Is this a reasonable request??

[brettagostini]

Hi.

I've finished dismantling my '18 Evinrude 140hp crankcase. I've found a broken ring and a broken main bearing...but that's for another post.

My question regards my crankcase, and how to get all the accumulated carbon, varnish, gunk, schmootz, and goo out of everywhere.

It would cost me a hundred bucks to buy enough solvent at Autozone to dip my crankcase. Would it be strange for me to go a shop and ask them to dip it for me? I'm sure there would be a fee, but is this something they do, or would they think I'm crazy?

Thanks.

 

[Dhadley]

Re: Is this a reasonable request??

That's something Marine machine shops do all the time. Whoever bores the block will probably hot tank it anyway.

 

[SuperNova]

Re: Is this a reasonable request??

You should be able to go to any machine shop and get it tank cleaned for a reasonable fee.
--
Stan

 

[brettagostini]

Re: Is this a reasonable request??

Thanks guys.

Dhadley, another quick question...

You said "whoever bores the block." Should I then assume that the block will need to be bored? Or, is that just a maybe thing. Is it possible I'll get by just honing the cylinders?

If its a maybe thing, how do I tell if it needs to be bored? (My Service Manual is going to be purchased out of my next paycheck, promis!! ;o)

And as a tagalong to that question, what would be a reasonable price if I need to get the cylinders bored?

Thanks.

 

[grid]

Re: Is this a reasonable request??

"'18" wasn't a year OMC made 140s, so it's hard to tell how much wear is there(!). If it's a '78 or '88, unless it's been sitting in the garage its whole life, it'll have enough oval wear to the cylinders to warrant boring at least .030 oversize. If it's worse than that, you may want to consider a good re-manned powerhead and be done with it. You can go .045 over with Wiseco, but the cylinder wall are awfully thin after that. Have the machine shop--using your new service manual--see how many cylinders fall within specs for not boring. If the broken ring gouged a wall, you need to bore. Honing won't work. My guess by your description is that all will need boring. Boring runs $30-$40 a hole, depending on your area, and tanking the block and clean-up, another $40.

 

[JustJason]

Re: Is this a reasonable request??

well... you need to buy a micrometer, a dial bore gauge for starters. and you need to map out the cylinders on both the x and y axis. and you need to do it in 3 locations, top, middle, and bottom. it is a process, but that's why getting a rebuild is pricey. you should mic the pistons as well. as its not uncommon to have different size pistons. if you've never done this kind of work before you might just want to drop the block and pistons off at a rebuild shop and have them measure it out, fit the pistons, order what needs to be ordered, and put it all together.
or... you can skip it... put it all together and hope for the best... but the best rarely happens this way. you should do more digging and find out if the busted ring was a symptom of another problem or not.

 

[Dhadley]

Re: Is this a reasonable request??

The machine shop will measure the cylinders. Go by the measurement, not by looks. I'd be willing to bet the cylinders are out of round anyway. Plus if you have to buy a piston anyway it doesn't make sense to not bore it.

BTW -- the Wiseco's are .044" over, not .045". There's plenty of meat to bore it to that. In fact you can go to .064" over. And no - you will not see any power increase.

 

[brettagostini]

Re: Is this a reasonable request??

OK... sorry... you guys lost me a little bit there. (It's an '81... not an '18, by the way. Sorry)

So I'm going to paraphrase this all back to make sure I got it straight in my head. Here goes:::

The cylinders are probably out of round or scored (especially with the broken ring.) So I most likely need to have my cylinders bored.

Also, if my pistons are out of round or otherwise too beat up, I need to buy new ones to replace those. (But I can keep any that might be still OK??) (One brand is Wiseco??). In this case, it makes sense to get the cylinders bored to match the new pistons, since the new ones won't match the worn old cylinder walls.

I could buy a micrometer and bore gauge(?) to determine the roundness of my cylinders and pistons, however, it might make more sense just to let a machine shop do this since they know what they're doing.

Did I get it right? I don't want to sound like I don't know what I'm talking about when I walk into the machine shop. (Of course... I DON"T know what I'm talking about... but they don't need to know that!)

 

[Dhadley]

Re: Is this a reasonable request??

A good dial bore gauge is way too expensive to buy to use once or twice. Just let a reputable shop measure the block and see what they say. Then go from there.

If the motor had been lugged enough to coke up the pistons and break a ring it's a safe bet there was way too much combustion heat. From there it's reasonable to think you'll find the cylinders out of round.

 

[flabum]

Re: Is this a reasonable request??

Just find a machine shop that does outboard block and let them bore it to whatever size cleans it up. Put a set of Wiseco pistons in it and your'e good to go. If you can't find any in your area, you can ship it to a reputable place. I know several places here in Florida as does others here know of places near them. If you have some spare change to put in the motor and the machine shop you use has the knowledge, you could have the block ported and the heads cut some to get a little extra pep out of the engine and keep it on pump gas.

 

[flabum]

Re: Is this a reasonable request??

BTW..... what happened with the main bearing? If you need a crank...I have a good one here for a reasonable price.

 

[wilde1j]

Re: Is this a reasonable request??

BTW, do NOT take the block to an automotive machine shop. You won't be happy with the results! Dhadley can recommend some good shops to consider.

 

[brettagostini]

Re: Is this a reasonable request??

Flabum, I wasn't dealing with the main bearing in this thread. But it looks in tact at first glance, but when you look closely you see a thin line on it. Turns out this thin line is a complete crack all the way through. I haven't removed it from the shaft yet. Dealing with other things.

But, since it looks in such good shape except for the crack, I'm thinking I just need to replace it.



Wilde1j, Why "don't take it to an automotive shop"? Why won't I be happy with the results? The FIRST thing I need to do is get a crack in the block welded, and I had planned to go to an automotive shop for that. I was planning to have the same shop do the tank cleaning and boring.

 

[Dhadley]

Re: Is this a reasonable request??

Where is the crack?

 

[brettagostini]

Re: Is this a reasonable request??

There is a small piece broken out at the front of one of the bypasses. Right where it meets the other section of the powerhead. You know the little thin piece. I need to get that piece welded back into place and have it retooled where the surfaces join.

 

[wilde1j]

Re: Is this a reasonable request??

Auto machine shops don't have the fixtures nor experience with two stroke blocks and piston fitting knowledge. Other than that, they're fine.

 

[Dhadley]

Re: Is this a reasonable request??

Double ditto.

As for that small piece, that may prove to be a problem. That has to be a perfect match with the front half. I don't believe the 81's used spegetti seal so if it leaks at all, the motor will run bad at best. Worst case scenario, and very likely, it'll stick a piston.

 

[Chinewalker]

Re: Is this a reasonable request??

The center main bearing is SUPPOSED to have a crack in it. Actually two of them. That's how they get it on the crankshaft...
- Scott

 

[brettagostini]

Re: Is this a reasonable request??

Dhadley,

Are you saying that my crankcase may be trash?? (You're right.... there are no spaghetti seals... just metal-to-metal.) Say it ain't so!

A friend who is a reputable auto mechanic has recommended a shop that does repairs to crankcases when his autoshop needs it done.

What are the chances that this piece could be welded/bent back into place and the surfaces retooled for an appropriate fit??

If I need to replace the entire powerhead my plans may be dead in the water. Its not financially feasible at this point.

 

[Dhadley]

Re: Is this a reasonable request??

Once you fix / weld the piece the surface cannot be machined past where it was originally. If you try to machine the entire mating surface to make it flat the main bearing areas won't be round anymore. You'd then have to line hone / bore the block & front half assembly. Like cutting the main caps on a Chevy. You cut the caps the line hone them while they're in place to make the hole round again.

The mating surfaces between the block and front half have to be perfectly flat. The sealer is anarobic which means it only hardens in the absence of air. If the surfaces are not flat the sealer won't cure.

If you surface the block or front half mating surface you'll make the main bearing holes smaller and oblong. Then the main bearing races won't allow the front to mate to the block properly.