The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: spiralz on 13.08. 2012 21:30

Title: How bad is this!?! **UPDATE**
Post by: spiralz on 13.08. 2012 21:30
 *angry* *sad2*

i've been really enjoying my (new to me) A10 which had about 1000 miles ago had an engine rebuild with various mods as listed in other post introducing myself....

i decided that after i had done about 500 miles to be on the safe side i would do an oil change..... *sad2*

i gave her a quick run to warm the oil then drained the tank, and removed the SRM sump plate and basically saw this....

(https://lh5.googleusercontent.com/-asW1i7lHut4/UClg5fAu1SI/AAAAAAAAAGU/DkwiG7edE3I/h120/2012-08-13+17.39.53.jpg)

the bike has been running fine

i have not been thrashing it just steady 45 - 65 country lane cruising....

does anyone know what this is??

it seems to be lumps of silicone some fine metal fillings and the remnants of a very fine shim/washer

i gave every thing a good clean replaced the oil (castrol 20/50) run the engine (seemed fine) oil returning to the tank fine...

VERY slight black smoke from right pipe but hardly noticable....

im stumped and worried....

thanks in advance for any input


Title: Re: How bad is this!?!
Post by: RichardL on 13.08. 2012 22:09
I think she's got to come apart mate. Either the previous mechanic placed the crank shims on the wrong side of the bearing or on the wrong side of the crank. They belong between the main bearing inner race and the crankshaft web on the drive side. Another possibility is that the main bearing inner race was spinning on the crankshaft. Neither good. Both mean it has to come apart to replace the shims, ensure the stability of the bearing, remove all the other shim bits and, while you're there, check out everything else.

Sorry for the bad news, but I think you must have known.

Richard L.
Title: Re: How bad is this!?!
Post by: chaterlea25 on 13.08. 2012 22:32
HI spiralz

Richad is on the money with the diagnosis  *sad2*
One thing to check as you (or your BSA tech LOL) dismantle the bike is to see whether the cush drive nut on the clutch end of the crankshaft had been fully tightened??
This needs to be tightened to 65ft lbs
I have found a lot of these loose !!!! this can allow movement between the drive side bearing and the crank
and the shim breaks up
Its fairly normal to find small fine metallic bits in the sump filter on a rebuilt engine

"LUMPS OF SILICON"  *eek* *eek* this stuff kills more engines than it fixes  *rant*  *angry*

Regards
John
Title: Re: How bad is this!?!
Post by: Rocket Racer on 14.08. 2012 06:57
Just goes to show how important checking and cleaning filters is.
While not nice to find a shim, its still not the end of the world, just a chance to become more acquainted with the inside of your engine ;)

At least it hasnt put a leg out of bed *eek*

Might be worth checking the end float before you tear it down. But it does need tearing down!
Title: Re: How bad is this!?!
Post by: spiralz on 19.08. 2012 19:05
Thanks for the replies, quick update;

called the place i bought it from told them although i bought a historic bike with little grounds for warranty that i felt it only reasonable to ask for their help in the matter as it was sold as fully rebuilt engine.

They have agreed they will strip repair and rebuild if i take the engine to them.

so i have removed the engine, this where the plot thickens a little.

the primary chain was very tight and the gearbox was fully forward with no room for adjustment so i checked the pitch and it has a 68 pitch chain in there but my bike 56' swingarm should have a 69 pitch chain!!!  *eek*

so this must/could be what's caused the whole issue? i mean i'm guessing a bit here but with the undue stress on the main shaft and bearing it may have caused the shim to be pinched and eaten up?  *problem*

i'm hoping that it hasn't done too much more damage but im sure i'll find out when it gets rebuilt at the garage...... not happy but at least there's light up the tunnel so to speak.

has anyone heard of this issue before.

cheers, Jim
Title: Re: How bad is this!?! **UPDATE**
Post by: fido on 20.08. 2012 06:20
No, I don't think the tight primary could affect the shims if they were put in correctly during the rebuild. I personally would not trust this firm to redo the engine if they were willing to send out a bike with the primary chain like that.
Title: Re: How bad is this!?! **UPDATE**
Post by: JulianM on 20.08. 2012 08:06
Hi Fido,

While I agree to your sentiments with regard to the wrong chain being fitted, it does only seem fair to let them honor their gesture that they have offered. It does seem like they want to do the right thing so maybe allow them a little slack?  Fingers crossed.

On a good note, it is very honorable of the company to offer this work and fair play to them for this!


Good luck both.
Julian
Title: Re: How bad is this!?! **UPDATE**
Post by: duTch on 20.08. 2012 09:44
Be a bonus for you too if they allow you to come and see what's going on in there, but maybe a bit optimistic?
 You say it was the correct chain, but just not enough rollers(68 of 69)?

 Cheers good luck with it, duTch
Title: Re: How bad is this!?! **UPDATE**
Post by: shuswapkev on 20.08. 2012 10:01
how can you get an uneven number of rollers???a half link??
Title: Re: How bad is this!?! **UPDATE**
Post by: duTch on 20.08. 2012 10:11
Yeah Kev, I was trying to pretend it wasn't happening! - how was brekky in Canungra,(without changing topic)?
Title: Re: How bad is this!?! **UPDATE**
Post by: spiralz on 20.08. 2012 12:24
 *ex*

I wasn't sure either but here is a 68 which I have;

http://www.tribsanoruk.com/product/2619/3/ (http://www.tribsanoruk.com/product/2619/3/)

and here is the one listed for my model (56-a10) which shows as a 69??

http://www.tribsanoruk.com/product/2618/3/ (http://www.tribsanoruk.com/product/2618/3/)

 *dunno*
Title: Re: How bad is this!?!
Post by: spiralz on 20.08. 2012 12:31
HI spiralz
 
One thing to check as you (or your BSA tech LOL) dismantle the bike is to see whether the cush drive nut on the clutch end of the crankshaft had been fully tightened??
This needs to be tightened to 65ft lbs
I have found a lot of these loose !!!! this can allow movement between the drive side bearing and the crank
and the shim breaks up


Regards
John

Thanks john,

the nut was as tight as to be honest, but the garage I took it back to said some things not right as there seemed to be no end float at all???
it's being pulled apart on friday so i will know more then....
Title: Re: How bad is this!?! **UPDATE**
Post by: duTch on 20.08. 2012 13:14
Don't get me wrong spiraz, I'm not disputing, just was when I first read it I thought that was a type of chain, but quickly realised what you meant, just asked the question to clarify, and keep it simple. Ive done half links in the past when the need arose.
 cheers duTch
Title: Re: How bad is this!?! **UPDATE**
Post by: fido on 20.08. 2012 18:03
Be a bonus for you too if they allow you to come and see what's going on in there, but maybe a bit optimistic?
 You say it was the correct chain, but just not enough rollers(68 of 69)?

 Cheers good luck with it, duTch

Yes, they might just give it a rub over with an oily rag and ring a few days later to declare it "ready". I remember when I lived in Coventry and bought a brand new bike from a dealer in Manchester. I had to ride it all the way back to Manchester for the first service in order to keep the warranty valid. One of the items on the first service was supposed to be a new oil filter but when I collected the bike I could tell they had not touched it as the road dirt was undisturbed.
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 20.08. 2012 19:46
Yes,  being able to observe the innards will tell you a lot.  Amongst other things,  I would want a new main bearing and to know to a certainty that the inner race is a good snug fit on the crank.  Then,  I would want the sludge trap cleaned on principle,  even if they said they did it last time.

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: Sparky on 21.08. 2012 20:28
*ex*

I wasn't sure either but here is a 68 which I have;

http://www.tribsanoruk.com/product/2619/3/ (http://www.tribsanoruk.com/product/2619/3/)

and here is the one listed for my model (56-a10) which shows as a 69??

http://www.tribsanoruk.com/product/2618/3/ (http://www.tribsanoruk.com/product/2618/3/)

 *dunno*


The 68 pitch chain shown in the link (ha ha, a pun!) indicates it is for the bike with sidecar.  My 54 to 57 parts book lists the engine sprocket for sidecar equipped engines at 18 teeth, whereas standard is 21 teeth.  Perhaps the mechanic (or previous owner) didn't note the distinction.  I recently had the second removable link used to insert the half link replaced with a riveted link.  With 69 pitches and a 21 tooth engine sprocket, my gearbox sits right in the middle of the adjustment slot.
Title: Re: How bad is this!?! **UPDATE**
Post by: Rocket Racer on 21.08. 2012 23:07
sounds like the answer is to fit a sidecar!
but fix the shim first ;)
Title: Re: How bad is this!?! **UPDATE**
Post by: spiralz on 11.09. 2012 20:40
Engine came back last week  *smile*

It had the following done plus i have a bag of old parts to show for it as well.

It was re shimmed (obviously)
They fitted an SRM cush drive nut.
All new gaskets
New Piston rings (one had broken in half)
One new valve (they noticed a hairline crack in it)
New main bearing

Question when i put it back in i set the valve clearances as per spec (according to haynes and haycraft books) is this right  (10/16)?

It started first kick...

now being very carefull running it in (i think)

i intend to change the oil at 100 then 500 then prceed as normal, How long do i need to run in for and is there anything else i should be aware of regards running in?

i have noticed after 50 odd miles the plugs are very sooty.

I would like to change the plugs but am unsure of the modern type of champions i need can any one advise please?

thanks
Title: Re: How bad is this!?! **UPDATE**
Post by: Rocket Racer on 11.09. 2012 22:17
Re the tappets, go to your haynes manual on page 46, there is a table of clearances. The big thing to note is the late '60-'62 A10's ran a different cam so if you have a '356 or 357 cam fitted need .008/.010 clearances. If you have more your engine will simply rattle more.

Can't help you with plugs, my A10 is an alloy head and on methanol, so not comparable.

Breaking in an engine is always another open ended question. It does depend what exactly your breaking in. For new plain bush crank and big ends (which like a gentle break in), the answer is different to rings which actually like to do some work during break in.
In my opinion the general answer is to quietly build up load on the motor over about 1000 miles, and then treat normally, but during break in to make sure the engine is given some revs, without necessarily running under heavy load. Does depend on your riding style and the clearances in the motor...varying revs is good, so B roads rather than A roads
Don't labour the motor,
if it feels like its tightening up... trust that feeling, it probably is.
Giving the motor some throttle is not a bad thing.

Sounds like it needed that pull down!
Tim
Title: Re: How bad is this!?! **UPDATE**
Post by: fido on 13.09. 2012 06:38
The broken ring is a bit worrying, I wonder what caused that?
Title: Re: How bad is this!?! **UPDATE**
Post by: morris on 16.09. 2012 21:24
Hi Spiralz,

I have been following your story with interest. After all, something like this is anybody's worst nightmare I suppose.

Regarding your question about spark plugs, I am running my iron head A 10 on NGK's B 6 HS. The Champion equivalent is L 82 C.
If your plugs are getting sooty, you may consider a hotter type. For NGK you go a number down (5 instead of 6)
When I bought my A 10 it came with the 5 type NGK, I think the previous owner tried them in order to get his plugs less sooty, but I found the mixture was set to rich, so after adjusting the carburettor needle, I went back to 6, and it's running fine now

There's some very useful information on this website;
http://www.championsparkplugs.com/sparkplug411.asp?kw=Heat+Range+Interchange+%28NGK-Denso-Champion-Bosch%29&mfid=2

Or try this one;
http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml

Good luck,
Patrick
Title: Re: How bad is this!?! **UPDATE**
Post by: JulianM on 18.09. 2012 07:30
Re the tappets, go to your haynes manual on page 46, there is a table of clearances. The big thing to note is the late '60-'62 A10's ran a different cam so if you have a '356 or 357 cam fitted need .008/.010 clearances. If you have more your engine will simply rattle more.

Can't help you with plugs, my A10 is an alloy head and on methanol, so not comparable.

Breaking in an engine is always another open ended question. It does depend what exactly your breaking in. For new plain bush crank and big ends (which like a gentle break in), the answer is different to rings which actually like to do some work during break in.
In my opinion the general answer is to quietly build up load on the motor over about 1000 miles, and then treat normally, but during break in to make sure the engine is given some revs, without necessarily running under heavy load. Does depend on your riding style and the clearances in the motor...varying revs is good, so B roads rather than A roads
Don't labour the motor,
if it feels like its tightening up... trust that feeling, it probably is.
Giving the motor some throttle is not a bad thing.

Sounds like it needed that pull down!
Tim


Good bit of advice there!

Running in.  We run in every single engine we build either on the dyno or on the rolling road for about 30 hours running time. Progressively increasing the load over a wide RPM spectrum,
Start at very low load but varied revs from about 1000 up to about 2/3 your max revs  but "light load"
Then move up in load gradually as time goes on, until on the 25th hour you are using 2/3 throttle and 3/4 max revs,
After that you can do what you like.

Very important though is to do as Rocket racer says and avoid "laboring" i.e., low revs heavy throttle.  This will seize a new engine very quickly indeed!!

Regards,
Julian
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 02.09. 2013 06:27
CRAP! My turn to discover twisted shims sitting on the sump screen. Made it about 3700 miles on this rebuild. It has to be a loose inner race. No question as to the location of the shims. This all started out so innocently - just convert to SRM dynamo belt drive, then, replace loose dynamo bearings, then, change oil including a tank and sump-plate cleanout, voila, plan time for a strip-down and reassembly.

Apologies in advance for the inevitable tales of discovery to come of this.

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: groily on 02.09. 2013 08:30
That's a bummer Richard, sorry to hear.
Had pretty much the same thing towards the end of last year as I might have mentioned  . . . but with any luck you'll have no other damage to speak of. My b/ends and T/S bush were still spot-on after a lot of miles, so I just replaced the shells and the slightly worn cam followers and oil pump worm and gear while it was stripped.
I tried to eliminate shimming by getting the crank outer web built-up to a perfect measured fit for the new inner race etc (while having the drive side mainshaft built up and ground to spec at the same time). Didn't work for very boring reasons so had to pull it apart again, get crank web outer face cleaned up (again) and then proceed as standard with shims  . . . .
So far so good, but whatever anyone says, not a great design feature on these things!
Were a ball bearing deemed solid enough (like on the early engines and ? some A65s - I know nothing!) it would have been a lot easier - and indeed I think one or more people here have sourced a modern high-spec ball bearing instead of the roller. Food for thought, but I stayed standard, using the roller supplied as standard by, IIRC, CD Autos.
Good luck anyway. Bill
Title: Re: How bad is this!?! **UPDATE**
Post by: muskrat on 02.09. 2013 10:27
Tale of woe's time by the way the thread is going.
Nipped up the cafe at 100mph last week. On inspection it looks like a combination of too much piston clearance and a slight tweak in the rod. Yep, L/H side.
Also timing side journal has worn 1-1/2 thou in 1000 miles so now has too much clearance as well, and end float has increased to 5 thou. Think I'll do a roller conversion.
Cheers.
Title: Re: How bad is this!?! **UPDATE**
Post by: trevinoz on 02.09. 2013 22:19
0.0015" in 1000 miles is a bit excessive, Musky.
What is your main bearing made from?
I had an aluminium bronze bearing once and it wore like that.

Trev.
Title: Re: How bad is this!?! **UPDATE**
Post by: muskrat on 03.09. 2013 14:52
G'day Trev. It's one of those steel shell bronze sleeve types. I prefer the solid type.
Cheers
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 03.09. 2013 15:49
Thanks for the comiseration.

Groily,

In trying to decide what to do about the drive-side inner race fitting properly, I went back and read the story of your metal build-up attempts last year. So, for the drive-side shaft, was that built-up and ground for a tighter fit for the inner race? If so, did that stay intact, even when the web build-up went south?

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: groily on 03.09. 2013 16:21
Yup, the shaft was quite fine Richard and presumably still is. It was 'build it up or risk loctite' (which might have been perfectly adequate, I don't know).

The 'only' prob was the outer face on the web, which my favourite people didn't make perfectly flat for sufficient width radially from the mainshaft. Some of the material got picked up by the cage - and a few shards flaked off. Quite an 'only' though, although I still think the idea's a good one in principle!

It's done a few more thousand miles with a single tailor-made shim and seems to be fine again (for a scruffy hack that is).

Best to you as you sort yours out, Bill
Title: Re: How bad is this!?! **UPDATE**
Post by: Topdad on 03.09. 2013 17:01
Hi Richard, sorry to hear about you engines descision to be a pain. However having read the various posts on this wouldn't it be better to go down the route of a conversion. There must be someone over your side of the pond who A) you could trust to do a good job and b) wouldn't cost you the earth ? It must save money and annoyance for the long term future . I only say this as when I rebuilt mine  I treated her to the conversion via SRM .I know I'm tempting fate but 8 yrs on still running without a hitch from that department . Just my own personal experience although it was merely luck that this was solved for me as I'd forgotten all about the shims when I plumbed for the conversion and merely a suggestion with certainly no intention on my part to play "the know it all" to such a capable guy as you ,regards BobH
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 03.09. 2013 17:50
Bob,

I suppose the roller conversion is done by more than one shop here in the US, but the one I know for sure does it will get no more of my work. If I were to do have it done, I think I would only be truly comfortable using SRM (no offense to fabulously talented machinists on this forum who do such things and put me to shame with their knowledge). Most of the decision as to what to do will depend on what I find inside the engine. If my timing side bush and journal are in good condition after some 3700 miles, and the inner drive-side race can be stabilized, I think I'll probabaly go with reshimming. If not, well, that's another issue.

Groily,

Did you have your fat tailor-made shim ground to thickness? Getting rid of shims that a are couple of hairs thick would be a good idea.

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: groily on 03.09. 2013 21:26
I had the shim made up by T&L Engineering as a single item, when they were sorting out the first 'ahem', to avoid that wafer-thin shims thing Richard.
Chances are after so few miles your other bits will be in good shape I'd have thought. The needle-roller conversion is assuredly a good thing, but to be honest, I've done a lot of miles on my engine, not treated it especially kindly (or unkindly), and the timing side has held up well. What I don't do much of is 'down to the pub' type riding, most runs are an hour or more non-stop which does reduce wear per mile, and always under light load until things are nice and warm. And nor do I run at Musky speeds!! - 60-ish suits me just fine on non-4-lane roads, it"'s only a Flash-spec engine after all. If I'm in a hurry i'll go a bit more quickly, but again, under 70.
The only time I was really pressed - about 3 months back - I had an exhaust valve seize at 75-ish on a dual carriageway, which was very noisy, inconvenient and required a van to rescue me. My own fault, I'd made a new lh exhaust valve guide when I had the motor apart to do the crank thing, and must have been too mean with the clearances for when things got good and hot. That'll teach me. Luckily, despite the pushrod leaping out and the piston ramming the valve shut again (well shut!), causing huge flames back through the carb and near enough setting it and me and the battery alight, it all survived and has done an uneventful couple of thousand miles since then. Tough beast, I reckon, and as reliable as ever, warts and all.
Here's hoping you haven't got any other nasties to deal with apart from the mainshaft and the race. Bill
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 03.09. 2013 23:00
Groily,

I hope you meant that for laughing, otherwise, my sincere apologies. (Edit: This probably doesn't help,  but I was laughing about the near fire,  not your grief with the mechanicals.)

It didn't occur to me until you mentioned "Musky speeds", but I was pushing a little harder than usual the last time I was out, but nothing over about 72 mph. Regardless, I don't really know when the tender shims decided to depart the shaft.

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: coater87 on 04.09. 2013 02:42
 Richard,

 Yesterday while hanging out at the magazine rack while my wife shopped, I came across an ad for another company here that does the conversion. I am taking it they are like an SRM sponsored company- but I cannot be sure. They do the conversion for $1199.00 U.S., and that includes a brand new SRM oil pump.

 The place is called limeylucasmotorcycles.

 Maybe you could ad a link? I am using a Linux computer, and am still on the steep side of the learning curve.

 Lee
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 04.09. 2013 11:50
Lee,

Yes, I seem to remember having seen these guys and this offer before. Maybe it was on the Cafe Racer TV program that I first saw them (not really sure). Thanks for the reminder. The good news is this is not the company I have ruled out. The bad news is, now I have to seriously consider spending the money.

Richard L.

http://www.limeylucasmotorcycles.com/
Title: Re: How bad is this!?! **UPDATE**
Post by: morris on 04.09. 2013 13:44
The bad news is, now I have to seriously consider spending the money.
Richard L.

Don't worry Richard, it's like my wife always says. Money is made for spending  *sad2*
Title: Re: How bad is this!?! **UPDATE**
Post by: muskrat on 04.09. 2013 15:20
G'day Richard. If the nut is torqued up correctly the shims should not escape even with a loose inner race. If the shaft is only a thou or so small I'd use loctite on it and the nut.
Cheers
Title: Re: How bad is this!?! **UPDATE**
Post by: a101960 on 04.09. 2013 17:21
Quote
CRAP! My turn to discover twisted shims sitting on the sump screen.

The most worrisome aspect of this, is the fact that had you not decided to remove the sump plate you, would have been completely oblivious to the fact that anything was wrong with you engine. This particular problem seems to be quite common. If an engine has been properly put together how, and why does this occur? I get quite paranoid about this sort of thing, and I remove and clean my sump plate and screen every time that I change the oil and the filter. I use Fuchs (Silkolene) Comp 4 20/50 fully synthetic oil in my engine and I change the oil every 1000 miles. It is quite expensive at £39.66 for 4 litres. However, I like to use the best oil that I can get. Will it make the engine last longer? Who knows, but I like to think that I have done as much as I possibly can to keep the engine well lubricated, and to help it stay as clean as possible internally. Contrast this with the days of my miss spent youth. I suppose that ignorance is what engenders confidence. My first bike back in the sixties was a BSA C11. I never changed the oil. I did not know any better. I did keep an eye on the oil level though, and topped it up now and again if  necessary. I had that bike for 3 years and thrashed it mercilessly, and despite all that it proved to be totally reliable. Come to think of it, I never carried so much as chain link with me, and it goes without saying I did not have any break down cover. None of my friends had any trouble with their old bikes in those far off days either. The bikes all got the same treatment. The only Achilles heel that I can remember was battery failure. Back then batteries did not seem to last very long at all. Isn’t it strange how these days all our pride and joys lead such a cosseted life, and yet there always seems to be problems with them. Back in the old days a complete lacking in any mechanical empathy, and also for that matter, not knowing any better, I for one rode around as fast as I could everywhere that I went totally oblivious to any ideas about maintenance. It has been said many times by many people, that modern bikes are totally reliable, and that our old Brits are very high maintenance. By today’s standards I cannot argue with that sentiment, but roll back the years to around 1963 and things were completely different or so it seemed. Such was the impetuosity and optimism of youth. I can never remember listening for odd knocks and rumbles. I just used start the bike up, and rode off with not a care in the world. And I always got away with it! I know that none of this is very helpful to you Richard. Just a bit of Irony really.

John
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 04.09. 2013 22:19
John,

That was a good read.

Given the loss of one very thin shim, it might have been a long time before I noticed anything obvious. I did consider riding through the end of the season, then I decided to follow my own good advice: "I'm afraid it must come apart, mate."

Up until last weekend I was a convinced user of Castrol GTX 20W/50, then, at the antique motocycle show and swap meet in Davenport, Iowa (100 degrees F. in the shade, felt like 108) I got schooled/spanked for how little I knew about the importance of zinc (ZDDP) in motor oil. Seems that its protective benefits with respect to our type of tappets are rather important. Because I didn't know about it, I didn't know that manufacturers have been reducing it over time to add longevity to catalytic converters. In the US, the standard now allows for 600-850 ppm. According to my friendly lecturer, 1400 ppm used to be typical and now cams and flat tappets are subject to scalling. I looked at the website for your Silkolene Comp 4 and it is pretty high at 1100 ppm. Also, Silkolene commented in a Q&A exchange:

 As for this ZDDP business, you may like to wade through the attachments if you've got a couple of days to spare! It suffices to say that oils with adequate, but not unnecessarily high ZDDP levels are fine, especially if the load-carrying is boosted with synthetic ester and the oil film thicknesses are maintained by shear-stable polymers. It's not just a simple 'high zinc good, low zinc bad' thing! Zinc level in the Pro and Comp grades is 1100ppm.

Unlike Castrol, Silkolene is forthcoming with their numbers. I also found an independent article saying Castrol was safe for flat tappets. Not sure yet if it's true. I'll know better tonight after I lift off the barrels.

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 05.09. 2013 02:06
Barrels off and lifters and tappets are quite good with no spalling. Good news for Castrol GTX, but still changing to Valvoline VR1 for the ZDDP. On the other hand, showing some piston overheating (or overexpanding?). Worse on the left side, as right side only has it on the rear surface. Bores look very good, with this piston issue barely having an effect that shows on the barrels. My inclination is a very light sanding for the pistons and a very light honing for the bores and Bob's your uncle! Maybe. (Not you, TopDad.)

Richard L.

EDIT: Should I add "under-oiling"?
Title: Re: How bad is this!?! **UPDATE**
Post by: Rocket Racer on 05.09. 2013 02:35
If you're going to dress those pistons (hard to see how bad from the pic's) use a file rather than sandpaper which will leave nasty abrasive grit embedded in the pistons, whereas a file will remove unwanted piston if done carefully.
If its been nipping up, I'd suggest giving the bore a hone to clean it up and ease clearances.


Barrels off and lifters and tappets are quite good with no spalling. Good news for Castrol GTX, but still changing to Valvoline VR1 for the ZDDP. On the other hand, showing some piston overheating (or overexpanding?). Worse on the left side, as right side only has it on the rear surface. Bores look very good, with this piston issue barely having an effect that shows on the barrels. My inclination is a very light sanding for the pistons and a very light honing for the bores and Bob's your uncle! Maybe. (Not you, TopDad.)

Richard L.

EDIT: Should I add "under-oiling"?
Title: Re: How bad is this!?! **UPDATE**
Post by: muskrat on 05.09. 2013 10:50
G'day Richard.
As RR said it looks like it has nipped up (probably un-noticed). Never use wet & dry sandpaper on a piston but I think even a fine cut file might be a bit too aggressive. A light buffing with a soft mop and white wax should be enough. You don't need to completely remove the scores, just smooth them over. A very light hone and some new rings will do the trick. Piston to bore clearance should not exceed 6 thou measured at bottom of skirt at 90 deg to the pin. Any more than that and you will hear piston slap, 4 thou is standard. As for oil, I use cheap 20/50 but add Nulon, gives the innards a teflon coating like a fry pan. *eek*
Cheers
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 05.09. 2013 12:36
Hey Muskrat and All,

Thanks for the advice. Not having the pistons loose, I haven't had a chance to measure the existing (pre-honing) clearance. I suppose it doesn't matters much but, considering the almost invisible affect on the bores, might this have been a one-time short duration event?

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: chaterlea25 on 05.09. 2013 21:04
Hi Richard and All,
I believe the pistons will clean up ok, "tuning for speed" recommends a "Swiss file"
Make sure your replacement rings are compatable with the pistons, lots of crap out there!!!!

Re oil,
I use straight 40 classic Castrol , before that I used Duckhams 40 (Fleetol??)
I use the Castrol in all the customer classic Brit bikes except Tri T120/40's with common oil for the engine, primary/clutch
I use the "Comp 4" in my modern B*W bit wouldn't if I had to pay £40 for 4 litres  *eek*
Seek out a trade deal and save almost half

Musky,
I am not a fan of adding additive to engine oil which have roller bearings, especially needle roller ones
The additive as you say adds a coating to the rolling components,
This reduces the working clearance and can cause bearing failure, It was a common cause of failure to the intermediate shaft needle bearings on BMC Mini's and the like

Best of luck with the repairs
John

Title: Re: How bad is this!?! **UPDATE**
Post by: muskrat on 05.09. 2013 21:21
 G'day John. I don't want to turn this into an oil thread. I've used Nulon in ALL my&friends engines, gearboxes and diffs in cars, trucks, 4x4's and bikes (except wet clutches) for over 30 years. Not one bearing failure yet. I would never use any of those sticky thick additives like Lucas or Morleys, they rob revs.
Cheers
Title: Re: How bad is this!?! **UPDATE**
Post by: chaterlea25 on 05.09. 2013 21:29
Hi  Musky
"Nulon" doesn't seem to exist on this side of the planet ????

John
Title: Re: How bad is this!?! **UPDATE**
Post by: bsa-bill on 05.09. 2013 21:41
Quote
"Nulon" doesn't seem to exist on this side of the planet ????

Think it might exist or similar exists as ZX1
I've used it in a rebuilt engine to cure a sticking valve, it worked fine, did a couple of hundred miles then drained the oil (keep it in a tin for future use)
it's not thick or sticky
Title: Re: How bad is this!?! **UPDATE**
Post by: RichardL on 05.09. 2013 21:57
To stay out of trouble with the moderator, I'm trying to stay away from the oil issue here. I am on rebuild and repair topics so I was glad to see, so far, nothing that appears to be damage induced by the wrong oil.

John, I'd never heard the term "swiss file" before, but the term seems to be in common use and, strangely, I own some (swiss files, not terms). Also strangely, I found this posted about using swiss files to work down piston high spots. It's three paragraphs from the end.

http://groups.yahoo.com/neo/groups/The_Sunbeam_Motorcycle/conversations/topics/97

Anyway, I'm going to see what buffing does first.

Musky,

Really, replace the rings? On first (not maginified) exam, they don't appear to have any damage. I hate to do it because they are original Hepolite, now 3700 miles old. I will look with strong magnification to see if there is an issue. I'll, no doubt, be back to discuss it.

Richard L.
Title: Re: How bad is this!?! **UPDATE**
Post by: trevinoz on 05.09. 2013 22:06
Richard,
                 Measure your pistons and bore. Usually seizing is caused by too little piston to bore clearance.

Trev.
Title: Re: How bad is this!?! **UPDATE**
Post by: Rocket Racer on 05.09. 2013 23:21
if the rings have marked from the seize, bin them.
I would do a light hone just to ensure the bore is cleaned up irrespective of clearances (which should also be checked)
in my opinion a failure has occurred, it wont just go away. some remedial action is required to prevent recurrence.
just my 10 cents worth