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Post by Jens Munk on Jul 21, 2020 15:02:10 GMT
Truth of the matter is that it has never been really good ever since I got it. When I got it, it had stock springs, I believe, and one of them had a broken leaf. All rubber mounts and bushings were due for replacements. Bushings were replaced and so were the springs with the only available at that time - the too high sitting heavy duty springs from Wadhams. Engine and transmissions have been overhauled and balanced and so was the prop shaft the first time (poorly - I just learned) - all of which had no notable effect on these irritating body vibrations. But I was not until not that long ago aware that prop shaft alignment could make such a big difference - my ignorance.
The last thing I did was to install the new 7-leaf springs giving the correct height. Again about the same level of vibrations as before until I filled the car with three passengers and their luggage. That was bad and hence I started to investigate and learn about u-joints.
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Post by enigmas on Jul 21, 2020 22:09:23 GMT
That does makes things difficult if you want your car to maintain it's original factory mechanical specifications Jen. I imagine it'd be useful if there was another P5B owner in your vicinity (whose car doesn't exhibit any vibrations) that would allow you to look over their vehicle so that you could investigate any inherent differences that may exist on close inspection. It would certainly save a lot of guess work! PS. I'm beginning to wonder how many standard P5Bs exhibit driveline vibrations? It'd be interesting to get some responses on this query.
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Post by Jens Munk on Aug 5, 2020 20:52:24 GMT
Update:
After all my attempts and measurement I have come to the conclusion that there is at present only one way to get the angles of the u-joints of the rear shaft right, i.e. flanges parallel, and modest. The rear end must be raised, which is possible with the HD springs, I have previously used.
So I have spent yet another day on to swap springs, and with the HD springs, 2 degree wedges tilting the pinion shaft up, 8 mm shims under the transmission mount and appropriate up/down adjustment of the center bearing, the engine is now at 3.8 degrees, the front shaft at 3.4 degrees, the rear shaft at 3.8 degrees and the pinion at 3.3 degrees (angles vs horizontal). And the prop shaft vibrations are gone!
Still a bit of a mystery to me why all this is necessary...
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Post by enigmas on Aug 6, 2020 0:27:32 GMT
Congratulations Jens....you've definitely had a torrid time correcting the angles.
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Post by drivader on Aug 8, 2020 21:40:34 GMT
Yes, it is probably time to do some actual vibration measurements to locate the culprit. Since I do in fact have an old but functional vibration meter laying around, how about using with the car on stands?
As for the transmission, it was rebuild a couple of years ago with assistance from John Wallet. Among other things all bushings were replaced and so was the converter. The drive plate has also been balanced when I had the engine balanced.
Wheels and brakes should be OK, but will check. Jens have you tried disconnecting the tailshaft at the transmission flange to ensure that the vibration isn't emanating from the engine or transmission. Transmission. Worn transmission bushes on the input shaft to the torque convertor. Worn bushes will allow the input shaft to slop about. Out of balance torque convertor or drive plate. (A fully reconditioned torque convertor I fitted was found to be out of balance) Rear Wheels/Rear Brake Assemblies/Final drive.* You really need to check these so that they can be discounted. 1. Are the wheels & tyres in balance and or running true. Jack the car up, remove rear wheels and free rev the engine in gear. 2. Brake drums. Theses are large cast iron lumps. As above in 1. 3. Bent rear half shafts. Not likely but possible. Observe flange rotation with engine trans engaged.
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Post by vincentacres on Aug 21, 2020 7:32:25 GMT
Have just been through the process of resolving a propshaft vibration. One universal joint was seized. Ordered new bushes from UK and a UJ locally. All 3 are the same and the part number in OZ is uj329 for any locals who have to do the same. The other 2 joints and the centre bearing were apparently fine. One drive home only so far but all appears well and no messing with angles required thankfully.
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Post by p5andrew on Jun 26, 2021 12:33:15 GMT
Oh joy! Oh rapture! Severe vibration finally eradicated.
When I purchased our P5B it had a very strong vibration which I had thought was probably due to the propshaft being out of balance. After rebuilding the propshaft with new U/J's and centre bearing, having a new sliding joint assembly fitted and having had the propshaft balanced (see previous posts) I was still left with a very strong vibration, particularly around 55-60mph. All rubbers replaced to the centre bearing carrier - still the same. Many hours spent trying various positions for the carrier - no change. Checked that flanges to transmission output and axle were parallel - they were not so taper wedges were machined up and fitted between the springs and axle - no improvement.
I recently acquired a spare axle assembly which came with propshaft and springs. The UJ's were good but there was very slight rock in the centre bearing, perhaps a thou' or two so was deemed good enough for now. The propshafts were swapped over and, hey presto!, no vibration. So it seems the problem all along was the propshaft being out of balance. The outfit who balanced the original propshaft assembly for me will now be invited to deal with it...
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Post by enigmas on Jun 26, 2021 14:10:02 GMT
There's nothing like expert repairs that are less than satifactory...if not incompetent!
I realise that you've been through a lot of drama trying to locate the vibration issue Andrew but are the universal joints on both complete tailshafts in correct phase?
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Post by p5andrew on Jun 27, 2021 9:41:31 GMT
I can confirm that the joints are in phase on both the original prop and also the one I have just fitted.
As a matter of interest, I also checked the brake drums for concentricity as there was a slight shudder on the pedal. We machined the drums true which removed the shudder but did nothing for the vibration. We also checked and balanced the rear hubs/half shafts which though probably within tolerance were slightly out of balance. Having our own engineering business has its uses!
The only vibration now present is engine/transmission-based and fortunately this is barely noticeable on the road and only occurs in the 1400-1900 rpm range so not there at cruising speeds. Having checked out the crankshaft damper and one or two other issues, I have concluded that the most likely culprit is the torque converter. While the engine was out I replaced the engine and gearbox mounts with new items from JRW and I also replaced the stabiliser rod bushes with some I made by cutting down some P6 shock absorber bushes. The crankshaft/con rods/pistons (+0.020")are those which came with the car and the crank was reground - the pistons appeared to be virtually new with only very slight scuffing on their skirts. The block is not the original as it was found to have a hairline crack running from the centre main bearing pedestal; a good block was obtained and bored +0.020" to suit the pistons. Having had the engine/transmission out only 18 months ago for a total rebuild (excluding the torque converter which was at that stage not thought to be in need of attention - typical!) my appetite for doing so again to check out the balance of the torque converter is not high at present!
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Post by enigmas on Jun 27, 2021 11:38:14 GMT
Been there and done that with the torque convertor on my P5 coupe many years ago now Andrew. I fitted a reconditioned convertor from a reputable business (the engine was fully rebalanced prior to fitting the convertor.) The car would jingle the ignition keys at exactly 60 kph. Above or below this speed there were no issues, This was very iritating as the speed is an average for driving in metropolitan areas. I put up with this for years! Eventually I'd had enough and replaced the torque convertor. I spoke at length with the proprietor of an alternative torque convertor business. This company also built convertors for race applications. He told me that some rebuilders merely mark the cases, split them, repair or replace the internals but do not rebalance the convertor. This may be your issue? Similarly the same issue occurred with my SD1 powered ZB MG Magnette (manual gearbox) except this time it was due to a brand new (laycock) pressure plate being 35 grams out of balance. The vibration was sudden and horrendous at about 3500 rpm the car felt as thougn it would shake itself to pieces! The fix was to remove the pressure plate and have it professionally rebalanced.
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Post by harvey on Jun 27, 2021 11:51:03 GMT
The only vibration now present is engine/transmission-based, I have concluded that the most likely culprit is the torque converter. my appetite for doing so again to check out the balance of the torque converter is not high at present! There are 4 positions that the converter can fit to the flexplate and you can move between them with out a major dismantling job. Just remove the half-moon cover plate, turn the engine to remove the 4 converter securing bolts, move the converter through 90 degrees relative to the flexplate, then refit the converter bolts and test, then repeat the process if it's worse or no better. Always fit the 4 converter bolts but leave them fractionally loose until the last one is started, then go round and tighten them
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Post by Phil Nottingham on Jun 27, 2021 13:27:04 GMT
The only vibration now present is engine/transmission-based, I have concluded that the most likely culprit is the torque converter. my appetite for doing so again to check out the balance of the torque converter is not high at present! There are 4 positions that the converter can fit to the flexplate and you can move between them with out a major dismantling job. Just remove the half-moon cover plate, turn the engine to remove the 4 converter securing bolts, move the converter through 90 degrees relative to the flexplate, then refit the converter bolts and test, then repeat the process if it's worse or no better. Always fit the 4 converter bolts but leave them fractionally loose until the last one is started, then go round and tighten them Yes that does work well
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Post by p5andrew on Jun 27, 2021 15:13:09 GMT
Many thanks to all for your thoughts. Trying the torque converter in alternative positions sounds like an excellent plan. I shall give it a go, though perhaps not for a week or two while I enjoy driving the car for a change! Also, my wife has designs on my time, having prepared a long list of house-related tasks. She is pretty understanding, but the Rover has been a pretty constant diversion over the last year or so. Actually, it has arguably kept us both sane!
I will report back in due course.
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Post by eightofthem (Andy) on Jun 27, 2021 19:50:40 GMT
I can't see why the converter was not reconditioned at the same time as the transmission, seems a bit odd that a re builder would offer that service of just transmission only, all you are then doing is pushing dirty fluid straight into a freshly built box and if the neck is worn damaging the front bush on first start up.
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Post by p5andrew on Jun 27, 2021 21:03:33 GMT
The reason why the torque converter was not rebuilt at the same as the gearbox is simple; I rebuilt the gearbox myself and as the converter was working well and according the documentation which came with the car had been reconditioned only a few thousand miles ago I decided to leave it alone. Incidentally, back in the day I used to rebuild these gearbox’s (about 40 years ago!) and still have my set of special tools so although rusty I am not entirely without experience. The torque converter was of course drained, though the fluid was clean.
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Post by eightofthem (Andy) on Jun 29, 2021 15:51:31 GMT
That makes sence now,I was under the impression you had been steered that by others.
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