| Author | Message | ||
     David Penn Unregistered guest Posted From: 72.58.168.236 |
I have some questions about engines... [to the moderator, I have tried to join the forum] I have a question regarding the overheating>relaxing of main bearing cap bolts>Low oil pressure problem. If someone were to come across a car which had overheated very recently and now had the low oil pressure, could this be corrected prior to catastrophe? I mean, is it as simple as re-torquing the main bearing cap bolts prior to any damage happening? What is it exactly that allows them to relax? I hear it is the engine block changing dimensionally. Is this correctable by tightinging the bolts? IF Not, what about a specially made oil pump which provides higher than normal pressure? In other words, just let the bearings have a little extra clearance, and shoot more oil in there. For me, a full rebuild of the engine is out of the question with replacement engines available so cheaply. First I have to see if I really have a problem, or if I just have a faulty oil light, which lights up on idle after the engine gets hot. I have ordered a mechanical oil pressure gauge to find out, and also a new sender for the oil light. I am hoping it is just the light, since there is no evidence that the car ever overheated. It runs cool now, even with the a/c on, sitting in a traffic jam, when it is 100 deg. Fahrenheit weather. Then, if I am to replace the engine, I have to decide what to do. I found a used 1999 Silver Spur engine with complete, with turbo, lots of power, which I can get for the same price as a rebuilt shadow engine. I have fantasized about installing this in my car to get the modern power plant in a chrome bumper car. This would involve some fabrication work to continue the rr363 hydraulics, since the modern motor has a mineral oil system and different positioning of accumulators. This is perhaps more trouble than it is worth. On the other hand if I did it, I'd have quite a car. But maybe it would ruin the resale value? I was thinking about rebuilt and replacement engines in general, and I thought that it might be unwise to use a 40-45 year old engine block as the basis for a replacement engine, given the design. I hear that the studs for the cylinder heads go way down into the bowels of the engine, and that these can release themselves after some time, and you can't get the heads tight anymore. So it seems to me, to at least use the block from a modern engine as the basis, even if you are not going to install emmissions controls and EFI, etc. After all, if you put in a block that is 20 years newer, you'd have 20 more years before it failed, wouldn't you? Or, are all the problems about old blocks correctable in a machine shop? The head stud problem, etc. In other words, if you found an old block that looked good, just because the head studs are holding now, does not mean that they will be holding a year from now. It seems to me there is no way to tell the condition of those things, so if anyone knows, can those problems be corrected in a machine shop, or is the problem fundamental to the degradation of the aluminium itself? (all this would have a bearing on what I would choose for a engine to replace the old one, if it needs replacing...There are rebuilt engines available, but I need to decide which one to get, especially if I can get a more recent one for the same price as an ancient one. And if I am going to get a used engine, I'd rather have a recent model if possible, like that 1999 model, even if I had to strip all the modern stuff off of it, change the rings, and fit carburetors to it. Thanks for any advice on any of my concerns (Message approved by david_gore) | ||
| James Feller Grand Master Username: james_feller Post Number: 319 Registered: 5-2008 |
Hi David, I suspect the oil light maybe a culprit, giving you misleading info David, also if there was really no oil pressure the engine should not run....it should have a cut out relay linked to the fuel pumps I think that should stop the engine. This was designed at the factory to help ward off catastrophic engine damage with respect to coolant loss thus overheat and permanent damage. The situation you describe above I don't believe indicates this....the cool running and good performance the car is exhibiting does not indicate the engine has sustained catastrophic damage....but again I cannot see or hear it so im only forming this opinion on what you describe. If indeed the engine sounds ok, is holding a steady enough coolant temp and performing well then it may just be the light giving a misleading diagnosis. I badly damaged/overheated engine usually exhibits some of if not all the below characteristics poor and or noising, lumpy running when hot hissing gurgling sounds water mixed in with the engine oil poor performance blue smoke from the exhaust condensation from the exhaust when hot ( note all engines will have condensation coming from the exhausts as the exhaust system needs to warm up. I believe there is a buzzer too that the factory did install on SZ cars to indicate imminent overheat...but your car is an SY so im not sure about the 'buzzer' on your model. As for transplanting a 99 Turbo charged V8 into a much older chassis its my opinion only that yes this would indeed be a lot more trouble than attempting to source a more period engine for the vehicle. The later turbo engines had vastly different manifolds and exhaust arrangements, mountings and the like. Not to mention the engine management system that would need to be carried over into the older car. As for resale....whos to say but frankly what you would have if you were able to successfully transplant a turbo charged motor into to an older SY car is a real handful and a bit of a mongrel to be honest. Not only would you have to uprate the suspension, compliance,exhaust systems but ignition and electrical systems were vastly different. What about the braking system too??? and yes you are correct wrt to HSMO. Later cars all ran mineral for brakes and suspension systems. All these items would need uprating to cope with extra weight and power the engine would produce. The block in later 20,000 series SZ cars and on is different too to earlier cars. A new firing order was introduced, pistons and crank are all different and uprate from the SY period. Would be interesting as an exercise though David that's for sure! What may I ask is wrong with the 99' car? is it a wreck with a good engine? In summary check that your current engine sustains good oil pressure and coolant temp and the oil is not contaminated with water. Check these first David before assuming the worst on your current engine, if in doubt get a mechanic to do a compression test as well.... Keep us informed on how you go! cheers J | ||
| James Feller Grand Master Username: james_feller Post Number: 320 Registered: 5-2008 |
Also remember that early 6.75 V8's in SY cars were down rated wrt power output for longevity really. While able to cope with much more power output they generally produced about 200hp when new. Early turbocharged cars produced 50% more power about 300 hp when introduced new in the Mulsanne Turbo Bentleys in 1982. Later cars mid to late 90's Bentley Turbos were easily producing 350-400 bhp. The Bentley RT's for 1997-1998 are said to produce 420 hp. So that's in effect, double the power of your early SY David. The SY chassis while similar to the SZ has much improved mechanicals to cope with the immense power increase. Don't forget about the uprated gearboxs, torque converter and final drive shafts, all these were uprated for Turbocharged cars from the naturally aspirated cars. In saying all of this, Crewe of course were testing their Turbo charged engine in the SY platforms for a decade or so for the impending 'wolf in sheeps clothing' SZ Mulsanne Turbo in 1982. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2913 Registered: 4-2003 |
If the motor has been badly overheated, then it can normally not be rebuilt. If never overheated, a 1959 Crewe V8 is readily rebuilt to perfection provided it has not been treated to water with only a dash of coolant in its cooling system. Mind you, the need to rebuild as Crewe V8 is very unusual and mostly only due to ageing of the cylinder liner seals in unfortunate cases. Fortunately, the liner seals were improved a decade ago and should not leak anymore. However, if a mildly-overheated motor now behaves, there is probably nothing really wrong with it. Only if the oil pressure is genuinely less than 2psi at idle and the tappets ratlle at idle could you blame bearings, and in that case retorqueing them is a waste of effort. At 800RPM, even a Crewe V8 in very poor shape is correctly dumping 90% of the oil deliverd via the pressure relief valve, and by 1500RPM 99% is dumped. If the pressure gauge is reading low, then it is usually an instrumentation issue and very, very seldom an oil pressure control issue. If the oil pressure regulator is faulty then there is quite a large job to be done albeit with very few parts costs involved. Many, in fact most, pre-1990, SZs and SY2s read low oil pressure on the gauge at all times (James, remember yours) simply because they still have the rubbish early UE40480 pressure sender fitted. Dump the UE40480. Many outfits like SpurParts decline to sell the expensive and unreliable electromechanical UE40480 and only offer the load cell one fitted to later cars, UD72639. UD72639 has the same calibration, costs 2/3 as much and lasts forever. RT. | ||
| James Feller Grand Master Username: james_feller Post Number: 321 Registered: 5-2008 |
Yes you raise a salinet point RT. the original oil pressure switches by now are all fairly rubbish at indicating anything other than the engine is on.... on my Spirit and Bentley Turbo RL both gauges used to indicate the engine was alive when cool, but when the engines were warm and at idle they usually indicated nothing more than they were getting a reading...once underway and the engines was powering, the gauges would rise but frankly they were little more than a cursory indication of 'combustion' thus pressure... I never bothered or worried about the gauge readings in the end. The only guage readings I made sure were accurate were the coolant temp and fuel...  RT, is correct in saying the pressure sender units attached to the side of the block, the gauges rely on, simply go to pot after years...could not hurt to replace them with the better units stated above in RT's post. J | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 130 Registered: 9-2003 |
Yes, the UE40480 (or Smiths part# PT1801-06 for '61-'71 Jaguar) is pretty expensive at $65.95 USD, but it has one post compared to UD72639 two posts. Is there a specific way to connect it? UE40480  UD72639  | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2917 Registered: 4-2003 |
The later o UD72639 type has two posts indeed, marked G and W. G is for the Gauge. W is for the Warning lamp, the switch being integrated into the later type. On those cars, the separate oil pressure warning switch is deleted. You may use eithe as you chose. I prefer to retain the separate unit as if one fails the other probably does not. When your switch finally fails, leave it there provided it does not leak and connect it to W on UD72639. There is a Service Bulletin from Crewe about this. UE40480 is absolute rubbish. Mine used to last as little as 6 months before they started to misbehave. RT. | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 131 Registered: 9-2003 |
Ah, makes sense. What's your SpurParts price on the UD72639? Also it seems to be a VDO unit. I don't see any 60psi/4.1 bar alternates. Just 5 or 10 bar and 80psi alternates by VDO. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2920 Registered: 4-2003 |
Larry, Indeed the UD72639 sender is sourced from Siemens-VDO. It is built on a standard VDO 360.xxx architecture like most VDO oil pressure senders. The markings are W-G (warning-gauge) as opposed to normal VDO W-K (Warnung-Kalibration). It is nominally rated at 5 Bar / 73 psi. So far so good. However the output calibration range is not a standard VDO range. Most VDO senders are rated at 10-199 Ohms or 10-184 Ohms. The specials supplied to Crewe are, I believe, 30-135 Ohms, which gives the correct readout on the dashboards of our cars. So, although the old PTR Smiths sender gives a 0-400kPa (0-4Bar) range of some 30-120 Ohms, the reading of the VDO gauge is the same in that range. Prices ? The PTR Smiths part number PT1001-06 (sender) is about twice the price you quote for PT1801-06 but PT1801-06 is a switch not a sender. ps the -06 suffix is for 60psi. If you cut a Jag PT1801-06 open as I did when I bought one for about $50 (and it doesn't work in an SY-SZ) you will see that it is merely a switch. Jag guys like a steady gauge, so the PT1801-06 switch plugs the gauge to NORMAL !! as soon as a reasonable pressure is reached rather than giving an analogue reading. UD72639 units sell here retail for somewhat less than the UE40480, all on-par with UK prices. UE40480 is so expensive because of the high rate of warranty claims. In either case, the specialist spares suppliers charge no more than for these items than would VDO or PTR for direct sales to individuals. VDO sells UD72639 senders to the Crewe primary spares network but will not supply to the trade, let alone retail, as the volume to distributors would be very low and it would be a logistical nightmare. Fortunately the supply chain in the Crewe network is not greedy. RT. | ||
| Doug Penn Yet to post message Username: dpmc Post Number: 1 Registered: 9-2013 |
I was the original poster of this discussion, I am now registered on the forum with this name. I have doubted that any problem exists, mainly just asking questions in case of an unexpected problem and for theory discussion. The car with the oil light problem is prior to serial # 9000 SY car, so I doubt it has the buzzer of fuel pump cutoff, and I should have said the car # upfront. It runs and looks as new with the only trouble being this oil light. I have heard of people selling cars cheap, on account of oil lights, only to be informed years later that a $9 sender is all that was needed. I wasn't gonna let that happen here. But I still wanted to know some of the answers pertaining to rebuildability of the engine and the phenomenon of the long head bolts which TEE ONE Topics has said can let go in old blocks, and I wondered about if this can be repaired or if the block is fundamentally metallurgically compromised. Thanks for all responses. I will report any interesting findings about the oil pressure. I also wonder if it is a good idea to take the radiator out and have it rodded out as a matter of course, and for no other reason other than it is over 40 years old and could probably benefit from this, allowing a cooler engine. (no matter how cool it runs, cooler would be better if some of the passages in the radiator are blocked. Well that was my idea anyway... I guess my real question is, could a radiator remain unblocked for 40 years, or would they all be partially blocked even with coolant flush every 2 years?) | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2921 Registered: 4-2003 |
Honestly, Doug, If the radiator works OK and if the coolant has always been just that (40%-50% spec inhibited glycol) then there should never be a problem. Rodding it would possibly cause more damage than good. If you consider having it rodded as a precaution, I would recommend a recore instead as a recore costs only about $600 and a repair over half that. RT. ps I must look up when the buzzer warning was introduced. It was probably when the early temperature gauge was deleted around Chassis 9000 (it measured at the rear of B-Bank cylinder head, read too high at normal running temperatures and owners worried, so Crewe deleted it). My '72 has a buzzer, but like the men on mars I have only heard it when pressing the test button. | ||
| Jan Forrest Grand Master Username: got_one Post Number: 507 Registered: 1-2008 |
From experience I've found that the main cause of rad failure is blockage by 'furring' (calcium deposits) left from using tap water. This can be delayed if you are living in a 'soft' water area, but can be avoided entirely by using distilled or de-ionised water in the cooling system. If it is too late for this a more aggressive approach is required. Citric acid crystals are the answer. Considering the quantity of coolant our engines require to keep cool I would recommend not less than a full kilo of the stuff poured directly into the cold header tank and left overnight to think about it. By the following morning the evidence of previously blocked passageways will be evident by a lowering of the coolant level. So far so good, but it's not over yet. Top up the system and use the car for a few tens of trips with the coolant being brought up to full operating temperature on each occasion. This allows the CA to achieve boiling point when it works far more efficiently. Fortunately although CA dissolves calcium compounds and most metal salts it is ineffective on most pure metals - particularly iron, steel, aluminium alloys and copper/brass. Eventually you can drain the system, flush it thoroughly and refill with a 50:50 solution of anti freeze and DI water. I've used this method on a variety of makes/marques and never had a problem from it. What the hell? It can't hurt! | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 132 Registered: 9-2003 |
Interesting. I've had a number of people over the years contact me that the PT1801-06 (and some using the PTR1801-06) showing varying pressure on the gauge dependent on temperature and RPM, working well on their SZ. Including correlating to testing the engine with external gauge. Other than every source that markets it under "sender", as opposed to other smiths oil units they specifically put under the "switch" column - you're the first to tell me otherwise. But, its a moot point if the VDO unit is better at a similar price. The exact full VDO part number specifically for our cars is 360-081-030-136C. Is the assumption that the last part means a range of 30-136 Ohms, similar to what you said above? | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 133 Registered: 9-2003 |
I don't know if I am not supposed to trust their answer, but I asked VDO directly: "In getting things correct, in terms of specs, can you send me the info on the Ohm range for the VDO 360-081-030-136C oil pressure sender? (Not the "bar" or psi ranges)" Their answer to me: Larry, The ohm range for that sender would be 10-180 ohms. Best regards, Technical Support Team Business Unit CVAM Continental Division Interior 6755 Snowdrift Road Allentown, PA 18106 USA 1-800-265-1818 http://www.continental-corporation.com Please visit the all new online VDO Instrumentation Catalogs! www.vdo-gauges.com |
