Engine life

[Jazzdude]

I was just wondering how long my Jazz engine is going to last.

I always service it regularly, generally use 98oct fuel and only use 100% synthetic engine oil and have never gone past 3000rpm (usually between 1500-2500rmp). How long (ie. Kms) do you think my engine will last.

[EG30]

there are a few more imortant factor to be considered:

number of cold starts ( vast majority of engine wears happens during cold starts )

length of your average trip ( ie does the engine gets fully warmed up b4 shutdown? )

stop start traffic driving or country driving

[Jazzdude]

If you never rev higher than 3000 rpm you are wearing a ridge in the top of your cylinders because the rods are never stretched with higher rpm and the piston rings never reach the top so no wear occurs in the upper reaches of your cylinders. This lack of wear results in the area below this ridge wearing away and the top sticks out over time.

If someday you need to rev higher you risk the possibility of breaking your rings or piston ring lands because when you hit the higher rpms the rings will bump into this ridge that is sticking out. That is why when someone "Finds" a great deal on a car that has been used by a little old lady and never driven hard and a young driver gets in and gives it the wack most of the time it's not long before the great deal falls apart.

You are not doing your engine any great favors by never revving it Honda's are designed with high rpms in mind and will last just as long if you take it to red line once a week or so. You do not mention how many km you have done already, if you still have low Km's or it is a second hand car start giving it some revs over a month or so like next week take it up to 4,000 a few times a day then the next month up to 5,000 for the next month and finally up to 6,000 or redline and kept hitting 6,000 or so once or twice a week for the rest of the time you own the car. If it's a new car start right now and take it up to 6,000 or red line but don't stay there for long and do this once a week and you will be fine and it will last longer than you will want to keep it.

Thanks for the reply. I bought the car brand new and its done about 59k. Is it too late? Also, its an auto, so how can I get it to reach the higher revs? At 120km/h its at 3000rpm (barely).

[vividjazz]

The auto will redline under hard acceleration just as a manual will and you have S mode which increases the revs for the same given speed as in D. You can also manually hold the revs with the virtual gears provided by the 7 speed paddle shift.

You must not live somewhere like Sydney where if you don't accelerate hard sometimes you'd become a hood ornament on a truck. When you see AC in the rear vision mirror its time to move. Thats the AC in MACK.

[EG30]

If you never rev higher than 3000 rpm you are wearing a ridge in the top of your cylinders because the rods are never stretched with higher rpm and the piston rings never reach the top so no wear occurs in the upper reaches of your cylinders. This lack of wear results in the area below this ridge wearing away and the top sticks out over time.

Are you saying if you don't rev the engine past 3000rpm you never reach TDC ( top dead centre ) for that piston Claymore? So by revving it past 3000rpm the rod is going to stretch right?

and kept hitting 6,000 or so once or twice a week for the rest of the time you own the car. If it's a new car start right now and take it up to 6,000 or red line but don't stay there for long and do this once a week and you will be fine and it will last longer than you will want to keep it.

and what determines taking the engine to its redline one or twice a week will make it last longer? Why not four or five times, or never hit the redline?

Your recommendations are the most absurd advice I've read from any forums for a long time Claymore.

[silver_screen]

im a mechanic. and he speaks the truth

Too many times have i seen this happen, cept when it happens its in the worst times..
most common example... dude buys brand new car and babies it all its like

Now it has 150k on the clock and sells it.. Younger guy buys car but his not one to trash without a reason so for a while drives it around normally.. but then he pulls over freeway one day to answer phone.... when his off the ph he quickly accelerates to get back on freeway.. ohh whats noise?? oh crap engine just died why??

I rip apart the block and the ridge as been smashed off from the high rpm and piston has been destroyed...

I saw a piston break into in an astra.. one side of the piston got stuck on the ridge and the other broke off... need to rev the engines a bit but not too much

[EG30]

.

It is a physical ridge that you can see and feel with your fingers caused by the rings wearing the cylinder and if the engine is never revved Are you saying if you don't rev the engine past 3000rpm you never reach TDC ( top dead center ) for that piston Claymore? So by revving it past 3000rpm the rod is going to stretch right? that is exactly what happens. If you knew what you were talking about you would know this already. Any apprentice mechanic knows this and if you never knew about ROD STRETCH I again suggest you google it so the next time you make a comment you won't come across as an ignorant ass like this time.

First of all you can reach TDC on any cylinder by turning the engine by hand on a bench Claymore, so by saying you don't reach TDC when you don't revving it past 3000rpm is plainly wrong. So who is an ignorant ass this time?

If that you are saying is correct when the rod stretch at 3000rpm to eliminate the ridge at the top of bores, what happens at 6000rpm? Does the rod stop stretching after 3000rpm or stretch in a linear fashion so the piston extends past the block and hit the cylinder head?

If your idea about the need to rev past 3000rpm all the time as to not to damage engine long term via wearing a ridge at the top of the bore is paramont, why haven't any manufacturer handbooks advised their customers to do so?

I'm not disputing bore ridges occurs, but they are caused by many factors inc operating loads and engine's tolerances and metallurgy and thus wear and tear of an engine. As any good engine builders would also tell you, loads to the engine as well as the rpm are two very important factors. Revving the engine to 4000rpm in neutral, in different gears and on flat land and going uphill puts totally different loads to an engine thus different wear characteristics accordingly.

You've made a big deal about the revs but yet no mention about operating conditions/engine load.

In a quality modern engine like Jazzdude's Jazz with very close factory tolerances, with his servicing schedule and driving habits well within factory's recommendations I can't imagine any ridge forming soon.

Eventually his engine will wear ( may in 400,000-500,000Kms assuming it's kept serviced and not abused throughout its life ), and as the bore wears and gets larger in diameter; you will see and feel the ridges as you described Claymore. That's because the top most piston ring sits a few mm beneath the top of the piston, thus a few mm below the top of the bore.

Thus the ridge is formed by not having any metal to metal contact in that area whereas the rest of bore area inside the combustion chamber is gradually being worn away via metal to metal contact with the piston rings under combustion conditions.

So for the ridge to occur, the bore has to wear 1st, I can't see how your theory of not driving past 3000rpm regularly is going to cause this premature wear Claymore.

[Jazzdude]

Thanks Claymore & EG30 for your replies. I have a real noob question (I don't know much...ok anything about engines), for Claymore. When you said "At low rpms the rings are not moving up in the bore as far as they do at higher rpms because the rod has not stretched and that is what causes the ridge", if the rings are designed to move that far up the ridge, but for an extended period of time they never have the chance to, you are saying that the area within which they move will become worn (the bottom half) while the top half is still like new. But if the rings were originally designed to be able to move that high up, then why would they come into contact with them later if I floor the car? Is it due to vibrations?

This is a question for both of you, lets say I never go above 3000rpm, with proper servicing etc. realistically how long can I drive my Jazz (even when I get another car, I am not planning on selling my Jazz, I like it too much)? That is when will it 'die' (beyond repair)?

Thanks again to both of you for your replies.

[silver_screen]

closer to the 300k mark i would say

[Jazzdude]

Thanks Claymore.

[EG30]

And for the original question from the poster if he continues to run his engine in the same rpm range and NEVER EXCEEDS that rpm range he will not have any problems but if he then sells the car or changes his driving habits and suddenly starts moving the rpm range higher then he will have problem.

You apparently have never taken apart any engine with broken ring lands caused by bumping the ridge well I have run into this problem several times and it normally happens when a new owner takes possession of a vehicle.

I have seen stripped engine with broken piston rings Claymore.

Broken piston rings are caused by many factors, in totally worn engines with plenty of lateral piston movement ie piston slap where the ring is banging against the bore and the ring groove as the engine runs at speed it's not surprising to see the ring snap into pieces as it's not designed to deal with those loads. With rebuilt engines they can fail very early if they were not the installed correctly with inappropiate ring gaps or incorrect type/size for the application.

Yes I've heard of new owners breaking engines, gearboxes, clutches in the first few weeks of their purchase of a car with previous careful owners. Have you ever considered this could be due to the fact that those mechanical components of cars of that age were well on their last legs that would have failed long ago with their lifespan only prolonged by the careful owners with high degrees of mechanical sympathy; along comes the new owners who push their new purchase to their limits and everyone wonders why failures were near instant.

[EG30]

This is a question for both of you, lets say I never go above 3000rpm, with proper servicing etc. realistically how long can I drive my Jazz (even when I get another car, I am not planning on selling my Jazz, I like it too much)? That is when will it 'die' (beyond repair)?

Jazzdude you own your car, you drive it whichever way you want. You don't need to over rev your engine or take it to the redline unless you wish to. There are people who still believe the Earth is not round and insist we do more research on it.

If you service your car regularly in accordance to Honda's recommendation with quality engine oil appropriate for your engine, drive it the way you normally drive it and assuming you don't have excessive number of cold starts and short journeys ( where the engine doesn't get the chance to fully warm up and fuel dilution becomes a problem ) I can't see why your engine can't last well over 300,000kms, quite possibly closer to 500,000Kms.

But really in today's modern engines ( esp quality engines like Honda's ) with precise fuel injection and close loop lamda control where the engine doesn't run rich except in warm up cycles; engines wearing out it's pistons rings/bores are least of the car's worries.

A vehicle is often deemed beyond repair when the cost of a repair exceeds the market value of a vehicle. So let's say in 15 years time your Jazz is worth $3000 and you need to replace the head gasket that went at say 300,000kms. The condition of the bores and pistons could well be in excellent condition still, but the cost of labour to pull the head off in 15 years plus the parts you would replace at the same time ( ie VRS set, new valve stem seals and valve guides while you are at it etc ) it could well cost you $5000+. It's still very repairable, but whether you would choose do it is another thing, and many people choose not to and wreck their cars as a result.

I sold an 1988 E30 BMW 325i to a fren a few years back. I bought the car with 86,000Kms on it and I've always kept it well serviced by changing the oil no later than 7500Kms, sometimes closer 5000kms with good quality oil ( nothing exotic, Valvoline XLD 20W50 in the early days, then Shell Helix 15W50, then Havoline 5W30 in the last few years that I owned it ). I always kept cold starts to a minimum ( ie I always parked the car in the spot where I won't need to shift the car in the morning only to shut it down again ), and never pushed the engine hard until the oil temp is closer to 100C. About 2 years after he bought it from me a coolant hose blew and he kept driving and overheated the car in a major way on the freeway and cracked the head.

When they removed the head you could see the cross-hatching marks on the bores from the factory's honing machine, they were no bumpiness along the bores when you run your finger along it and the pistons were still tight in the bores ( ie you cannot move them laterally in the bores by hand ). And this was at 268,000Kms!

I had a bunky EG breeze which I sold last year, it had no service history and the under the rocker cover it was pretty dirty, it had done just over 300,000Kms and yet it used no oil even after I filled it with thin 5W30 oil, and doesn't smoke even after some hard revving! Couldn't tell you how hard I revved this thing as it didn't come with a tacho. So if a used and abuse Breeze was still pretty intact at over 300,000kms a car such as your with a very careful owner I won't worry about the longevity of your engine just yet.

Jazzdude when in doubt you can always consult your friendly service advisor at your Honda dealership or your local mechanic. I'm sure they would tell you to just drive it normally, service it well and enjoy your ride.