CAS orientation error = extra length of belt * 0.8 (in this case 2.4mm) The CAS slot is about 26mm, the retaining bolts are 6mm so that leaves 20mm for movement. Normally the CAS sits dead center in the slot so a 3mm longer timing belt should mean the center of the bolts in the slots are about 10.6mm from one side of the slot and 15.4mm from the other side.
Timing belt 2 or 3mm was just an estimate, we didn't want to cut up two brand new belts to measure the difference, it may well be more than that. There are too many variables to go by to get an accurate answer down to the degree or millimetre. It could just be some batches of the belts which aren't right as some of the cars with aftermarket belts are fine, so it may well be only a portion of the cars that are experiencing timing issues. Your calculations might theoretically be right but the numbers with which you worked off are not exact, just a guesstimate. Remember, there is also excess belt between the cams themselves so that completely changes the timing of the four rows of valves in relation to eachother and also to the crank. It's not just a matter of turning the CAS a few mm like you said to achieve the 15 degrees. To all those who wanted a name it is obvious which ones are the problem, it's just in my best interest not to go bagging certain brands of belt. Emmanuel.
Crap, that just doesn't add up!! Assuming you are correct in that the belt ended up 1 tooth out over only 10 revolutions, this would imply that ANY zed fitted with one of these belts would end up with bent valves the moment you actually tried to start the engine. The only way you could end up being one tooth out after 10 revolutions was if there was an extra tooth in the belt, or one of the cam gears had slipped a tooth. It's the reason why they use TOOTHED belts in the first place!! unless they jump a tooth they cannot get out of alignment even with minor differences in length!! Don't you think that over the span of 15 years an OEM belt would stretch even just a little bit? if this stretch was such a problem as you are saying that would imply that all zeds would end up bending valves after only a few years of running. either the non-OEM belt you were using had an extra tooth (In which case you would have ended up 5 teeth out of alignment after 10 revolutions not 1) or you didn't conduct the test properly (or at all) and your just scare-mongering. Grrr AB (having a bad day)
it's also irresponsible not to tell people which brand may cause dramas on their engine. It's not bagging a particular companys timing belt. If you don't tell us then it would be like saying "Don't go to AMEC as they are a non-genuine nissan mechanics". Also I want to get one of these belts and an compare them with the kevlar reinforced ones to see how much different they are. If I don't know the brand I can't buy one. Also to be 15 degrees out at the CAS would require the belt to be 32mm longer - something that would be very very obvious to the naked eye. Plus I would be fairly sure the auto tensioner would not be able to take up that slack so the amount of deflection of 5-6mm at the center of each sector between timing gears on the belt would never be achieved. If the error in length is evenly added around the belt then you'd need a belt so long it would be blatently obvious. Also you don't need to cut the belts to measure them. Put a line mark of the ground and on the belt. Line the belt marking up with the line on the ground and then roll the timing belt of the ground till it comes back around to the line again and mark the ground. The distance between the two marks on the ground is the belt length.
actually.. I'll retract the statement "In which case you would have ended up 5 teeth out of alignment after 10 revolutions not 1" as it's not correct. It is highly likely that the belt that you have actually has one extra tooth as that is the only way you could see the effect that you have. AB
Audiobuzz, you haven't read it properly. We're not saying that the belt continues to get further and further away from its proper location the longer that the engine has run. It initially moves that little bit until it appears that it is one tooth out and stays that way. I believe I said earlier that the aftermarket belt had the same amount of teeth as the OEM one. Guys, I made this post in good faith to avoid people stuffing around trying to work out why it appears it is one tooth out only to have people arguing the point. I, a number of qualified mechanics and members of this very site witnessed the difference in length between the two belts, not once but a few times now. It would be irresponsible of me to NOT notify you people about this problem. As for the brand of belt, it is obvious which one can be to blame for this little problem. I'm advising the use of an OEM belt as it's the proper one for the job. Emmanuel.
Re: Audiobuzz, Have you brought it to the attention of the Dayco reps that the belt is causing problems and if so what is there reply?
Emmanuel, Your right, thats not how a read your post and the "after 10 turns" was the red herring for me. unless the belt is stretching (more than an OEM ono) I fail to see how the 10 turns induces an extra tooths worth of offset that wouldn't be there when you first fit up the belt. I appologies for snapping as I'm running on only 3 hours of interupted sleep. :wacko::wacko: Keep up the discussion and I think it's worth isolating a difference in length vs a stretching of the belt as the engine is tensioned on the first rotation. It's the stretching that I'd be most worried about as it indicates a lack of strength in the construction. :zlove::thumbsup::thumbsup: AB (going home to bed)
All this quiet mouth stuff is bullshit If these products are wrong and defective then they should be recalled, And we should know which products they are In case our cars have one in it so we can check. Also what is being done to fix the problem. If this is a Dayco problem then have have they been told? I am sure as hell positive that they would want to know if the belts are wrong. If you buy a belt from Bursons. I can tell you they will definitely be a DAYCO belt.
I've found 4 manufacturers of VG30DETT timing belts and we've only excluded GATES and the OEM one. So is it DAYCO or BOSCH ?
What's with the secrecy? If something you have used is faulty, and ..... you have fitted/used it correctly, I don't see the issue with legal liability for mentioning the name. Actually, the company will probably thank you for the heads-up. Just my opinion. CheerZ Vincent
Litigation... From what I have learned, it's unlikely that a company would be able to sue in a defamatory sense if you are making a statement that is: - the truth or fact; - it is a 'fair comment'; or - it is in public interest It is without a doubt in the public's interest to know if a certain brand is not working properly with the Zeds... In addition it's probably good for us and the company to do because it the company is trying to sell us a product that is said to do something but doesn't... There might be trade practices/fair trading issues...
