There seems to be some confusion about what should be done when replacing your timing belt. Recently I have been checking with local NSX repair shops on what they have been doing when they get a NSX timing belt job. I was not happy with the answers i received. I consider myself a expert on this topic since i have probably performed this operation a zillion times and more than anyone around here. I have also been trained by the factory on how to do this from NSX engineers. Im doing this for NSX community and would like help out everyone from not spending too much or not getting it done right. These are common questions:
Should I replace the water pump when replacing the timing belt?
answer. yes the water pump is driven off the timing belt. if the water pump leaks (and they do) The belt will have to be replaced again. Also there is a updated pump and timing cover to prevent this.
Does my engine need to be removed to replace the timing belt?
answer. no. Honda as always designs a car to be worked on. Yes its hard to in the car. but a lot harder to remove the engine.
Do i need to replace my timing belt tensionier?
answer. not always. if your NSX is low milage and not severly driven. it would be ok. The repair trade has coached technicians to replaces all tensioniers and pulleys. i would on a domestic or German car. But i wouldnt on a NSX. This is a high quality car. the nsx is engineered for long life. I have not seen one fail. if money is no object replace it and everything else around there! if your on your second timing belt job, yes replace it. you have 100k on it and its only street driven . its fine. inspect for laterial movement or noise, but it should be fine.
When do i need to replace my timing belt?
answer. every 100 kms/ 60k miles or every 7-10 years.
What about cam seals and cam plugs , when its all apart?
answer. When doing the timing belt, there is a lot of parts that need to be removed. this accesses a lot parts that might be getting old and will soon in near future need to be replaced. since your nsx is all apart some item should be inspected and it would make financial sense to replacing them. cam seals- inspect them for leaks. they are at the front of the engine where the timing belt is and if they leak on to your timing belt ; guess what? yes it would have to be replaced again. Why? because coolant or oil destroys a belt. it makes the rubber swell. From my experience. i have seen maybe 2% fail. sometimes there is a little bit of sweating which is normal. cam seals are usually oversold. cam plugs are at the back of the engine where the heads are. these are very common on NA1s to get hard and leak. since they are at the back of the engine , there is no damage to the timing belt. the only reason to do during this repair is for ease and less labour to replace them. TDC sensor. this sensor tells your computor where the the pistons are so the ecu can program fuel and timing. this part is way oversold. there is a sealant over it which does nothing. it melts over time. this causes nothing to happen. i have never seen one fail. valve cover gaskets? yes this a good idea to replace. since the NSX is aging and rubber parts get hard with age and heat. also since the valve cover are off anf there is no extra labour. wise choice. tip. get the kit. its actually cheaper than getting all the seals and gaskets seperatly. lastly harmonic balancer? these balancers with age and abuse start to crack where the rubber bonds the two peices together. when they fAIL , they make a mess. worst case is this. the balancer comes apart (heavy steel) gets thrown around (imagine at 8000 rpm!) gets jammed through the timing cover , jamming the timing belt , engine comes to a dead stop and the valves hit the pistons. need i say more? yes there are cases of this happening. two choices her. install a new one (expensive 300-400) or install a part availble through SOS to protect the timing cover and belt.(about 100). external belts. yes if they are old and original. you have to take them off costs nothing to put new ones on. i like to replace the oil filter cooler seal and hoses too. they cost about 40 and no extra labour. they get hard and leak after. spark plugs? yes . again not much labour involved.
What if i dont replace the timing belt?
worst case . timing belt breaks(rare) and engine will have to be removed to replace valves and maybe pistons( expensive) oh yah you will still have to replace the timing belt too.
well i hope this has cleared up some things and if you NSXers have any questions . please send me a message.
Robert
Should I replace the water pump when replacing the timing belt?
answer. yes the water pump is driven off the timing belt. if the water pump leaks (and they do) The belt will have to be replaced again. Also there is a updated pump and timing cover to prevent this.
Does my engine need to be removed to replace the timing belt?
answer. no. Honda as always designs a car to be worked on. Yes its hard to in the car. but a lot harder to remove the engine.
Do i need to replace my timing belt tensionier?
answer. not always. if your NSX is low milage and not severly driven. it would be ok. The repair trade has coached technicians to replaces all tensioniers and pulleys. i would on a domestic or German car. But i wouldnt on a NSX. This is a high quality car. the nsx is engineered for long life. I have not seen one fail. if money is no object replace it and everything else around there! if your on your second timing belt job, yes replace it. you have 100k on it and its only street driven . its fine. inspect for laterial movement or noise, but it should be fine.
When do i need to replace my timing belt?
answer. every 100 kms/ 60k miles or every 7-10 years.
What about cam seals and cam plugs , when its all apart?
answer. When doing the timing belt, there is a lot of parts that need to be removed. this accesses a lot parts that might be getting old and will soon in near future need to be replaced. since your nsx is all apart some item should be inspected and it would make financial sense to replacing them. cam seals- inspect them for leaks. they are at the front of the engine where the timing belt is and if they leak on to your timing belt ; guess what? yes it would have to be replaced again. Why? because coolant or oil destroys a belt. it makes the rubber swell. From my experience. i have seen maybe 2% fail. sometimes there is a little bit of sweating which is normal. cam seals are usually oversold. cam plugs are at the back of the engine where the heads are. these are very common on NA1s to get hard and leak. since they are at the back of the engine , there is no damage to the timing belt. the only reason to do during this repair is for ease and less labour to replace them. TDC sensor. this sensor tells your computor where the the pistons are so the ecu can program fuel and timing. this part is way oversold. there is a sealant over it which does nothing. it melts over time. this causes nothing to happen. i have never seen one fail. valve cover gaskets? yes this a good idea to replace. since the NSX is aging and rubber parts get hard with age and heat. also since the valve cover are off anf there is no extra labour. wise choice. tip. get the kit. its actually cheaper than getting all the seals and gaskets seperatly. lastly harmonic balancer? these balancers with age and abuse start to crack where the rubber bonds the two peices together. when they fAIL , they make a mess. worst case is this. the balancer comes apart (heavy steel) gets thrown around (imagine at 8000 rpm!) gets jammed through the timing cover , jamming the timing belt , engine comes to a dead stop and the valves hit the pistons. need i say more? yes there are cases of this happening. two choices her. install a new one (expensive 300-400) or install a part availble through SOS to protect the timing cover and belt.(about 100). external belts. yes if they are old and original. you have to take them off costs nothing to put new ones on. i like to replace the oil filter cooler seal and hoses too. they cost about 40 and no extra labour. they get hard and leak after. spark plugs? yes . again not much labour involved.
What if i dont replace the timing belt?
worst case . timing belt breaks(rare) and engine will have to be removed to replace valves and maybe pistons( expensive) oh yah you will still have to replace the timing belt too.
well i hope this has cleared up some things and if you NSXers have any questions . please send me a message.
Robert
