The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: owain on 21.07. 2019 22:11

Title: Metal shavings in oil
Post by: owain on 21.07. 2019 22:11
Hi all,

I've just drained the oil from my A10 and noticed a thick layer of metal shavings on the magnetic sump plug. Does anyone experience this? I removed the timing and chaincase covers and noticed that the clutch was a bit wobbly see video: https://www.youtube.com/watch?v=6bR5odP63GU ) with slight signs of abrasion on the inner chaincase wall.

The clutch hub nut was pretty loose, so my first thought was to just tighten it really damn tight to eliminate the wobble. The odd thing is that there aren't many metal shavings in the chaincase but quite a bit on the sump plug... Haven't experienced any engine knocking or odd sounds from the engine otherwise.

I'm planning on riding my A10 to France and Belgium in 3 weeks. So I'm wondering whether I should remove the top-end to inspect the pistons/inside the crankcases...or just tighten up the clutch hub nut and go...or perhaps, stick one of those fancy inspect cameras through the sump?
Title: Re: Metal shavings in oil
Post by: ironhead on 21.07. 2019 23:07
Hi Owain.

How long since the last rebore? During the first 500 miles or so there will be a build up of very fine metal dust coming off the cylinder walls & rings.
If the engine has done a lot of miles with regular oil changes & your getting noticeable flakes of steel on the magnet My first guess would be cam & or follower problems. Constantly having to adjust valve clearances will indicate this. Could also be crank shims disintergrating, hows the end float?
With the clutch nut coming loose, I would remove it completely & check both tapers as running it loose for a while can damage both & just tightening the nut may not work. There is always a bit of wobble on these clutches due to the narrow bearing set up used.
Title: Re: Metal shavings in oil
Post by: duTch on 21.07. 2019 23:43

 
Quote
.........With the clutch nut coming loose, I would remove it completely & check both tapers as running it loose for a while can damage both & just tightening the nut may not work. There is always a bit of wobble on these clutches due to the narrow bearing set up used.

 If I recall owain has a Plunger model so the clutch is on a spline= no taper
Title: Re: Metal shavings in oil
Post by: ironhead on 22.07. 2019 00:57
Yep, different scenario then. Maybe need to check the 2 x1/2 clips at the back of the clutch & not REALLY tight on the nut & make sure the tab washer is in good nick & folded over. ( as the drum has been rubbing on the case)
Title: Re: Metal shavings in oil
Post by: owain on 22.07. 2019 08:43
Thanks for quick replies. It has definitely no more than 200 miles since it's last rebore. I'll check the end-float later this evening. I've completely removed the clutch now, can't find anything amiss. Just the loose hub nut.
Title: Re: Metal shavings in oil
Post by: Swarfcut on 22.07. 2019 09:05
Owain.. Engine and chaincase are completely separate, so there is no mixing of the oils. All engines produce varying quantities of metallic debris, and without knowing its previous history it is difficult to tell whether this material is "old stuff" being washed out or a new problem. In the absence of any major catastrophic impending doom noises I would be inclined to wash out the tank and sump as best you can, remove muck and sediment from nooks and crannies in the timing case, refill with fresh oil and remove the sump plate from time to time to see if the situation continues. That way you can plan for remedial work, and get a firm idea whether a problem exists. As it has been recently bored, I would expect some nice new shiny bits in the oil.

 Clutch Chainwheel...They all rock a little bit, the design relies on a single row of rollers, so not much stability even when new.  Remove the clutch for inspection, you should find the gearbox input shaft has no lateral movement. This is controlled by a ball race at the kickstart ratchet end of the mainshaft. A large circular flat thrust washer locates the clutch, this fits over two semi circular steel half rings (abutment ring in the parts book). The gearbox input shaft is splined, not tapered, so all this just pulls off. Loss or failure of this thrust arrangement will allow the chainwheel to contact the inner chaincase and allow the centre retaining nut to loosen. The groove in the mainshaft for the two half rings is shallow, so pay close attention to their correct fitment.

  Damage and wear on the roller "tracks" means new parts, but short term a set of new rollers will offer a small improvement. Grease the rollers on assembly.

  Give the big clutch retaining  nut some Loctite, even though there is a tab washer, inner shaped to fit the input shaft splines. Give it a good tighten with the old "put in top gear, brake on" trick.

 Make a nice tubular peg spanner for the cush drive crank nut, it needs to be well tight, 60-70 Ft/lbs is suggested. Most are butchered by hammer and drift.

 Swarfy.


 Additional. See you have the clutch off now, have a good look at the abutment rings as they  have to support the whole clutch, a bit like hanging on with just fingertips. the groove is less than 1.5mm deep. Turn them over to put an undamaged inner edge towards the gearbox. Stick them to the shaft with a dab of grease, then carefully place the thrust washer over them. Originally this washer came in varying thicknesses to assist in chain alignment. When I first got my bike the half rings were missing, the thrust washer happily running on the three rivet heads that hold the oilseal carrier!
Title: Re: Metal shavings in oil
Post by: Greybeard on 22.07. 2019 11:11
You can buy a special tool for the cush nut on the crank.
Title: Re: Metal shavings in oil
Post by: coater87 on 22.07. 2019 11:40
200 miles sinse rebore and new rings?

 Run it like you stole it Owen, that metalic smeary stuff is what happens when rings and bore are breaking in together.

 Most of it probably happened in the first 100 miles, and it will continue to taper off.

 Hope Teddy is still enjoying the bike too!

 Lee
Title: Re: Metal shavings in oil
Post by: chaterlea25 on 22.07. 2019 19:50
Hi Owain
It would have been nice to hear how or what resolved your last issue with the ignition so that you now feel confident to head off across to Europe  *????*
Feedback to problems solved serves as an information bank for others who may run into the same or similar issues

Check that the oil tank is clean, and change the oil before you head off on your trip
On newly built engines I change the oil at approx 300 miles, then at 800 and again at 1500

John
Title: Re: Metal shavings in oil
Post by: owain on 23.07. 2019 22:20
Still haven't got around to checking the end-float (too busy with work this week!). Yeah, it had new pistons and new rings fitted during it's last rebore. So far it seems the most likely culprit.

Tonne-up Teddy is still loving the wind in his beard. I've replaced the crusty old twin exhausts with a new siamese exhaust to reduce the noise for him. I'm wondering whether adding wraps to the exhaust header would also help reduce noise  *dunno2*
Title: Re: Metal shavings in oil
Post by: metalflake11 on 24.07. 2019 08:36
Hi Owain
It would have been nice to hear how or what resolved your last issue with the ignition so that you now feel confident to head off across to Europe  *????*
Feedback to problems solved serves as an information bank for others who may run into the same or similar issues.

Check that the oil tank is clean, and change the oil before you head off on your trip
On newly built engines I change the oil at approx 300 miles, then at 800 and again at 1500

John

Could agree more John.

Otherwise it's just problems with possible solutions that may or may not have worked, and the same questions being asked over and over.
Title: Re: Metal shavings in oil
Post by: RDfella on 24.07. 2019 11:11
Have to say I'd be rather concerned about 'shavings'. Can't be the rebore settling in, that'll produce a thin grey sludge from the cast iron barrel. And cast iron isn't shiny. Basically just makes the oil a little black. And these shavings are steel, not alloy, to stick to a magnet. If the bike were staying at home, I'd ride it gently keeping a watchful eye on it. I wouldn't consider taking it away as whatever this is can only get worse. Unless, of course, this is swarf left in the engine at build time.
Title: Re: Metal shavings in oil
Post by: raindodger on 24.07. 2019 18:49
Gentlemen.
            'Shavings' suggests shims breaking up, check crank endfloat as a priority.

Regards.
Tim.
Title: Re: Metal shavings in oil
Post by: owain on 25.07. 2019 08:26
Righto, I checked the crank end float this morning and there appears to be a huge endfloat of 0.021" (0.54mm). Way more than the 0.003" maximum I've seen suggested https://www.a7a10.net/forum/index.php?topic=1758.msg11713#msg11713 (https://www.a7a10.net/forum/index.php?topic=1758.msg11713#msg11713). I'll do an engine tear down later today :(

PS: I also tied off the thread about the ignition issues I was having.
Title: Re: Metal shavings in oil
Post by: Swarfcut on 25.07. 2019 08:53
What a shame that you have a bit more hassle. Still, an ideal excuse for cleaning out that little old sludge trap. Budget for a set of sludge trap plugs, the crank shims and possibly a new main bearing. Taking the inner race on and off the crank can result in damage to the rollers. Alternative types of bearing are now available, NJ or NUP which leave the rollers in the crankcase, but are more complex and expensive. Some folks have used a simple and cheaper deep groove ball race as on the very early Longstroke A7, and this is an easy way to eliminate float entirely.  Lots of debate on the Forum as to the relative merits of these bearing choices.

 Swarfy.
Title: Re: Metal shavings in oil
Post by: owain on 25.07. 2019 12:36
Update: I've removed the engine and split the crankcases (at least, managed to remove the drive-side as I haven't managed to take the sprocket off timing side yet...).

I pulled the roller bearing off the drive side and the suspected shim was intact...but look at the state of these brand new pistons! (see attachment). As I mentioned the motorcycle has done less than 200 miles. Surely, this is not pistons should look like whilst running in the motorcycle?? I should also mention that during the first 100 miles, I had a few partial engine seizures whilst riding on the motorway. Although, could the huge amount crank end-float (0.021") have caused this amount of piston wear? 0.021". Irregardless, the bores on the cylinder don't look too bad (can't feel any scoring when running my finger nail down the cylinders) or maybe I'm letting my optimism blind me...Reckon the pistons are salvageable?
Title: Re: Metal shavings in oil
Post by: bikerbob on 25.07. 2019 13:51
Your end float is about 10 times what it should be also with pistons like that I would checking to see if the bores were bored to the correct tolerances seeing as you say you  experienced what you suspect was partial seizures whilst running in.
Title: Re: Metal shavings in oil
Post by: coater87 on 25.07. 2019 16:16
 I am taking it that "motorway" means 70 mph? Like our interstates? *eek*

 I think your break in procedure might be on the quick side.

 
Title: Re: Metal shavings in oil
Post by: Swarfcut on 25.07. 2019 17:53
Forget the endfloat for now, go down to your reconditioner and ask him to give the bores a light hone. The bore is a shade too tight, the pistons need a light "polish" but should be OK to try again before spending on another set. Bear in mind  air cooled engines need a bit more TLC in the break in/running in period. Suggested bore clearance measured from the piston are listed in the BSA Service Sheet 701. For your engine 3 to 5 thou at the bottom of the piston skirt is the published figure.

 Swarfy.
Title: Re: Metal shavings in oil
Post by: Triton Thrasher on 25.07. 2019 18:19
The bore that caused that needs a bloody heavy hone, rather than a light one.
Title: Re: Metal shavings in oil
Post by: owain on 25.07. 2019 19:02
I think you're right that I was a bit rough on it breaking it in, Although I still experienced partial engine seizures whilst riding on the back roads in N.Wales. 

I took the pistons and the cylinders to a machinist this afternoon. They said it was difficult to tell with the amount of scoring on the pistons but found it to be around the ballpark of 0.003". They too said that the pistons were 'usable' but advised me to get a new pair and to come back for them to remeasure and hone the cylinders to the correct size.

Also removed the sludge trap. An absolute mission but it appeared to be pretty clean inside. I'm not hugely keen to be spending another £100 on a set of pistons though. Then again, these ones do have a decent amount of scoring all the way round and I don't fancy knackering my cylinders (even if the next rebore would entail sleeving the cylinders).

It is also possible that my motorcycle was running too lean and getting too hot I suppose? Then again the pervious machinist was kind enough to join the crankcases together without me asking and without considering the end-float tolerances, so I'm too impressed tbh.

Either way, this seems like peanuts compared to those ignition problems that were plaguing me for months!  *beer*
Title: Re: Metal shavings in oil
Post by: Swarfcut on 25.07. 2019 19:27
Owain.... Advised to get a new pair!!!!! Yes, 'cos they are in the business of selling pistons!  OK, a "reasonable/heavy" hone  (Thanks TT) may be more appropriate, but you will not damage the bore further. Try those pistons again, but do your research as to bore clearance....those folks do not realise what is involved and the reason for your problems...... Ignorance  of published data.

 Swarfy.
Title: Re: Metal shavings in oil
Post by: RDfella on 25.07. 2019 20:38
As an experienced engine builder, I wouldn't even consider using those pistons. If none were available it might - as a bit of a bodge - be possible to linish them, but then you're going to have excessive clearance = piston slap & oil consumption. They have seized. They're toast I'm afraid.
Title: Re: Metal shavings in oil
Post by: Swarfcut on 25.07. 2019 20:56
RD..In an ideal world I would agree with you. But for a back on the road fix, it is well worth giving them another try. A little bit of slap and rattle may be perfectly acceptable rather than true perfection, bearing in mind the use the bike will have. OK, if it rattles and clanks too much, then a further investment is necessary, but for the sake of a few gaskets it is worth a try.

Owain... Just make sure the rings are free, and that the lands and skirts are nicely polished. Well worth another try with the bores honed to suit.

Swarfy.
Title: Re: Metal shavings in oil
Post by: Triton Thrasher on 25.07. 2019 21:57
3 thou would seize solid skirt pistons, I’m pretty sure.

I don’t know much about slotted pistons, but yours did seize.
Title: Re: Metal shavings in oil
Post by: JulianS on 25.07. 2019 22:53
I would not risk pistons like that in my engine. I am also sceptical about the rings, I would have expected to see more bedding in, even after only 200 miles, you can see the blow by.

Are the pistons new hepolite ones? If yes some dealers refuse to sell them with the original rings, due to poor quality, and replace them with Italian GPM rings.

Title: Re: Metal shavings in oil
Post by: ironhead on 25.07. 2019 23:07
Update: I've removed the engine and split the crankcases (at least, managed to remove the drive-side as I haven't managed to take the sprocket off timing side yet...).

I pulled the roller bearing off the drive side and the suspected shim was intact...but look at the state of these brand new pistons! (see attachment). As I mentioned the motorcycle has done less than 200 miles. Surely, this is not pistons should look like whilst running in the motorcycle?? I should also mention that during the first 100 miles, I had a few partial engine seizures whilst riding on the motorway. Although, could the huge amount crank end-float (0.021") have caused this amount of piston wear? 0.021". Irregardless, the bores on the cylinder don't look too bad (can't feel any scoring when running my finger nail down the cylinders) or maybe I'm letting my optimism blind me...Reckon the pistons are salvageable?


Owain, Looking at this picture of the piston it seems to have heavy scoring on the side. Have you another photo you could put up showing the front & rear skirts? ( could be more than just bore / piston clearance at play here)
Title: Re: Metal shavings in oil
Post by: ironhead on 25.07. 2019 23:29
I am taking it that "motorway" means 70 mph? Like our interstates? *eek*

 I think your break in procedure might be on the quick side.

Even more so with an outrigger attached  *eek* *eek*
Title: Re: Metal shavings in oil
Post by: BSA_54A10 on 26.07. 2019 07:33
I have been running in new rings "like I stole the bike" for near 20 years now and a seizure like that is not from careless running in.
The plugs & piston top will reveal if it was too lean and the underside will reveal if it was suffering from low oil.
As this is a new engine, nothing to loose from refitting the old pistons once they have been cleaned up.
The worst case is they might need to be replaced in a short amount of time.

Definately looks like bored way too close, the sort of thing that happens when a mechanic who has never worked on an air cooled engine knows better than you.
Title: Re: Metal shavings in oil
Post by: owain on 26.07. 2019 11:44
I'll post some more pictures of the pistons after lunch. I tried cleaning one of them up but the scoring is still noticable all the way round. I'm using the A10 (when it is working) as a mid-long distance bike, so I'm starting to lean towards the side of biting the bullet and buying a set of new pistons now and get it done properly.

Yeah they were the new hepolite pistons and piston rings fitted. There is a shop nearby with some NOS A10 +060" pistons that might be worth paying the extra £30 for instead of a new set of hepolites... Then again, I never had this problem with my old bikes i.e. Triumph TR7 and BSA B33.
Title: Re: Metal shavings in oil
Post by: berger on 26.07. 2019 13:27
Owain this is the offending item that never seized but the result of glaze busting the bore with an excited honing person. the other bore deglazing was ok and so was the piston but this one tormented me with clanging about for over a year.
Title: Re: Metal shavings in oil
Post by: chaterlea25 on 27.07. 2019 00:13
Hi Owain,
I would go for new pistons
With a sidecar attached I would go for 0.005in. clearance
Theres nothing wrong with the modern pistons even though some had dodgy rings but I think this problem has been sorted
Make sure the carb is sorted before you go for any long runs, and start off with short trips and keep checking the plug colour
Make doubly sure the ignition timing is as near perfect as possible and the same on both cylinders

John
Title: Re: Metal shavings in oil
Post by: RDfella on 27.07. 2019 20:39
Nowadays things aren’t as simple as they were. We know what the bore size should be, and manufactures make pistons to achieve the correct clearance. BSA etc will also specify what the clearance should be. But what we don’t know is whether modern pistons are metallurgically similar. Do they have the same coefficient of expansion as originals? If they expand more, we’ll need greater clearance, but how much is anyone’s guess. Whilst I wouldn’t recommend it for road use, but I always used to bore motorcycles that were to be raced .003” over recommended size. Same for a certain make of turbo marine diesel that came through my workshop frequently in the 70’s. The latter were almost guaranteed to seize at standard spec. and at ten grand a piece .003 was cheap insurance. Actually .005” over standard was needed for the hotter version of that engine (causing lots of blow-by when cold). Those uprated engines really needed oil-cooled pistons.
Getting back to the BSA – the oil pump will need to be stripped and checked – I’d be amazed if the teeth didn’t show signs of pumping debris. And make sure the ignition isn’t retarded, as that causes overheating.
Title: Re: Metal shavings in oil
Post by: ironhead on 27.07. 2019 23:17
I'll post some more pictures of the pistons after lunch.

HI Owain.
 Have you fished lunch yet? *razz* Could you post some pictures of the uncleaned piston from all sides.
Score marks in different places tell stories.
Title: Re: Metal shavings in oil
Post by: owain on 30.07. 2019 09:06
Thanks for the tips RDfella, I'll be sure to strip down the pump for an inspection and clean. Fortunately I have a spare pump laying around somewhere as well, which might be usable for parts if the pump is showing signs of wear.

Sorry about the delay with the pictures, I've attached some more pics of the pistons now. I've cleaned one up and left the other one as I found it (new pistons are on their way!).

I've also cleaned the sludge trap but I was a bit heavy handed when wrapping the new sludge trap plug (plus I wrapped directly on the threads, rather than either on the crank or plug itself). I wish I did a cleaner job and it'll be a bugger to remove during the next strip down, then again I wanted to be sure that the plug was totally secure :/
Title: Re: Metal shavings in oil
Post by: Greybeard on 30.07. 2019 09:32
I've also cleaned the sludge trap but I was a bit heavy handed when wrapping the new sludge trap plug (plus I wrapped directly on the threads, rather than either on the crank or plug itself). I wish I did a cleaner job and it'll be a bugger to remove during the next strip down, then again I wanted to be sure that the plug was totally secure :/
Bit confused about the word 'wrapped'. I don't think you have wrapped the thread with plumbers tape. Are you are talking about using a centre punch to lock the thread?
Title: Re: Metal shavings in oil
Post by: owain on 30.07. 2019 11:17
Maybe it's a term I've made up. I always thought people would say to 'wrap' the thread? haha using a center punch to lock the thread is what I mean though.
Title: Re: Metal shavings in oil
Post by: ironhead on 30.07. 2019 11:37
Thanks for the tips RDfella, I'll be sure to strip down the pump for an inspection and clean. Fortunately I have a spare pump laying around somewhere as well, which might be usable for parts if the pump is showing signs of wear.

Sorry about the delay with the pictures, I've attached some more pics of the pistons now. I've cleaned one up and left the other one as I found it (new pistons are on their way!).

I've also cleaned the sludge trap but I was a bit heavy handed when wrapping the new sludge trap plug (plus I wrapped directly on the threads, rather than either on the crank or plug itself). I wish I did a cleaner job and it'll be a bugger to remove during the next strip down, then again I wanted to be sure that the plug was totally secure :/


Hi Owain,
Looks like tight bores as the others have suggested.  Heavy scoring on the side of the piston & not much or none on the skirts usually means a bent rod or bore mis alignment but yours look like heavy scoring all over. *eek*
Title: Re: Metal shavings in oil
Post by: RDfella on 30.07. 2019 12:05
Heavy scoring? That's moderate to light. See pic below for heavy scoring. Note too over 1/2 inch has melted off the piston crown (which then went out the exhaust to weld up the turbocharger)..
Title: Re: Metal shavings in oil
Post by: Swarfcut on 30.07. 2019 12:34
RD  Nice one for the great mechanical disaster album.

 Owain. Are your new pistons another oversize?  The machinist you used may have bored and honed to published figures, and assumed the pistons were smack on for dimension. They may have been not quite right and it is always best to double check by measuring the piston, allowing a clearance and boring to that. In effect the freshly bored cylinder is like a big nut, only at the correct bore at the bottom of the " thread ".  Honing attempts to make the sharp peaks of the thread into a plateau, and is done with various methods, not all ideal, such as...fixed stones in a rotating carrier, adjustable for fine increases in cut, stones on a three legged carrier, pressed onto the bore by centrifugal force, and abrasive balls  bonded onto what looks like a sweep's  flue brush. Some of these are more suited to breaking the glaze, rather than accurately honing to a finished size.

  Ask to see the hone....you need them to use one that has some form of incremental adjustment if you are going to use your new pistons in that old bore. The existing bore needs accurately sizing to the new pistons give an adequate running clearance.

 Don't just dump the old pistons...They have some value.

 Swarfy.

 
Title: Re: Metal shavings in oil
Post by: muskrat on 30.07. 2019 21:25
 Don't just dump the old pistons...They have some value.

 Swarfy.


Yes I cut'em in half and make trophy's for the bike show.
Cheers
Title: Re: Metal shavings in oil
Post by: morris on 30.07. 2019 21:36
Don't just dump the old pistons...They have some value.
 Swarfy.


Yes I cut'em in half and make trophy's for the bike show.
Cheers
Cut them in half horizontally at the height of the gudgeon pin hole . Upside down they make a nice little ashtray...  *smile*
Title: Re: Metal shavings in oil
Post by: RDfella on 30.07. 2019 21:40
Not if they're 10:1 morris ..........
Title: Re: Metal shavings in oil
Post by: duTch on 30.07. 2019 22:34

 
Quote
Maybe it's a term I've made up. I always thought people would say to 'wrap' the thread? .......

 Maybe they meant 'rap' ?  *conf2*
Title: Re: Metal shavings in oil
Post by: Minto on 31.07. 2019 02:20
Don't just dump the old pistons...They have some value.

 Swarfy.


Yes I cut'em in half and make trophy's for the bike show.
Cheers

Muskrat
What do I need to do to win one of those, they’re lush!
Title: Re: Metal shavings in oil
Post by: Triton Thrasher on 31.07. 2019 06:38
Quote

Yes I cut'em in half and make trophy's for the bike show.
Cheers

Quote
What do I need to do to win one of those, they’re lush!

Break down on the parade lap of the showground.
Title: Re: Metal shavings in oil
Post by: muskrat on 31.07. 2019 08:00
G'day Owain.
Good to hear your going for new pistons. What oversize are they? The old ones would take a lot of work to make trophy's let alone make good for re-use in your motor.
Minto. First you'd need to ship the bike over for the Berry Bike Show https://tinyurl.com/y3jd7spq I'll take good care of it, promise.
Cheers
Title: Re: Metal shavings in oil
Post by: owain on 31.07. 2019 16:32
Cheers again for the advice everyone. I left the cylinder and new pistons (+0.060") with the machinist today (SEP in Derbyshire...Not the one who did the orignal tight bore). It'll be honed to 0.0045"ish piston clearence, hopefully will pick it up and reassemble this weekend. Hopefully the next time these pistons will off will be when the cylinder will be lined and taken back to std bore!

I think I'll leave the old pistons in a box in the garage instead of on my wall. I don't want to be reminded of my appaulling running in procedure  *lol*
Title: Re: Metal shavings in oil
Post by: RDfella on 31.07. 2019 17:58
Don't be hard on yourself - seems to me to be more a conflation of other issues than purely a running in matter.
Title: Re: Metal shavings in oil
Post by: duTch on 31.07. 2019 22:26

 
Quote
......It'll be honed to 0.0045"ish piston clearence, .......

 I read too many decimal places  *eek*    but to be sure, that's 4.5 thou hey....?
Title: Re: Metal shavings in oil
Post by: ironhead on 31.07. 2019 23:07

 
Quote
......It'll be honed to 0.0045"ish piston clearence, .......

 I read too many decimal places  *eek*    but to be sure, that's 4.5 thou hey....?

That is 4.5 thou Dutch *smile* decimal is in the right place.