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jharmon203

How to determine an engine rebuild was done correctly

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jharmon203

I was hoping to get some good advice on how to determine an engine rebuild was done correctly. I have been looking on many sites that advertise boats and some have rebuilt engines due to a failure in the winterization process.

What are some things to look for or what tests can I do to ensure everything is working properly?

Thanks so much in advanced for your replies!

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JeffK

I would say a compression and leak down test would be a great place to start.

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DIE2SURF

^^^^ ending with a power turn.

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oldjeep

I would say a compression and leak down test would be a great place to start.

And then next a water test where you are testing acceleration and looking at the oil pressure among other things.

Also if there was a failure in winterization you typically replace not rebuild since the block is usually the casualty.

Edited by oldjeep

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67King

Used oil analysis should be added to the list.

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minnmarker

Used oil analysis should be added to the list.

Blackstone labs in Indiana does oil analysis but it'll only tell you something if there are 30+ hours on the oil. They can tell all kinds of things about bearing wear, valves, water or gas i the oil, etc.

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jk13

if there was a failure in winterization you typically replace not rebuild since the block is usually the casualty.

This^^.

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67King

Blackstone labs in Indiana does oil analysis but it'll only tell you something if there are 30+ hours on the oil. They can tell all kinds of things about bearing wear, valves, water or gas i the oil, etc.

We use Blackstone and Polaris pretty extensively in our race cars, and I consult with a great many of our customers. Even teh best, most robust oils don't ever see 30 hours on the oil. 4-5 is more typical. If you have a problem, it can tell you plenty. Especially if the rebuild was poor, as you'll have heavy wear. If anyone does this, I can certainly help give my feedback.

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Woodski

@jharmon: several great suggestions, oil test and compression / leak down test to check engine health. If a rebuild is done incorrectly a failure will probably happen during the infant mortality stage or quite soon after the rebuild. To offset this, lean towards one that has accumulated several hours after the rebuild.

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Bill_AirJunky

I would say compression test, leak down test, check oil pressure & temp while doing the on water test. Possibly get an inspection camera & check the cylinder walls. If it's a new engine, you should still be able to see the cross hatch marks.

How long does Blackstone take to get you results? Is the average seller really going to wait for the results for you?

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oldjeep

And how much oil do you need? I'm trying to imagine my response to - can I drain 4oz of oil out of your engine? Uh- no

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67King

And how much oil do you need? I'm trying to imagine my response to - can I drain 4oz of oil out of your engine? Uh- no

Yeah, about 4 ounces. I'm trying to imagine my response to an "Uh - no." Probably "thanks but I'm not interested if I can't evaluate the health of the engine."

Results usually take a few days. As for if the seller will wait, that is a risk the buyer would have to take. Some folks will buy sight unseen. Others will not buy until they can take a test drive and/or have them checked out. Any delay is a risk, but if the concern is specifically about whether or not a freshly rebuilt engine was properly rebuilt, then that is absolutely something that is an informative test. It isn't something I would do on a run of the mill boat with a few hundred hours.

On edt, one thing you have to beware of is that on any newly rebuilt engine, until it is broken in, things will look bad. Until your rings are seated, you'll have low compression and high leakdown. You'll have wear metals in the oil. If we're talking a brand new engine, then I would assume it would come with some kind of warranty. I'm been under the impression that we're talking about a recent rebuild (presumably a season old since the failure modes were winterization related).

Edited by 67King

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Michigan boarder

We overhauled my engine last year. Did about a dozen dyno pulls, and it has 23 hours of run time. I drained the water and the oil already this fall, but have not pulled the filter yet, so there is oil in there still. Do you guys think it would be worth testing?

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jharmon203

@jharmon: several great suggestions, oil test and compression / leak down test to check engine health. If a rebuild is done incorrectly a failure will probably happen during the infant mortality stage or quite soon after the rebuild. To offset this, lean towards one that has accumulated several hours after the rebuild.

I know one particular case that I was interested in, the block was completely replaced and the owner had since been out on it wakeboarding and surfing. Many of the boats I look at are quite a distance so the oil test wouldn't really be feasible unfortunately.

This has all been great information! Thanks everyone for your contributions.

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Woodski

M-B: Yes to your oil test question. The reason is for future reference to watch for any trends to hopefully catch something prior to a catastrophic failure.

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minnmarker

We overhauled my engine last year. Did about a dozen dyno pulls, and it has 23 hours of run time. I drained the water and the oil already this fall, but have not pulled the filter yet, so there is oil in there still. Do you guys think it would be worth testing?

Yes, if you have not refilled the oil and started it since you drained the oil.

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Michigan boarder

M-B: Yes to your oil test question. The reason is for future reference to watch for any trends to hopefully catch something prior to a catastrophic failure.

Cool.

Yes, if you have not refilled the oil and started it since you drained the oil.

Correct, I have not. Ran it on a hose in the driveway on Labor Day, fogged it, then drained the water. Then drained the oil. Then hauled it to storage (pole barn across the street from my office). My plan was to pull the filter this weekend, install the new one, fill with fresh oil, do a good cleaning, and start to figure out my projects. I'll contact Blackstone tomorrow and get set up with what I need to do.

Edit: sgt1970-442, if you read this, I'm not doubting the engine build - just taking steps to make sure it lasts a good long time.

Edited by Michigan boarder

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robbennett

If it is a fresh rebuild. Then your warranty is your best line of defense. If it is fresh with no warranty I would probably steer clear because who rebuilds and sells if they aren't trying to dodge problems. Someone who rebuilds and sells is more likely to go the cheaper route than someone who rebuilds and keeps.

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Woodski

@MB: You might also want to cut the filter open and see what it captured. If the only one since the rebuild, there will probably be a fair amount of stuff captured within, certainly not uncommon on a fresh rebuild. Again, a process to observe changes over time.

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Michigan boarder

@MB: You might also want to cut the filter open and see what it captured. If the only one since the rebuild, there will probably be a fair amount of stuff captured within, certainly not uncommon on a fresh rebuild. Again, a process to observe changes over time.

You read my mind, I planned on that too. It is actually the second filter, Sgt. changed out the first one and the break in oil after we ran it up and down a bit and before the big dyno pulls.

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