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Post by dmaxwell on May 16, 2022 22:03:24 GMT
Yes, US gallons.
David California
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Post by z900rs on May 18, 2022 21:02:36 GMT
Thanks Peter, I'm pretty happy with exterior and interior, currently working on detailing the engine bay, and chasing all the minor oil leaks.
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Post by tarnowl on Jun 1, 2022 16:54:46 GMT
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Post by tarnowl on Jun 1, 2022 17:03:46 GMT
Now We have removed the front subframe with the engine, so that we can start to strip the assembly down and make repairs as necessary.
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Post by tarnowl on Jun 1, 2022 17:13:38 GMT
The radiator is ready for replacement and repair, but what are the 2 small threaded ports for as they were not connected to anything? Also, On the other side it seems unbelievable that the oil cooler receives sufficient cooling by merely being attached to the main radiator? Attachment DeletedAttachment Deleted
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Post by tarnowl on Jun 1, 2022 17:15:02 GMT
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Post by dmaxwell on Jun 1, 2022 18:19:48 GMT
The two small threaded ports are probably for the auto transmission cooler. Looks like someone has added an external cooler to the radiator and ran the hoses to that instead of to the built-in cooler.
David California
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Post by Phil Nottingham on Jun 2, 2022 7:02:44 GMT
That is the wrong oil cooler for the transmission. The correct one is inside the rad and is connected by the 2 unions near the bottom. They are notorious for leaking and antifreeze or water in the ATF wrecks the box. Mk 3s had the oil cooler at the front of the rad far more efficient than the rad version and one mounted behind. There is a thread on a conversion on here and my FB page has pictures of my conversion in my public albums www.facebook.com/media/set/?set=a.1089946194449935&type=3
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Post by Sam Bee on Jun 3, 2022 18:01:29 GMT
It is a common practice to add a suplimentary cooler to keep the transmission oil temp down (but not too much!). Such a cooler can thus be small. Plumbing is from the gearbox to the radiator (as per normal), then from rad' to the cooler, with return from the cooler direct to the gearbox. This is what I am fitting, but then I have an engine pushing out 210+ h.p.
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Post by tarnowl on Jun 4, 2022 6:58:07 GMT
I have noticed that there are a fair few who have fitted supplementary oil coolers to replace the original method of cooling using the main radiator. Is it because people have found the original method of cooling the ATF to be insufficient or unreliable? I note that JRW offer not only the standard radiator core, but also an uprated version, aimed at those who have problems keeping the temperature down. This has never been a problem on my P5B Coupe, but as I live in southern France, I am wondering if I might be better to move to an uprated rad, as it can get quite hot here and maybe a more efficient cooling might be better all round? Comments would be appreciated please?
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Post by johnwp5bcoupe on Jun 4, 2022 11:44:47 GMT
I went retro back to the MK3 as all the mounts are there a bit of machining on the connectors and a tricky bit of pipework! but it does the job beautifully :-)
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Post by tarnowl on Jun 4, 2022 16:26:56 GMT
Hi John, Very nice, but is the original lacking in some way as a cooler? Is it inefficient? Also, if it is better, is it still possible to get Mk3 oil coolers and brackets? (David Green springs to mind?)
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Post by enigmas on Jun 4, 2022 23:51:09 GMT
John's work as always on his pristine coupe is exemplary. The Mk3 P5 Rover was the final iteration of the 6 cyl IOE powered car both in sedan and coupe version. It ran virtually the same power train transmission and brakes as the P5B with the obvious exception of the GM alloy V8. The BW35 transmission even incorporated a rear pump within the rear section of the casing which allowed the car to roll start if towed to the 60 kph mark. My hybrid mk3 coupe (utilizing a 4.4 litre P76 V8) still uses the original mk3 case and rear pump, though fitted with OZ BW40 internals. It still runs the original Mk3 oil cooler as fitted to John's P5B.
Now the question as to the care and longevity of the BW35 is not always necessarily down to maintaining low transmission fluid temperatures but maintaining an optimal transmission temperature. This parallels in ways why a thermostat and correctly sized radiator and appropriate cooling fans are needed for the engine. Running an engine either too hot or too cold is detrimental to the long term life of an engine. The two opposites with engine oil temperature, either "mayonnaise" (too cold, entrained moisture) or "blackeden & burnt", too hot running beyond the oils ability to both lubricate and cool engine components are effectively to be avoided.
Most big engined 6 cyl sedans in OZ (from 3.5 to over 4 litres) from the 60s to the 80s that used the BW35/40 used the simple and cheap expedient of running trans coolant lines through the bottom tank of the radiator. This method sufficed for the most part. If the car was to be used for towing purposes (large trailer or caravan) then an auxilliary trans cooler wouldbe fitted. The Rover MK3 version is an early design type cooler. There are more efficiently designed versions today made from aluminium which pass the ATF through myriad tubes before it is returned to the transmission. In some cases the air cooled trans cooler is plumbed in series with the coolant lines in the bottom radiator tank. Depending upon the climate, the fluid also needs to be brought up to optimum running temperature for effective operation. Viscosity of the oil is affected by temperature and this directly affects the transmissions operation. You may note that the trans in your P5B or mk3 performs better after the car has been warmed through. The function of the valve body, bands and clutches are directlty affected by the ATFs viscosity.
There is an optimal temperature for trans fluid, this is in the range of 170° - 225°F. If the transmission is slipping or the vehicle is worked hard, the temperature could rise above 240 degrees.
If you are really anal about your transmissions health, then options such as a trans temperature gauge and trans thermostat can be plumbed into the coolant lines.
If you care for your classic car I'm sure your not likely to abuse it through careless boy racer treatment. A modicum of mechanical knowledge is an asset for the ongoing care of your classic. Simply put, "You pays your money and takes your choice."
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Post by tarnowl on Jun 5, 2022 6:50:50 GMT
Many thanks for the informative response. To me, it seems like a good plan to use an external oil cooler and perhaps the set up in the Mk3 is tried and tested, so probably the best option. Are these coolers still available?
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Post by johnwp5bcoupe on Jun 5, 2022 9:02:41 GMT
Hi John, Very nice, but is the original lacking in some way as a cooler? Is it inefficient? Also, if it is better, is it still possible to get Mk3 oil coolers and brackets? (David Green springs to mind?) The MK3 oil cooler works fine for me I noticed the difference on my first run! it's entirely made from copper so should disperse heat well, you may be lucky finding a MK3 cooler David should be your first call ;-)
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Post by Sam Bee on Jun 5, 2022 11:12:56 GMT
Very nice John. There are two uses of oil cooler, either for engine oil or transmission fluid, I was talking of the latter. I have found that a well maintained V8 has no problems with engine temperature, apart for being stuck in a traffic jamb on a very hot day. As pointed out, one must not run too cold, engine or BW35. As well as fitting a gearbox oil cooler it is wise to fit a temperature gauge to keep an eye on it. The effect on the life of an automatic box is directly related to temperature, as the following from the internet:
At elevated operating temperatures, ATF oxidizes, turns brown and takes on a smell like burnt toast. As heat destroys the fluid’s lubricating qualities and friction characteristics, varnish begins to form on internal parts (such as the valve body), which interferes with the operation of the transmission. If the temperature gets above 125 degrees C., rubber seals begin to harden, which leads to leaks and pressure losses. At higher temperatures the transmission begins to slip, which only aggravates overheating even more. Eventually the clutches burn out and the transmission calls it quits. The only way to repair the damage now is with an overhaul. As a rule of thumb, every 15 degree increase in operating temperature above 80 degrees C. cuts the life of the fluid in half!
It should be noted that such degredation of the ATF results in premature wear to gearbox mechanical parts too.
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Post by johnwp5bcoupe on Jun 5, 2022 13:58:28 GMT
Yes I gathered we were talking about the transmission cooler :-) The other thing is we are all guilty of is leaving the box in Drive on a hot day when in a traffic jam or queuing for a long time, the transmission fluid gets hot and so does the engine! using a combined radiator was never a good idea
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Post by Phil Nottingham on Jun 6, 2022 8:27:07 GMT
The Mk3 cooler is only available secondhand. I used a new Mocal 13 Row version as recommended by the firm that rebuilt my autobox in 2019. The Facebook link above shows the set up. Fitting was straightforward
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Post by Sam Bee on Jun 6, 2022 20:44:48 GMT
I have a Mishimoto, it is only 3/4 inch deep.
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Post by eightofthem (Andy) on Jun 7, 2022 9:47:34 GMT
Excessive heat is the biggest killer of automatic transmissions. The " thing " that is fitted on the P5B is nothing more than a heat exchanger and is not fit for purpose on such a large vehicle. Fit a separate fluid cooler, I would not worry too much about over cooling unless you live in a very cold climate, in which case leave the original set up in place. Also dare I say it, keep to the original fluid specification.
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Post by Torben Jespersen on Jun 7, 2022 20:54:44 GMT
well well, time is running. I collected my P5B (VIN 84800004A) from Timon Van Lenthe in Holland in December, test started the engine and tested the BW gearbox. Pulled the engine in the morning of Christmas eve . At pressent the body is mounted in a "rosseretti" and sandblasted. Front and A-posts are rebuild and I have just started welding on the C and D posts. This bodyshell has all the illness mentioned and illustrated in this fantastic forum ....and a bit more...i assume... I hope to be able to send it to the paintshop and begin fiddling with the mechanical parts next winther. The engine needs full restoration, gearbox is still under consideration
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Post by lagain on Jul 6, 2022 19:54:28 GMT
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Post by MK IA Norway Viking on Jul 7, 2022 9:36:21 GMT
... and the ad says "no expense spared and undergone comprehensive restoration valuing north of £170,000 leaving nothing unturned". Will that even be remotely possible I would not take this ad seriously, and think we should remain sober about our cars. That said, values are going up - especially now with the rate of inflation being what it is.
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Post by johnwp5bcoupe on Jul 7, 2022 10:59:50 GMT
That price and 170K + you think they could have done the Coach Line George
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percy
Rover Rookie
Posts: 74
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Post by percy on Jul 7, 2022 12:50:09 GMT
Yes and the sill trim seems to be a bit short as well. The painting of the waist level coachline seems to be a real problem for restorers of all abilities. It's often missing or in the wrong position.
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