Engine Rebuild gone wrong?

TheOldHokie

TheOldHokie

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The Evil Twin said:
Yup. Back in my days as a field steamfitter, I would weld cast iron all the time. Don't use TIG, as localized heating is too high and you can cause cracking that you may not see. Best bet is MMA (stick weld) with 7018 rods. Preheat it with a heat gun to a few hundred degrees. Do not, under any circumstances, cool it with anything afterwards.
Click to expand...
My concern would be distortion. I am a rank amateur and everthing I weld moves pretty significantly. Can you really weld that thin section without distorting the cylinder bore? You are dealing with a thousandth maybe two.....

Dan
 
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GreensvilleJay

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hmm, in #16, he says 'face of freeze plug' or similar...so now I'm curious...
Is this 'booboo' really the freeze plug ?
If so,remove and replace seems the best course of action.

If it's not the freeze plug..what is it...why is it there, what does it do ?
 
TheOldHokie

TheOldHokie

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GreensvilleJay said:
hmm, in #16, he says 'face of freeze plug' or similar...so now I'm curious...
Is this 'booboo' really the freeze plug ?
If so,remove and replace seems the best course of action.

If it's not the freeze plug..what is it...why is it there, what does it do ?
Click to expand...
The picture is clear. He drilled through the freeze plug and put a divot in the outside of the cylinder wall.

Dan
 
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GreensvilleJay

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OK, that makes sense of the picture.there isn't a freeze plug there, that's been removed and the 'rough red with scuff' is the water side of the cylinder.
I was seeing it as a deeply set in red freeze plug with a shiny booboo...
 
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Vlach7

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It's up to you if you think you over damaged the exterior of the piston wall/sleeve, if it has a sleeve? let an experienced mechanic see it in person the rest of us are working with a picture. I would not weld on the sleeve due to possible penetration and distortion, but carefully and slowly build up the cast iron to seal/cover it to reduce chance of damage to the cylinder wall.
 
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GreensvilleJay

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hmm..wet or dry sleeve ?
if it's 'wet', the sleeve IS the 'inside of the water jacket, so replace it..not the block
if 'dry' , there's cast iron between the sleeve and the water, maybe fine
for sure it needs a proper inspection.

problem with getting another block is ,well,' you might as well replace a LOT of things while it's apart.'...
 
The Evil Twin

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TheOldHokie said:
My concern would be distortion. I am a rank amateur and everthing I weld moves pretty significantly. Can you really weld that thin section without distorting the cylinder bore? You are dealing with a thousandth maybe two.....

Dan
Click to expand...
Yes, that's why I would use MMA for the lower heat factor. In this case, you'd basically be "patching" and not welding two pieces.
It's not a task for Harry Homeowner, IMO.
 
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hedgerow

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I have welded and had welded a lot of heads and engine blocks over the years. Mostly its worked out ok. All the ones I have done or had done were for engines the availability of good parts were zero. A quick google and there are all kinds of complete engines and engine blocks out there for this model. Engine rebuilds take too much time and money to that a chance using a block like this one welded or not.
 
Flintknapper

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The Evil Twin said:
Yup. Back in my days as a field steamfitter, I would weld cast iron all the time. Don't use TIG, as localized heating is too high and you can cause cracking that you may not see. Best bet is MMA (stick weld) with 7018 rods. Preheat it with a heat gun to a few hundred degrees. Do not, under any circumstances, cool it with anything afterwards.
Click to expand...
Agreed. I've successfully welded non-critical cast components with 7018 rods (low hydrogen) and rods with 55% nickel. Both work well.

Preheating is imperative to prevent cracking from too much heat (too quickly) but also to prevent rapid 'cooling' which is the nemesis of cast iron welds.
 
The Evil Twin

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Flintknapper said:
Agreed. I've successfully welded non-critical cast components with 7018 rods (low hydrogen) and rods with 55% nickel. Both work well.

Preheating is imperative to prevent cracking from too much heat (too quickly) but also to prevent rapid 'cooling' which is the nemesis of cast iron welds.
Click to expand...
Yessir. I have used a heat gun before AND after patching cast iron. I've seen guys do a water quench on cast iron axles and it literally makes me cringe. It's not a Samurai sword dude.
 
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new-to-engines

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It is a dry sleeve, and I am pretty confident I haven't gone through to the sleeve after more examining and measurements. I'm going to take it into a machine shop and see what they say, most curious to find out about pricing.

Like has been shared there are used blocks on Ebay for about $300, and I found a brand new unused one for $500. I have a feeling I'll end up leaning towards that, even if I can get it repaired I'm getting worried about long term issues.

One additional question will getting a new crankcase cause any other issues in terms of parts "matching up" to a different block. Not sure if there is any wear/break in of parts with a block that would cause issues with using a new one instead of the original?
 
TheOldHokie

TheOldHokie

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new-to-engines said:
It is a dry sleeve, and I am pretty confident I haven't gone through to the sleeve after more examining and measurements. I'm going to take it into a machine shop and see what they say, most curious to find out about pricing.

Like has been shared there are used blocks on Ebay for about $300, and I found a brand new unused one for $500. I have a feeling I'll end up leaning towards that, even if I can get it repaired I'm getting worried about long term issues.

One additional question will getting a new crankcase cause any other issues in terms of parts "matching up" to a different block. Not sure if there is any wear/break in of parts with a block that would cause issues with using a new one instead of the original?
Click to expand...
Parts will match up but regardless of new or old block wear items like pistons, rings, and bearings need to be renewed. Typically crankshaft gets reground and cylinders rebored or resleeved as well. A reman gets a new oil pump. Camshaft and lifters if being thorough...

Dan
 
The Evil Twin

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Pistons and rings for sure. Water pump and oil pump (because you don't want to have to go back in there). If there are a lot of hours in the engine, consider bearings. I'd highly encourage you to take the head to a shop to make sure it is flat before putting it on.
 
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GreensvilleJay

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yeesh...possible option #3...'pad and pencil' time. make the list, check prices,do the sums....compare a 'proper' rebuild to buying a complete running engine.
In the past I've bought complete tractors just for a part or two as it was cheaper.

If you do buy a running engine,your tractor is 'up and running' sooner than doing a total, proper rebuild and Spring is just 33 days away !

Options, consider all options BEFORE you open your wallet....
 
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sitric

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It seems to me, many of you didn't read the op. It is a marine application engine that he was rebuilding. Unless I'm missing something, he was already rebuilding it, and secondly, no getting the tractor back in service before spring. If it was me, and I am understanding op's situation, I would not slack on the process. Being stuck out on the water isn't the same as being stuck out on the back forty.
 
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GreensvilleJay

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oospy... OK, went back 30+ posts....yes 'marine' engine. so 'resetting' my thinking...

Best option ....Buy a NEW block and a lot of new parts...
next option, a used block ,but have it magnafluxed,decked,cleaned,etc.('good as new' )
along with a lot of internals and have rest properly refurbished as required. especially the alternator(special) , cause you want great batteries when the engine fails 6 miles from shore.....

To me 'rebuilding' implies using the old parts as they are. 'Building' implies all new parts or at least confirming old parts are within 'spec'
 
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