pok marks(holes) in port passages on '84 115 (pics)

[rothfm]

Hi all,

Wondering if anyone has seen this, or has any thoughts? I'm rebuilding a 1984 Johnson 115. Got the block back from the shop. Measured, cleaned, honed and ready for me to continue.

Upon looking closely, I noticed several ports have small "pok" marks...ie...little holes in the side of the port..Mostly the exhaust ports and most are fairly small and not deep. But I have one that is larger and deeper than the rest. I took some pics of the one in question. 2 pics show a 90degree scribe tool sticking into the hole.

Is this something to worry about? I filled it with fluid and it didnt drain, doesnt seem to go anywhere. Should I consider filling it? having it welded somehow? I was just about ready to start putting things back together. Otherwise the block came out very nice.



Thanks for any thoughts.

mark

 

[emdsapmgr]

Re: pok marks(holes) in port passages on '84 115 (pics)

Once the pics are blown up, they are pretty grainy. Somewhat hard to really see the issue. The holes may be due to prosity caused when the alum block was originally cast. If there was any realy problem over all these years, the internal forces would have cracked the cast iron liner right at the small/thin bridge between the cylinders. That's the weakest part of the cyl liner and is the area with the most heat/stress. The one bridge in the picture look good. The thing to check is to see if the thin aluminum bridge behind the cast iron face is whole (not cracked.) If the cast iron liner bridge and it's aluminum behind is intact, you should be good to go. Once you get a crack completely through the cast iron and aluminum part of the bridge, the block is scrap. Aluminum can be welded, but you'd need an expert for this job. Also, you'd be introducing heat into an area that might dimensionally deform once it's heated/cooled.

 

[Faztbullet]

Re: pok marks(holes) in port passages on '84 115 (pics)

Its fine.....just a air bubble in the casting ......

Once you get a crack completely through the cast iron and aluminum part of the bridge, the block is scrap

Not quite true as I have fixed several for customers, labor intensive but it can be salvaged and sometimes better to get a block vs repair cost..

 

[emdsapmgr]

Re: pok marks(holes) in port passages on '84 115 (pics)

Fast, I had a stock 79 high port 200 block that locked up (overheat) at 5000 rpm's. It cracked the bridge in the cast iron liner and the alum behind it. Took it up to a factory OMC service tech at Waukegan and it said the block was scrap due to the fracture. Bet it's a job to try to repair something like that...wish I would have known that at the time-those are scarce blocks.

 

[rothfm]

Re: pok marks(holes) in port passages on '84 115 (pics)

Thanks Gents, apreciated.

Its not near those bridges, and in the center of the port. Other ports have them too, including the intake side, just much smaller. I do believe those may be from the casting manufacturing process. I have a same vintage 90 that I just opened up to see, and it too has some of these.

Ok, will continue the rebuild--agreed, its in fine shape and been running since 1984--so I imagine it wont be an issue.

thanks again. I Feel better, wheew. Spent lots of time on this, and soon a bunch of money.

 

[Faztbullet]

Re: pok marks(holes) in port passages on '84 115 (pics)

It cracked the bridge in the cast iron liner and the alum behind it.

That would have been a easy fix as you would just had to bore all 6 and install the thick sleeve. The crack would not have mattered then would not effect the new sleeve bridge., plus all the port would have needed ground to match. It would have been expensive as I would not have advised a customer to put $700 in a block like that, as it would have been cheaper and easier to find a 235 block and had it ported.