Promax block crack ???

**roadkill636** · 11-25-2019, 04:46 PM

So I bought a Promax and once I got it home and rubbed a bit of oil off the block I found a crack and these 2 holes at the bottom of the block. Not sure if the seller knew about it or not. Looking thru the searches and found that someone else had a block that had the same crack same place but got it welded and the Merc repair guy said that they crack there regularly.
Did I just buy a anchor? And what's with these holes?

The pic with the weld is from another thread another member here .

**Dave S** · 11-25-2019, 05:13 PM

I shoot..... many ..... blocks....... Just my frustion.... Leter Reip...... times we live in......

**rock** · 11-25-2019, 08:38 PM

The holes are unimportant and I think that weld pic is of my promax (Hydrostream in the background). Mine was done to prevent the crack.

Rock

**roadkill636** · 11-25-2019, 09:16 PM

Yes Rock that is a pic from your thread. But my Blood k has cracks and I dont know about these promax blocks and what is on the other side of the crack. Is it just a simple exhaust leak? Is it a ph stud? Is it in a water jacket that will get into the exha8chest and cyl?

**rock** · 11-25-2019, 09:24 PM

I have one in the shop and will try to give it a look tomorrow. Seems like it's about the stud in the exhaust. Remind me if I don't get back to ya. Working in the same building as the shop but not in the shop right now. Hangin a bunch of sheetrock tomorrow.

Rock

**Capt.Insane-o** · 11-25-2019, 10:26 PM

They usually happen when the person doesn't pick the powerhead straight up off the adapter plate or tightening the block down and it isn't seated properly. As much those are the last 4 nuts you tighten and don't get all king kong on the wrench.

**rock** · 11-25-2019, 11:17 PM

I have never had one break and freaked when the block came back with the weld on

it. This site is where I learned it was preventive. Never know what you'll learn here. Some of it even useful.

Rock

**tlwjkw** · 11-26-2019, 05:15 AM

never "cracked one" with nut install but have with stud install.. never heard of it done as a preventive measure.. if its welded its been cracked.. story sounds good though..

**tux974** · 11-26-2019, 05:58 AM

Mercury started making a tad longer studs with more threads just on the course side exactly for that reason! Deeper into the block since its a very thin area back there.
If you look up the 280 PH studs you will see different part #'s....... 2- 2 1/2" and 2- 2 3/4".

**tlwjkw** · 11-26-2019, 06:07 AM

.... exactly.

**roadkill636** · 11-26-2019, 07:23 AM

Question is. Is this crack likely to go thru a coolant passage and or exhaust chest and able to get back up into the cylinder?

**rock** · 11-26-2019, 08:33 AM

Block was not cracked before we sent it to Gene at G Force. Man did good work but was not a good businessman. Kind of like Ron.

Rock

**tlwjkw** · 11-26-2019, 08:50 AM

his idea or yours?.. jus one side?.. jus courious....

**tcrabtree** · 11-26-2019, 10:55 AM

Promax blocks are very prone to this. I Have 1 that cracked in the same spot & have saw several others. Weld it up & install a gusset to strengthen it , no big deal. Never Over torque the back 2 studs, that will cause it.