Z32 Help on choosing Timing Belt replacement scope

Discussion in 'Technical' started by MakeItWork, Apr 22, 2024.

  1. MakeItWork

    MakeItWork New Member

    Have just acquired 1990 grey imported 1999 2+0 NA MT. It has 130k km on the clock, and runs very smoothly, but have no idea on the maintenance history. In theroy timing belt should have already been done at 100k km = only 30k km ago, but 48 months goes quickly, so I guess it should be done. With such low mileage, time is the primary driver of maintenance interval.
    Key qns :
    Type of belt : Should I go for the Gates 300% stronger racing belt (https://rgsperformance.au/products/...issan-z32-300zx-twin-turbo-na-free-delivery)? I saw another thread saying something like don't bother if you don't race, but I am assuming that such belt would be expected to last a lot longer than 48 months. I certainly don't expect to rack up 100k km within 4 years, and would strongly prefer NOT to have to do it again in 4 years. Does even the standard Gates belt have a longer life expectancy than 48 months recommended for OEM belt?
    Camshaft Seals and springs : Should they be replaced every time = highly likely to fail before the next 100k km/ 5-10 years?
    Crankshaft seal : This looks pretty trickky. Is it likely to fail next 100km / 5-10 years. Some engines are notorious for main seal problems. Is Z32 one of them?
    Water pump : Is it highly likely to fail before next 100k km/ 5-10 years ? What if already replaced at 100k km? I suppose I won't be able to tell, and maybe low mileage means time is the primary driver of maintenance interval.
    Tensioner pulleys and hydraulic tensioner : Ditto?

    In some ways, I prefer to leave things alone if not "broken", since the procedure is complex and plenty of opportunity for install misstake (although have awesome support from resources like this http://www.ttzd.com/tech/timingbelttech.html), but definitely don't want to repeat the long procedure any time soon - eg didn't replace water pump and it failed in a year or two.

    It probably boils down to a call between something like these two options :
    Bearing wholesalers kit like this with stadard Gates belt : https://alliedautoonline.com.au/pro...3-0l-allied-auto-online-tk-nis007h-tk-nis007h
    ...but no where near as comprehensive full kit like this with water pump, cam springs etc : https://www.carcraze.com.au/genuine-nissan-300zx-z32-vg30-timing-belt-kit-base which is triple the price with a Nissan OEM belt.

    Would appreciate any thoughts/experience from others.
  2. rob260

    rob260 Administrator Staff Member

    A racing type belt is stiffer to reduce belt flap. The trade-off is that it wears out faster. This seems to be largely misunderstood.

    The service interval for a timing belt is 100,000kms. It is NOT 100,000kms or 4 years. This also seems to be widely misunderstood!

    Yes you should replace all of the components while the front is off the motor.

    I am probably biased but i think that the kit I sell (and fit) is pretty good https://rgsperformance.au/products/...ssan-z32-300zx-twin-turbo-or-na-free-delivery

    The tensioner in that allied auto kit that you posted is notoriously prone to premature failure. Yes I am speaking from experience with that specific tensioner - there's a reason I don't sell them any more!
    Last edited: Apr 23, 2024
    geron likes this.
  3. MakeItWork

    MakeItWork New Member

    Thanks Rob - good to know that 48 months is not viewed as a limit after all, which means in theory I should have another 70k km to go, if job was done at 100k km, but I have no way of knowing.
    I see you have the Gates belt in the kit. Is it perceived as better/stronger(?) than the OEM?
  4. rob260

    rob260 Administrator Staff Member

    Gates manufacture three different belts to suit the 300zx (including the racing one you linked to). They also manufacture the oem nissan belt.

    The Gates belt that I use in the kit is made from NBR rubber rather than CR rubber. The advantage is superior chemical and heat resistance, and higher strength to weight compared to the alternative gates belt and the OEM belt.
    Last edited: Apr 23, 2024
  5. ryzan

    ryzan Moderator Staff Member

    If you don't have documented proof it hasn't been done, then it probably hasn't been done.

    Similarly if you don't have proof that other items like crank and cam seals have been repalced then they probably haven't been. While I agree with the 'if it ain't broke don't fix it' approach for a lot of things, these cars are now ~30 years old and a lot of parts do have a finite lifespan. As you said, replacing a lot of these parts are a big job and for this reason you'll find a lot of owners less likely to have done this sort of maintenence, especially over the past 10 or so years where the value of 300's has been rock bottom.

    While you're at it, I'd definitely recommend doing a 'plenum pull' to replace all the rubber hoses, valve cover gaskets etc. as well. While it's a big job to do both at the same time, I find it easier to do both together than separately as it makes a few jobs easier, and consider a plenum pull and 100k service a 'must do' for pretty much any 300 with unknown history at this point.

    Finally, I would strongly recommend doing some research on others experience with Carcraze over the past few years since they changed hands before spending any money with them, a lot of horror stories...
  6. geron

    geron National Petroleum Equipm

    Great information provided by Rob and Ryzan.
    I can back this up saying that it's not normal for the oil seals to leak on the VG30 and 4yrs expiry timeframe for the timing belt is nonsense.
    I changed the timing belt on my Z 15yrs ago and it was a daily driver for more than 5yrs going from Umina to Baulkham Hills. Its still in the car which is now a once a month machine and still no oil leaks or belt noise, at all!

    The trick with oil leaks is to 'never overfill' the car with engine oil. Always underfill it.
    Also, always use 'genuine' OEM seals and once fitted properly they should pretty much last the life of the engine, IMO.

    The VG is bullet proof, contrary to what others might think. Unless if severely overboosted with a poor tune or not using a rust inhibitor in the coolant, overfilling the engine with oil, basically doing stupid things like this.
    Not using a rust inhibitor/antiboil/antifreeze with the coolant will rust the internals of the engine and RUST will cause so many problems with water flow and cake inside the hoses and eventually can/will result in a blockage somewhere and overcook the engine.

    MORBOOST Active Member

    do you have a sticker in your engine bay like this? mine is on the drivers side strut tower the sticker is metallic and is made to have the km's and date scratched on, also look around for excessive RTV on mating surfaces on parts that would be removed during a timing belt service.
  8. MakeItWork

    MakeItWork New Member

    Great to hear that the seals don't normally leak. The engine runs super smooth, even from cold, and feels strong. No rattles or ticking noises - eg from cam springs. No oil leaks, so all I can hear ringing in my head is my favourite motto = "if it ain't broke, don't fix it". That said, the impact of a broken belt is SO terminal and decisive, that I am tempted to do that replacement, just for peace of mind. A friend of mine found out the hard way. I dont want a repeat of that.
  9. MakeItWork

    MakeItWork New Member

    Nah - no fancy sticker telling me anything about it's history. I don't think there is any telltale RTV, but I will check further/
  10. geron

    geron National Petroleum Equipm

    'If it aint broke don't fix it' for sure however sometimes there are exceptions such as deletes or 'while there I can do this' to prevent from having to do things twice based on future likelyhood of failure, mainly for time consuming/hard jobs.
    One example, if the gearbox is ever removed, a rear main seal replacement is a good idea, while there, if it's still the original seal from factory. Also, check mounts and change if necessary.
    Common sense is needed when it comes to preventative maintenance and be headache free for the long term!
    Once the car is running 100%, leave the bonnet closed and don't tinker with it, due to boredom!! Just enjoy using the machine and do something else if bored.
    I've seen this happen way too many times.

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