'84 Merc 150 V6 - Is my block destroyed?

[MAtkins]

It's taken some time but I've finally got my block back from the machine shop.
It's bored .030 over on all cylinders. The machine shop indicated no problems.

While cleaning the surfaces that the heads bolt onto, I noticed a small scratch.
Does this render my block destroyed?

 

[Faztbullet]

Re: '84 Merc 150 V6 - Is my block destroyed?

Is that a scratch or crack? If a crack it will be cheaper to find another block...

 

[wired247]

Re: '84 Merc 150 V6 - Is my block destroyed?

Which scratch are you talking about? The one at the 8:30 ish position on the top of the bore and edge of the water jacket looks like a scratch. I wouldnt worry about that one. The other one at bottom of the picture on the outside water jacket looks more problematic but its hard to tell from the pic. If it is cracked and it was mine I'd weld it and dress up the sealing surface and MAYBE have it decked if I couldnt get it straight by hand.

 

[MAtkins]

Re: '84 Merc 150 V6 - Is my block destroyed?

It's a hairline scratch, not a crack.
It's really small. You can see it real well in the pic because the sun hits it just right.
If not for that I might not have even seen it.

I see it pretty clearly in the pic.
It's almost @ 9:00 and goes across the top of the bore and also the outside water jacket wall.
It's a perfectly straight line.

 

[wired247]

Re: '84 Merc 150 V6 - Is my block destroyed?

Pretty much a total non issue. Go over the deck with a sanding block or get it decked for $50 if it really bothers you. Its the one at the bottom of the pic that looks worse from your pic but its probably just a casting flaw.

 

[MAtkins]

Re: '84 Merc 150 V6 - Is my block destroyed?

thanks wired.
Does it look clean enough to use or do I need to keep scrubbing?

I'm using a metal scraper, scotch-bright heavy duty & mineral spirits.
You mentioned a sanding block?
I've been told numerous times *not* to sand it at all.
Can I use sand paper? If so, what grit? Wet or dry? ????

 

[wired247]

Re: '84 Merc 150 V6 - Is my block destroyed?

You dont want to take much metal off. Just clean it up a bit. Check with a straight edge as you go. Nothing too coarse. 180 grit at the coarsest. To be honest its probably fine the way it is.

 

[MAtkins]

Re: '84 Merc 150 V6 - Is my block destroyed?

OK thanks.
I'll probably run something real fine on a block, very lightly and call it good.

 

[Faztbullet]

Re: '84 Merc 150 V6 - Is my block destroyed?

just true it up as wired posted or have it decked, you can safely have .020 cut off deck. Odd that shop didnt surface it boring

 

[MAtkins]

Re: '84 Merc 150 V6 - Is my block destroyed?

They didn't impress me much.
I got it to my dealer a week before Christmas and they didn't get it back to him until the 24th of January.
They jacked their prices up till my bore job was almost double my original quote.
They extracted a bolt for me & charged me $42.00 for that but they didn't clean *anything*.

 

[racerone]

Re: '84 Merc 150 V6 - Is my block destroyed?

It almost looks like mark / scratch left by a boring bar tool bit.------Remember you can not just clean up this spot there.----The whole surface across the 3 cylinders must be flat.

 

[CharlieB]

Re: '84 Merc 150 V6 - Is my block destroyed?

As already posted, you can safely deck .20 off that deck, slightly raising compression, and power. But you must do BOTH sides the same.

I'd drag a fingernail across it, if it 'catches' then deck it. If not, clean and reassemble, it will be fine.

Note, the critical portion is the steel liner, not that alum around the liner. If you can snag a fingernail on the liner, deck it.