How long should an engine last?

[PeterM]

Surely car engines wont last as long - they are started form cold far more often ( several times a day ) depending on how you drive . I remember BMW put 1,000,000 miles on one its 2l engines with only routine service - and when they stripped it i was still within original tolerance for leaving the factory !
Surely its not the actual engine that fails - its the ancillary stuff - starter / fuel pump etc from the environment ?

Is it harder thrash an OB from cold (?) as most boats are launched from places with a few minutes at least to warm them up before anywhere near WOT ? Cars - max revs in the first 50m if you want to in each gear !

[ian parkes]

Seems there are lost of ways of looking at it , all make some sence .

Duncan iam interested how you can work out hop many HP your engine is making from measuring air flow ?? and how you can monitor airflow .

[BogMonster]

Originally Posted by ian parkes

Seems there are lost of ways of looking at it , all make some sence .

Duncan iam interested how you can work out hop many HP your engine is making from measuring air flow ?? and how you can monitor airflow .

EFI engines normally have an airflow meter for engine management and I guess if you assume a fairly constant fuel:air ratio then you can work out how much fuel it is burning and thus how much power you are generating. Well in theory anyway...

[ian parkes]

Originally Posted by BogMonster

EFI engines normally have an airflow meter for engine management and I guess if you assume a fairly constant fuel:air ratio then you can work out how much fuel it is burning and thus how much power you are generating. Well in theory anyway...

Like the economy lights and so called MPG computers that some cars have . Mine used to do 99mpg down hill

[9D280]

99 is easy to achieve depending how your MPG-ometer is calibrated - Assuming you have fuel injection, the Engine management knows how long the injector has been open and how many times it has done so in a given time. Take a distance reading from the odometer , one quick division and job done.

The "99mpg" is simply becaise you are gravity assisted down a hill. Assuming you're doing steady speed, all you are doing is overcoming the friction in the engine & bearings, tyre drag and above about 40mph, wind resistance. Downhill there is every chance that the slopw will be more than enough to overcome that. There will be just enough fuel being squirted in to keep the emmissions low (i.e keep the catalyst warm - otherwise it could be switched off entirely, giving an instantanious "infinite" MPG 'coz you wouldn't be burning fuel, but you would be covering distance). If the compooter takes the "instantaneous" reading over, say, the last 20m, then you will easily clock 99.9 - probably more, but your display will only have 2 or 3 digits!

I had a drive in a new Focus recently, it doesn't have an "instantaneous" MPG reading, but if you reset the rolling average (according to the manual it looks at the last 600 miles), it will show 99.9 if you reset it on a downhill, but will only show you a number after a good few hundred metres of driving. (it's taking the average over a longer sdistance) After the first bit of level or uphill you will never see 99.9 ever again! (until you reset it on another downhill stretch)

Yeah could be very theoretically sussed out by airflow, but why bother when you have a VERY accurately calibrated set of injectors you can use.......

[codprawn]

I have had cars with fuel computers that read much higher than 3 digits. Best I ever saw was 3860 mpg in a Rover SD1 vitesse - down a steep hill at about 100mph in neutral. Going up it was reading 6mpg!!! The worst reading though for any car - even a 1.0L is in a traffic jam - 0mpg - that's why you should switch off.......

[Stoo]

So how come that in 9 years of use, I have blown two heads on my Yammy 150? I maintain it, run nothing but Yamalube, have it professionally winterized and stored indoors. The guy who replaced the last head, and who is a friend as well, suggested that many manufacturers quietly suggest that their engines are really only designed for a life span of about 1000 hours. Personally I can't beieve that. I believe a read that the average guy runs his engine less than 100 hours a year, but if 1000 hours is right, wouldn't we be storming the plants and buring them to the ground? Incidently, no one has ever found a reason for the meltdowns (i.e. busted oil pump, plastic bag in the impellor etc.) Just good old fatigue...

Either way, I have spent $16,500 on replacement heads! Other than that small detail, the thing runs like a clock!

[ian parkes]

Originally Posted by Stoo

So how come that in 9 years of use, I have blown two heads on my Yammy 150? I maintain it, run nothing but Yamalube, have it professionally winterized and stored indoors. The guy who replaced the last head, and who is a friend as well, suggested that many manufacturers quietly suggest that their engines are really only designed for a life span of about 1000 hours. Personally I can't beieve that. I believe a read that the average guy runs his engine less than 100 hours a year, but if 1000 hours is right, wouldn't we be storming the plants and buring them to the ground? Incidently, no one has ever found a reason for the meltdowns (i.e. busted oil pump, plastic bag in the impellor etc.) Just good old fatigue...

Either way, I have spent $16,500 on replacement heads! Other than that small detail, the thing runs like a clock!

It is hard to explain , is the head a common problem on the Yam 150 or have you just been unlucky.
there have been many engines over the years famouse for cracking and warping cylinder heads ie most diesel engines from the last decade and every british built car from the 60's 70's etc Hilman imp triumph dolomite sprint , stag etc, and the Japs were probably the first to be able to make an alloy head that didn't warp . Still lots today that are crap .

[Stoo]

Originally Posted by ian parkes

It is hard to explain , is the head a common problem on the Yam 150 or have you just been unlucky.

Certainloy rhe first one looked like the head might have been warped... there had been some signs of water penetrating. The second one showed no such signs...

Guys like me (i.e. ones that don't know anything about motors) just figure that they should work for a really long time, especially when they are well-maintained. I recently bough a new dive tank, and after a year and only about five uses in fresh water, it was rusted out under the boot. The manufacturer told me that I should have removed the boot after each dive and dried the tank! As a result, my warranty was voided. (Ya, I know this has nothing do do with engines, just strikes me as a dumb way to build a dive tank... or an engine!)

[BogMonster]

I figure a Yamaha should work for a really long time otherwise what is the point in spending the extra cash over the cost of any other engine...

[peterb]

Recently spent some time driving a Yamaha 150 (and other Yamaha models) and I regularly drive a Honda 150 (based on the VTEC engine).

I have no idea of the relative cost, but IMHO the Honda unit is smoother, quieter and generally a better unit.

(Sits back and waits to be castigated )

Since I'm a tight beggar and only drive RIBS when someone else is paying me, I hope I am unbiased.

[codprawn]

Honda make some brilliant engines so I am not suprised. Drive a Civic type R and you will know what I mean!!!