Engine Health - Longevity

[ewendc2r]

Hi,

Looking at a b20 engine that has had a hard (track) life for the majority of it but was well built and has had no issues as far as i know.

Assuming the engine was assembled very well and machining was on-the-ball, would this 'hard life' have any other effect other than increased piston ring wear? i.e. Its built from quality parts, but will it be reliable? Its not a seriously highly strung motor, just well assembled...

Thoughts?

Toda says I can expect a very long life out of a rebuilt motor -- in excess of 100,000kms without dramas. Is the main reason with a 'race engine' that they don't last long that the rings wear quickly?

Thanks ... :)

[GSi_PSi]

Provided the engine has been fully balanced and blueprinted, the stock bore 84mm is retained, bearings all to spec , bolts nuts been torqued to spec and
the tune is a good balanced not highly strung (more timing added etc) with rev limit in appropriate position. There is no reason why a b20 wouldnt last the same as any other b series motor.

[ewendc2r]

Interesting - What is your opinion of highly strung?

Does compression ratio have an impact on piston ring wear? (Assuming same piston / wall clearances)

So why do 'race engines' need to be rebuilt? i.e. just to replace rings / bearings generally?

How many kms would you expect your rebuild to last gsi-psi?

[GSi_PSi]

Tuning is a major part of why an engine will fail, running on a dud tune will shorten the life of the motor.
The higher your compression ratio the more chance of knocking if lower octane fuel is used so be careful with more higher ratio engines as australia isnt that great with 98octane being the highest octane fuel being readily available. Japan which has 100ron would be good to go for 12+ compression ratio builds.
Race engine are sitting on the higher rpm for extended periods of time, lap after lap, any engine put through that abuse will react the same.
My build is fairly stock , with regular maintenance etc should be fine for about another 80,000kms

[TODA AU]

Regarding race engines that need to be rebuilt... In the real world, race engines need to perform @ peak performance otherwise they don't win... :p
So to keep them at their optimum, the service intervals are shorter than road engines & the pull down periods are also shorter.
Most race engines when build well, are good for 2 seasons when they're looked after & not subjected to driver error.
Poor maintenance & driver error can change this quite quickly as can bad fuel or mounting the wrong ripple strip...
But in cases where the engine has been a good workhorse & hasn't failed, a freshen up often is more of a health check rather than a full overhaul
When freshened up, the bores are checked but not always honed, When honed the rings are replaced. Pistions are often good to go again, but not always.
Likewise the bearings but not always changed, but when changed the crack is often micro-polished. If a bearing has failed, the engine would have been pulled prematurely so the maintenace process would already be an overhaul rather than a check & repair.
FWIW, in race donks, valves are usually reseated (in some cases replaced) & cams re-timed. Disposable & wear parts like gaskets, belts, water pumps, valve springs, head bolts, rod bolts & titanium retainers are all replaced.
Roadies are a differnt story...
They are not subjected to sustained high rpm where vehicle speed is limited by terain & cooling air is blocked by your opponents rear bumper bar.
But they do have to put up with repedative thermal shock, poor maintenace & long service intervals.
My 5 cents....
Either buy the ex race engine or buy a freshly built one...
9 times out of 10, 2nd hand performance roadies are usually not much more than polished turds that'll need a freshen-up (or full overhaull) sooner rather than later anyway
(no offence to anyone trying to sell a motor)
& the other side of that is a well built performance street engine when looked after will generally see 200,000+km
It not only comes down to who builds it or who tunes it... but after say 20,000km it really comes down to who owns it & if they look after it.

[ewendc2r]

Adrian,

When you say look after the engine, what do you mean exactly? How would you look after an engine?

I'm trying to price up several options -- From build to buy existing and the built engine is attractive however as discussed reliabile performance is paramount & although it seems the engine may have been built very well, im still just not confident given its hard life so far on if im going to be the unlucky one to throw a rod or spin a bearing.. But I might have also come up with a solution head wise, so planning the shortblock as well..

damn a lot of reading / spreadsheeting ....!!!

[ewendc2r]

Whats an engine inspection worth too by the way?

[Mr_will]

Adrian,

When you say look after the engine, what do you mean exactly? How would you look after an engine?

I'm trying to price up several options -- From build to buy existing and the built engine is attractive however as discussed reliabile performance is paramount & although it seems the engine may have been built very well, im still just not confident given its hard life so far on if im going to be the unlucky one to throw a rod or spin a bearing.. But I might have also come up with a solution head wise, so planning the shortblock as well..

damn a lot of reading / spreadsheeting ....!!!

pending corrections from the more knowledgeable Adrian, the basics would be:

1) not subjecting the engine to heavy load when its cold

2) using good quality oil

3) changing said oil regularly

4) regularly checking things like coolant and thermostat to make sure that the engine is operating at the optimum temperature

[ewendc2r]

So all the common sense things; no black magic!! Thanks

[TODA AU]

pending corrections from the more knowledgeable Adrian, the basics would be:

1) not subjecting the engine to heavy load when its cold

2) using good quality oil

3) changing said oil regularly

4) regularly checking things like coolant and thermostat to make sure that the engine is operating at the optimum temperature

Mr Will is on the money... +1 rep
Further to that, if your engine builder gives you a specific oil grade to use... Make sure you use it.
Don't second guess that & move to a lighter grade.
If the car sees the race track, service intervals are more frequent.
Good rule of thumb is to replace the oil before every outing for a track only car & before & after each track day for a roadie,
+ the usual mainenance schedule.
Just remember if the oil breaks down, your engine dies.

[ekfour97]

useful info toda . do you recommend changing the filter as often as the oil when car is used for track and road ...

[ewendc2r]

That's how I've treated my b18 ... I'm overly cautious with oil and engine temps ... Thanks for the confirmation Adrian..

[ewendc2r]

oh -- And since oil filters are cheeaapp ... I change it each time i change the oil.

[dc2r-0636]

i use to change my oil filter every 5,000kms wen i did an engine oil change
but now i change my oil every 5k and oil filter every 10k. should be fine :)