Restoring a '71 Sprint

[john.p.clegg]

Brian(friend)

I have some engineers blue in the shed but must admit I don't know how to use it???

Please

John

[types26/36]

[quote="john.p.clegg"]Brian(friend) I have some engineers blue in the shed but must admit I don't know how to use it??? quote]

John,.........you don't know how to use a shed??? did you live in a mansion or manor house when you were a child?? .......its actually quite easy ..... open the door.....pile in the rubbish.....close the door!.......the problem begins when you want something.......example ....engineers blue

[john.p.clegg]

Brian (friend)

Stop being a tit,I know how to use the shed!!!! but the engineers blue has me beat,I thought it was for colouring steel prior to scribing and cutting....

John

[bill308]

"Production tolerences or Design tolerences?"

John

Nice catch John. I should have posted design tolerances. Presumably, if a component did not meet design tolerances, it wouldn't have been fitted.

Bill

[memnon]

That presumption comes from a man who has limited experience of BL! (British Leyland) And probably in part explains why the UK no longer has a mass appeal car manufacturer

[GrUmPyBoDgEr]

And my 2 penneth to your question John & your answer Brian.
I may have mistakenly mentioned production tolerances when I was meaning production engines.
If an engine was suspected of not being "standard" then the components would be measured & compared to the "Engineering drawings". These would be the only official manufacturer's document available.
My experience of modern engine production has taught me that in order to avoid daily, batch, tool, temperature etc. etc. deviations, the machine settings will be tighter than the specifications on the official drawing.
This narrower tolerance band is constantly observed until it starts either moving up towards max. or down towards min.
Once this starts to happen the responsible person knows that a tool or setting change is needed. This provides the production people a safety margin in which they can make the needed rectification without manufacturing "out of tolerance" parts, which could happen if they were working to the maximum drawing tolerances.
From your question John, I believe that you have knowledge of the science of quality control & that "3 or 6 Sigma" is no stranger to you

Well I think this one's been done to the Nth degree now.
Reminds me a bit of the "Die Cast" Cylinder head debate that we had a while back: Different uses of a common language & differing interpretations of certain terms.
Also a high degree of "Folk Lore", like "This man in the Pub told me--------"

Cheers & have a good weekend
John. P

[bcmc33]

My experience of modern engine production has taught me that in order to avoid daily, batch, tool, temperature etc. etc. deviations, the machine settings will be tighter than the specifications on the official drawing.
This narrower tolerance band is constantly observed until it starts either moving up to max. or down to min. P

John,

Do I take it from this that you had no experience of 60's/70's engine production before the 80's/90's revolutions? You missed all the best fun.
The 80's & 90's became very serious, and it was a different sort of fun when the 'powers-that-be' gave us the opportunity to 'copy' the Japanese to do the things that the Japanese had copied from us in the first place.

Must get off this soap box now. Unless someone wants to pay my ?1,000 per day seminar fee to get the full story.

[john.p.clegg]

Talking of soapboxes....
I also mourn the passing of the Great British Motorcycle Industry as in the sixties Japan invaded our shores with far superior machines built "hearsay has it" on new tooling to much closer tolerances provided by the allies after the war....whereas our machines were "clapped out" at best after years of non-investment.
Not to mention the Germans....

John

[GrUmPyBoDgEr]

I was employed in Aero Engine design up until 1981 & was therefore acustomed to painstaking accuracy.
I do recall visits to British Leyland & Triumph factories as an apprentice in 1964.
The assembly methods they employed were more than an eye opener to us lads who were working our way through Aero engine manufacturing workshops.
As John mentioned, the machines in the Bristlol Siddeley (Later RR Bristol) were also antiquated.
Oh another factory visit was to Stirling Metals in Nuneaton. They cast Magnesium parts for us & also Minilite Wheels for Tech Del.
We apprentices were thinking how we could smuggle some of the pile into the coach to take back home
I started working in Germany in 1976 & it was an eye opener to see how well equipped all of the workshops were.
I think it was just last year that GB made its final payment to USA to pay off the War debts

Cheers
John

[GrUmPyBoDgEr]

Brian (friend)

Stop being a tit,I know how to use the shed!!!! but the engineers blue has me beat,I thought it was for colouring steel prior to scribing and cutting....

John

Aah, I see where the confusion comes from.
In metal working there are 2 recognised Blue's.

1. "Marking out Blue"
A thin spirit based blue liquid which can be painted on to castings etc. to improve the visibility of scribed centre lines etc. which are set out on a "Marking out table". Practically eliminated now since the introduction of CAD/CAM methods.

2. "Engineers Blue"
A thick greasy consistency, which is smeared very thinly onto one of the components mating surfaces to check extent of contact.

3. Both are very easily lost in sheds.
I know where my Marking blue is but the Engineers blue's got me beat also

Cheers
John

[john.p.clegg]

Thanks John

That clears up the confusion a bit,could you expand on point 2 please

John

[GrUmPyBoDgEr]

Thanks John

That clears up the confusion a bit,could you expand on point 2 please

John

OK, here's an imaginary example:-
You have an incurable oil leak at the differential flange, so you need to check the flatness of the sealing faces or more accurately put, how both faces mate with each other.
That means that any high spots need to be identified & eliminated.
Having thoroughly cleaned both flange surfaces a very very thin smear of Engineers blue needs to be applied over the whole of one of the flange surfaces.
Both parts are then put together avoiding any sliding or rotational movement & either pushed or lightly together clamped by the fastening bolts
After that both parts are separated using the same amount of care.
The part that had no Engineers blue applied to it is then checked visually.
If imperfect some areas will have had Blue transferred to them & others not.
The Blue areas are the high spots & need to be removed.
Having done that the check must be repeated until the Blue is transferred to the whole of the surface.
The process is iterative & can be time consuming.
It is vital to use as little Blue as possible when doing this job & it's total removal prior to re-checking is equally vital.

There is no real application for this process on any Elan parts, that I can think of at the moment.
The Crankcase halves & other "gasketless" joints of the old "Bristol" radial piston engines used to be overhauled using this process for example. In many other industries it has similar uses.

Hope that helps a bit?
Cheer
John

[john.p.clegg]

Thanks John but I'm not sure about having no use on the Twincs knowing how oil tight they are????

John

P.S. check out Woodvale in Free Parking, especially the video.....that would give the Zetec boys a run for their money....

[bcmc33]

I was employed in Aero Engine design up until 1981 & was therefore accostomed to painstaking accuracy.

In the late 70's we at Ford took on some of the aero industry disciplines for design and manufacture, but it was really the lessons learned from the Japanese that started the great revolution. In a nutshell; we never had any real problems with accuracy ? precision is the most important factor, and that?s what let us down. And that's definitely worth a ?1000 fee to explain that one in detail.
What the Japanese could never understand was all the great lessons they learned from the US & UK in the late 40's and 50's that were no longer practiced in the US & UK. The US & British quality gurus are almost household names in Japan - I bet not 0.00001% of people could name one over here even now.
If you want a good descriptive example of what really sent British manufacturing industry to the dogs - read chapter 2 of Miles Wilkins Twin Cam book as it typifies some of the malaise that was rampant at the time ? with full government support.

That clears up the confusion a bit,could you expand on point 2 please

An example for John --- My first car was a 1948 Riley RME with a suspect engine. With the engine removed it was taken to a local automotive engineers shop to be rebored, the crankshaft reground, new pistons and the conrod bearings. To my surprise the conrods did not have Vandervell shell bearings as expected, but white metal cast machined bearings. The white metal bearings were deliberately made a little tight on the crankshaft to allow for ?bedding-in?. To do this properly meant a fine layer of engineers blue on the crankshaft journals, tightening the conrod onto the journal and rotating the conrod. When the conrod is removed the bearing ?high spots? are highlighted by dark blue marks and these marks are the areas that need to be eliminated by lightly scraping over the marks with small scraping tool (the sort of thing all engineering apprentices made during their time). This procedure is repeated until a nice light blue colour covers the whole bearing surface ? that?s when you know you have a near perfect bearing and journal match.
I learned this technique as an apprentice matching large brass or bronze bearings (6 to 12 inch diameter) to rolling mill shafts. I have to say that this was much easier than the comparatively more delicate white metal bearings.

It was at this time when I learned how important it is mark parts as 1, 2, 3, 4 and front, rear etc. to make sure that on any future strip-down you can get them back in the correct position.

[GrUmPyBoDgEr]

Thanks John but I'm not sure about having no use on the Twincs knowing how oil tight they are????

John

P.S. check out Woodvale in Free Parking, especially the video.....that would give the Zetec boys a run for their money....

I think for the Twincam the best solution is liquid sealant; nearly all of the parts that are responsible for the leaks e.g. cam cover & front covers have design faults such as insufficient number & spacing of clamping bolts/nuts & the covers themselves are not stiff enough to provide the required clamping force all along the sealing face/gasket.

Thanks I watched the Video & I envy anyone who goes to that event.
The attractions there tick a lot of boxes for me (not the "playing at War" boys though )
I didn't know that the Griffin ever had a reduction g/box to run contra-rotating props.
Is it possible that someone did a modification to that engine so that it could run close to the ground with smaller diameter props?

The engine sound that really floats my boat is the Matra V12 on the Mullsan(Sp.?) straight at Le Mans.

Cheers
"One of the Zetec Mob"