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Post by danie on Aug 11, 2010 21:48:52 GMT 2
Hi All
I couldn't resist the temptation to find out whether a Polyurethane Doughnut would be any better than the standard rubber product, so I have contacted a local company which specialize in the manufacturing of Polyurethane products.
According to the company they would be able to manufacture a suitable "doughnut" , only problem though - Polyurethane products do have limited heat properties.
Question is : How hot (max temp) do the Gearbox and Transfer Box coupling flanges get under hard driving conditions ? Heat will obviously be transferred via the Gearbox and Transfer Box shafts towards the Flanges - and the Flanges will be in direct contact with the Polyurethane Doughnut.
I do not have any idea how hot the Flanges would get under hard driving conditions, and unfortunately my Lada is still "under construction" at the moment. - so I cannot do any heat tests to find out myself.
Does anyone have an idea how hot the Flanges get under hard driving conditions ?
Regards
Danie
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Post by ronnie on Aug 12, 2010 9:19:42 GMT 2
Hi Danie
I could not put a temperature to it, but it gets very hot. The oil is hot enough to burn your hand. Remember what happened to the sealed bearing after the run on the hi-way. The hot oil started to come through the bearing.
Ronnie
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Post by lada & korean parts on Aug 13, 2010 8:00:42 GMT 2
hey guys,they're called a "FLEXIBLE COUPLING" for a reason...... there is NO WAY a poly one will flex......... we've had people try that before doesn't work same as peeps who do poly mounts & bushes,they're rubber for a reason............
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Post by marius on Aug 13, 2010 10:04:58 GMT 2
Hi Andy
I tend to agree with you (at least on this one ;D)
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dgc
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Post by dgc on Aug 13, 2010 11:38:24 GMT 2
hey guys,they're called a "FLEXIBLE COUPLING" for a reason...... there is NO WAY a poly one will flex......... we've had people try that before doesn't work same as peeps who do poly mounts & bushes,they're rubber for a reason............ Hi Andy, What is the reason? What effect does a non-flex coupling have? Douw
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Post by ronnie on Aug 13, 2010 16:48:34 GMT 2
Hi Douw I have the feeling any firmer Doughnut may transmit more noise,(and vibration), the same as the bracket I made to stabilize the rear of the transfer box. I am also sure if a minor change like that would stop the vibrations the Russians would have done it long ago. There is only one way to really know, providing it is not going to cost a lot of money TRY IT Ronnie
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Post by danie on Aug 13, 2010 19:16:42 GMT 2
The flexibility of different Polyurethane products vary from very flexible, to rock solid - it all depends on the application, as well as composition of the specific product.
My biggest concern about Polyurethane is that it might not be able to cope with the heat - generated by the Gearbox and Transfer Box, which will be transferred to to Flanges via the shafts.
Regards
Danie
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Post by lada & korean parts on Aug 14, 2010 2:03:54 GMT 2
hey guys,they're called a "FLEXIBLE COUPLING" for a reason...... there is NO WAY a poly one will flex......... we've had people try that before doesn't work same as peeps who do poly mounts & bushes,they're rubber for a reason............ Hi Andy, What is the reason? What effect does a non-flex coupling have? Douw Hi Douw, flexible coupling helps eliminate vibration & takes up the torque when you drop the clutch at traffic lights,and helps with movement between gearbox & transfer case. we have had 3 or 4 customers who have tried poly,& they complained about excessive shudder,vibration,premature bearing wear,even tearing the floor pan....... there was a list of things they complained about,but it's been a few years since anyone has fitted one,so can't remember everything they said. but when they fitted the original couplings back on,no more problems.
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Hein
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Post by Hein on Aug 14, 2010 9:34:53 GMT 2
Hi Guys
Just a note
I noted that in the workshop manual it says that the doughnut should be balanced with washers. It does not explain clearly how to do this, but it could be a good idea to take it to a prop shaft balancer to see how they would do it.
Hein
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Post by ronnie on Aug 14, 2010 9:42:34 GMT 2
Hi Hein I don`t know how they balance the intermediate shaft but normally one of the three bolts in the doughnut has a thick balancing washer on it. When you strip it out you should mark all parts so you can reinstall in the same position. I wonder how many people do this . Mine did not even have the washer fitted. If you look in the manual you will see it is called a balance plate. Ronnie
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Post by Hein on Aug 14, 2010 10:20:16 GMT 2
Hi Ronnie
My Lada also do not have the washer. I ran the TC in neutral and noted that just before 4000rpm it gets out of balance for a short while. I do not know if i need it.
Hein
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Post by ronnie on Aug 14, 2010 10:58:42 GMT 2
H Hein When I have time I will try a washer. There is only 3 places to put it as it is on the side facing the T/C. I just get tired of laying underneath Ronnie
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Post by marius on Aug 14, 2010 11:59:54 GMT 2
Hi Comrade ;D I might also not have those washers I'm not sure whether they are actually balancing washers - esp if they are all going to be the same size and weight? Perhaps Ventz can enlighten us on those washers? I did send him an email in this regard. My feeling is whether you have them or not - they are not going to make a difference - if they are only ordinary washers. Regards Marius
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Post by ronnie on Aug 14, 2010 14:21:16 GMT 2
Hi Marius
If you read the manual it tells you to make note of the no of balancing washers and to reassemble with them in the correct place. Any object with weight fastened off the centre line will affect the balance. I suppose some vehicles will not require any washers. The funny thing about mine is one bolt out of 6 on the doughnut is about 5mm shorter than the rest, and it looks like an original. It is short enough to render the self locking nut useless.
Ronnie
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Post by marius on Aug 14, 2010 15:36:09 GMT 2
Hi Comrade Should have read the manual first I would replace the shorter bolt - that could make some difference. Still think if the weight on those washers are the same (whether 3 or 6 of them) - wouldn't make a difference with or without them But I could be wrong Regards Marius
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Post by ronnie on Aug 14, 2010 19:22:33 GMT 2
Hi Marius yes I will replace the shorter bolt one of these days. Remember The washer is quite thick and only goes on ONE bolt, This could either create an imbalance or cure it. I also have windows 7. Mind you It means very little to my old mind ;D Ronnie PS the shorter bolt could also ceate an imbalance
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Post by spikes on Aug 14, 2010 20:11:09 GMT 2
Hi all Marius, congrats on your new status and enjoy the new OS! (watch out for MS sneaky ways of updating various bits) On the vibration issues, has anyone ever defined acceptable, bad or serious levels of vibration The easy and basically free solution would be to stick corrugated roads:) Cheers Spikes
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Post by marius on Aug 14, 2010 21:59:34 GMT 2
Hi guys I thought there were at least three washers - now it all makes sense I've never been too keen on any new Microsoft OS - ALWAYS full of teething troubles. Heard a lot of good things about Windows 7 and I'm real tired of XP though it ran quite stable. Regards Marius
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Post by ronnie on Aug 15, 2010 9:45:19 GMT 2
Hi Spike
I also have wondered what is acceptable and what is not. I would say if you run through the vibration period quickly it would be acceptable, otherwise no. I still believe with the design, you will not completely eliminate it. Marius can tell us if his was free of vibration when it was new or not. I know mine was not from day one.
Ronnie
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Post by danie on Aug 15, 2010 10:18:36 GMT 2
Hi Spikes / Ronnie
I think it could be very time consuming to eliminate all possible causes of vibration - and while "time is money" I just wonder whether enough time has ever been spent at the factory, or at the agents in this regard.
Everyone just seem to accept that "vibrations are normal" - and I think very obvious causes of vibrations are often been overlooked.
For instance - when I removed the Transfer Box from my Lada, I discovered that the Centering Ring, which fits at the rear of the Gearbox output shaft, was completely missing ! I also discovered that the rubber Pilot Bush at the inside of the Transfer Bush flange was worn - so in my Lada's case there was no way how the Tranfer Box and Gearbox could be lined up properly......
Without bashing the Agents I know that at least one of them also make use of mechanics who work on other cars (other than Ladas) every day.........I just wonder if all those mechanics always know about small things on Ladas like Centering Rings...........
Regards
Danie
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Post by ronnie on Aug 15, 2010 11:42:35 GMT 2
Hi Danie / Spikes
What you say is very true,but I doubt with the design if you can completely eliminate the vibration without altering / modifying something. I only really know one agent and I did not see anything which vaguely resembled a Mechanic when I was there.
Ronnie
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Post by darryn on Aug 15, 2010 13:01:20 GMT 2
This thread has been very interesting. I encountered some "difficulty" this week with my TC. One of the threaded bolts (holding the TC on the body) stripped, and I had to cut new thread with an M7 die. I'm not too happy about this. The intermediate shaft I have in my lada at the moment is the Universal joint from the 1600. This shaft seems to be at least 8mm too short, so it causes the TC to tilt towards the gearbox. With the flanges as far forward as possible, the input flange of the TC had a gap at the bottom of up to 4mm, while it was lined true on the horizontal. What I did was put washers (3.2mm worth) between the donut and the flange of the intermediate shaft. It made the gap smaller and the amount of vibration noticeably less. I'm also not crazy about the idea of shimming the shaft assembly, but I'll try more shims on the gearbox side of the donut. Also, the rubber bushes on the mountings are perished too, so I'll start looking for a place to redo these.
Any tips, especially about the shims on the donut itself?
Laters. Darryn.
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Post by danie on Aug 15, 2010 14:41:53 GMT 2
To my mind the only way to make 100% sure the balancing is correct, is to send the Doughnut (with Flanges on both sides, connected to a loose Gearbox Output shaft on one side, and CV joint- connected to a loose Transfer Box Input shaft on the other side) to a Company which specialize in balancing shafts and things..........to get hold of loose output / input shafts might be a bridge too far, but it can be done.
At work we manufacture stub shafts for mounting at the flywheels of big Diesel engines - we always send these stub shafts to a local Company for balancing.........at R250.00 each......
Regards
Danie
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Post by ronnie on Aug 15, 2010 14:45:22 GMT 2
Hi Darryn I have never seen a 1600 so I can`t say much, but find it strange that there would be a difference in the length of the intermediate shafts. I would imagine the more shims you use the more difficult it will be to keep everything in line. Perhaps some one will have a shaft for you .I know what you mean about garage space. I moved from 3 big garages plus large workshop to 1 garage. Now it is either me in the garage, the car in the garage but not both at the same time . Ronnie
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Post by spikes on Aug 15, 2010 19:11:36 GMT 2
Hi all, still on the vibration topic, I found the attached paragraphs. The bold and italics are mine Some indicators to defining transmission vibration. I also think the large boom box (read Lada Interior) resonates and can be a confusing but contributing factor to the vibration Regards all, Spikes PS to Marius, there is cold weather approaching from the west Attachments:
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Post by spikes on Aug 15, 2010 19:18:55 GMT 2
Hi Here is the attachment: OEM overdrive transmissions typically slow engine rpms by 30 percent. If you can cruise at 2,000 rpm in high gear with your Turbo 350, you will be cruising at 1,400 with a 700-R4 or other GM overdrive transmission. Such low engine rpms open a can of worms for the car because of the increased torque required to maintain the same road speed. On top of this, the torque converter locks up at some number of rpm to effectively connect the crankshaft to the ground with no slippage anywhere in the system. The resulting driveshaft vibration will be rhythmic or pulsating and will cause mirrors, gearshift levers, and miscellaneous car parts to vibrate at different times.The vibration happens because the power coming out of the engine is not smooth. Every time a cylinder fires, the crankshaft is accelerated. The accelerations are called torsionals and there are four of them per crank revolution in a V-8. As engine rpm declines and the required torque goes up, so does the strength of the torsional spikes. Overdrives reduce the four crankshaft pulses to 2.8 pulses per revolution of the transmission output shaft. Downstream, the driveshaft is already changing speed twice per revolution because of U-joint angles, making it very sensitive to these lower frequency torsional disturbances. From Street Rodder (online: www.streetrodderweb.com/tech/0205sr_driveshaft_vibrations/index.html)
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Post by ronnie on Aug 15, 2010 19:25:38 GMT 2
Hi Spikes I am afraid this means nothing to my tiny mind . You will need to make it simple for me. Ronnie
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Post by spikes on Aug 15, 2010 19:36:39 GMT 2
Hi Ronnie Read the bold italic sentence. Those are clear indicators of vibration. I included the rest of the reference for the young and studying members of the group. My Lada does not display any of the symptoms in the reference but I can feel a vibration at 100 to 105 km/u in 5th. It lasts for about 10seconds. Past 105 its gone regards Spikes
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Post by marius on Aug 15, 2010 19:49:31 GMT 2
Hi guys Thanks for the cold warning Spikes - I'm going to need it. Already lost one a couple of days ago due to sudden cold. My Niva vibrated from the start mainly due to TC and intermediate shaft not being aligned correctly. The shaft was also not greased - told that it comes from the factory like that. I was also told that I should replace the output bearing on the TC - it was in perfect condition and a tight fit - hopefully it still is Another problem was when I measured the rear bumper from the ground up I found that the car was lower on the right side than the left. They apparently stretched the rear coil spring trying to sort it. That also a caused some vibration.To this day there is still some difference. I still have some vibration at around 110 - but not much. Now I have to go clean some twins
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Post by ronnie on Aug 16, 2010 14:10:40 GMT 2
Hi Danie
I don`t think it is a good idea to manufacture a polyurethane doughnut as you will not have the locating pins, 3 on each side of the doughnut to ensure it is centred. I think you will end up with more problems than you had before. ( and you will have spent money for nothing). Just my thoughts.
Ronnie
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