| Author | Message | ||
     Jeff Martin Frequent User Username: jeff_r_1 Post Number: 249 Registered: 07-2018 |
I had the thing sleeved a number of years ago and the guy who did it locally left fine lathe marks in the bore, this in turn caused the seals to stick and the return spring did not have the strength to return the piston. I have also installed a new and stronger return spring. I gave it, what I thought was a light hone, while this cured the sticking problem, it seeped brake fluid after that, it was quite the mess after that. (I think the bore is not parallel any more causing the seeping problem) I am now using silicon brake fluid to get around the hygroscopic stuff, because it still seeps. (brakes work fine with silicon with no leaks at the wheels) I friend said they always seep, it's a problem that comes with the rather large bore. Is it normal for them to seep, thinking of buying a new one, but what's the point if even the new will seep fluid ? Thoughts on this, surely it was just a bad sleeving job, RR would not design and produce a leaky master cylinder ??? | ||
| Martin Webster New User Username: martin_webster Post Number: 10 Registered: 09-2018 |
Jeff, There should be no seepage at all. I had a new master and slaves fitted 13 years ago and the fluid is changed every two years (not silicone) but there is never any loss of fluid in the system. B88HR | ||
| ChristopherCarnley Unregistered guest Posted From: 5.62.43.182 |
The correct method of re-sleeving is to parallel bore the cylinder slightly oversize of the liner which should be a thin walled stainless steel tube. The liner is then slip set in with high grade Permabond adhesive. The cylinder is then drilled through for the hydraulic feed. If the cylinder is "dry" fitted i.e. just pressed in, then there is nothing to prevent the fluid being squeezed through the feed hole and past the liner/cylinder interface. Past Parts in Ipswich do it the correct way. (Message approved by david_gore) | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 250 Registered: 07-2018 |
That would make sense, and I can see that happening with the machinist that did it, he's past away ages ago so I can't ask him. He was rebuilding one of the 4.5 litre engines and I had to help him out with the crank shaft damper modifications and loan him my manual and other articles. At the time there were no computers, or at least I didn't have one. He took the original pistons and had someone weld all the top ring grooves shut as well as the upper landings. (the top rings were all broken of course) After all the piston's were "Goobered" in aluminum, he would machine them down to spec, I never though that was such a good method, seemed very hokey. After many months I went back there to get my manual and literature that I loaned him and his helper eventually found them covered in lather shavings and dirt. I was pretty pissed off, never went back there ! There are two places here, "White Post Restorations" and "Apple Hydraulics", both in the US. I had Apple Hydraulics do all the brakes and clutch on my Jaguar, they used either brass or bronze, is there any advantage to stainless steel over the others ? | ||
| ChristopherCarnley Unregistered guest Posted From: 5.62.43.240 |
Jeff, Look at Karps Power Braking, in California. (Message approved by david_gore) | ||
| Jim Walters Frequent User Username: jim_walters Post Number: 338 Registered: 01-2014 |
Jeff, I have bored and sleeved hundreds of cylinders over the past 40 years and still do several every month. I only use 660 rotocast bronze as I think the stainless tubing used is too soft and wears prematurely. The brass sleeves are also too soft in my opinion, I have redone lots of cylinders previously sleeved in brass by others. 660 bronze is a very hard material and does not curl off when machined, it chips off. It costs more to use bronze as each sleeve has to be cut down from a standard size blank to fit but it is the best material to use and the only way I will do them. I guarantee my work for for life. If sleeves are just pressed in dry they will most likely leak eventually, they should be installed with Loctite 620 and the sleeve to cylinder clearance has to be correct for the Loctite to work properly. I also powdercoat each cylinder I sleeve.  SRH8505 SRC18015 SRE22493 SRK36971 NAC-05370 www.bristolmotors.com | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 251 Registered: 07-2018 |
How busy are you, you had some in a pile waiting to be done ? I still have to get the car back together, so another 2 or 3 months at least. I can stop by this Thursday, 22nd, this month. Thanks ! | ||
| Jim Walters Frequent User Username: jim_walters Post Number: 339 Registered: 01-2014 |
Hi Jeff, I couldn't do it for you until after August 7th, really booked up but I'll put you on the list if you like. SRH8505 SRC18015 SRE22493 SRK36971 NAC-05370 www.bristolmotors.com | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 252 Registered: 07-2018 |
August 7th isn't far away, put me on the list, thanks ! | ||
| Jim Walters Frequent User Username: jim_walters Post Number: 340 Registered: 01-2014 |
Consider it done. You can drop it off anytime you are going by, I just couldn't get to it until after the 7th. Thanks. SRH8505 SRC18015 SRE22493 SRK36971 NAC-05370 www.bristolmotors.com | ||
| ChristopherCarnley Unregistered guest Posted From: 5.62.43.230 |
There is up to 8% lead,Pb in SAE660, and a lot softer material than the stainless used. (Message approved by david_gore) | ||
| ChristopherCarnley Unregistered guest Posted From: 159.242.227.88 |
The basic free machining stainless 303 has a Brinell Hardness of 228 HB. Centrifugally cast SAE 660 has a Brinell Hardness of 65 HB. However, you old machinist may have made such a mess of it that thin walled harder steel ones may be inapplicable. (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 3965 Registered: 04-2003 |
Christopher, Putting on my stainless steel cap from my past - type 303 stainless steel was effectively type 302 with a higher Manganese and Sulphur content. These elements combined to form Manganese Sulphide inclusions in the soft austenitic matrix of Iron, Chromium and Nickel inherent in these grades. The relative softness of these alloys created problems when machining as the metal would stretch during machining instead of breaking away easily from the tip of the tool creating a build up on the tip of the tool which made clean cutting even more difficult. The Manganese Sulphide inclusions in type 303 acted as both a lubricant and chip breaker for the tool allowing higher cutting speeds and a better surface finish at the expense of a reduced corrosion resistance compared to Types 302 and 304 stainless steel. If a reasonable compromise between wear and corrosion resistance at normal engine block temperatures is required and depending on availability, I would be looking at one of the precipitation hardening stainless steels in preference to the straight austenitic grades with the probable advantage of better machinability to "put a dollop of cream on the cake" as the old saying goes. As always, you should seek more specific advice from a metallurgist or experienced engineer conversant with current alloys and their characteristics; my knowledge is decades old now and certainly out-of-date. | ||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 739 Registered: 10-2008 |
Jim, those cylinders look superb. Here in the uk, I use Past Parts who's work I have found excellent. I have recently sent new cylinders for stainless sleeving before fitting them on MG's as they are less prone to seizure with lack of use and the quality of repro cylinders are not like the originals. | ||
| ChristopherCarnley Unregistered guest Posted From: 77.234.43.180 |
David, Optima and compromises, the Karps sysytem as well as Past Parts, uses 304 as a compromise to machinability, cost, and that the steel can be crosshatch honed. The system originates, (no you guessed it) in N.S.W. with J Halliday & Sons. My comments referred to the "belief" that stainless steel is "too soft", whereas I am certain that the choice of the bronze is down to ease of machining, and finishing. It is 27C in Yorkshire, and I decided to silver solder a 5 mm thick C106 model loco boiler barrel! It will now take all day for it to cool, and see what a billhooks I have made. (Message approved by david_gore) | ||
| Jim Walters Frequent User Username: jim_walters Post Number: 341 Registered: 01-2014 |
My "belief" that stainless is "too soft" comes from my experience of re-sleeving cylinders that had previously been done in stainless. By far the majority of cylinders that I have sleeved that had previously been done but ultimately failed have been the ones done in brass. However, every once in a while I'll get one in that had been done in stainless and showed enough wear in the bore to cause the seals to fail and leak. In almost every case the customer did not know the cylinder sent had been sleeved before so to be fair I have no idea who sleeved them, what grade of stainless was used, or how many application cycles they had on them. An old machinist showed me how to bore and sleeve cylinders and explained why he used 660 bronze over 40 years ago now, made sense to me at the time and I've just kept doing them that way. I still think, based on my experience, that 660 bronze is the best material to use. Cost of material is not my primary reason for using 660 bronze for sleeving, quality of the finished product is. SRH8505 SRC18015 SRE22493 SRK36971 NAC-05370 www.bristolmotors.com | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 253 Registered: 07-2018 |
I don't know anything about stainless steal, but I do know that it does not wear well, it doesn't keep an edge on a knife, I don't think there is any carbon in it. Yeah, it's really tough to to work with, but it does not wear well. I believe it's the carbon in the cast iron that makes for a good master cylinder. I also think bronze works well because of the nickel in it. Kind of like titanium, very difficult to cut and machine, but does not wear well either. I had a top of the line Shimano cog set where the last three gears were titanium to save some weight, it barely lasted a season and the chain started to skip. The steel rollers on the chain wore it right out. | ||
| David Gore Moderator Username: david_gore Post Number: 3966 Registered: 04-2003 |
Jeff; Time to put my Tribology hat on....... 1st Question for everyone: Why does a hardened crankshaft journal wear and the soft crankshaft bearing shell does not when both are fully lubricated by engine oil? | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 254 Registered: 07-2018 |
The question assumes a fact, that I don't agree with. If the oil is kept clean enough by regular oil changes, the bearings should wear first, at least that's the way it's supposed to happen and it did on my Jaguar when I had the engine done. The crank was only polished while wear showed up on the white metal on the bearings, I can't remember on my Bentley, but I think the crank did not need grinding. If the oil is not changed enough, especially with a by-pass oil system, carbon (which is hard and is created by burning fossil fuels) is embedded into the soft metal of the bearing. If enough carbon builds up on the bearings, it starts to wear the hardened crankshaft journals. That's the way I see it. Other things speed up the wear on the crank shaft, engines that are allowed to idle when cold, with the choke on too long. Too many short runs with out the engine being allowed to come up to temperature. Running too cool a thermostat. All this adds more carbon to the oil and for the filter to handle, especially engines that are set to rich _ which causes more carbon build up. Engines that have too low of a compression ratio (like our cars) don't burn the fuel efficiently and add even more carbon to the the recipe. It takes more fuel to ignite a low compression engine, then it does with higher compression. OK, here we go...  A club member (Bill Fayne in BC Canada) with a Phantom 3 (I think) was doing well getting 8 miles to the gallon because the compression wasn't high enough. | ||
| David Gore Moderator Username: david_gore Post Number: 3969 Registered: 04-2003 |
Re my question above, Chris Carnley has requested I post the following comment on his behalf: "The two MK VI bearing pictures below are for your question on relative wear. If you look closely at picture DGF2, you can see the nickel barrier layer between the lead/indium anti friction layer and the copper lead backing. If you put it up I will then explain why your assumptions may not be correct." Image DF1:  Image DF2:  So far, everyone has mentioned one aspect of the answer but not the second.  | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 261 Registered: 07-2018 |
So what's the point here, the bearings are worn as they should be rather then the crank _ right ? One is worn more then the other, why is that, but I bet the crank is fine and not worn ? | ||
| David Gore Moderator Username: david_gore Post Number: 3971 Registered: 04-2003 |
Jeff, I will explain further based on my visit to a NSWGR locomotive workshop many years ago to get more information on "remetalling" locomotive diesel engine sleeve bearings. The skill of the "artisans" [and I really mean artisans] doing this procedure had to be seen to be believed however what intrigued me was the mention of wear on the hardened journals as well as the soft bearing shells observed when the engines were stripped down for overhaul. This is the clue to the answer........ | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 264 Registered: 07-2018 |
But are you comparing apples to oranges here, a locomotive deiseal engine are not gasoline engine ? | ||
| David Gore Moderator Username: david_gore Post Number: 3972 Registered: 04-2003 |
Jeff, The cause I am referring to is common to both petrol/gasoline/LPG and diesel engines. Think "outside the square"..... | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 265 Registered: 07-2018 |
Well the bearings are worn into the copper right where the most stress is... Once that happens, the copper starts wearing on the crankshaft ? I still think poor filtration systems, like by-pass oil systems and dirty oil plays a big part of this. The quality of the oil too, and not allowing the engine to get up to temperature. Burning fuel creates water vapor that gets into the oil, the water in turn replaces the oil film between the bearings and crank, and wear on both surfaces occur. That's why I have always preached about getting the engine up to temperature as soon as possible; running a hotter thermostat, even in the summer, and not letting the vehicle sit there and idle in the drive way to warm it up. A diesel engine in a locomotive and on a boat is under stress all the time, pushing water through the prop or under load driving the generator(s), it doesn't get a rest like a car coasting down hill. All that extra stress makes the wear occur much more, when the engine is cold. I never quite understood why guys with diesel trucks allowed the engine to sit there and idle for over 1/2 hour to warm it up. That's doing more harm then good, why not plug in the block heater all year round ? Or just drive it gently until it reaches full operating temperature ? | ||
| ChristopherCarnley Unregistered guest Posted From: 77.234.43.149 |
All white metal bearings have to have 3 basic properties, conformability, compatibility and embeddability. Quite simply, the bearings in an oil drip fed total loss system, with very high initial loadings, as in large steam engines open to the muck and grime, will absorb abrasive particles and act as "laps", wearing away the hard steel crank pins. The prewar R-R cars with thick white metal shells have the same features, no oil micro-filtration and little air filtration. The cranks wear very badly. The EPW cars, after the full flow filters were fitted, fare a lot better, as the oil washes away much of the muck, by the filtered pressurised system, from the nitrided crankshaft, av 850 HB . Many exceptions disprove the assumed "rule", which is not therefore a generalisation. There is a very interesting book called "Vanwall" and tells the story of how Tony Vandervell wrestled the tri-metal thin shelled bearings from Cleveland Graphite in the1930,s and goes onto detail how the GP 2 litre Vanwall engine was designed around the crankcase of the R-R B40 engine and 4 No 500 CC water cooled Norton engines. (I blame Professor Edwin Gregory droning on about Sir Henry Fowler, for the above, but he left me an interesting chart on white metals, by Mundy, Bissett and Cartland, from Journal of Inst, Met, 1922,No 2.) (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 3973 Registered: 04-2003 |
At last I can announce a winner......it is Christopher Carnley our UK contributor who specialises in Early Post War RR/B vehicles with his contribution above. Yes, the journal wear was the result of abrasive particles drawn through the diesel engine air filtration system when working in our arid country regions, heavily polluted mine loadouts and city industrial locations. These particles were trapped in the soft white metal layer of the bearing shells and acted as a "lap" on the hardened crankshaft journals wearing them extensively whilst little wear was evident on the bearing shells. This problem was alleviated on the mine sites by Donaldson Cyclopac prefilters that "spun out" the dust particles before the intake air passed through the ordinary engine air filters. I don't know if these filters were fitted to the NSWGR diesel locomotives or whether the standard filters were subject to more frequent checks for effectiveness. | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 266 Registered: 07-2018 |
So why didn't they just use an oil bath filter, that should have solved the problem. | ||
| David Gore Moderator Username: david_gore Post Number: 3974 Registered: 04-2003 |
Jeff, From personal experience of driving a 1950's Australian-made car on a friend's country farm in Far-West New South Wales with regular dust conditions, oil bath air filters are a real "pain in the behind" as the oil quickly turns to mud in these conditions thus eliminating the ability of the oil to "wash" the dust out of the incoming air. This environment is less prone to extreme dust problems than the open-cut mine sites especially those I visited in the Pilbara region of Western Australia where every engine was fitted with a self-cleaning cyclonic prefilter to minimise dust clogging. | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 328 Registered: 07-2018 |
Well I'm still working on the leaky master cylinder problem. I bought a new reproduction from Flying Spares and the casting is defective, I can clearly see all sorts of pitting down the bore, it may as well be rusted. I think that the molten cast iron was possibly too hot and these air pockets form, but I'm not too sure about that conclusion. Never the less for £240.00 it's unacceptable. Why would White Post Restorations not guaranty their work when they sleeve a master cylinder and one used DOT 5 brake fluid ? I did ask them and I'm just waiting on an answer, but I would like to hear what others have to say about that. I have DOT5 fluid in my 68 Jaguar and it does not leak _ the brakes work well, so I don't see why it would not work in the Bentley. |
