chewed up camshaft

[Scott Walters]

Hi all,
I've got a camshaft with one of the ends chewed up in the bushing, and
a pile of accumulated metal stuck in there.
My (limited) understanding is that when something like this happens,
it indicates larger problems, specifically internal engine damage that
causes a loss of oil pressure. According to
http://www.honda600coupe.com/Road_and_Track.pdf, the Honda 600
"doesn't have oil pressure in the traditional sense" due to roller
bearings on the main crank.
So, how do I approach this? Replace the damaged parts and don't worry
about it? Have the oil pump checked out? Have the engine rebuilt and
everything inside of it checked out? Suspect a clog in the oil
delivery system?
Thanks,
-scott

[richmccolman]

Hi Scott,
From the picture, various parts (rockers, camshaft, etc) have the appearance of being very "dry" looking, with no visible oil coating. (Or is that the result of you having cleaned the oil off those parts yourself while working on it?) My camshaft housing and associated parts always look wet with oil.
My first impression is that you're not getting oil pumping up to the camshaft housing. If so, that could mean larger troubles, of the sort you alluded to.
Or am I misreading things from your photo?
Whatever the issue, good luck with it.
Richard

--- In
2cylinderhondas@yahoogroups.com
, Scott Walters wrote:
> Hi all,
> I've got a camshaft with one of the ends chewed up in the bushing, and
> a pile of accumulated metal stuck in there.
> My (limited) understanding is that when something like this happens,
> it indicates larger problems, specifically internal engine damage that
> causes a loss of oil pressure. According to
http://www.honda600coupe.com/Road_and_Track.pdf,
the Honda 600
> "doesn't have oil pressure in the traditional sense" due to roller
> bearings on the main crank.
> So, how do I approach this? Replace the damaged parts and don't worry
> about it? Have the oil pump checked out? Have the engine rebuilt and
> everything inside of it checked out? Suspect a clog in the oil
> delivery system?
> Thanks,
> -scott

[Eric Geiger]

that was my exact first thought as well richard, it looked very dry.
Eric J. Geiger
PRG Nocturne
XXX-XXX-XXXX  phone
XXX-XXX-XXXX  fax
XXX-XXX-XXXX  mobile
egeiger@...
www.prgnocturne.com

On Oct 27, 2012, at 7:47 PM, richmccolman wrote:
> Hi Scott,
> From the picture, various parts (rockers, camshaft, etc) have the appearance of being very "dry" looking, with no visible oil coating. (Or is that the result of you having cleaned the oil off those parts yourself while working on it?) My camshaft housing and > associated parts always look wet with oil.
> My first impression is that you're not getting oil pumping up to the camshaft housing. If so, that could mean larger troubles, of the sort you alluded to.
> Or am I misreading things from your photo?
> Whatever the issue, good luck with it.
> Richard
> --- In
> 2cylinderhondas@yahoogroups.com
> , Scott Walters wrote:
> > Hi all,
> > I've got a camshaft with one of the ends chewed up in the bushing, and
> > a pile of accumulated metal stuck in there.
> > My (limited) understanding is that when something like this happens,
> > it indicates larger problems, specifically internal engine damage that
> > causes a loss of oil pressure. According to
> http://www.honda600coupe.com/Road_and_Track.pdf,
> the Honda 600
> > "doesn't have oil pressure in the traditional sense" due to roller
> > bearings on the main crank.
> > So, how do I approach this? Replace the damaged parts and don't worry
> > about it? Have the oil pump checked out? Have the engine rebuilt and
> > everything inside of it checked out? Suspect a clog in the oil
> > delivery system?
> > Thanks,
> > -scott

[feltonminicycle]

Typically it is various particles stuck to the oil pick up screen on the oil pump. Sometimes is broken oil pump rod especially if someone installed it facing the wrong way (oil grooves inward). The good news is you can get to the oil pump with engine in car. Bad news is you should flush the crud out of the bottom pan. It's usually rubber particles from the primary drive.
You will probably need 2 rockers, 2 shafts, cam, cam end bearing. Oil pump or primary drive parts but no telling til you take it apart.
Miles

--- In
2cylinderhondas@yahoogroups.com
, Scott Walters wrote:
> Hi all,
> I've got a camshaft with one of the ends chewed up in the bushing, and
> a pile of accumulated metal stuck in there.
> My (limited) understanding is that when something like this happens,
> it indicates larger problems, specifically internal engine damage that
> causes a loss of oil pressure. According to
http://www.honda600coupe.com/Road_and_Track.pdf,
the Honda 600
> "doesn't have oil pressure in the traditional sense" due to roller
> bearings on the main crank.
> So, how do I approach this? Replace the damaged parts and don't worry
> about it? Have the oil pump checked out? Have the engine rebuilt and
> everything inside of it checked out? Suspect a clog in the oil
> delivery system?
> Thanks,
> -scott

[Scott Walters]

Thanks for everyone's comments here. The (engine) left camshaft
bushing looked well lubricated, with a nice coat of oil on it, but the
cam housing itself was as dry as photographed. I didn't clean
anything out.
Regards,
-scott

On 10/28/12, feltonminicycle wrote:
> Typically it is various particles stuck to the oil pick up screen on the oil
> pump. Sometimes is broken oil pump rod especially if someone installed it
> facing the wrong way (oil grooves inward). The good news is you can get to
> the oil pump with engine in car. Bad news is you should flush the crud out
> of the bottom pan. It's usually rubber particles from the primary drive.
> You will probably need 2 rockers, 2 shafts, cam, cam end bearing. Oil pump
> or primary drive parts but no telling til you take it apart.
> Miles
> --- In
2cylinderhondas@yahoogroups.com
, Scott Walters wrote:
>> Hi all,
>> I've got a camshaft with one of the ends chewed up in the bushing, and
>> a pile of accumulated metal stuck in there.
>> My (limited) understanding is that when something like this happens,
>> it indicates larger problems, specifically internal engine damage that
>> causes a loss of oil pressure. According to
http://www.honda600coupe.com/Road_and_Track.pdf,
the Honda 600
>> "doesn't have oil pressure in the traditional sense" due to roller
>> bearings on the main crank.
>> So, how do I approach this? Replace the damaged parts and don't worry
>> about it? Have the oil pump checked out? Have the engine rebuilt and
>> everything inside of it checked out? Suspect a clog in the oil
>> delivery system?
>> Thanks,
>> -scott

[theenginebuilder]

Scott,
The upper end has been starved for oil. Either the oil pump is worn out or it is possible that the oil filter is clogged.
My experience has shown that with the need to dig into the pump area and check for other damage you might as well rebuild the engine. Pieces are hard enough to find and it would be a waste to repair the top end only to destroy it again because of some other problem or something that was overlooked.
Several of us when put together have the parts you need.
What else are you going to do this Winter for entertainment!?
Bruce

--- In
2cylinderhondas@yahoogroups.com
, Scott Walters wrote:
> Hi all,
> I've got a camshaft with one of the ends chewed up in the bushing, and
> a pile of accumulated metal stuck in there.
> My (limited) understanding is that when something like this happens,
> it indicates larger problems, specifically internal engine damage that
> causes a loss of oil pressure. According to
http://www.honda600coupe.com/Road_and_Track.pdf,
the Honda 600
> "doesn't have oil pressure in the traditional sense" due to roller
> bearings on the main crank.
> So, how do I approach this? Replace the damaged parts and don't worry
> about it? Have the oil pump checked out? Have the engine rebuilt and
> everything inside of it checked out? Suspect a clog in the oil
> delivery system?
> Thanks,
> -scott

[Bram Evenhuis]

Does the cam still turn? If so you are somehow lucky, I had the same problem after I turned the engine off the cam and its bearing almost melted together. Next step; cut the chain to remove valvetrain.
The cause was in my case ,the old ROUND rubbers in the clutch damper had desintecrated. So I had to rebuild the complete engine.
Good luck Bram.

[zinc2u]

Hi Scott,
   From your most recent post,  I can see that your engine problems are VERY SERIOUS.  You will need to disassemble that engine and remove the lower crankcase.  You will need to check whether it was your oil pump which failed (e.g. broken pump rod) and/or whether your filter screen at the oil pump is plugged with metal particles.
    You will need to clean all the metal and other debris out of the engine.  The steel parts in the transmission are more forgiving when they encounter aluminum particles and this area should be ok after it is cleaned and inspected.
     I saw a post from Miles about the primary drive ...... the 1970 version of N600 sedan had a primary drive with round dampers which would disintegrate and clog up the oil pump screen.  Check if your primary drive is the older or newer style.  Since no black particles are present in the valve cover area,  I am betting you have the newer style primary drive.  It will look like black grains of sand with a rubber feel.  The part to check is the unit behind the clutch.  It has the two primary drive chains going to it.  You can feel if it is a snug fit between the center shaft and sprockets.  To see the dampers,  you need to remove the cover plate where the clutch bolts to the primary drive.
    This will probably be a costly repair on this engine if it suffered oil starvation to the entire engine.  You will know this when you look at the oil pump.  If the screen is completely blocked with debris or the pump is damaged,  the engine was starved of oil.  If that is the case,   you might want to look for another used engine.  When the pistons are starved of oil,  the piston skirt can collapse and may show scoring from the excess heat generated by the friction between the piston and cylinder wall.  If the crank is damaged due to oil starvation, it may appear to be okay but it will start to wear quickly and it could be 100 miles or several thousand miles before it fails. The engine noise will grow in time.    When these engines are new or low mileage,  they are fairly quiet.  The older they get,  the more you start hearing mechanical sounds from the engines  (rod knock, piston slap, cam area noises,  chain noise, exhaust leaks,  sheet metal vibrations).
   The best case scenario for you will be the main lubrication system did not fail and all the damage was confined to the top end area near the camshaft.  Since your picture (and testimony) indicates this area was dry when it should have been flooded with oil,  I am not expecting any good news.
Good luck,
Dale

> Thanks for everyone's comments here. The (engine) left camshaft > bushing > looked well lubricated, with a nice coat of oil on it, but the > cam housing > itself was as dry as photographed. I didn't clean > anything > out.
> Regards,
> -scott
> On 10/28/12, feltonminicycle z600miles@...
> wrote:
> > Typically it is various particles stuck to the oil pick up > screen on the oil > > pump. Sometimes is broken oil pump rod especially if > someone installed it > > facing the wrong way (oil grooves inward). The > good news is you can get to > > the oil pump with engine in car. Bad news > is you should flush the crud out > > of the bottom pan. It's usually > rubber particles from the primary drive.
> > You will probably
> need 2 rockers, 2 shafts, cam, cam end bearing. Oil pump > > or primary > drive parts but no telling til you take it apart.
> Miles
> > --- In
> 2cylinderhondas@yahoogroups.com
> ,
> Scott Walters wrote:
> >> Hi
> all,
> >> I've got a camshaft with one of the ends chewed
> up in the bushing, and
> >> a pile of accumulated metal stuck in
> there.
> >> My (limited) understanding is that when
> something like this happens,
> >> it indicates larger problems,
> specifically internal engine damage that
> >> causes a loss of oil
> pressure. According to
> http://www.honda600coupe.com/Road_and_Track.pdf,
> the Honda 600
> >> "doesn't have oil pressure in the traditional sense"
> due to roller
> >> bearings on the main crank.
> So, how do I approach this? Replace the damaged parts and don't > worry > >> about it? Have the oil pump checked out? Have the engine > rebuilt and > >> everything inside of it checked out? Suspect a clog in > the oil > >> delivery system?
> Thanks,
> >> -scott

[Scott Walters]

Hi Bram,
Yeah, the camshaft does turn. '72 Coupe (oops, posting model
information may have been helpful).
It was running hot and I was noticing that the engine was getting hot
by the points/vacuum advance first but I didn't put two and two
together. Leaked engine oil would start smoking around that area. I
started taking it apart to check the valve timing after ruling several
other causes out. And yup, it jumped time.
An internal piece of fin (to control oil flow? I wonder how important
that is) broke off of the camshaft housing at some point. I don't
know if it happened long ago when someone else was working on it and
it was at least safely removed from the engine, or if it vibrated
loose recently and wound up stuck in that bushing. The amount of
metal piled up in that one place is pretty spectacular and the wear on
the camshaft in that bushing is not even. It has clear gouges in it.
(Photo wasn't very good.) So I have a pet theory here. I don't see
anything resembling black rubbery sand and if I understand correctly,
that was really only a problem on the '70 Sedan.
Again, thanks to everyone for the thoughtful advice. One way or
another, I've got some work to do.
-scott

On 10/28/12, Bram Evenhuis wrote:
> Does the cam still turn? If so you are somehow lucky, I had the same problem
> after I turned the engine off the cam and its bearing almost melted
> together. Next step; cut the chain to remove valvetrain.
> The cause was in my case ,the old ROUND rubbers in the clutch damper had
> desintecrated. So I had to rebuild the complete engine.
> Good luck Bram.

[scottwalters32]

Hi everyone,
I'm wondering a few things about putting this back together.  For those who missed the saga, I settled on 1mm oversized pistons and had the cylinder heads rebored.  I also have half of an engine's worth of replacement parts stuck in there.  The oil pump rod exploded and tore up the eccentric cam on the primary drive sprocket.  Whatever engine these good parts came from should have been rebuilt instead of this one.
The flywheel was balanced, judging by the holes drilled in it.  There's no key or anything else to fix it a specific position on the crankshaft with respect to the crankshaft position.  The implications of this didn't occur to me so I didn't mark the position myself.  Any guess about how the flywheel was probably balanced?  What kind of business might be able to balance this?  Replacement pistons would also affect the balance I imagine.
What bolts should I be putting what compounds on?  Someone recommended anti-seize, and the service manual calls for threadlock on some bolts.  With an aluminum block, torque is pretty low.  Was the thing originally built with anti-seize on the bolts?
I searched for a few accounts of "what do I need to keep in mind while I put this back together" in here and read them but didn't see comments on those things.  All thoughts appreciated.
Happy western world new years, everyone!
Cheers,
-scott