Engine Remanufacture

& I think I moved the decimal place over 1 too many spaces.. IIRC it was closer to $1000/hole

Thats a good thing, but i would imagine some of the parts are getting tough to find.

There’s no shortage of cylinder blocks…. 🙂

Thats a lot of parts,, I asked about the sleeving due to the fact that if the block was not sleeved its life would be finite, you can only bore a block so many times before you run out of block.

And $175 a hole for the Rousch rings and piston is to my mind a very reasonable price,,, almost bargain basement.Now if someone can convince him to cast some Merlin blocks and forge some cranks. Anyone know if the block is sleeved or not?

They don`t have a block as such like automotive engines, they have a crankcase and separate cylinder blocks. They have removable wet-liners.
New liners have been manufactured, but the large castings are probably a step too far, partly because they are not a consumable, and the costs, but it would be perfectly possible to make one.
There are about 11,000 parts in a Merlin and I wouldn`t like to try and make a new one!

Pete

You go do that. As an aside this part was being made in the 1940’s at the height of WW2 at a rate of over 100K of them every month. Tolerance at the time was .5253 to .526. Thats a runout of .0007!! According to you paul, the machining industry has made no significant steps forward in the last 70 yrs.

No one has claimed that inch measurements to 4 decimal point (dp) are impossible, just that they’er best suited to a grinding or lapping process.

However a question have been asked if these can be achieve on a lath in a garage. And no …..Paul did not anywhere claim that no significant steps forward in the last 70 yrs….. where did that come from?

You seem to be claiming that the ability manufacture to the necessary accuracy (claimed as 6dp but on imperail or metric? ……..upon re-reading you post its still unclear) to produce WW2 aeroengines has been lost. I say not .

You seem to be claiming that as time passes its possible to increase the number of dp’s you can manufacture to is increasing. I agree, (but your claim here is contra to your claim above)

You seem to be claiming that increasing the number of dp’s somehow improves an aeroengine product. I say, above about 4 dp, it does not . (you can seal fluids, achieve 50,0000 hour reliablities , and everything else with this magnitude of accuracy, …..also sure inch measurements 7dp is possible but not for aeroengines now or WW2 )

You seem to be claiming that increasing the number of dp’s increases manufacturing difficulty and scrap. I agree (but again your claim here is contra to your claim above)

A really good engineer selects a design which delivers a solution that meets the customers technical specification, is delivered on time and within budget. A dreadfully poor and incompetent engineer is one that needless specifies a dimensional accuracy way beyond what the product needs, as a result delivers late and at massive cost. The WW2 aeroengine engineers understood this very well and were not dreadfully poor and incompetent .

Rolls Royce don’t what to deliver small number of WW2 aeroengine components because;-
1 They know the devil is in the detail, most of which has been lost.(i.e. a tiny undocumented detail of say a heat treatment process, has a significant impact on structural properties, sure these are more predictable than 50 years ago but still at a cost, alternatively old fashion trial/error is also hugely costly )
2 For the task to be done properly they know its well beyond both the understanding and the budget of the expectant customer.
3 Any attempt to short cut the above = component failure, crash, death, law suit. (Favours are not recognised in court)

If any of the surviving WW2 aeroengine manufactures really had a need to manufacture as they did 50-60 years ago they would find it a walk in the park, be that a somewhat expensive walk.

What I find a little disturbing about your claims of mega high accuracy i.e. 6dp on the Daimler Benz engine and hence the inference that there once existed a now lost Nazi super technology………. Complete and utter rubbish (that’s “garbage” to you)

Anyway given your post above, I suggest you switch to de-cafe as you need a very steady hand to turn those tenth of thous.

And $175 a hole for the Rousch rings and piston is to my mind a very reasonable price,,, almost bargain basement.Now if someone can convince him to cast some Merlin blocks and forge some cranks. Anyone know if the block is sleeved or not?

You go do that. As an aside this part was being made in the 1940’s at the height of WW2 at a rate of over 100K of them every month. Tolerance at the time was .5253 to .526. Thats a runout of .0007!! According to you paul, the machining industry has made no significant steps forward in the last 70 yrs.

well i have been making and selling a gas piston for a rifle for many yrs now, i tollerance it to .5265 allowing .0002 either way. I have made and sold 100’s of them. I make them on an old machine lathe, the only modern equipment on the lathe is a digital readout. So please do not tell me its ridiculous. Sorry to get off track but to tell me i cant do what i have done for yrs. is ridiculous.

as to manufacturing to seven digital points, yes it is difficult, but the company doing it is light yrs. ahead of a tool and die shop. Thier reject rate is appaling, but thats what the customer is paying for.

I’ll forward your post to the grinding, honing, & lapping machine manufacturers to let them know their machines are no longer needed as you’ve proven the work can be done on a manual engine lathe in a garage!
BRAVO & well done !

Jack makes pistons & rings & yes you can buy them, I think they run about $175 a hole.

I hear that Jack Rousch (Rousch Racing) has been making new parts for the RR Merlins, mainly no doubt due to the fact he has a P51 or two, and an F82. I have no clue what parts he is making or if they are available for commercial sale. Wonder how big of a step it would be for him to make a complete one.

…the same as they do it now-a-days!

These are the tolerances for my Volkswagen Golf:

Main Journal (New): 53.978 / 54.037 mm

Main Clearance (New): 0.020 / 0.060 mm

Interestingly a much greater tolerance on the main journal but a smaller tolerance on the clearance (by selective fitting of bearing shells).

So when the Intellectual property expires these engines could and probably will be manufactured in India or China using modern technology and cheap labour.
http://reprap.org/wiki/Main_Page

Sorry but I wouldn’t fly behind one if were built over there no matter how much money it saved. The quality would not be there. I think there a plenty of Western shops who could do the work. Besides, I don’t think there will ever be a demand for mass production of these engines. Perhaps in the tens or dozens, but I can’t see that figure going extremely high.

well i have been making and selling a gas piston for a rifle for many yrs now, i tollerance it to .5265 allowing .0002 either way. I have made and sold 100’s of them. I make them on an old machine lathe, the only modern equipment on the lathe is a digital readout. So please do not tell me its ridiculous. Sorry to get off track but to tell me i cant do what i have done for yrs. is ridiculous.

as to manufacturing to seven digital points, yes it is difficult, but the company doing it is light yrs. ahead of a tool and die shop. Thier reject rate is appaling, but thats what the customer is paying for.

What’s that in real measurements?

I knew you’d ask…..but those are the original units from a wartime publication! 😉

Just as an example of ‘wartime’ tolerances the following are for a Gipsy Major:
Creaking,
Main Journal (New): 51.968 / 51.987 mm

Main Bearing (New): 52.050 / 52.056 mm

Clearance (New): 0.063 / 0.088 mm

Not too shabby! 🙂

Agreed but…remember that the crank is ground, & the rod end is honed to size……the same as they do it now-a-days!
With these processes, “a tenth is a thick as a side of beef” to the toolmaker.
Impossible to machine to these tolerances by milling/turning.

Mauld,

I’m sure India or China could do the remanu. but……..you wouldn’t get me in the kite(s).
Cheers.
Paul

As near as dammit plus/minus a tenth of a thou for the main bearing.

What’s that in real measurements?

Just as an example of ‘wartime’ tolerances the following are for a Gipsy Major:

Main Journal (New): 51.968 / 51.987 mm

Main Bearing (New): 52.050 / 52.056 mm

Clearance (New): 0.063 / 0.088 mm

Not too shabby! 🙂

Good for basic shapes but for complex stuff you need this..
http://www.youtube.com/watch?v=ps0WEZbDjHE

Very impressive I look forward to the time when we all have one in the home.