Asciidv

Today I replaced the strainer assembly with a straight forward turned piece of black nylon bar with a hole up the middle. This was a tight fit into the base of the pump and cleared the floor of the sump by about 1/2". With the sump back on, I started up the engine, and YES, total success! Good and steady oil pressure without any fluctuations. So all I need now are the new sealing rings to put into the strainer assembly and all will be as good as new. Here is a video showing the oil pressure. The engine is missing a bit, but I am sure new plugs will soon sort this out. [video=youtube_share;MVr4ma7W50E] Barry.

Richard Bannister is now onto the case with Richard Farrant having provided the lead with a part number (Thank you Richard). I must say that Bannisters are absolutely first class and should be the first people to deal with for B series engine spares. I have used the 'other people' in the past but there is just no comparison if your request is a little odd. Thanks, to all who have responded, Barry.

The video doesn't tell the whole story. Prior to even trying to start the engine, I dropped the sump, cleaned out all the old oil and replaced the filter. The lack of ZERO oil pressure on this first start was due to a faulty gauge. Having replaced the gauge I now see the correct oil pressure (around 8lbs at tickover, which is correct according to the manual) in fits and starts. Could a sealing ring have deteriorated in 8 years? When I cleaned out the sump, nothing struck me as being particularly solid like old rubber, but I suppose I was looking more for metal. It is a mystery! Barry.

Trevor, I do have a workshop manual for this engine but there is no mention of a sealing ring. The whole strainer assembly hardly has a mention at all. Are parts books available? The idea of a floating strainer seems a bit too complex for the purpose. Surely a fixed strainer at a depth of say 1/2" from the bottom of the sump would be just as good? Anyway, the plan for this weekend is to run the engine with a fixed pipe direct from the base of the oil pump to within 1/2" from the floor of the sump. This will prove or disprove the notion that the air is entering the system through the strainer pivot joints. Incidentally the sump on this engine is a nightmare to remove. There are 5 sump nuts on either side of the engine completely masked by a sideways extension of the sump. Getting them all back on takes at least two hours, so the plan is to leave them off until final assembly time arrives. As one of you might have guessed I have been a little reluctant to disclose into which vehicle this engine is fitted for it is a FIRE ENGINE without any military leanings at all. I hope I can be excused.... https://www.youtube.com/watch?v=9fOwWxXLipcBarry Barry.

Here is a short video which shows the problem; Thank you for the responses so far, I will reply to the suggestions in detail a little later. Thanks, Barry. (It is an HD video, so it will play full screen for maximum clarity).

I am needing some advice from all of the HMVF Rolls B80 experts! I bought this machine 8 years ago and now is the time to breathe life back into the engine. At the time that I bought it I was told that the engine was fine (which I tend to believe). The problem that I have is that the oil pressure fluctuates. The key to the problem (I think) is that if I take the oil pressure gauge pipe and hold it under a bath of oil, oil pumps out, then air, then oil, then air.... It seems that the oil pump is sucking up air as well as oil. On this engine the oil pump is connected to the strainer by a pipe which has two pivoted joints. The joint closest to the strainer allows the strain to tilt up and down so that it can 'float' on the surface of the oil - according to the manual. I think that actually it will always remain submerged in the oil along with the pivoting joint. The second pivoting joint allows the whole strainer to rotate in a horizontal plane so that it can swing through about 90 degrees in the sump. Why you would want this to happen I just cannot guess. This joint is just above the oil level and is a very loose coupling. I think the problem lies here. If you take the joint apart you see that the pipe from the strainer has a flange and a pin locates under the flange to hold the pipe in place. Just under the flange is a groove and I wondered if an 'O' ring might fit here. In the picture you can see the 'O' ring in place. However the 'O' ring can only seal on a very narrow area of the casting just above where the pin emerges. It doesn't seem a very clever design if it is meant to be like this. Also I have my doubts that 'O' rings were even available in the early 50's? So what do you think? Has anyone ever encountered anything like this before? Any suggestions would be gratefully received. Barry.

I just cannot wait for the news from Brighton!

I am having the wooden wheels from my 1914 Dennis re-hooped. The plan is to have oversize hoops made and then turn the hoops to size when on the wheel. The hubs will be fitted and everthing will be turned with respect to a shaft running through the hub. This will ensure that the wheel assembly is truly round and that I can obtain the correct interference fit for the tyre band. Some things concern me. First I doubt if the tyre band is very round as it will have just been ring rolled and welded up so all the precision making the wheel round will have been wasted! Secondly no-one yet has has been brave enough to say how much oversize the wheel should be. I wonder what was the original specification? Incidentally I did think that the pi-tape that Andy suggested was ideal for this work so it is now winging its way towards me. If anyone wants to borrow it, just ask. I already have a suitable bore gauge so the metre long digital vernier calipers will not be necessary! However, all the time, I come back to thinking that the wheels were put together 100 years ago by blacksmiths who were more use to cart wheels, so surely we can get it right today. (Just as final note, my hoops had been loose in the tyre band so someone in the past just seam welded them in. I spent weeks and weeks with a hacksaw blade cutting them out). Barry.

Here is a U.K. supplier of those special drills for drilling square holes. They are not particularly cheap! Barry

Yes, I own up! I only looked at the pictures! Somehow I missed the words that explain all...:nut:

......and now when I look a little closer did you cheat and have them laser profiled!?

What a lovely job! A very nice square in the centre, those special square drills you bought have have certainly come in handy! I am however puzzled as to why you didn't start off with a bit thicker plate and then just milled the channel in? Best wishes, Barry.

Although the filter size may be the same on military B60/B80 engines, those supplied for commercial use (like fire engines) had differing sizes. I spoke today with Bannisters and they were very good, wanting to know if my filter had a flat sealing ring or the later 'O' ring type. I now have a filter winging it's way towards me. I have been trying to revive a B80 which has not started until a couple of weeks ago for 8 years. As you will see from the video there is a problem with the oil pressure. When it was last running oil pressure was good, so I suspected that there might have been a problem with the oil pressure relief valve. [ATTACH=CONFIG]87569[/ATTACH] When I took this apart it was particularly 'gunged up' so I hope that it is the solution to the low oil pressure. Has anyone had similar experiences? One final question. My oil strainer not only pivots in the vertical direction (so that it can float on the oil surface) but it can also rotate through 90 degrees in the horizontal plane. Does anybody know why? Barry.

Resuming a discussion from 4 years ago....! Can anyone tell me the best place to buy a B80 oil filter like this one; It is the spiral wrapped felt blanket type. Is there only one type of this filter? Marcus Glenn didn't seem to be very sure. Barry.

I always thought the Thorny wasn't quite the standard of a Dennis!

Tony, is it time for castellated nuts next?!Barry.

Steve, I had thought that there must be some 'trick' to this. For the moulder to produce his own centre lines (especially on the thin features like the angled spokes) must take a great deal of skill and experience. When this wheel pattern goes off to the foundry it would be wonderful if they gould take some pictures to show how it is done. Barry.

Steve, How exactly do they cast this? I was puzzled by the Dennis wheel and the recent pictures have raised the same question. There must be a simple trick but what is it? Barry.

Although there must be a 1001 ways to resolve the piston problem, here is another, which resolves both the weight problem and also gives the required increase in compression. Quite simple as much of the crown is turned off as possible leaving a small spigot in the centre which is then screw cut. An aluminium disk is then screwed on to replace the removed material. Barry.

Wally, The book that you took the scan from, seems a very interesting book. What is it called? Thanks, Barry.

Too small for a Leyland Mastiff.....

Things will definitely go easier and quicker now that you have canine assistance. Where did he spring from as this is the first photographic evidence of animal help?!:cool2: Barry.

I was a bit disappointed to see you using a 'modern' edge finder to assist with your machining operations. I had imagined that if you machined whilst wearing a flat cap you would complement it by using a piece of 'fag paper' to find your work piece edge!. Used since the dawn of machine tools it still gets you to within a thou and and half. The alternative to the device shown in the previous post is an electonic edge finder. A 'beep' and an LED shows when you have made contact with the metal. The advantage with this type of device is that you can work in all 3 axes, but it is of course restricted to electrically conductive materials. For non-conductors - well that is when the 'fag paper' is used.

This is going to be interesting! Are you going to cast the core box from something like plaster of Paris? Barry.

Well, that is a difficult question to answer. Perhaps it was the fourth unnecessary rivet that drove Thornycroft into decline due to the extra expense. Two weeks ago I was at a Dennis Factory open day, where you could see steel entering one end and complete bus chassis leaving the other end. There were no Fire Engines on the lines (and never will be anymore) but at least they are still manufacturing despite Steve having left them several years ago! Barry