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Originally Posted by jcb986
Sideways....
I have never heard or ever seen a flywheel cause this kind of problem. Even during my drag racing days. The rear main may have been starved from oil and overheated, then the crank warped. The bearing does not have to spin and that's a huge plus. Let us know what all you did and what you spent. I'm curious how each tackles this problem of rebuilding a flat 6 and how they may cut a corner to save a few bucks. By the way, what year is the Boxster and what did you get it for $$$$$.
PS. Maybe you should do the assembling in your living room. Built a Lotus engine one time like that.  |
Normally I would agree, however ....
Afetr speaking with the Vibration guy at my work who does the balancing etc on the turbines and then with speaking to a very close friend who is an exceptional mechanic for diesel engines He confirmed that on diesels with failed flywheels he has see major imbalance issues.
On diesels they dont rev fast enough to cause any major issues other than the need to replace the DMF however according to the N&V guy at work an unbalanced 20kg mass on the end of a crank the diameter of the boxster's spinning above 5500 rpm can exert more than 1800 NM of force onto the shaft right at its nearest support point (the first main bearing)
This force is way more than the shaft is designed to take and can very easily flex the shaft to the extent that the clutch cover will contact the gearbox housing.
A rotating mass contacting something hard at those speeds is enough to bend the shaft permanently leading to further damage.
The car has full dealership service history right up to its current milage so the oils etc used are all Porsche recommended items which again makes this scenario even more strange !
We have had a few shaft failures on our turbines here at work due to similar balance issues so its really not surprising that this has happened.
I also had work back yesterday from a local porsche specialist saying that he would not have believed my theory up until late last year when he had a GT3RS come in with similar issues. On stripdown of the GT3 they discovered that the crank had bent due to the flywheel/clucth contacting the housing too !
The car is a late 2000 2.7 Boxster, full dealership history 122,000 miles
Labour has cost me nothing as its done myself and all the parts required to repair have come to just under £800
The car cost me £6500 and currently would sell at a dealership here for £9995 with the spec and options mine has.
So all in Im still not out of pocket really but I really didnt want to be lying under my car after a week of ownership.
Ive managed to save a load of cash due to getting teh crank and its cradle via ebay from a car which had a damaged engine but where the crank was saved. It went right down to the last 7 seconds of bidding but I came through and got it paid for straight away
Assembly will be done in my workshop which is at the rear of the garage its in
didnt see the point being clean taking it apart as it was all completely dead anyhow !
All the parts are to be cleaned and checked before re assembly and thats happening this weekend