Mercruiser V6 seized from Rodent Damange

robmac · 08-02-2011, 12:02 PM

bkgoodman,I am in Nashua and have an engine crain if you need one. I agree with all the advice you've gotten,free up the frozen cylinder then inspect each cylinder for scoring and ridges. I have built alot of engines along with freeing up siezed ones (which I then drove ) and as stated prior if it's apart make sure you get a master engine set and replace all seals and gaskets timing chain and gears etc.. PS,not a fan of Skips or his former location.

bkgoodman · 08-02-2011, 12:26 PM

Robmac: Thanks!

I did buy a hoist last night, so I'm borrowing a friend's truck, and I should have the engine back to my place within a few days.

I knew I needed the gasket set - I didn't know/think about the timing chain and gears. I am going to do a ring job too (never did one - don't know what it entails).

Assuming I can get the engine to budge loose, I don't know if I should take it to a machine shop? Hone it? Have them do it? Have them lap the valve seats or whatever while it's apart? Do that myself?

I can't really judge the condition it's in. Maybe if you're in the area you could take a peek

-BKG

Woodsy · 08-02-2011, 01:02 PM

Not be a buzzkill here... BUT!!

http://nh.craigslist.org/boa/2521116656.html

I just randomly typed in v6 in the search box! I have rebuilt more than a few motors and my advice would be something like the above.... keep one boat or strip one for the parts you need for the other. For $1500 you get a running motor, spare outdrive, spare everything! How can you beat that??? Hell use this boat this year....

Rebuilding a motor is fairly straightforward if your meticulous and know what your doing. You could spend alot of $$$ on your rebuild, but if you screw up one little thing... you could trash the whole motor and essentially throw your money away.... There is a reason mechanics rarely rebuild motors in thier shops anymore.... the headache and potential hassles are not worth it.

With the motor out of the boat already and everything disconnected you might have an issue figuring out where all the wires & hoses connect. Also, dont forget you have to align the motor using an alignment tool before you put the outdrive back on. otherwise you will chew up your gimble bearing in about an hour of run time.

Woodsy

PS: If the boats been unused for 9 years you can bet the all the hoses and the waterpump in the outdrive need replacing!

lawn psycho · 08-02-2011, 02:49 PM

I totally agree with Woodsy.

If you were talking a show car and wanted original motor that's one thing but that's not the case here.

Someone posted about setting valve lash as easy. Yes, after you've done a bunch of them. The net is filled with guys screaming for help after rebuilding motors and not starting or breaking something and having a bunch of re-do work and expense.

By the time you track everything down you need you'll have wished you just bought a rebuilt motor. But, I also know people that enjoy the challenge so it comes down to how much time and energy you want to put into the project.

patman · 08-02-2011, 04:06 PM

What probably happened is that the rodent urine did the bulk of the damage.

If you want to go industrial strength, skip the marvel, and use CLR, household vinegar, Oxalic Acid, or molasses. Give it a good soak then try to turn it over. Beware though, these will clean it down to the bare metal, which means it'll flash rust in no time flat unless you get some oil or something on it to protect it.

Example from another site, 12 days in molasses.

Before...

...and after:

bkgoodman · 08-02-2011, 04:35 PM

Quote:

Originally Posted by patman

What probably happened is that the rodent urine did the bulk of the damage.

If you want to go industrial strength, skip the marvel, and use CLR, household vinegar, Oxalic Acid, or molasses. Give it a good soak then try to turn it over. Beware though, these will clean it down to the bare metal, which means it'll flash rust in no time flat unless you get some oil or something on it to protect it.

Yes, I think it was the rodent urine. The head looks fine, just the top of the piston, and inside of one of the cylinders.

Just to be absolutely clear: I am to use only one of these, or a combination? How long should I soak it? Should I flush it out with oil afterwards? Will I damage the (good) metal if I leave it too long? Which one is best?

patman · 08-03-2011, 12:09 PM

Quote:

Originally Posted by bkgoodman

Yes, I think it was the rodent urine. The head looks fine, just the top of the piston, and inside of one of the cylinders.

Just to be absolutely clear: I am to use only one of these, or a combination? How long should I soak it? Should I flush it out with oil afterwards? Will I damage the (good) metal if I leave it too long? Which one is best?

Only one of those should be done. They all work at different speeds, and with different degrees of hazard. You definitely need to rinse it off afterwards, and yes, there is definitely a possibility of damaging good metal if you leave it too long. How much overshoot you have depends on how long the method takes to begin with.

Molasses - few days to a few weeks, not very caustic
Vinegar - a day to a couple of weeks, mildly caustic
Oxalic Acid (wood bleach) - minutes to hours, very caustic

But...as mentioned above...even assuming you have all the parts, and they're pristine and ready to go back together, are you up for the challenge?

Edit:
Here's some before/after of 12 days in vinegar (warning...language):

http://www.jalopyjournal.com/forum/s...73&postcount=1
http://www.jalopyjournal.com/forum/s...&postcount=179

bkgoodman · 08-03-2011, 09:07 PM

Okay - I got the engine in my garage. It actually looks very good in all. The head has that brownish-greyish color like it's spent it's life in oil, and is still well oiled with not even a trace of surface rust.

All the parts were there, all the rods, head bolts, etc were bagged up. It looked pretty complete.

Some surface rust on the rest of the engine - the water pump is bad, but I was going to replace that anyways. Everything else is not too shabby.

Then we get to the "offending cylinder"....

I gave it a quick scrub with a wire brush to get some of the really egregious rust dealt with, and vacuumed it out.

Do you think it's salvageable?

Larger Version

Larger Version

So right now, I have the engine sitting on its side at like a 45 degree angle, with the offending cylinder filled to the brim with vinegar. We'll see what that does in a few days.

Whataya think? Is it salvageable or am I scrod?

brk-lnt · 08-04-2011, 06:34 AM

Quote:

Originally Posted by bkgoodman

Whataya think? Is it salvageable or am I scrod?

In theory, any engine is "salvageable". The question is, is it worth the time and money you need to put into it in order to make it run again?

I still think that this is more of a "if you have to ask you can't afford it" kind of scenario, where if you have to ask, you're *probably* in over your head. But, I don't know you personally. I do know a lot of people with halfway rebuilt engines in their garages though...

When you look at the link someone else posted, you can get a boat, engine, outdrive, etc. for $1500... It's hard to justify putting more than about $500-$700 into this rebuild. And, I think that by the time you're through with it, you'll have spent at least that much, and probably a helluva lot of time.

Woodsy · 08-04-2011, 09:27 AM

I don't know your situation...

I just dont see the point in wasting all that time and money (anywhere from $500 minimum to $$$ max) and still have a huge chance of failure, when for $1500 (just 1 example) to $2000 you can have a turn key replacement with lots of extra spare parts.

Judging by the pics.... even if you free up the cylinder the piston will probably need to be removed and the cylinder honed... looks like you have some serious pitting.

Woodsy

Dave R · 08-04-2011, 02:06 PM

That looks pretty bad. I would not count on getting it working with that bore. Looks to me like the head was removed and the engine was left exposed to weather for quite some time. There's rust in places that could only be caused by the head being left off, not "rodent" damage.

bkgoodman · 08-04-2011, 02:15 PM

Quote:

Originally Posted by Dave R

That looks pretty bad. I would not count on getting it working with that bore. Looks to me like the head was removed and the engine was left exposed to weather for quite some time. There's rust in places that could only be caused by the head being left off, not "rodent" damage.

Eessh!

The head definitely wasn't off. (I'd seen it a few weeks prior). It is also just this ONE calendar which is bad. The rest are completely fine.

Blue Thunder · 08-06-2011, 06:46 PM

Quote:

Originally Posted by Dave R

That looks pretty bad. I would not count on getting it working with that bore. Looks to me like the head was removed and the engine was left exposed to weather for quite some time. There's rust in places that could only be caused by the head being left off, not "rodent" damage.

Completely agree with Dave R. That cylinder had water in it for some period of time. Need to determine how and solve that problem too.

BT

bkgoodman · 08-06-2011, 10:46 PM

Quote:

Originally Posted by Blue Thunder

Completely agree with Dave R. That cylinder had water in it for some period of time. Need to determine how and solve that problem too.

BT

It's been out of the water - for nine years! I think that when people are saying they don't think it was rodent damage, they're eluding more to something like my "mechanic" leaving the head off and boat uncovered - or something like that.

robmac · 08-07-2011, 08:00 AM

It sure looks prior to cleaning as though it ha alot of water in it for a long period of time. Didn't you write that they were starting it each year? Those are pretty tough engines and take abuse pretty well but I agree that without knowing where it came from and how it got into the affected cylinder you might be throwing $ down the drain if you have block or head damage. Were the plugs still in the head? Was the engine cover and carb breather cover off? Something is missing, is it your engine?

Blue Thunder · 08-07-2011, 09:59 AM

Quote:

Originally Posted by bkgoodman

It's been out of the water - for nine years! I think that when people are saying they don't think it was rodent damage, they're eluding more to something like my "mechanic" leaving the head off and boat uncovered - or something like that.

I hear ya bkg, I'm just trying to help. If the head was left off, all of the cylinders would look like that. That damage/rust, IMO, is from either the intake or exhaust valve being open and water entering the cylinder somehow. On the intake side, the water would have to enter through the carb/intake manifold. On the exhaust side it would come from the exhaust riser which is cooled by lake water (unless you have a closed system). If one of the times over the 9 years the boat was stored you turned the engine over, if it was done by hand and you went the wrong way, the exhaust valve could've been open and you would suck the water/anti-freeze right out of the riser into the cylinder. This is even more plausible if the riser had a unknown crack in it.

BT

bkgoodman · 08-07-2011, 11:10 AM

It's not that I don't want to buy a block - it's the right way to go.

However, there's the block - the installation - hauling (I don't have a trailer - and the boat's in a boatyard in Merrimack), plus an additional $600 for some outdrive work - and of course marina fees for the summer.

It all is adding up pretty heavily!

Maybe if I sell a whole lot of my Winnipesaukee iPhone chart apps... ;-)

ITD · 08-08-2011, 03:29 PM

bk, don't forget there is another couple of inches of cylinder beyond that piston, I doubt the cleaning solution is working there.

VitaBene · 08-08-2011, 07:40 PM

Quote:

Originally Posted by bkgoodman

It's not that I don't want to buy a block - it's the right way to go.

However, there's the block - the installation - hauling (I don't have a trailer - and the boat's in a boatyard in Merrimack), plus an additional $600 for some outdrive work - and of course marina fees for the summer.

It all is adding up pretty heavily!

Maybe if I sell a whole lot of my Winnipesaukee iPhone chart apps... ;-)

BKG, Given this info- Woodsy's suggestion makes more sense than ever.

MarkinNH · 08-08-2011, 08:43 PM

Quote:

Originally Posted by VitaBene

BKG, Given this info- Woodsy's suggestion makes more sense than ever.

Yup, I am seeing an awful lot of boats showing up in yards and parking lots with "For Sale" signs on them in the last couple of weeks. With the state of the economy and the season winding down there are probably some good deals to be had. Might be cheaper and easier in the long run to just right this one off and start fresh with another boat.

patman · 08-04-2011, 08:06 PM

Quote:

Originally Posted by bkgoodman

I gave it a quick scrub with a wire brush to get some of the really egregious rust dealt with, and vacuumed it out.

[...]

So right now, I have the engine sitting on its side at like a 45 degree angle, with the offending cylinder filled to the brim with vinegar. We'll see what that does in a few days.

Whataya think? Is it salvageable or am I scrod?

Well, you're kind of at the 'what have you got to lose' stage there. It would be faster and simpler to get a donor engine and swap that in, but if you're up for a challenge, and willing to fail miserably as a distinct possibility, go for it.

To set expectations, the best case for this without going to the machine shop is an engine that runs, but smokes and burns oil a bit. The possibilities go downhill from there.

Careful with that wire brush, Eugene. Don't scar up things unnecessarily. Resist the temptation to go at it with anything more substantial than a plastic scraper. Maybe a brass bristle brush or a very VERY fine (read: worn out) Scotchbrite pad if you're careful, but work slowly.

Make sure you've got the whole cylinder filled, completely submerging it is best. You'll get a rust line where the top of the liquid meets the air. If/when the piston frees up, the vinegar will go somewhere...probably past the rings and into the bottom end. Make sure you can rinse everything down to stop the corrosive action of the vinegar, and also get some oil or something on afterwards to keep it from rusting again. If nothing else, wipe it all down with paper towels and then hose it down with WD-40.

This is really a caveman approach, but...it might just work.

bkgoodman · 08-05-2011, 09:41 PM

After 2 days in vinegar.

I tried to capture the texture of the cylendar wall here. It looks a lot better - but I don't know if it's good enough. Do you think it need a hone, or a rebore?

(Click an image for a larger view)

patman · 08-05-2011, 10:51 PM

A lot better, but...no, not good enough. Load 'er up again for another soak.

In theory, a hone would do it because you just need to clean it up, but remember that is taking material off of the cylinder walls. The bigger you make the hole (and that's relatively small amount, it could be .001") the sloppier the fit, and the worse the compression/burning oil problems will be. At some point it gets loose enough that an overbore is the only answer. Once you get to that stage, you've jumped up in cost, and you should overbore all 6 holes (probably .010" or .020"), buy pistons to fit the bigger holes, have the rotating assembly balanced, etc, etc.

If you want to roll the dice, soak it for another couple of days, and see what it looks like then. Maybe going over it gently with a fine grade scotchbrite periodically. The bore needs to be smooth enough to not catch your fingernail on anything.

VitaBene · 08-02-2011, 04:38 PM

Quote:

Originally Posted by patman

What probably happened is that the rodent urine did the bulk of the damage.

If you want to go industrial strength, skip the marvel, and use CLR, household vinegar, Oxalic Acid, or molasses. Give it a good soak then try to turn it over. Beware though, these will clean it down to the bare metal, which means it'll flash rust in no time flat unless you get some oil or something on it to protect it.

Example from another site, 12 days in molasses.

Before...

...and after:

Wow! I never heard of using molasses and I am kind of a gearhead.

To the OP, if you are doing a quicky motor job you need to make sure that all of the lower end (rods, caps etc) need to go back exactly as they came out. That means conn rod in the same cylinder, same cap in same direction because all of these components have already worn in together. If not you will put the entire thing back together, torque everything and it won't turn over.

bkgoodman · 08-02-2011, 04:47 PM

Quote:

Originally Posted by VitaBene

To the OP, if you are doing a quicky motor job you need to make sure that all of the lower end (rods, caps etc) need to go back exactly as they came out. That means conn rod in the same cylinder, same cap in same direction because all of these components have already worn in together. If not you will put the entire thing back together, torque everything and it won't turn over.

It's already been taken apart by my mechanic - and everything's just in a box. I'm not 100% on what parts exactly you are talking about.

The head is still in one piece - but off the block. I think the pushrods are all out and sitting in a pile. (What do you advise?)

The crank/pistons are still in-tact - lower unit is not open. By "cap" do you mean the thing on the other end of the connecting rods that go "round" the bearings and hold them in place? (I haven't done this in a while - and never inside the lower unit

)

brk-lnt · 08-02-2011, 05:38 PM

Quote:

Originally Posted by bkgoodman

. (What do you advise?)

In all seriousness, write it off.

At this stage your odds of getting that motor back running correctly and reliably for under $1000 and 100 hours are pretty slim, and likely diminishing daily.

What you have on your hands is a "fun" hobby project for sometime who rebuilds marine motors regularly. IMO (having done a few strange projects automotive and marine in my time) I think you have a losing battle on your hands if the motor has been disassembled and pieces scattered by a person other than yourself.

NoBozo · 08-02-2011, 05:54 PM

Quote:

Originally Posted by brk-lnt

In all seriousness, write it off.

At this stage your odds of getting that motor back running correctly and reliably for under $1000 and 100 hours are pretty slim, and likely diminishing daily.

What you have on your hands is a "fun" hobby project for sometime who rebuilds marine motors regularly. IMO (having done a few strange projects automotive and marine in my time) I think you have a losing battle on your hands if the motor has been disassembled and pieces scattered by a person other than yourself.

I CONCUR: I think Woodsy has an idea.

NB

VitaBene · 08-02-2011, 10:03 PM

Quote:

Originally Posted by NoBozo

I CONCUR: I think Woodsy has an idea.

NB

You can buy a long block from the place I used (linked earlier) for less than 1200. I also like woodsy's idea.

You will still need the engine stand, especially if you are transferring parts onto a rebuilt long block.

08-02-2011, 01:02 PM	#3
Woodsy Senior Member Join Date: May 2004 Location: Weirs Beach Posts: 1,968 Thanks: 80 Thanked 980 Times in 440 Posts	Not be a buzzkill here... BUT!! http://nh.craigslist.org/boa/2521116656.html I just randomly typed in v6 in the search box! I have rebuilt more than a few motors and my advice would be something like the above.... keep one boat or strip one for the parts you need for the other. For $1500 you get a running motor, spare outdrive, spare everything! How can you beat that??? Hell use this boat this year.... Rebuilding a motor is fairly straightforward if your meticulous and know what your doing. You could spend alot of $$$ on your rebuild, but if you screw up one little thing... you could trash the whole motor and essentially throw your money away.... There is a reason mechanics rarely rebuild motors in thier shops anymore.... the headache and potential hassles are not worth it. With the motor out of the boat already and everything disconnected you might have an issue figuring out where all the wires & hoses connect. Also, dont forget you have to align the motor using an alignment tool before you put the outdrive back on. otherwise you will chew up your gimble bearing in about an hour of run time. Woodsy PS: If the boats been unused for 9 years you can bet the all the hoses and the waterpump in the outdrive need replacing! __________________ The only way to eliminate ignorant behavior is through education. You can't fix stupid.

08-03-2011, 09:07 PM	#8
bkgoodman Senior Member Join Date: Sep 2010 Location: Nashua, NH Posts: 66 Thanks: 27 Thanked 16 Times in 6 Posts	Okay - I got the engine in my garage. It actually looks very good in all. The head has that brownish-greyish color like it's spent it's life in oil, and is still well oiled with not even a trace of surface rust. All the parts were there, all the rods, head bolts, etc were bagged up. It looked pretty complete. Some surface rust on the rest of the engine - the water pump is bad, but I was going to replace that anyways. Everything else is not too shabby. Then we get to the "offending cylinder".... I gave it a quick scrub with a wire brush to get some of the really egregious rust dealt with, and vacuumed it out. Do you think it's salvageable? Larger Version Larger Version Larger Version Larger Version So right now, I have the engine sitting on its side at like a 45 degree angle, with the offending cylinder filled to the brim with vinegar. We'll see what that does in a few days. Whataya think? Is it salvageable or am I scrod?

08-04-2011, 09:27 AM	#10
Woodsy Senior Member Join Date: May 2004 Location: Weirs Beach Posts: 1,968 Thanks: 80 Thanked 980 Times in 440 Posts	I don't know your situation... I just dont see the point in wasting all that time and money (anywhere from $500 minimum to $$$ max) and still have a huge chance of failure, when for $1500 (just 1 example) to $2000 you can have a turn key replacement with lots of extra spare parts. Judging by the pics.... even if you free up the cylinder the piston will probably need to be removed and the cylinder honed... looks like you have some serious pitting. Woodsy __________________ The only way to eliminate ignorant behavior is through education. You can't fix stupid.

08-02-2011, 12:02 PM	#1
robmac Senior Member Join Date: Jan 2005 Location: Nashua,Meredith Posts: 951 Thanks: 213 Thanked 106 Times in 81 Posts	bkgoodman,I am in Nashua and have an engine crain if you need one. I agree with all the advice you've gotten,free up the frozen cylinder then inspect each cylinder for scoring and ridges. I have built alot of engines along with freeing up siezed ones (which I then drove ) and as stated prior if it's apart make sure you get a master engine set and replace all seals and gaskets timing chain and gears etc.. PS,not a fan of Skips or his former location.

08-02-2011, 12:26 PM	#2
bkgoodman Senior Member Join Date: Sep 2010 Location: Nashua, NH Posts: 66 Thanks: 27 Thanked 16 Times in 6 Posts	Robmac: Thanks! I did buy a hoist last night, so I'm borrowing a friend's truck, and I should have the engine back to my place within a few days. I knew I needed the gasket set - I didn't know/think about the timing chain and gears. I am going to do a ring job too (never did one - don't know what it entails). Assuming I can get the engine to budge loose, I don't know if I should take it to a machine shop? Hone it? Have them do it? Have them lap the valve seats or whatever while it's apart? Do that myself? I can't really judge the condition it's in. Maybe if you're in the area you could take a peek -BKG

08-02-2011, 02:49 PM	#4
lawn psycho Senior Member Join Date: Jul 2009 Location: On the move... Posts: 987 Thanks: 113 Thanked 248 Times in 133 Posts	I totally agree with Woodsy. If you were talking a show car and wanted original motor that's one thing but that's not the case here. Someone posted about setting valve lash as easy. Yes, after you've done a bunch of them. The net is filled with guys screaming for help after rebuilding motors and not starting or breaking something and having a bunch of re-do work and expense. By the time you track everything down you need you'll have wished you just bought a rebuilt motor. But, I also know people that enjoy the challenge so it comes down to how much time and energy you want to put into the project.

08-02-2011, 04:06 PM	#5
patman Senior Member Join Date: Jun 2008 Location: NH Posts: 384 Thanks: 56 Thanked 156 Times in 78 Posts	What probably happened is that the rodent urine did the bulk of the damage. If you want to go industrial strength, skip the marvel, and use CLR, household vinegar, Oxalic Acid, or molasses. Give it a good soak then try to turn it over. Beware though, these will clean it down to the bare metal, which means it'll flash rust in no time flat unless you get some oil or something on it to protect it. Example from another site, 12 days in molasses. Before... ...and after:

08-04-2011, 02:06 PM	#11
Dave R Senior Member Join Date: Jul 2004 Posts: 2,985 Thanks: 246 Thanked 744 Times in 444 Posts	That looks pretty bad. I would not count on getting it working with that bore. Looks to me like the head was removed and the engine was left exposed to weather for quite some time. There's rust in places that could only be caused by the head being left off, not "rodent" damage.

08-07-2011, 08:00 AM	#15
robmac Senior Member Join Date: Jan 2005 Location: Nashua,Meredith Posts: 951 Thanks: 213 Thanked 106 Times in 81 Posts	It sure looks prior to cleaning as though it ha alot of water in it for a long period of time. Didn't you write that they were starting it each year? Those are pretty tough engines and take abuse pretty well but I agree that without knowing where it came from and how it got into the affected cylinder you might be throwing $ down the drain if you have block or head damage. Were the plugs still in the head? Was the engine cover and carb breather cover off? Something is missing, is it your engine?

The Following 2 Users Say Thank You to Blue Thunder For This Useful Post:
VitaBene (08-08-2011), Winnisquamguy (08-18-2011)

08-07-2011, 11:10 AM	#17
bkgoodman Senior Member Join Date: Sep 2010 Location: Nashua, NH Posts: 66 Thanks: 27 Thanked 16 Times in 6 Posts	It's not that I don't want to buy a block - it's the right way to go. However, there's the block - the installation - hauling (I don't have a trailer - and the boat's in a boatyard in Merrimack), plus an additional $600 for some outdrive work - and of course marina fees for the summer. It all is adding up pretty heavily! Maybe if I sell a whole lot of my Winnipesaukee iPhone chart apps... ;-)

08-08-2011, 03:29 PM	#18
ITD Senior Member Join Date: Apr 2004 Location: Moultonboro, NH Posts: 2,941 Thanks: 481 Thanked 695 Times in 390 Posts	bk, don't forget there is another couple of inches of cylinder beyond that piston, I doubt the cleaning solution is working there.

08-05-2011, 09:41 PM	#22
bkgoodman Senior Member Join Date: Sep 2010 Location: Nashua, NH Posts: 66 Thanks: 27 Thanked 16 Times in 6 Posts	After 2 days in vinegar. I tried to capture the texture of the cylendar wall here. It looks a lot better - but I don't know if it's good enough. Do you think it need a hone, or a rebore? (Click an image for a larger view)

08-05-2011, 10:51 PM	#23
patman Senior Member Join Date: Jun 2008 Location: NH Posts: 384 Thanks: 56 Thanked 156 Times in 78 Posts	A lot better, but...no, not good enough. Load 'er up again for another soak. In theory, a hone would do it because you just need to clean it up, but remember that is taking material off of the cylinder walls. The bigger you make the hole (and that's relatively small amount, it could be .001") the sloppier the fit, and the worse the compression/burning oil problems will be. At some point it gets loose enough that an overbore is the only answer. Once you get to that stage, you've jumped up in cost, and you should overbore all 6 holes (probably .010" or .020"), buy pistons to fit the bigger holes, have the rotating assembly balanced, etc, etc. If you want to roll the dice, soak it for another couple of days, and see what it looks like then. Maybe going over it gently with a fine grade scotchbrite periodically. The bore needs to be smooth enough to not catch your fingernail on anything.