Dephaser pulley diagram

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MONDO9
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Dephaser pulley diagram

Postby MONDO9 » Thu Jul 31, 2008 9:57 am

Is there a diagram/exploded view of the dephaser pulley system available. Would like to try and understand the problem before a dealer starts changing things willy nilly.
:?:
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MONDO9
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Re: Dephaser pulley diagram

Postby MONDO9 » Thu Jul 31, 2008 1:51 pm

No exploded views then?

Can anyone explain to what it is that actually goes wrong with the dephaser? Is it a seal problem, a bearing problem..........!!!
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ft101
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Re: Dephaser pulley diagram

Postby ft101 » Thu Jul 31, 2008 2:16 pm

As far as I can tell from the sound that mine is making, there are teeth involved. I would guess that the operation is not entirely dissimilar to Rover's VVC system (which is a far more reliable system it seems).

I'm completely guessing here btw, based on what I know about variable valve control systems and also the grinding sound that mine is making. Once replaced (if I don't get shot of the car) i'll ask for the old part so I can take a closer look.

Here is the Rover VVC mechanism: https://www.mgcars.org.uk/pics/mgfcam2.jpg

If you look at the control sleeve, there are teeth - i'm guessing something similar is in use by Renault and these are inferior quality, so are slipping and causing the grinding. Would love to know the real story, and if i'm close.

BTW here is a great article on VVC (which is great when done properly :D )

https://www.mgcars.org.uk/news/news174.html

regards

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Re: Dephaser pulley diagram

Postby AlexB » Thu Jul 31, 2008 2:55 pm

Exploded view is here:
https://img486.imageshack.us/img486/7945/vvt12349we.jpg

This is the description by the manufacturer -- Delphi:
https://delphi.com/manufacturers/auto/po ... train/vcp/

These are photographs of the dephaser:
https://f.foto.radikal.ru/0609/d5468e8b41b0.jpg
https://c.foto.radikal.ru/0609/4224d00a7e49.jpg
https://photofile.name/photo/romanlk/321 ... 679894.jpg
https://photofile.name/photo/romanlk/321 ... 679937.jpg

This is the faulty dephaser taken apart, old model -- P/N 7701474362.
https://photofile.ru/photo/megamike/2180 ... 436198.jpg
https://photofile.ru/photo/megamike/2180 ... 436443.jpg
https://photofile.ru/photo/megamike/2180 ... 436449.jpg
https://photofile.ru/photo/megamike/2180 ... 436445.jpg
https://photofile.ru/photo/megamike/2180 ... 437432.jpg
https://photofile.ru/photo/megamike/2180 ... 437433.jpg
It rattles as the locking pin stops doing its job. One can also see wear of the components.

This is the intermediate edition of dephaser, P/N 7701478079. The same design, metal filings discovered inside the new part...
https://photofile.name/users/south27/3500248/75608005/

The third (currently the latest) reincarnation of the same part, P/N 7701478505. The same design, the pin is probably improved.
https://photofile.ru/photo/dvlion/951365 ... 095427.jpg
https://photofile.ru/photo/dvlion/951365 ... 095428.jpg
https://photofile.ru/photo/dvlion/951365 ... 095429.jpg
https://photofile.ru/photo/dvlion/951365 ... 095430.jpg
https://photofile.ru/photo/dvlion/951365 ... 095433.jpg
https://photofile.ru/photo/dvlion/951365 ... 095431.jpg

These came from this source:
https://www.renault-club.kiev.ua/forum/i ... topic=7022

One of authors of this research MegaMike from the above forum discovered that the cause of the problem is excessive wear causing increased axial play (more that 0.15mm) and, as a result, oil leaking away from the dephaser back in the sump. However, the other failed dephaser had a small axial play, but the plastic flat seals were faulty... In addition, the locking pin alone appears to be unable to hold the load. It has a conical surface loaded with a side force. A projection of this force pushes the pin out of the hole. A simple calculation shows that the strength of the return spring is insufficient given a very high strength of valve springs (valve springs have to be strong to work at high revs) creating high torque on the camshaft. When a dephaser is not worn and is filled with oil this problem is not noticeable, but when it is dry then a scary rattle appears. There were 3 part numbers released, which is an indication that Renault and Delphi are well aware of the problem!

Here one can find a detailed analysis of the design fault, it is in a wrong language for most of us:
https://www.renault-club.kiev.ua/forum/i ... ntry118155
To summarise, the design of conical surface of the locking pin and the return spring is not good, which includes geometry, choice of materials and the strength of the return spring. As a result the locking pin is bound to stop performing its function at some stage. It is a "joint" fault of Delphi, who supplies dephasers, and Renault, who did not test this part sufficiently well. An option is that testing was done on a prototype engine before it was enhanced by using "racing" style hard springs and cams with roller rockers.

This is an overview of dephasers:
https://www.pmgsinter.com/downloads/orlando2002_wied.pdf

Renault discusses this problem in their technical note TN4432A.

This is it, I guess. The problem is down to lubrication failure and poor design by Delphi. It makes me think about possible use of special oils having extreme pressure properties, such as VW PD 505.01 (e.g. see Fuchs and Motul range at https://www.opieoils.co.uk), or ester-based racing lubricants as a "patch" to the problem, and someone reported using Mobil 1 5w-50 oil with a great deal of success. I wonder if the recently introduced RN0700 oil specification will help to keep dephasers alive until the big service...

A funny finding: Delphi reduced weight of this part by 30-40% by using aluminium. Was it a good idea?
https://www.prnewswire.com/cgi-bin/stori ... 961&EDATE=

The rumours that the latest version of dephaser includes a return valve are not true (see the photographs above). There are very minor modifications to the lock pin and the return spring.
Last edited by AlexB on Thu Aug 07, 2008 11:05 pm, edited 7 times in total.
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Re: Dephaser pulley diagram

Postby ASTRO69 » Thu Jul 31, 2008 9:15 pm

Thanks for the info links and explanation. Excactlly what I was looking for.

Cheers

Simon

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Re: Dephaser pulley diagram

Postby silencer51 » Thu Jul 31, 2008 11:39 pm

It's funny how car manufacturers just can't learn from a competing company's mistakes.

In this case, if Renault had done its homework and checked into Alfa Romeo's dephaser issues we might not have had to deal with this problem... Every 147 & 156 owner fears the dreaded 'diesel rattle' on a cold start that signals dephaser system failure...

And guess what... It too was caused by oil starvation.

It took them 3 or 4 revisions of the part to get it right, and they finally added a secondary valve in there to provide better oil flow if I remember correctly.

As for the question - "is the new part more reliable than the old one?" Only time will tell I'm afraid...
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Gray Megane II 1,6 5dr hatch 05/2003
Set dephasers to stall!

ft101
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Re: Dephaser pulley diagram

Postby ft101 » Fri Aug 01, 2008 9:28 am

Regarding this dephaser issue.. i've had my car two weeks and in the mornings it has failed to start first time every time, and has had the rattle... I took it out yesterday and ragged it a bit, upto 6000 rpm first, second, third even. Did this with the engine hot.

This morning, the engine started first time and without a rattle.

I'm not saying its fixed, but certainly suggested that the top end doesn't get all the oil it needs and also that an occasional ragging will do it good ??

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Re: Dephaser pulley diagram

Postby Hany Saad » Fri Aug 01, 2008 9:59 am

Dear all,

thank you so much for these professional info concerning the dephaser issue,it was really very useful.
from what I read that the pieces were modified 2006,so do you think that cars manufactured 2006 and over will not suffer this problem or lets say will suffer it less.Also Renault Egypt are using synthetic "Total" oil "Quartz 9000",will switching to Mobil 1 reduces the problem as you mentioned??

any help will be highly appreciated.
Megane II 2006 sedan,Grey eclipse (B66),1600cc,16V, VVT,steptronic

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Re: Dephaser pulley diagram

Postby AlexB » Fri Aug 01, 2008 11:43 am

ft101,

As I understood from my reading, if it started rattling, then its is already damaged. The locking pin does not hold the rotor in place -- this will cause excessive additional wear and the things will get worse very soon. Read the "horror stories" -- the end is the same every time... Even if you start using a "magic" oil now, it will only reduce the additional wear leaving you with the existing problem.

This is what your locking pin looks like now. Whatever you do, it will keep popping out...
https://photofile.ru/photo/megamike/1150 ... 067121.jpg
Last edited by AlexB on Mon Feb 23, 2009 8:10 pm, edited 3 times in total.
AlexB
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MONDO9
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Re: Dephaser pulley diagram

Postby MONDO9 » Fri Aug 01, 2008 11:53 am

Just phoned my local Renault dealer for the price to supply a dephaser pulley.....£112 plus vat (updated version). And guess what....they have 17 in stock!!!!! And I get told from RCS they are not aware of any problem. Why in stock, any part Ive went for in the past is a 2-3 day delivery.
Seriously considering buying one and doing it myself saving £500 quid in the process.

Is the updated version a straight swap or do i need other bits (apart from belts n stuff)

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Re: Dephaser pulley diagram

Postby AlexB » Fri Aug 01, 2008 12:03 pm

Hany Saad,

I am not an automotive professional and I don't own a 1.6 litre model. I just became curious when MONDO9 started this thread and did a quick web search on the subject...

Yes, from what I read it seems that the cars manufactured starting with some day in 2006 (possibly the end of it) have modified dephasers. Nobody cared so far to disassemble a new dephaser, so we have to wait for an enthusiast to come along.

Yes, Mobil 1 0w-40 has a better basestock than Total Quartz 9000 5w-40, hence it is a better oil. It is likely that 5w-40 oils of both makes are equivalent to each other as their basestocks are mostly group 3. None of these oils are certified by Renault, but all 0/5w-40 oils of these makes have MB229.3 stamp, which seems to be equivalent to RN0700. I have no idea if any particular type of oil can prevent dephaser problems. You can discuss the oil questions with oilman in Parts and Accessories -- there is a relevant thread.
AlexB
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Re: Dephaser pulley diagram

Postby AlexB » Fri Aug 01, 2008 12:09 pm

Another pearl of Delphi+Renault design is the dephaser pulley being kept in place with only one central bolt and friction! :nut
Read the manual carefully before disturbing it.

MONDO9 wrote:Just phoned my local Renault dealer for the price to supply a dephaser pulley.....£112 plus vat (updated version). And guess what....they have 17 in stock!!!!! And I get told from RCS they are not aware of any problem. Why in stock, any part Ive went for in the past is a 2-3 day delivery.
Seriously considering buying one and doing it myself saving £500 quid in the process.

Is the updated version a straight swap or do i need other bits (apart from belts n stuff)

Cheers
AlexB
(no, a different AlexB)

MONDO9
Passed Theory
Posts: 43
Joined: Wed Jul 30, 2008 8:14 am
Currently Drives:: Megane II 1.6 VVT Dynamique 2003

Re: Dephaser pulley diagram

Postby MONDO9 » Fri Aug 01, 2008 12:22 pm

AlexB wrote:Another pearl of Delphi+Renault design is the dephaser pulley being kept in place with only one central bolt and friction! :nut
Read the manual carefully before disturbing it.

MONDO9 wrote:Just phoned my local Renault dealer for the price to supply a dephaser pulley.....£112 plus vat (updated version). And guess what....they have 17 in stock!!!!! And I get told from RCS they are not aware of any problem. Why in stock, any part Ive went for in the past is a 2-3 day delivery.
Seriously considering buying one and doing it myself saving £500 quid in the process.

Is the updated version a straight swap or do i need other bits (apart from belts n stuff)

Cheers


I will do. I did notice the one bolt???? and the apparent lack of locating features???? I am an engineer to trade and work for an automotive company that supply Renault as it happens. Really hate forking out mega bucks for an apparent straight swap for a part that cost about a 10'r to make at delphi!!!! The job looks straight forward enough, just access issues me thinks.

AlexB
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Re: Dephaser pulley diagram

Postby AlexB » Fri Aug 01, 2008 12:29 pm

No the teeth are not involved -- there are no teeth in this design. The ECU operates the dephaser for an instant directly after the startup in order to fill it with oil and lock it in the retarded position. Then it stops doing anything until the engine becomes hot, relying entirely on the pin. If the pin does not work -- you get a rattle of approximately 300*4/60=20Hz (starter cranks the engine at 300 rpm). It goes away as the unit fills up with oil. In addition, I would imagine, the ECU may discover strange readings from the camshaft position sensor and attempt again to move the dephaser in the locked position. Is it what you hear?

ft101 wrote:As far as I can tell from the sound that mine is making, there are teeth involved...
AlexB
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MONDO9
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Re: Dephaser pulley diagram

Postby MONDO9 » Thu Jan 15, 2009 11:56 am

Well got the updated pulley, timing belt and timing tools..eventually! Will be changing the dephaser tomorrow, myself. So I will let you all know how much hassle it actually is!


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