| Author | Message | ||
     Marty Unregistered guest Posted From: c211-30-227-162.carlnfd3.nsw.optusnet.com.au |
Hi All, Work progresses on B239LH. Most of the rust has been uncovered now, and major dissassembly has taken place. Coolant leaks at the inlet manifold have been rectified, and some of the oil leaks identified and remedied. it is much easier to work on the motor with the guards removed!! Exhaust manifold nuts where all loose, as where the 4 bolts on the exhaust tappet covers. Question.... How much work is involved in converting an earlier 4 1/4 litre motor from by pass oil filtration to full flow oil filtration? Apparently some cars were modified by the factory?Is it warranted? The car will probably travel 1-2,000 miles per annum, with an annual oil change. Any thoughts welcomed. Cheers Marty (Message approved by david_gore) | ||
| Bill Coburn Moderator Username: bill_coburn Post Number: 912 Registered: 4-2003 |
Marty/ If you can find it, the Technical Library has all the service bulletins for that car which includes detailed instructions on doing the conversion. The original pipes and filters you would have to find in a wreck but you may be lucky otherwise I would use modern braided lines which are probably even better. The first crankshaft failure on a Rolls-Royce engine occured in Australia with an early Mk VI with a by-pass filter. | ||
| Peter Colwell Frequent User Username: peter_colwell Post Number: 51 Registered: 3-2005 |
I once owned for twenty years, a 1954 Landrover with similar engine design to Rolls-Royce up to 1958. Ie, overhead inlet and side exhaust valves. It ran very sweetly and quietly, as did the six cylinder version on later Rover 3 litre cars. It had by-pass oil filter, and operated on very dusty dirt roads all the time, but the bearings and general engine condition were still good when sold at 108000 miles. In other words, by-pass might not be ideal, but it is not bad either. I have seen tests done on oil contaminants in both types, and the results were not as clear cut as might be imagined. For such low mileage, and presumably clean conditions, conversion may not be worth the effort.... | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1277 Registered: 4-2003 |
We had a 1958 Holden Wagon as first owners until it was replaced by the R-Type and horror ! a Volvo 164. I commandeered the old wagon on my 17th birthday, by chucking the original grey motor and fitting a lumpy go-faster red motor with twice the horsepower. My mother could no longer drive it, hence the new Volvo was hurriedly acquired. It had done 160,000 miles when I fitted the 192CID motor, with only a new timing gear fitted at 120,000 miles. I sold the motor for $25, and it ran for at least 60,000 more miles before I lost touch with the buyer. The 132CID grey motor had no oil filter at all. For years the Canberra dealer had pressured my father to have a NASCO bypass filter fitted, but it never happened as my father regarded a bypass filter as detrimental. Instead, regular oil changes did the trick. His theory was and is that only a full-flow one will do, and that the long engine life was due to having no tacked-on filter. When he was in the market for a MkVI or R-Type, York Motors made grave warnings about any car without the full-flow conversion. Bert Ward and his colleagues at Yorks were completely outspoken about the need for the conversion of earlier cars, confirming the doubts about the usefulness of a bypass filter. It was a factor in buying an R-Type, along with the boot space suitable for more than just a lunch box and a can of Coke. Marty, early 4 ¼ L cars need the block to be removed for machining to fit the full-flow filter, whilst it is bolt on in-situ for later cars if you can find the parts. I am sure that Bill Coburn can define the engine number from whence they were factory-prepared for a full-flow filter as he modified his Silver Dawn SDB94 in the 1970s. More recently, another Club member has just modified his Silver Dawn 4 ¼ with a homegrown kit. We await his write-up anxiously as it has travelled quite some thousands of miles in the months since its rebuild. According to my records, cars from Bentley chassis B2MD have the full-flow filter. Cars from B2HD are machined ready for a full-flow retrofit in-situ as that was how the motors were run on test. This ready-machined status applies to Silver Dawns from the C-Series, Silver Wraiths from the F–Series and Phantom IV from the B-Series, but the full-flow filters were standard production immediately on Silver Dawns from the C-Series, Silver Wraiths from the F–Series and Phantom IV from the B-Series: presumably the poor Bentleys missed out for those chassis from HD to MD so that stocks of bypass filter apparatus could be depleted ! RT. | ||
| Robert Wort Grand Master Username: robert_wort Post Number: 366 Registered: 12-2004 |
The conversion carried out by another Club Member on his 4 1/4 litre Silver Dawn was carried out by John Harriman. Unfortunately, he hasn't got a PC so as soon as he has finished his write-up of the exercise, I will send it onto Praeclarum. In the meantime, here are two photos of his conversion prior to camouflaging the pipework.   | ||
| Martin Cutler Yet to post message Username: martin_cutler Post Number: 1 Registered: 7-2007 |
Thanks guys, Being an LH, that should mean no machining of the block is necessary. I am keen to do this, so will dig out the info at the next club meeting. I am not afraid of regular changing of oil, but the full flow filter would keep my mind at ease. Cheers Marty | ||
| Peter Colwell Frequent User Username: peter_colwell Post Number: 52 Registered: 3-2005 |
Further to my earlier post about by-pass filters. Cars so fitted normally have an extremely fine gauze filter on the pump intake, which takes the place of the full flow filter to some extent. The downside being that this filter can block fairly easily, with predictable results. But usually plenty of warning. That may well have been the cause of the crank failure mentioned earlier by Bill C. The upside of by-pass is that the oil itself stays very clean. By-pass filter elements are much finer than full flow, because they do not have to deliver the same amount of oil as full flow, which must deliver 100% of engine needs at all times. Under laboratory tests, which results I no longer have, I remember that some elements of oil contamination were actually better under by-pass conditions than full flow. While full flow has many advantages, it is not quite as simple as would appear at first thought. |
