Home
>
Main Forum
>
Topic Grant's project - "keeping us all informed" |
Grant's project - "keeping us all informed" grant - Friday, 4 January, 2013, at 7:51:36 pm |
Re: Grant's project - "keeping us all informed" dghii - Friday, 4 January, 2013, at 10:25:30 pm |
Other than tha IMS bearing .. Pedro (Odessa, FL) - Saturday, 5 January, 2013, at 7:57:30 am |
Good points... but I never tracked that engine. I did my first, but not this one. *NM* Bruce In Philly (2000 S Boxster, now '09 C2S) - Saturday, 5 January, 2013, at 8:20:32 am |
Juts for clarity to all... this was not my car.... it was Bruce's grant - Saturday, 5 January, 2013, at 9:03:38 am |
Interesting information Guenter in Ontario - Saturday, 5 January, 2013, at 10:45:22 am |
Good point MikenOH - Saturday, 5 January, 2013, at 12:02:55 pm |
Some thoughts on IMS bashing....... Bruce In Philly (2000 S Boxster, now '09 C2S) - Saturday, 5 January, 2013, at 10:20:53 pm |
Re: Some thoughts on IMS bashing....... Gary in SoFL - Sunday, 6 January, 2013, at 7:10:49 am |
Quote
Bruce In Philly (2000S Morte)
Hmmm..... makes you wonder eh? .....Grant, maybe you want to use Jake Raby's updates to the new engine? He knows the failure modes well...... but again, the truth is a little foggy without the real data... and Porsche likes it that way.
I still loved the car....... Bruce In Philly (2000 S Boxster, now '09 C2S) - Sunday, 6 January, 2013, at 9:19:01 am |
Modes of failure mikefocke, '01S Sanford, NC - Sunday, 6 January, 2013, at 11:23:53 am |
Odd..... Bruce In Philly (2000 S Boxster, now '09 C2S) - Sunday, 6 January, 2013, at 12:04:50 pm |
Not so odd really... grant - Sunday, 6 January, 2013, at 5:01:07 pm |
Well said, Grant, and modestly put. *NM* Laz - Sunday, 6 January, 2013, at 8:29:37 pm |
Boy I sure blew a lot of '60s engines mikefocke, '01S Sanford, NC - Monday, 7 January, 2013, at 2:44:35 pm |
So the point is, don;t loan Mike your car? grant - Monday, 7 January, 2013, at 6:59:37 pm |
Don't be old enough to remember how truely poor the old ones really were! *NM* mikefocke, '01S Sanford, NC - Tuesday, 8 January, 2013, at 4:30:45 pm |
Re: Not so odd really... San Rensho - Monday, 7 January, 2013, at 7:39:10 pm |
Quote
grant
... a modern porsche motor is designed to be very light and have a very high specific output. This means it must be stressed much higher in both output/L and in terms of RPMs. Not only is it stressed more, but to achieve this they must use more complex valvetrains - and that's where most of the problems lie. Look at all the chains, vario-cams, end bearings, guides, shows, tensioners etc - all operating at up to 7k rpms. Lose a tensioner, a cam alignment hydraulic doo-hickey etc and things snowball, and not in a good way.
Compare that to an iron block, with half the output/L; a single cam in block, 4500-5k effective redline, solid lifters, and pushrods.
Finally, the were all rebuilt by 100k due to worn cams, rings and cylinders. OTOH, your 3.2 M96 motor went 150k miles with full performance until ti went "boom". I bet very few 426s did that.
That said, i had friends who in the day spewed the guts of their hemis and GTOs when timing failed. But i agree, it was fewer.
As we push for the highest power and the lowest weight, that agricultural durability is compromised. Extended drain intervals dont help much either.
So there are two sides to the story, or at least I think so.
You are right, these engines are engineered to run on the hairy edge, but what causes catastrohic engine failure? It's not the state
of the art inovations, like complicated valve train management or the high tech cylinder coating systems, it's really simple stuff, an IMSB, that costs a couple of bucks,that fails, chain tensopner pads that fail, simple oiling problems. It's simple systems that cause most of the problems and that is Porsches failure.
Grant
Re: Grant's project - "keeping us all informed" Alcantera - Sunday, 6 January, 2013, at 9:35:28 am |