorry. The boat is an 85. Engine comes back as an 85 as well been doing a lot of research and calling old mercruiser mechanics. Have been told by a few of them that they made a 3.7 v6 in 84 and 85 only. Boat has a 3.7 tag on the outdrive as well. Something about the distributor having a weird piece that the points ride on. 2 are flat. 2 are round and 2 are pointy. Honestly I don't have a clue though. I've been harassed a ton on other boards that they never in the history of mankind made this engine(v6 3.7) but like I said I've personally talked to some mechanics, and read some boards where people have them too.

 

[Don S]

Re: Freeze plug?

Ok. So here's my story sorta long, sorry. The boat is an 85. Engine comes back as an 85 as well been doing a lot of research and calling old mercruiser mechanics. Have been told by a few of them that they made a 3.7 v6 in 84 and 85 only. Boat has a 3.7 tag on the outdrive as well. Something about the distributor having a weird piece that the points ride on. 2 are flat. 2 are round and 2 are pointy. Honestly I don't have a clue though. I've been harassed a ton on other boards that they never in the history of mankind made this engine(v6 3.7) but like I said I've personally talked to some mechanics, and read some boards where people have them too.

Never heard of a 3.7 V6 by Mercruiser, and I doubt anyone else has. Take some pictures of your engine and post them. Or look for a serial number tag just above and aft of the starter on the block where the flywheel cover is bolted to. That will end what the engine is for sure.
The drive may say 3.7, but it is not the right drive for any V6. Just a used replacement someone put on the boat.

 

[racerman16]

Re: Freeze plug?

K. Tomorrow I will get some pics and look for the tag.

 

[achris]

Re: Freeze plug?

Doesn't matter about the tag on the drive, means very little. And it could easily be the right drive for a 3.8L (229 cu.in.), 185hp. Both that engine and the 3.7/'470' series ran the same ratio, 1.84:1.

Chris......

 

[Don S]

Re: Freeze plug?

Doesn't matter about the tag on the drive, means very little. And it could easily be the right drive for a 3.8L (229 cu.in.), 185hp. Both that engine and the 3.7/'470' series ran the same ratio, 1.84:1.

Chris......

I think he meant the decal on the drive said 3.7
The 3.7 on the drive was from 88, while the 3.8 (229) was from 83-84 and yes they were both the same ratio. But, the 3.8 drive was a MC-1 and the 3.7 was an Alpha I.

At this point we don't know what the engine or drive is for sure, which is why I asked for pictures and serial numbers.

 

[achris]

Re: Freeze plug?

I think he meant the decal on the drive said 3.7
The 3.7 on the drive was from 88, while the 3.8 (229) was from 83-84 and yes they were both the same ratio. But, the 3.8 drive was a MC-1 and the 3.7 was an Alpha I.

At this point we don't know what the engine or drive is for sure, which is why I asked for pictures and serial numbers.

Agreed... Just saying IF the engine is a 3.8, (and based on the description of the points cam lobes in the distributor, I'd say it is) and the drive is from a 3.7, then no problems, same ratio. Also agree, without serial numbers and photos, we can only go by what the OP posted.

BTW, 229/185/3.8 came with an 'R' drive, not an MC-1...

Chris.......

 

[Don S]

Re: Freeze plug?

BTW, 229/185/3.8 came with an 'R' drive, not an MC-1...

Agree, my mistake, thanks for checking.