I think I screwed up my engine while trying to take the crankcase apart

[BillyB11]

Hi all,

I am currently trying to rebuild my 67 Johnson 6hp. This is the first mechanical work I have ever done, but I would like to get this motor running and learn about engines in the process. So far everything has gone very well as I have been very careful to read up on every procedure to avoid making mistakes. Today, I got a little bit careless and think I might have screwed up bad.

I was taking the two taper pins out to disassemble the crankcase. The first one came out no problem using a punch. The second one is where i ran into problems. The second pin was mushroomed so I tried to carefully file the mushroomed portion off. I was trying to be very careful, but I nicked the area where one of the screws goes in and now I am afraid it will not be air tight and I will lose compression. Furthermore, the pin I was trying to get out is stuck and I am not sure how to get it out. Furthermore, I am nervous to try anything as I feel like ive already created a big mess and possible ruined the motor.

I have attached a picture with some annotations to make it clear what I have done.

UPDATE: I actually feel a little bit better now, (the pin is still stuck so that sucks), but I just reattached the screw to the area where I nicked the wall. It appears that the screw does not sit flush against that wall, so I would suspect that what I have done should not affect the compression.

Thanks,
Billy

 

[F_R]

You mentioned the pins are tapered, so I assume you are trying to drive them out in the right direction (??). Yeah, the one giving you trouble is a tad difficult because you can't get a direct shot at it from the rear end. Using a brass punch helps to keep from mushrooming it.

I can't make out just what the problem is with the screw hole, but you say it's ok, so it is.

 

[Joe Reeves]

Do not attempt to reuse that filed off tapered centering pin.... buy a new one!

As F_R states.... I too believe that you are trying to force the tapered pins out in the wrong direction. The mushrooming that you filed, cut, sawed off was simply die to hammering it in at one time.

If you forced the first tapered pin out in the wrong direction, you're lucky you didn't break the surrounding aluminum off the crankcase. Lean on that manual a little harder or check in here first before you do something you're not sure of.

 

[racerone]

Have you priced those special tab washers on the connecting rod screws ?----Drill a relief hole in the pin.---That may help get ot out.

 

[BillyB11]

F_R, your comment "the one giving you trouble is a tad difficult because you can't get a direct shot at it from the rear end" makes me a little bit nervous that I have been going at this from the wrong direction. I have been trying to drive it down from the direction shown in the photo I shared. Meaning, I have been drive the pin toward the exhaust manifold. Are you implying that is the wrong direction?

 

[racerone]

THat is totally wrong !!------Those pins are critical for re-assembly so that bearings line up properly !

 

[BillyB11]

thanks for your comments racerone, i realize at this point i have definitely screwed this up, will at least need new a new pin, but more than likely will need to take this to a machine shop and have a pin fitted for reassembly

 

[BillyB11]

Also, I still have not gotten the pin out. Any advice on how to get it out from here and where to look for any collateral damage I may have caused

 

[BillyB11]

Thanks for your responses everyone... at this point it is clear to me that I tried to remove the pin in the wrong direction. I am very interested in continuing to rebuild this motor, so my questions are...

(1) Do you think i did any major damage
(2) How do I get the pin out now
(3) Do you think I expanded the hole that the pin goes through such that I need to go to a machine shop
(4) Where should I look at this point to ensure that I did not do any damage to other parts

Billy

 

[boobie]

I would take it to a machine shop right now before any more damage is done and have them work on it.

 

[tpenfield]

Does the pin really need to come out in the first place, or would you still have been able to re-build the engine with them in. :noidea:

As I recall, my Merc 7.5 had some alignment pins in the crankcase halves when I rebuilt it last year . . . I left them in throughout the rebuild.

Whatever nicks or gouges you have made in the crankcase casting may be fixable with gasket sealant or JB-Weld :noidea:

When I rebuild stuff, I usually take apart what really needs to come apart, and often there is some learning in that.

 

[racerone]

???----Mercury does not use this type of dowel !!-----That pin has to come out.------Cheaper and better to find a used block.-----There are lots of them around.----Yes there are.

 

[BillyB11]

Everyone, thanks for all your responses... I really do appreciate,

So circling back, I definitely screwed up and I regret that! I really am interested in rebuilding this but obviously I have created an issue that is going to make it more difficult.

-Boobie, your advice is noted... I have been looking for a machine shop, not really sure where to go, but will definitely keep in mind.

-racerone, if I understand your last post correctly, you are suggesting I find a new block? I am certainly not opposed to that, but I have looked online and I am not really sure where to find one. Furthermore, should I get a new block, what does that mean for the pistons? Will I then need to take it to a machine shop and get the new block rebored for my pistons? If you could give me any follow up and give me some guidance on where I could go about finding a new block that would be much appreciated.

-Anyone with any other suggestions would also be welcomed. I would hate to have to abandon this project due to my silly mistake.

Billy

 

[racerone]

Many of these motors around with low hrs.----Nothing special to do with fitting your pistons in a good used block.-----Your location does matter !-----Do you have the motor apart now ??----No decision can be made till all the parts are on the work bench.----Myself I know how to line it all up and rework the holes for new dowels.---Would fix ir up to the way it left the factory.

 

[BillyB11]

Thanks again for the reply racer, The engine block is not apart now as I have yet to remove the dowel that I tried to force through the wrong way. I am currently trying to figure out the best way to accomplish this without causing further damage. Given that I have probably caused some damage already, I have been looking for new engine blocks on the internet, so far I have found a couple for around $75. Does that sound like a reasonable price?

Thanks,
Billy

 

[BillyB11]

I know below there are a lot of questions/conjectures and I apologize in advance for my novice understanding of engines. I took on this project as a way to not only get my outboard running in good condition, but also to learn about internal combustion engines in general. ALL OF THE HELP THE IBOATS COMMUNITY HAS PROVIDED THUS FAR IS GREATLY APPRECIATED (RACERONE, F_R, JOHN REEVES, BOOBIE, TPENFIELD THANK YOU FOR YOUR RESPONSIVENESS)

Alright, I have managed to removed the dowel that I drove in the wrong way. I was hesitant to do this (per boobie's adviace), but as I have found replacement blocks available per racerone's suggestion, I wanted to removed the dowel and assess the situation knowing that further damage to the block was possible.

Aside from what I may have screwed up during the dowel removal, I feel like the engine is in great shape. I see no scoring or pits in the cylinders -- this makes me want to try to salvage this engine block if possible.

I am assuming at minimum I need a machine shop to rework the hole for the dowel I screwed up and possibly have the shop make me a dowel to fit the new hole

Furthermore, I would guess that the excessive strain I put on the block when trying to remove the dowel in the wrong direction could have warped the mating surface. I have seen online people using a straight edge to determine if this is the case, but I figure that if I am taking the block to a machine shop anyway, I should have the professionals check this (not sure if this is correct and not sure what exactly to ask the shop to do)

I live in the St. Louis area, so a marine machine shop is not the easiest thing to find. Do you think regular automotive machine shops will be able to help me, or do you think it is best that I ship the engine to a marine-specific shop

Also if anyone has any ideas/estimates on what this should cost I would appreciate that info (I dont want to get ripped off)

Is there anything else I should have the machine shop look at if/when I do send it?

I assume that if I do end up going the route of a new block that I will need to send the block to a machine shop to get the cylinders honed. I am not sure if that is also true if this engine block turns out to be okay.

Thanks,
Billy

 

[Joe Reeves]

A regular machine shop is what we in the marine repair trade use when needed. No need to look for a specific type shop.

 

[interalian]

A regular machine shop is what we in the marine repair trade use when needed. No need to look for a specific type shop.

True, except for boring cylinders. Some shops don't have blind bore capability. I used a shop that specialized in motorcycle work to do my machining. I even had to send it to another city 2 hours away as there wasn't one place in Calgary (1 million plus peeps) that could do it.

 

[BillyB11]

Joe Reeves and Interalian, thanks for your responses, much appreciated!

If anyone has answers to my other questions I would much appreciate it.

Thanks again for everyones help. Happy thanksgiving!

Billy

 

[Tim Frank]

If you can find a good used block for $75-, I'd order it ASAP before someone else beats you to it.

There is not much, if anything, that a machine shop will do for you for $75-. (IMO )