Author Topic: The Dutch 450  (Read 4045 times)

Offline K2-K6

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Re: The Dutch 450
« Reply #15 on: November 29, 2017, 01:11:26 PM »
Yes Ash,  there's some things on which decisions are made that have such a fundamental impact but look,  in the primary consideration phase,  to be insignificantly small.

If we open up discussions about it then the route through what really happens should be more clear for others looking in.

As Jensen points out with his posts and tests,  sometimes it's going to define that which you don't want to do.  It's always going to deliver something of value.

Nigel.
« Last Edit: November 29, 2017, 01:26:07 PM by K2-K6 »

Offline K2-K6

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Re: The Dutch 450
« Reply #16 on: November 29, 2017, 02:17:54 PM »
One of the core reasons for how the engine was to be run in was given as the original fill of oil had to remain in the engine to complete that process.

The projection was that the oil contains small abrasive particals that come from internal wear,  which continue to refine the moving components if left in place.
My view is that process is completely wrong,  I don't see what basis it has as it also leads to a curious decision regarding honing.

It's worth going through why the the bores are honed to see what should be happening.

When a bore is finished from initial machining it won't necessarily have either a degree of topographical accuracy or surface finish in place to be suitable for an engine.
Primary function of honing with rigid stones is to allow the stones to lay flat on the original bore and by their movement path they will correct any imperfections to bring surface variance to within required tolerance.
Secondary function is to leave that characteristic crosshatch pattern that will, long term,  retain some oil during use of the engine to help lubrication.
Thirdly,  and this is the most short lived property,  it should be left by method and grit size,  with the burrs resulting from essentially gouging the metal's surface,  in place.
It's this "fault " that is going to cut / lap the new piston rings.

Going to the piston rings,  when made ( we'll talk about rings from this era as things are different for much later engines) and as they are fitted to pistons, they,  when placed in the bore,  are not as round as the new bore. This means they won't seal as required.

Running in is how they are made to fit. Using those burrs left over from honing,  the piston rings are,  in engineering terms, lapped to fit their own cylinder.
It happens specifically by the burrs breaching the lubricating oil and cutting the ring material. If you hand grind a wood chisel on on a flat oil stone,  this is exactly the same process. The oil acts as a soap to allow the abrasion to work, also to remove debris from the lap site.
The practical limitation of this comes as the burrs ultimately break down and dissappear from the bore surface. This would probably be finished by about 300 miles of engine life with normal production materials.
It's this process that defines the running in period of these types of engine. It's probably certain that it's mostly over by the time you get 500 miles and prompts the first oil change to remove any of the byproducts of this event.

What happened here was that based on that first theory of bedding the engine in, it becomes clear right at the end of the thread that he chose to plateu hone for the bores from the outset.
What this means is a much further refinement of the honed surface to closely approximate a perfectly,  post running in bore surface that is used in current engine production methods.
 It might sound like the best quality that can be achieved but needs to be paired with piston rings prepared for that eventuality.
This though gives a problem with the rings that need the old type hone to be properly brought into service. What the current engines do is to pre-lap the piston rings, and so avoid the initial running in procedure.

It's suggested that it's because the oil is of such film strength that the rings take a long time to seal, when in reality the original hone method is designed to breach any oil film.
It's a fleeting transaction and a fine balance but that is how it takes place.
It's not a surprise that it took 7000miles before he thought the rings were sealing.
« Last Edit: November 29, 2017, 02:25:54 PM by K2-K6 »

Offline UK Pete

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Re: The Dutch 450
« Reply #17 on: November 29, 2017, 04:34:37 PM »
Nicely written Nigel

Offline K2-K6

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Re: The Dutch 450
« Reply #18 on: November 29, 2017, 09:58:11 PM »
Just to expand that theory about abrasive content of oil running within an engine.

In the tested example,  every effort is made to filter the oil far in excess of normal running by passing it through external filtration along with replacing the engine's own filter at fairly short interval. You'd have to consider that this would directly oppose the particals theory.

But much more basic than that,  the piston rings are the only part you really need to wear any appreciable material from to make them seal as effectively as possible. Oil with abrasive would not be selective in this way and it's correct to make every effort to reduce any real chance of it happening.

A general abrasive in the oil longer term would be highly detrimental to all other bearing tolerances throughout the engine.

Conventional running in period is constructed to take advantage of that hone / lapping effect,  distributing the removed material into the oil and filter,  then discarding both when the bulk of any change has been reasonably allowed to complete. It's one of the most significant sectors in the engine's life, completed properly it'll  be run in a much cleaner status from then onwards.
« Last Edit: November 29, 2017, 10:00:42 PM by K2-K6 »

Offline jensen

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Re: The Dutch 450
« Reply #19 on: December 02, 2017, 11:16:14 AM »
Hi,

Found this post after ashimotok0 pointed out. I thought I was registered to this forum, but it was the other one, the SOHC/4 site. I was active there under the name supersports400. Written one large thread  about my CB400F, http://forums.sohc4.net/index.php?topic=65233.0.

Intresting views and comments on my thread here, I will certainly respond when I have a little more time on my hands.

Jensen

btw, this is my SOHC4:

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« Last Edit: December 02, 2017, 11:30:57 AM by jensen »
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Offline K2-K6

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Re: The Dutch 450
« Reply #20 on: December 03, 2017, 11:24:36 AM »
Hi Jensen.

As I originally wrote at thread beginning,  I found your experience and recording of it fascinating. My aim here was to expand some of the points based on my own thoughts about the impact of using synthetic oils in this way.

I believe, as you do, that there is a whole raft of disinformation about using synthetic oils in place of originally specified types. These seem to be perpetuated generally on threads around the world with no good or scientific basis. It often makes me wonder if you need to look after a camshaft, why then accept some casual reference to clutch slip that would prevent you following the most productive choice to preserve the valve train components.

It seems so many comments are made based on obscure sentiment rather than any sensible evaluation.

Any input you may have is certainly welcome,  although you appear to contribute a fair amount of your time in making your own threads. I hope I don't compromise those.

Nigel.

Offline jensen

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Re: The Dutch 450
« Reply #21 on: December 03, 2017, 12:01:41 PM »
Yes Nigel,

I agree, how could I not. I have dismantled many 450 engines the past decade, and all have more or less the same issue's. Looking at the damage, anyone can tell, even with an untrained eye, that lubrication is (one of) the culprit(s). However, there are some designer issue's too, particular focussing on the valve train and crank set-up. On top of that, the engine is very sensitive how it's handled.

My goal was to build an engine to spec, use a modern oil to break in the engine, and see what happened while covering miles. The changes I made are not dramatic, but going from the centrifuge oil filter set-up to paper filter set-up was mandatory using a modern detergent oil (no matter if synthetic or not).

Until today my bike is working flawless, no major damage to the cams and other parts. Every year I try to ride as much miles as I can, to make as many test miles as possible (and because I like to ride it).

Every time I adjust the valve clearance (once a year) I measure the clearance with a precision of 0,01 mm to see changes in the valve play. I do see that the left exhaust valve clearance is changing faster then all three others, despite the used oil. But the speed of wearing out is much lower then all the examples I have seen.

I do ride a lot of highway and back roads, using the bike as they did in the past, as a rider, not as some show bike, low revs and short distances. I don't take the bike to classic rides, since the average speed is very low, and high way's are commonly avoided.

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Offline jensen

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Re: The Dutch 450
« Reply #22 on: December 04, 2017, 09:55:27 PM »
Hi Nigel,

Working through your comments, I stumbled upon this sentence : "It's not a surprise that it took 7000miles before he thought the rings were sealing".
What do you exactly mean by "thought" ? I measured the that the maximum compression was reached at this point (and a leak down test gave the lowest leakage at this point), and I suspected that this was due to the seating of the rings. The leak down tests also show that this is the case.

I have to say that your comments are precise and well build up arguments, I was hoping for this kind of quality of comments at the Hondatwins site, but unfortunately just a few comments were worth the effort. Writing a thread like that should give the writer energy, unfortunately, it started to cost energy, not giving it. Another reason I did quit, is that I got a few not so nice private messages regarding this and other threads I started.

btw, I did not quit the tests for the general comments, I found that not many people where really reading it, so I stopped writing in depth details about the process.
« Last Edit: December 04, 2017, 09:58:23 PM by jensen »
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Offline K2-K6

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Re: The Dutch 450
« Reply #23 on: December 04, 2017, 10:35:24 PM »
Jensen,  I think  It's my poor grammar  / literary skills so it looks an odd comment.

I'll expand,  you've judged that it reached optimum condition based on your compression measurements at around 7000 miles. I'd expect to see that level of completion at around 750/1500 Miles with the hone more conventionally completing it's work by that much shorter interval.

Hope that explains,  if not just say.

I guess it's part of writing on here essentially unedited,  I go back over it to make corrections but some of it maybe slightly odd emphasis.

Nigel.

Offline K2-K6

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Re: The Dutch 450
« Reply #24 on: December 06, 2017, 01:32:32 PM »
Before I forget to include it, is a general running in point about why the recommendations are made by the manufacturers. This expands my thoughts rather than comment on the original thread.

The engine speed asked for by manufacture and layers put in,  usually increasing speed steps, is something I believe is very misunderstood. As far as I can determine from engineering principle,  it's predominantly the linear speed of lapping that calls for limits of rpm during this period.

More specifically,  you've a fixed pressure exerted by the piston ring spring action,  ideally you'll have an optimum piston speed ensuring that the linear lap speed doesn't exceed a predetermined maximum. This is of course usually given as max rpm. The first miles of using new bore and rings is going to be the most productive, purely because the maximum cut from hone is available.

Interestingly honing is not considered to be heat generating,  seems only 1 to 2 degrees is typical. It's this characteristic that can make it such an accurate method of precise component finishing.

It's commonly given that engine rpm restrictions are to prevent too much heat,  I'd disagree with that. Certainly you'd not want to overheat a new engine,  but then the same applies to any engine throughout it's life.


Offline K2-K6

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Re: The Dutch 450
« Reply #25 on: December 07, 2017, 06:46:59 PM »
A curious question Jensen, is your view of filtering the oil so thoroughly influenced by that oil "debris" that collects in the crankshaft oil distribution channels?

I was just looking through the link to crank preparation that Ash has posted over on the cl450 rebuild thread and saw in much more detail what accumulates within there.

Another question,  if you smell the oil after it has run in your engine then compare that smell to new oil,  is there a noticeable difference between the two,  if so how would you describe the change?

Offline jensen

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Re: The Dutch 450
« Reply #26 on: December 10, 2017, 09:47:52 AM »
Hi Nigel,

Quote
based on your compression measurements at around 7000 miles. I'd expect to see that level of completion at around 750/1500 Miles with the hone more conventionally completing it's work by that much shorter interval

Yes, but I wasn't surprised, and knew upfront that it would gonna take a long time to reach the maximum compression. When looking for example to the BMW flat 3 and 4 cylinders (K-series), one of the complains was that these bikes used a lot of oil from new. It took a long time before the rings were set, something around 4 to 5 K km. These BMW's used synthetics from the factory as I remember, and there where a lot of discussions going on. Nowadays, all engine are machined to perfection, with very low tolerances, and using synthetics from new.

The CB450 is an old bike, made in a time that precision wasn't that high, and breaking in was a process to correct a these mis-matches between parts in general. The process of breaking in was much more important than it is now, a lot has changed. This was also the reason for me to experiment with breaking in on synthetics.

Using synthetics in my classic bikes is a no-brainer for me since I've seen the effect of using this kind of oil in an engine. Many years ago (1997) I bough a new XRV750 Africa Twin, and before starting the bike I changed the oil to synthetics. Since then I always used synthetics in this bike, thus including the breaking in process.

I travelled many kilometres on this bike, and in 2017 I sold her with 360.000 km on the odo. Every year the bike was on the dyno, every year I tested the compression, and between 8.000 and 10.000 km it reached the maximum compression. In the beginning the bike used oil, but stopped using oil around 8000 to 10.000 km. The last compression test at 345.000 km on the odo showed that the compression was still very good (way within the specifications). The bike didn't use oil in an amount that I had to fill up between oil changes (8.000 to 10.000 km).

The only engine parts I had to replace were the clutch plates at 220.000 km's. The other thing I changed on the bike were the spark plugs, I went from normal spark plugs to Iridium ones. Since the XRV has two plugs per cylinder, the costs were very high in the 90's, but I didn't have to change those either every time (however I checked them every year).

Quote
if you smell the oil after it has run in your engine then compare that smell to new oil,  is there a noticeable difference between the two,  if so how would you describe the change?

It smells good, but since that's an indirect measurement and depending on emotional and physical health, it doesn't say not much. I didn't smell gas / petrol, but it doesn't smell the same as new oil. The colour is much darker too.

Quote
is your view of filtering the oil so thoroughly influenced by that oil "debris" that collects in the crankshaft oil distribution channels?

Since the high detergent power of modern synthetics, debris is not collected in the crank or in a spinner filter (the oil just cleans the spinner filter), it collects the debris in the paper filter itself.

A substantial part of debris in the oil are clutch plate particles, the other is waste of burned oil and fuel leaking through the oil rings. The larger particles of the clutch plates and the other debris are caught by the paper filter, the smaller parts are pumped trough the engine.

I use an external filter setup because the filter setup from Cappellini Moto uses a paper filter which is too small according to me (there is just not enough room to place a bigger filter). The used filter (from a Suzuki motor scoot) is just a single layer of paper, and not like many larger oil filters for cars, multi layers.
« Last Edit: December 10, 2017, 09:50:06 AM by jensen »
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Offline K2-K6

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Re: The Dutch 450
« Reply #27 on: December 11, 2017, 12:51:50 PM »
I see what you mean about the BMW K engine situation Jensen, but feel that maybe an odd benchmark to base an engineering led evaluation on.

That engine series as far as I know used Nykasil plated bores which differ significantly from iron examples,  also using different piston ring specs to match the bore surface.
In addition, the layout gives particular problems with the bores laying flat which appear to gives poor oil evacuation from cylinder walls. It know they struggled with them in development terms ( I rode a 750  but not the 4 cylinder)  with the " sump" very close to the crank which doesn't appear to help clear oil from moving parts.
They also put the cylinder head on left of bike so when left on side stand any oil running out of the crank assembly, after switch off, collects in the cylinders next to the rings. Think they end up pinning some of the rings like a two stroke to prevent the ring gap being on the lower side of the piston.

I think if you run any bore with more oil than ideal in it,  then it would influence the rings bedding in rather than the oil type. It looks to me that to attribute any short comings to the use of synthetic oil in this engine gives the wrong impression.

It just looks like too many compromises in design to really evaluate oil type during run in and the affects it could impart.
Ultimately a dead end development wise for them,  too many compromises. I don't feel it should influence decisions for a move conventional layout and bore material.

Offline Bryanj

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Re: The Dutch 450
« Reply #28 on: December 12, 2017, 07:17:55 AM »
Cant comment on the oil in these bikes but can for commercials, The Merc v 6/8 commercial motor is run in with mineral oil then changes to synthetic but it is common to find zero oil consumption with mineral and measurable on synthetic, now as these take 39 litres on oil change and synthetic is a helluva lot more expensive careful maths has to be used to determine which works out cheaper especially taking in the oil change intervals of 100,000 Km on mineral and 180,000 Km on synthetic. the Dafs i now drive are doing 150-200 000 Kms a yesr. When looking at the change mileage do take into account that a lot of commercials use a centrifugal "Spinner" as well as paper filters and on the new stuff we can get 9 MPG at 44 Tonne

Offline K2-K6

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Re: The Dutch 450
« Reply #29 on: December 16, 2017, 12:00:18 PM »
I think thing's like that are relevant Bryan as it's something that can give a view of just how long the lubrication properties of oil can survive given the ideal conditions.

Also something that I was approaching there with my question to Jensen about oil smell, that was right in the assumption I was looking for fuel contamination that degrades the oil most on bikes I think.

Just listening to the newer big commercial diesels you can hear just how accurate the injection systems are nowadays. The very small amounts metered,  especially at low speeds makes them really quiet. Also significant is the mpg you stated,  that's pretty impressive to move that total load. Shows there's not much fuel going to waste.

I can see the conundrum Jensen faced regarding oil choice as wearing in of the bore and rings is a process that's diametrically opposed to trying to not cause wear to the cam. It seems that, for this 450 engine, those two areas could not be more distant in pure engineering terms. How you best achieve both at the same time is bound to bring up considered discussion.

 

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